text:
The prototype colliding-wind pinwheel WR 104
Peter G. Tuthill School of Physics, University of Sydney, NSW 2006, Australia John D. Monnier University of Michigan at Ann Arbor, Department of Astronomy, 500 Church Street, Ann Arbor, MI 48109-1090, USA Nicholas Lawrance School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006, Australia William C. Danchi NASA Goddard Space Flight Center, Infrared Astrophysics, Code 685, Greenbelt, MD 20771, USA Stan P. Owocki Bartol Research Institute, University of Delaware, Newark, DE 19716 Kenneth G. Gayley University of Iowa, Iowa City, IA 52245
Results from the most extensive study of the time-evolving dust structure around the prototype "Pinwheel" nebula WR 104 are presented. Encompassing 11 epochs in three near-infrared filter bandpasses, a homogeneous imaging data set spanning more than 6 years (or 10 orbits) is presented. Data were obtained from the highly successful Keck Aperture Masking Experiment, which can recover high fidelity images at extremely high angular resolutions, revealing the geometry of the plume with unprecedented precision. Inferred properties for the (unresolved) underlying binary and wind system are orbital period 241.5±0.5 days and angular outflow velocity of 0.28±0.02 mas/day. An optically thin cavity of angular size 13.3±1.4 mas was found to lie between the central binary and the onset of the spiral dust plume. Rotational motion of the wind system induced by the binary orbit is found to have important ramifications: entanglement of the winds results in strong shock activity far downstream from the nose of the bowshock. The far greater fraction of the winds participating in the collision may play a key role in gas compression and the nucleation of dust at large radii from the central binary and shock stagnation point. Investigation of the effects of radiative braking pointed towards significant modifications of the simple hydrostatic colliding wind geometry, extending the relevance of this phenomena to wider binary systems than previously considered. Limits placed on the maximum allowed orbital eccentricity of e <∼ 0.06 argue strongly for a prehistory of tidal circularization in this system. Finally we discuss the implications of Earth's polar (i<∼16∘) vantage point onto a system likely to host supernova explosions at future epochs.
stars: individual(WR 104 (catalog )), stars: mass loss, instrumentation: interferometers, stars: imaging, stars:winds, outflows
The first well-resolved images of the dusty, IR-luminous Wolf-Rayet star WR 104 revealed an elegant plume stretching hundreds of AU from the bright core and following a trajectory closely matched to an Archimedeian spiral (Tuthill et al., 1999) . The origin of this geometry is simple and highly intuitive: material is embedded within a uniformly-expanding spherical wind driven from the hot stars at the heart of the system, yet the orbital motion of a central binary causes a rotating wake embedded within the flow. These images gave immediate confirmation of the colliding-wind binary nature of dust production in WR 104, and at the same time presented astronomy with a new type of object for study: a "Pinwheel" nebula.
Although we found no specific predictions in the literature for such a spiral dust plume in dusty Wolf-Rayets such as WR 104, the same combination of orbital and outflow motions led Kuiper (1941) to predict exactly this geometry for the circumstellar environment around the eclipsing binary β Lyr. In fact use of the term "Pinwheel" to describe such a structure can be found as early as 1950 (Struve, 1950) , and theoretical study of colliding-wind binary systems has since developed an extensive literature (e.g. Stevens et al., 1992; Walder & Folini, 2000, and refs therein) . The basic picture of colliding-winds mediating dust production was formulated to explain the episodic dust-producer WR 140, which became something of a 'Rosetta Stone' system in important papers establishing the model (Williams et al., 1990; Usov, 1991) . It is also interesting, although perhaps tangential to the work of this paper, to note that Archimedian spirals may arise in quite distinct mass-loss environments such as the binary reflex-motion induced structure recently seen in AFGL 3068 (Mauron & Huggins, 2006) .
Observational confirmation of the pinwheel nebula around WR 104 has not yet been attained by adaptive optics imaging due to the requirement for a stable, well characterized point-spread function enabling recovery of structure at the diffraction limit (Rajagopal et al., 2004) . However, a number of other techniques have been used to confirm the presence of the spiral plume including high spatial resolution lunar occultations (Mondal & Chandrasekhar, 2002) , variations in the visible lightcurve of 241 days in accord with the orbital period derived from interferometry (Kato et al., 2002) , together with extensive follow-on observations with aperture masking interferometry (Tuthill et al., 2002, 2003; Monnier et al., 2007) . Reports of binarity in the WR 104 system (Crowther, 1997) appeared shortly before the original discovery of the spiral, with the spectral classification for the object given in van der Hucht (2001) as WC9d + B0.5V (+VB), although given the uncertainties we refer to the second component spectrum (actually brighter by a factor of ∼2) as OB. Detailed radiative transfer modelling, confirming the appearance and basic observational properties of the pinwheel, has been performed by Harries et al. (2004) .
The discovery of similar structures in an expanding list of host systems has served to motivate further interest in these objects. The second such system to be found, WR 98a (Monnier et al., 1999) , showed a similar morphology implying approximately matched basic properties (in terms of orbital period and windspeed) to the prototype WR 104. However, a more diverse population is also coming to light including WR 112 (Marchenko et al., 2002) which appears to have a significantly longer 25 yr binary period, and the high orbital eccentricity 8 yr system WR 140 whose periodic periastron passages have been shown to throw off a remarkable series of dusty arcs (Monnier et al., 2002; Marchenko & Moffat, 2006) . Recently, a dramatic association of at least two and probably five such spiral systems was discovered near the Galactic Center at the heart of the massive Quintuplet Cluster (Tuthill et al., 2006) .
The status of Wolf-Rayets as candidate progenitors to type Ib/c supernovae (reviews can be found in Bethe, 1990; Vanbeveren et al., 1998; Woosley et al., 2002) has generated considerable interest in their mass loss histories. In particular, structures within the circumstellar environment, into which the supernova blast wave expands, have the capacity to interact with the ejecta modifying the lightcurve and observed properties of the explosion. Indeed, Ryder et al. (2004) observed a residual fluctuating or rippled signal, obtained when subtracting a spherical best-fit model from the observed radio lightcurve of supernova 2001ig. The most likely interpretation for these modulations, they argue, arises as the supernova shock encounters periodic density enhancements embedded in the circumstellar environment by a colliding-wind binary pinwheel system. With the rapidly solidifying links between supernovae and gamma-ray bursts (Woosley & Bloom, 2006) , the mechanisms by which such mass-loss signatures may become encoded within the lightcurves of the most energetic explosions in the cosmos are being explored (Moran & Reichart, 2005) .
In this paper, we present the results of the most extensive diffraction-limited imaging study yet performed on the prototype pinwheel system, WR 104. Observations encompass three different near-infrared filter bandpasses and eleven distinct epochs covering more than six years (almost ten orbital periods) of the system. With the structure of the time-evolving plume revealed in unprecedented detail, we are able to address key outstanding questions regarding the way in which the dust formation is mediated by the colliding winds of the binary. Multi-wavelength observations are helpful in teasing apart the complex three-dimensional geometrical, thermal and illumination effects which go into creating the phenomena we see as a pinwheel nebula.
2 Observations
Monitoring of a number of dust-forming Wolf-Rayet stars was performed as part of our aperture-masking interferometry program begun at the Keck 1 telescope in 1996. This has produced astrophysical results spanning a range of different areas within contemporary stellar physics including studies of young stars (Danchi et al., 2001; Tuthill et al., 2002) ; evolved pulsating stars and giants (Tuthill et al., 2000; Monnier et al., 2004) ; and dusty mass-loss shrouds in proto-planetary nebulae and transition objects (Monnier et al., 2000; Tuthill et al., 2002) . A full description of the experiment including a discussion of the conceptual principles and signal-to-noise considerations underlying masking interferometry is given in Tuthill et al. (2000) while further discussion of systematics and seeing induced errors can be found in Monnier et al. (2004) .
Observations presented here all used a partially-redundant annular mask geometry first suggested by Haniff & Buscher (1992) which was found to deliver robust imaging for targets as faint as mK∼6 mag with complete Fourier coverage out to the 8 m maximum baseline passed by the mask. The detector used for this work was the NIRC camera with image magnifying front-optics modifying the plate scale so as to sample the diffraction-limited beam (Matthews et al., 1996) . A relatively rapid-exposure (Tint=0.14 sec) and high data volume (data cubes containing 100 frames) speckle observing mode was utilized, although this was not as well developed as it could have been and suffered from an inherent low duty cycle of at best 20% set by the camera electronics.
Observations of science targets were interleaved with those of nearby unresolved point-spread function (PSF) reference stars, and the extraction of calibrated visibility and closure-phase data followed established practices within speckle or masking interferometry (Tuthill et al., 2000) . All V2 and closure phase data products were stored in the FITS-based Optical Interferometry data exchange format (OI-FITS Pauls et al., 2005) , and are available on request from the authors. Images were recovered using a number of different numerical methods including the CLEAN algorithm (Högbom, 1974) and with several maximum entropy (Gull & Skilling, 1984) based methods (Sivia, 1987; Ireland et al., 2006) . With some variation in levels of fidelity and resolution obtained, all methods produced similar structures to those presented in the following sections, and hereafter we show exclusively the results of the VLBMEM package (Sivia, 1987) .
A journal of masking observations of WR 104 is given in Table 1, while information about the three interference filters within the infrared H, K and L bands utilized in the study is given in Table 2. A number of different PSF reference stars were observed, all of which are relatively nearby (typically within about 5∘ on the sky) and tailored to give roughly similar received counts under various observing configurations. The primary calibrator stars utilized were SAO 186681, SAO 186841, 14 Sgr and HD 165813 although occasionally additional stars were used for confirmatory checks.
In addition to their scientific merit, it is worth noting that the images presented in later sections are a strong testament to the power of aperture masking interferometry in the recovery of high fidelity images. In particular, the pinwheel around WR 104 resolved here possesses strongly asymmetric structure at intermediate dynamic range to the bright core. Deconvolution to obtain at least the full diffraction limit is essential (and ideally, some super-resolution beyond it), as the structure recovered is formally only a few resolution elements across. Seeing conditions over the twelve observing nights found in Table 1 varied over a wide range from extremely poor to very good. Robust, high-fidelity images were recovered for all epochs and in all filters observed.
This is in contrast to the failure to recover significant reliable structure from the one attempt (we are aware of) to image this target with adaptive optics (Rajagopal et al., 2004) . The presence of asymmetric and time-varying extended structure at high resolutions which is nevertheless completely predictable in morphology makes WR 104 almost ideally suited as a "test pattern" target against which imaging experiments may be benchmarked, and we look forward to confirmatory results from new generations of AO instruments.
2.1 K-band images
Images recovered from data taken at 11 separate epochs in the CH4 filter are presented in Figure 1. Although there are 12 observing dates given in Table 1, the first two of 1998 Apr 14 and Apr 15, being separated by only one day, did not give significantly different images and these data have been averaged together for the remainder of this paper. Experience has taught that images recovered from filters within the infrared K-band usually deliver the highest fidelity. The PAHCS filter at longer wavelengths has significantly lower angular resolution with a corresponding loss of detail. On the other hand, the H filter at shorter wavelengths suffers from more severe seeing-induced calibration noise, and furthermore the target star WR 104 is also two magnitudes fainter here than at K (due to the rising IR excess). We therefore begin our discussion of the image morphology with images recovered from the CH4 filter in the K-band, and we later contrast the results from the other filters against this reference.
The images of Figure 1 demonstrate the recovery of extended structures around the bright core with typical image dynamical ranges in excess of 100:1, although higher noise levels due to poor seeing did limit fidelity on occasion (e.g. Jun01 and May04 epochs). The predominant feature at all epochs is a curved plume originating in a bright compact core, and wrapping around a full turn at which point there is a rapid fading in surface brightness to about 1% of the image peak. Beyond the bright first coil, at angular radii >∼ 100 mas, there can often be seen further windings of a continuing spiral, or in some cases substantial segments of arcs, at a significance at or somewhat above (e.g. Apr98, Jun98) the noise level in each individual image.
The overplotted dashed line on each image in Figure 1 gives the best-fit Archimedian spiral model, which is discussed in greater detail in the following section. Each image has been registered so that the mathematical center of the best-fit spiral (and not the brightest pixel) defines the coordinate origin.
2.2 Archimedian spiral model
An automated procedure was used to extract the coordinates of points lying along the crest of the bright spiral ridges from the images of Figure 1. A model could then be fit to all 11 epochs of data simultaneously. This model consisted of a uniformly-rotating Archimedian spiral, with free parameters: P the rotational period, W the angular expansion (wind) speed, i the inclination to the line-of-sight, ϕ the position angle of i, and θ0 the position angle of the model at the first epoch (Apr98). There were two additional translational degrees of freedom associated with the registration of the model to the image at each epoch.
With nearly 10 complete rotations of the structure covered by our data series, it was possible to obtain significantly more precise estimates for the model parameters than previously published work. In particular, best-fit models constrained P to be 241.5±0.5 days, a value in very good agreement with the previous best interferometric value (243.5±3 d; Tuthill et al., 2002) and with the reported photometric period (241 d; Kato et al., 2002) . The windspeed W was found to be 0.28±0.02 mas/day (or 102±7 mas/yr), also in accord with prior findings (Tuthill et al., 2002) . Our best fit for i=12∘, although the 1-sigma uncertainty covers a range from 0∘ – 16∘. Precise constraint of the inclination was hampered by the nearly face-on viewing angle to the system: 12∘ only results in a 2% distortion of the aspect ratio. Sky orientation parameters were found to be ϕ=84∘±15∘ and θ0=269∘±1∘.
Despite the fact that the model was only fit to ridge points extracted from the bright inner winding of the spiral, it can be seen from Figure 1 that it also provides a relatively good representation of the structure in the fainter outer regions. This implies that the second winding of the spiral follows closely the expected trajectory from simple expansion, and that the plume remains relatively well defined and compact as it evolves.
A key finding of the modelling study was that the mathematical origin of the best-fit spiral was always systematically offset from the center of the bright core of flux in the images in a highly consistent fashion, as can be seen from Figure 1. This "standoff distance" between the spiral center and brightest pixel was found to be 13.3±1.4 mas which amounted to a rotational displacement downstream along the locus of the spiral of 85∘±14∘. Implications for the physical model of the dusty colliding-wind binary from the modelling and imaging presented here are discussed further in later sections.
2.3 H and L-band images
A series of 11 images recovered from H-filter data are presented in Figure 2. Although image fidelity is somewhat lower than for the CH4 filter, the inner bright spiral structure is well displayed at all epochs. Similarly, Figure 3 shows images recovered from the PAHCS filter from the short-wavelength side of L-band. Data were only collected in this band for the first six epochs of our study (see Table 1), and the resolution obtained is lower than the other filters due to the longer wavelength. The spiral structure of the inner coil is again readily apparent.
Archimedian spiral models were fitted to all H and PAHCS images following the procedure described above. Model parameters such as rotational period and winding angle were found to be in accord with the results from the CH4 filter, however the lower quality of the image data meant that the fits did not significantly advance our knowledge of these properties.
A more profitable strategy for interpretation of the H and PAHCS images was to fix the spiral model parameters P, W, i and ϕ to their values obtained above, and to examine the new data for evidence of systematic changes from this baseline model. One relatively subtle change found was in the mean rotational orientation of the spiral (model parameter θ0). It was found that the mean rotational displacement of models fitting the H images were retarded by 6∘ (counterclockwise) while the PAHCS images were found to be advanced by 4∘ (clockwise) compared to the CH4 reference model. This effect was seen in two independent data-fitting approaches, the first used a similar strategy to that above in fitting to points along ridge crests, while the second entailed the generation of an average CH4 image which was then rotated and fit to each trial H/PAHCS image. The latter procedure was found to be more robust as it was less sensitive to resolution effects which might blur out the exact location of the ridge crest.
A strong note of caution needs to be emphasized here because these relatively small changes in rotation are obtained from comparison between images with differing angular resolutions. In order to investigate the effect of the decline in image resolution going to longer wavelengths H–CH4–PAHCS, simulations were performed in which images were artificially smoothed, and models fit to determine if there were systematic changes in the recovered parameters. Indeed, we found clear and systematic changes of best fit rotation angle, measured to be about 5∘ in a counterclockwise sense when the simulated resolution was degraded to imitate the transitions H–CH4 and CH4–PAHCS. This makes intuitive sense: lowering the resolution tends to blur the center together, and the projecting arm of the spiral appears to rotate as more of it is lost to the expanding core. However what is interesting is that this resolution-induced rotational bias is in the opposite sense to the observed clockwise rotations of 6∘ H–CH4 and 4∘ CH4–PAHCS. It is therefore likely that the true magnitude of this rotation with observing wavelength is underestimated here by a factor of two due to the bias counteracting the signal. However, the fitting of any models to images at the resolution limit is challenging, and spirals perhaps even more so as due to their self-similar nature. The confirmation and unveiling of detailed substructures within the WR 104 plume must therefore await more powerful telescopes or imaging arrays with still higher angular resolution.
2.4 Lightcurves
Although our imaging experiment was not specifically designed to yield flux measurements, it was possible to extract photometry within our three near-infrared filters to within ∼0.1−0.2 mag, although for some nights there were light clouds which compromised the measurement accuracy. These measurements are presented in Figure 4, and show the infrared fluxes to be fairly constant in the H and CH4 filters (to within a few tenths of a magnitude). A larger variation is seen in the PAHCS filter, although it lacks any clear sinusoidal signature with phase and may arise from higher noise levels due to atmospheric contamination (this filter lies near the edge of the infrared L band window).
3 Basic Geometry and Physical Properties
In order to illustrate the physical properties of the WR 104 pinwheel system in the discussions that follow, a cartoon of the basic geometry is given in Figure 5. A pole-on view onto a 20∘ opening half-angle spiral shock is depicted, together with key elements of the system such as the central binary star, the optically thin inner region of the plume and the dusty first and second coils.
If we are able to measure the physical speed of the dust plume, then this may be combined with the apparent angular velocity to yield the distance to the system. Following Tuthill et al. (1999) , if we identify the terminal WR windspeed obtained spectroscopically as V∞=1220 km/s (Howarth & Schmutz, 1992) then we may combine this with our proper motion of 0.28±0.02 mas/day to yield a distance to the system of 2.6±0.7 kpc. By far the dominant error is from the ∼25% uncertainty in the windspeed found by comparing the results of different line profile studies (Rochowicz & Niedzielski, 1995) (velocities as high as 1 600 km/s have been reported for WR 104 (Torres et al., 1986) ).
The distance derived in this fashion is somewhat larger than the 1.6 kpc estimate from possible membership of Sgr OB1 (Lundstrom & Stenholm, 1984) ; a discrepancy which motivated Harries et al. (2004, hereafter HMSK) to question the validity of this method. These authors preferred the smaller distance scale on the basis that the WR wind may be subject to radiative braking at the OB star (Gayley et al., 1997) , and thus the terminal wind velocity may not be representative of the bulk motion of the observed dust plume. It is instructive to pursue this controversy further, for it illuminates some of the unique and interesting properties of these Pinwheel systems.
Let us consider a very simple picture in which we distinguish only 3 populations of gas in the colliding wind system: the free WR wind, the free OB wind, and the material around the shock surface which will contain both, but with modified density and velocity. We will furthermore, for the present, restrict our attention to the hydrodynamic treatment of the inner shock with opening angle given by HMSK. This ignores possible modifications to the shock geometry due to radiative braking, and we devote the Section 4 to a discussion of these effects.
For an ordinary (non-rotating) bowshock system, these populations of gas interact strongly in the heart of the system but at large distances are able to flow more-or-less unimpeded for they occupy distinct regions of space. As the dust is known to form around the colliding-wind interface, the arguments of HMSK would be correct in suggesting a lower velocity for the material in the dust plume from the various braking mechanisms (radiative, shocks).
However, this picture breaks down for the Pinwheel systems when we introduce the rotation of the plume driven by the binary orbit. Recent three-dimensional hydrodynamical simulations of colliding-winds in binary systems which include the coriolis effect have shown strong departures from the simple non-rotating case (Lemaster et al., 2007) . Asymmetric shock strengths on the leading and trailing edges of the shock spiral were demonstrated. Although these simulations were mostly concerned with the inner regions of colliding wind systems, there will also be important consequences at large radii which need to be considered for the case of WR 104's dust plume.
The resultant geometry will be much more complicated because the OB wind will become thoroughly wrapped and entangled within the spherically-expanding WR wind. The interpenetration of the two winds leads to a very different outcome than for the non-rotating case. It is no longer possible for the distinct populations of gas to travel at different speeds without interfering, and in the orbital plane containing the shock, at large radii all populations of gas must collide and eventually come to a common velocity. The two key questions we need to answer to understand the form of the spiral plume are (1) what is this final velocity VF, and (2) how long will it take until the material in the plume is moving at VF?
We may answer (1) with a quantitative discussion of the wind kinetic energy. Following HMSK, for the WR component we adopt a mass-loss rate ˙M=3×10−5M⊙/yr, and a windspeed V∞,WR=1220 km/s, while for the OB star we have ˙M=6×10−8M⊙/yr and V∞,OB≈2000 km/s. The opening angle for the shock can now be calculated from the formula given in Eichler & Usov (1993) to be θ=17.4∘ half-angle (rounded to 20∘ half or 40∘ full opening angle in HMSK). Note that this explicitly ignores any widening of the opening angle due to radiative braking (see Section 4), but we proceed with this value for the present to ensure consistency with HMSK. At large radii, the solid-angle subtended by the shock cone will be Ω=2π(1−cosθ)=0.03 sr, so that in the non-rotating case, about 3% of the WR wind and 97% of the OB wind will participate in the collision. We define Rbowshock to be the volume ratio of the WR wind involved in the initial bowshock.
In the rotating case, however, a far larger fraction of the WR wind will eventually collide due to the entanglement of the winds. Winds along the two polar axes, with solid angle Ωp=2π(1−cos(π/2−θ))=4.1 sr from the WR can propagate unimpeded. However all gas within an equatorial angular band within ±θ from the plane of the orbit must eventually collide with the plume – for our geometry of θ=20∘ this corresponds to 34% of the total WR wind. Of this 34%, it is crucial to point out that only Rbowshock = 3% will undergo a 'prompt' collision at or just downstream of the shock stagnation point, the remaining 31% will only collide at larger radii as the spiral windings gradually entangle the winds.
If we assume, as seems reasonable for a relatively wide colliding-wind binary, that the shock is mostly adiabatic with little radiative energy loss. The kinetic energy flux of the asymptotic flow for the entangled winds can be found:
12˙MFV2F=12RWR˙MWRV2∞,WR+12ROB˙MOBV2∞,OB (1)
Here, RWR and ROB are the fractional volumes of the WR and OB winds that are involved in the collision; from the geometrical arguments above we take RWR=0.34 and ROB=1.0. Substituting values into this equation we calculate that the fast (but tenuous) OB wind will modify the final VF in the equatorial plane from 1 220 km/s to 1 226 km/s: an insignificant change.
The model may be further refined by adding a third population of radiatively braked material, as suggested by HMSK. Let us suppose (as an upper limit) that all WR wind impinging upon the θ=20∘ conical shock (3% of the total) is so braked. A preliminary estimate of 800 km/s for VP the streaming velocity of material in the shock cone has been obtained by fitting to the C III 5696 Å line profile (G. Hill et al., 2007 in preparation). If we add this third population of gas to Equation 1, we obtain VF=1171 km/s: a decrement of only 4% on V∞,WR. We therefore answer part (1) of our question above that VF=V∞,WR with only very minor adjustment, confirming that the momentum-dominant WR wind will overwhelm other wind populations.
The second part of the question, finding how long will it take for the WR wind to predominate, has a bearing on the shape of the inner spiral: it will be distorted away from Archimedian if the matter is accelerating. A rough estimate can be obtained from a simple "mass loading" argument applied in the equatorial plane of the system. Let us suppose that in the wake immediately behind the OB star, a mass Rbowshock×˙MWR of matter in the plume has a velocity VP≪V∞,WR. If material were to continue on this trajectory, after time t it would be overtaken by a mass of the faster wind equal to
m=(1−VPV∞,WR)tPRWR˙MWR (2)
where P is the orbital period. We may solve this equation for t/P to give the fraction of an orbital period in which a mass of material has collided with the plume from the free WR wind which is equal to that already present from the initial bowshock. Using values from above, we find that 0.1 of an orbital period is sufficient to double the piled-up mass at the inner wall (see Figure 5), and by the time matter has reached the dust formation zone at a quarter turn, it will be strongly (∼70%) momentum-dominated by the V∞,WR wind.
This analysis confirms the general picture that the spiral plume in this system is rapidly and comprehensively momentum-coupled to the strong WR wind. The implied distance should therefore be 2.6±0.7 kpc at which the displacement between successive spiral coils is 170 AU, and the excellent match to an Archimedian spiral confirmed. It is very interesting to speculate that the spiral geometry, which allows a far larger interaction between the winds and generates active shocks at much greater radii than a non-rotating system, may also help play a role in the physics of dust nucleation in these systems. Indeed, due to the differing velocities of gasses in the region immediately behind the wake, material will be piled up both at the inner and outer walls (see Figure 5). Numerical simulation in three dimensions of this fascinating 'twist' to a conventional bowshock geometry, extending the coriolis force hydrodynamic treatment of Lemaster et al. (2007) to large radii, may prove a valuable guide for further progress in understanding these structures.
4 The Potential Role of Radiative Braking in WR 104
For WR+OB binary systems in which the momentum of the Wolf-Rayet wind substantially exceeds that of the OB star, the WR wind can penetrate very deeply into the acceleration region of the OB-star wind, and in such cases it becomes relevant to consider the role of the OB-star light in providing the momentum balance against the WR wind. The analysis by Gayley, Owocki, & Cranmer (1997, hereafter GOC) suggests that this can lead to a "sudden radiative braking" of the WR wind that can hold the stagnation point along the line of centers farther off from the OB star. This could also modify the angle for the global wind interaction cone, with ramifications for the observations of dust formation. GOC further provide scaling relations to identify whether such radiative braking is likely to be of importance for any given system, and even provide a diagram (their figure 5) to classify several of the known close WR+O binary systems. Let us now apply these criterion to ascertain the potential role of radiative braking for WR 104.
Note first that the systems identified by GOC as likely to have radiative braking are mostly relatively close binaries with periods on the order of days or weeks, and separations of only a few OB-star radii. For wider systems, spherical expansion dilutes the WR wind more strongly in the region around the OB-star, making it easier for the OB-star wind to maintain a standard wind-wind ram pressure balance. But if the WR/OB wind momentum ratio,
PWR/OB ≡ ˙MWRVWR˙MOBVOB, (3)
is sufficiently high, then even in a relatively wide system, such as WR 104, the standard ram pressure balance could potentially be supplanted by radiative braking. The model wind parameters for WR 104, from Section 3, do indeed imply an extreme momentum ratio, PWR/OB≅305, and so even the relatively wide separation of D≅2.4 AU, or d≡D/ROB≅50 OB-star radii, might still induce radiative braking prior to achieving the hydrodynamical stagnation of the winds.
4.1 Estimating the braking radius in WR 104
The following discussion makes use of a number of parameters that are described in greater detail in GOC; for convenience here we provide a brief glossary introducing significant quantities. Radiative acceleration is assumed proportional to η which is found from the effective opacity due to the integral of the forest of spectral lines in the wind. The parameter α was introduced by Castor et al. (1975) to describe how sensitively the line force increases with wind acceleration. GOC found it convenient to define normalized quantities for radiative braking separation drb and momentum ratio Prb which could be used to scale the actual separation and momentum ratio to gauge the significance of braking in individual cases (see GOC for detailed derivations).
To locate WR 104 on the GOC figure 5 classification diagram, this wind momentum ratio PWR/OB and separation d must be further scaled by associated radiative braking values, Prb and drb. To determine those, we first need to evaluate the parameter η, given by GOC eqn. (29), which unfortunately includes an undefined parameter v∗ (for that parameter, see Gayley, Owocki, & Cranmer 1996). Reconstruction of the GOC analysis leads to
η = 1αα/(1−α)(1+α)(LOBLWR)1/(1−α)2GMWRV2WRROB = 43(LOBLWR)2(Vesc,WRVWR)2RWRROB, (4)
where the latter equality applies to the simple case that the power index α=1/2, and also recasts the scaling in terms of the ratio of WR wind speed to surface escape speed. Note that, in addition to replacing the undefined v∗, this formulation has the advantage of being manifestly independent of the separation D, as required by GOC eqns. (11), (12), and (17).
Applying the wind parameters from Section 3, we find (assuming α=1/2) that for WR 104, η≅1.65. Plugging this into GOC eqn. (30) then leads to drb≅2.1. For a standard velocity index β=1, we then further find Prb≅0.642. Using these with the above values for PWR/OB and d, we then find a scaled momentum ratio
^P ≡ PWR/OBPrb = 3050.642 = 475, (5)
and scaled separation
^d ≡ ddrb = 502.1=24. (6)
In the log^P vs. log^d plane, systems with radiative braking are defined by the triangular region with both log^d>0 and log^P>2log^d. The former ensures that the momentum of the OB-star light is sufficient to keep the WR wind from impacting the OB-star surface, and is easily satisfied in this case. The latter condition implies that there can be no normal ram pressure balance between the winds, and thus that radiative braking must stop the WR wind; since for the above parameters, we have ^P=475>407=^d2, implying that this is condition is also satisfied, although more marginally. If, for example, the estimated wind momentum ratio were reduced by more than about 15%, or the separation were increased by more than about 7%, then the system would no longer satisfy this latter condition. In those cases, a normal ram-pressure balance is still allowed, but even then radiative braking can play a role if the braking radius is outside the wind-wind balance radius.
From GOC eqn. (18), we find that the braking radius for the above standard parameter set is
rb = xbD = D1+(d/η)1/3 = 0.254D = 12.1ROB. (7)
For comparison, for the simple case of constant flow speed (i.e. velocity power index β=0), ram pressure balance in the absence of direct radiative forces occurs at a radius (cf. GOC eqn. (2))
rs = xsD = D1+√PWR/OB = 0.054 D = 2.6ROB. (8)
For such a purely hydrodynamical balance, a global momentum analysis (Canto, Raga, and Wilkin 1996; Gayley & Owocki in preparation) yields a transcendental relation between the cone-opening half-angle θs and the momentum ratio PWR/OB,
tanθs−θs = πPWR/OB−1. (9)
For large momentum ratio PWR/OB≫1, use of a small-angle approximation for tanθs≅θs+θ3s/3 gives the asymptotic form,
θs ≅ (3πPWR/OB)1/3 ; PWR/OB≫1. (10)
To recover θs=90o for the symmetric momentum case PWR/OB=1, we can write a more generally applicable approximate solution, accurate to within about 6% for all PWR/O,
θs ≅ 12131/90+P1/3WR/OB (11)
where using 121=(180/π)(3π)1/3 gives this angle in degrees.
For our estimate of PWR/OB=305 for WR 104, we then obtain θs≅18o, in good agreement with the value from Section 3 derived from the heuristic formula of Eichler & Usov (1993) .
4.2 Radiative force influence on the shock-cone angle
An important question is then, by how much can the effects of radiative forces from the OB star potentially widen this shock cone? Only a complete simulation can answer this definitively, but we can make conceptual progress using heuristic approximations to attempt to better constrain the circumstances under which we should expect an important radiative modification of the bow shock geometry. Two approaches that borrow from the existing sudden radiative braking analysis can be termed the "Global Momentum Augmentation" (GMA) and the "Radiative Wall" (RW) approach. Each gives similar results for the opening angle, and so here we briefly outline just the former, deferring to Gayley & Owocki (in preparation) for a detailed discussion of both approaches.
In the GMA approach, the radiation interaction with the incident WR wind is assumed to augment the OB-star wind momentum flux by a globally constant factor, set by the requiring that the stagnation point of the combined effective momentum fluxes equal the braking radius in eqn. (7). We write this factor as γτ, where γ is the ratio of the OB-star radiative momentum flux to its wind momentum flux, LOB/˙MOBvOBc, and τ is an optical-depth-like parameter that simulates the coupling of the OB radiative momentum flux to the WR wind. In analogy to the global analysis cited above (Gayley & Owocki, in preparation), we find for the large momentum ratio limit,
θs ≅ 121(1 + γτPWR/OB)1/3 . (12)
In this scenario radiative braking would alter the shock geometry whenever γτ is appreciable, and since γ in WR 104 is expected to be large, this is not a terribly restrictive requirement for the coupling parameter τ. Since the braking radius rrb scales roughly with η−1/3 when braking is important, the condition that the effective momentum ratio used in rs be reduced enough to achieve rrb=rs (see eqs. [7] and [8]) is tantamount to requiring
γτ ≅ (ηROBD)2/3PWR/OB . (13)
This implies a shock opening angle
θs ≅ 121(ηROBD)2/9, (14)
which for η=1.65 and D/ROB=46.5 evaluates to θs≅58o, representing a factor ∼3.2 increase over the purely hydrodynamic value θs≅18o. This may be a significant overestimate, because of the optimistic assumptions made about the radiative momentum coupling, but it demonstrates that radiative braking could indeed increase the shock cone opening if the WR wind opacity continues to be high throughout the flow.
A similar result can be reached through the radiative wall approach. Although both approximations are too heuristic to be considered quantitatively reliable, they do suggest that strong radiative braking for the assumed parameters in WR 104 should be expected to widen the bow shock angle considerably, possibly by a factor of 2 or more when compared to the purely hydrodynamic result θs≅18o, as long as the incident WR wind maintains the same high levels of opacity for the OB starlight that it must have had to have been radiatively driven from the WR star. This assumption is currently of unknown validity, and indeed if we take the opposite limit, and say that the line-opacity is just what is needed to drive the relatively weak OB-star wind, then radiative braking will be much weaker and would not likely alter the shock-cone geometry in any measurable way.
To address intermediate values of the effective WR wind opacity, recalling that η, for fixed α, is simply proportional to the integrated spectrum-weighted line opacity distribution with no regard to optical depth (i.e., self-shadowing) corrections. Thus one may either make assumptions about this line opacity to predict η, or one may use observations of the bow shock cone to infer η and reason to conclusions about the line distribution. Further analysis will be required to constrain these expectations more quantitatively, but it seems at least plausible that radiative braking may be important in the wind-wind interaction and shock-cone geometry of WR 104, if the line opacity of the WR wind interacting with the OB starlight is substantially enhanced above what is needed to drive the OB-star wind itself. Reversing the logic, it may be concluded that evidence for a significant widening of the bow-shock cone relative to what may be explained hydrodynamically may be interpreted as evidence that the WR wind does indeed carry with it an intrinsically high opacity when it impinges into the region of strong OB-star radiative flux.
Our images of the WR 104 plume are able to rule out some of the more extreme enlargements to the cone opening angle in the above scenarios. Fits to the data by HMSK found that model cone half-angles of 40∘ or greater (twice the hydrostatic value) were rejected. With still higher angular resolutions than those obtained here, it should be possible to get a direct measurement of the cone opening angle from the images, revealing the role played by radiative braking on the shock geometry.
5 The Profile of the Spiral Plume
Using the excellent fits provided by the theoretical spiral locus to the observed plume of emission from Figures 1, 2 & 3, an investigation of the brightness profile along the length of the dust plume was performed. The flux, summed over a band following the model spiral, was accumulated over all images recovered. Average profiles, plotted as a function of angular displacement along the spiral, are given in Figure 6 for all three filter bandpasses. Also overplotted is the same profile along the spiral calculated from the synthetic radiative-transfer images of HMSK. All experimental curves follow a similar form (with some departures for PAHCS which we attribute to the systematically lower resolution) exhibiting a steep rise in flux from the spiral center to a point about 90∘ downstream followed by a rapid drop as the bright core of the system is traversed. There now follows a region of roughly monotonic decline between about 150−400∘, at which point there is a very sharp drop in brightness flattening to level of less than 1% of the peak for the second coil (CH4 filter only).
The initial sharp rise in flux seen in Figure 6 gives another way to visualize the "standoff distance" between the spiral center and brightest pixel, measured earlier to be 13.3±1.4 mas or 85∘±14∘ downstream along the spiral. Given the 241.5 d period, this corresponds to a kinematic age for the material of 57±10 d. This value is in remarkable agreement with the value of ∼ 58–87 d for the delay between periastron passage and the peak in the dust production in the well-studied episodic colliding-wind binary dust producer WR 140 (Williams et al., 1990; Marchenko et al., 2003) . The finding that the peak in dust production occurs at some distance downstream from the colliding-wind stagnation point (∼30 AU for WR 104) points to a more complicated picture for dust formation physics in colliding-wind binaries than the simple shock compression/cooling models (Usov, 1991) . A number of avenues for additional physics have been presented (see also Crowther, 2003) , with one likely element being escape from the dust-hostile immediate circumstellar radiation environment. Chemical seeding of the WR wind (predominantly helium) with hydrogen from the OB star at the contact surface may help to enhance dust formation pathways (Le Teuff, 2002) , although such mixing may not be very rapid. Shielding from the intense radiation field does appear to be a key ingredient, and sets the playing field for sharply nonlinear grain growth in which small clumps may self-shadow larger areas downstream in a runaway process. Recent numerical simulations of colliding flows have shown that matter is squeezed into thin high-density shells threaded by still higher density filaments as a result of supersonic turbulence (Walder & Folini, 2000) . It was suggested these conditions can persist for a considerable time in the flow before dissipation by internal shocks and vortex cascades. Further to these earlier ideas, we now also add the idea of wind entanglement which can generate significant shock activity well downstream of the nose, as discussed in earlier sections. Whatever mix of these or other elements may go into the next generation of colliding-wind dust formation models, there certainly seems scope to address the outstanding issue of whether the dusty-WC phenomena has a necessary link to binarity (Monnier et al., 1999; Williams & van der Hucht, 2000; Monnier et al., 2007) , or whether novel dust formation pathways in an isolated wind may also be important in some circumstances (Zubko, 1998; Cherchneff et al., 2000) .
After the peak at 85∘, the profiles of Figure 6 exhibit a steady decline (but note the logarithmic y-axis). This is in accord with the relatively flat temperature profile found in models of the centrally-illuminated dust spiral models of HMSK, although the bright peak near the heart of the system is not reproduced in the simulations. A fairly detailed comparison between the radiative transfer results and published masking images of WR 104 can be found in HMSK, although our new results here highlight some discrepancies which we hope will motivate future refinements. The flux level of the second winding of the spiral is well reproduced at the beginning (480∘–600∘) but the secondary bright knot in the model tail seen at 2 complete turns was not observed in the data. Although a detailed comparison is beyond the scope of the present paper, one possible implication is that the optical depth of the dust in the model is not high enough in the core of the system. Increasing it may help to generate the bright peak at 85∘, and at the same time decrease the illumination on the second coil therefore suppressing the spurious feature at 720∘.
The very sharp decline in flux between 400–480∘ is a result of the shadow cast by the first winding of the spiral onto the second, causing a rapid drop in temperature for the eclipsed material. This feature has been commented upon since the discovery of the pinwheels (Tuthill et al., 1999) , and was also reproduced in radiative transfer models (HMSK). What is particularly interesting is that the terminator is found at an angular ordinate of ∼440∘ along the spiral, or about 80∘ beyond one complete revolution. This extra angular displacement (easily visualized in the figure as the full revolution 360∘ location has been marked) gives further independent confirmation for the existence and size of the optically thin inner cavity surrounding the central stars. We refer the reader back to Figure 5 for an easily understood and intuitive depiction of the angular locations of the inner optically thin plume, and the geometry of the shadow cast upon the second coil by the first.
Also of interest in helping to constrain future generations of dust plume models are the multi-wavelength observations of the spiral given in Figures 1, 2 & 3. In particular, there was a systematic rotational displacement found with observing wavelength with a (lower limit) position angle of 6∘ from H–CH4 and 4∘ from CH4–PAHCS (true values may be a factor of ∼2 larger – see discussion in Section 2.3). This implies that the transverse temperature profile of the plume can be explored by our high resolution techniques. Short wavelength observations will preferentially weight the hottest material on the inner edge of the plume facing the central stars, while longer wavelengths will give a better indicator of the bulk concentration of warm dust. Again, we must defer detailed modelling of these effects to a future paper, but note that preferential radiative heating of the inner wall was predicted in models of HMSK. An alternate scenario is that of asymmetric heating by shocks of differing strength at the inner and outer walls, as recently demonstrated in the rotating hydrodynamic simulations of Lemaster et al. (2007) .
6 Geometrical Implications of the Plume Structure
A key finding from earlier studies of the WR 104 pinwheel has been the low eccentricity of the orbit of the central stars (Tuthill et al., 1999, 2002) . As noted earlier (Monnier et al., 1999) , this finding may be a "smoking gun" pointing to previous episodes of tidal circularization and likely Roche-lobe interactions with possible mass transfer and/or envelope stripping. Such an event provides one of the two possible pathways to the creation of a Wolf-Rayet (Paczyński, 1967) ; the other being strong wind-driven mass loss in a single star (Chiosi et al., 1978) . With our long time-sequence of observations sampling all phases of the orbit, we are able to put tight constraints on the allowed levels of orbital eccentricity in the case of WR 104. Although it would be possible to fit eccentric spiral models directly to the data, we favored a more indirect approach as for small to moderate levels of eccentricity, the departure in shape from an Archimedian spiral was subtle. The most easily detectable effect that an eccentric orbit has in perturbing the rotating spiral model away from its ideal form will be in departures from a constant rate of rotation.
We have therefore performed a careful fit of the best-fit orientation of the spiral structure at each epoch, and compared the values obtained with the model of a simple, constant angular velocity. This was done in two different ways which gave similar results: firstly by fitting to points extracted from the crest of the bright spiral ridge, and secondly by fitting each full image to a mean template. The uniformity of the angular rotation rate extracted from the real data, which is given in in Figure 7, was then compared with results from model simulations. A family of synthetically-generated spiral images of varying eccentricity were fit in an identical fashion to the real data, allowing us to derive quantitative limits on the levels of eccentricity present in the WR 104 orbit. Figure 7 shows the rotational uniformity from the data and examples from two of the synthetic eccentric model images. The rotation is seen to be highly uniform, ruling out all but very modest eccentricities. A 2σ upper limit of e <∼ 0.06 was obtained in this fashion.
Having thus established the properties of the best-fit uniform Archimedian spiral model, it was then possible to generate a stacked composite image averaging over all epochs of data taken in the CH4 filter. Individual data frames were corrected for inclination on the sky (simulating a perfectly face-on view) and de-rotated to coincide with the first (Apr98) epoch before being co-added. A composite image, displaying significantly greater dynamic range than any of the single-epoch images from Figure 1, is given in Figure 8. Variations in morphology between different epochs beyond those expected from the rotating spiral model are minor, and all appear to be within the noise level of the image recovery process. We therefore hope that this image, as a mean over all epochs, may provide a resource to modellers and others interested in the best possible snapshot of the geometry of these pinwheel systems.
The flat infrared lightcurves of Figure 4 discussed above affirm the status of WR 104 as a "constant" dust-producer (Williams, 1997) , yet stand in contrast to the large 2.7 mag "quasi-periodic" variability (periodic component >∼ 1 mag) in the visible lightcurves reported by Kato et al. (2002) . With a narrow cone half-angle (20∘; HMSK), face-on orientation to the line of sight and very low levels of orbital eccentricity, the spiral dust plume gives no obvious mechanism for modulating the visible flux from this system. The lack of detectable infrared variation argues for steady and constant dust production at all orbital phases, with minimal effects from any inclination to the the line of sight. Visible light scattered from the dust plume may be more strongly modulated by rotation and inclination effects, however it is difficult to see how variations in the V lightcurve as large as >∼ 1 mag could arise from this. Possible scenarios include opacity effects from gas (or possibly small quantities of dust) associated with the innermost regions of the shock cone which modulate the light of the OB star, line-of-sight (polar-axis) dust creation independent of the colliding wind mechanism, or some geometrical effect from a sharp opacity gradient possibly created at an earlier phase (further discussion can be found in Kato et al., 2002) .
7 WR Systems as Supernova Progenitors
As a final point of discussion, we also explore the implications of future evolution of this system with particular regard to the face-on viewing angle to Earth. The formal Archmiedian spiral fits yielded an inclination i=12∘, but for such a small angle to the line-of-sight the uncertainty was large and fully consistent with the range from 0∘ – 16∘. A further source of uncertainty arises from the limitations of the simple two-dimensional spiral model used. In reality, the pinwheel is of course a three-dimensional structure which may present us with more complicated opacity effects such as limb-brightening. If we consider a single circular cross-section through the conical shock, as this is carried downstream by the WR wind, it will become inflated and distorted by the spherical expansion into an elongated "D". Eventually at large radii, the plume shape will resemble an equatorial band wrapped around a sphere, subtending an angle equal to that of the shock cone. This underlying spherical geometry gives rise to a fundamental insensitivity to the line-of-sight inclination: modest changes of tilt for such a structure result in only a very small or zero change in observed aspect ratio. For these reasons, our upper limit of 16∘ may be an underestimate. Firmer constraint of the inclination from the data presented here would require detailed radiative transfer modelling with varying lines of sight onto a three-dimensional structure.
Despite these quantitative caveats, it remains apparent that in WR 104, Earth has an approximately pole-on view onto a relatively nearby, massive WR binary system. Given the prehistory of mass transfer and envelope-stripping suggested above, it therefore seems likely that Earth also lies in the polar direction with respect to the spin axis of both WR and OB stars due to the prior angular momentum evolution of such binary systems (e.g. Zahn, 1977; Tassoul, 1987) . As both objects in the system should eventually explode as core-collapse supernovae, it is interesting to speculate on how our "privileged" polar vantage point may affect our experience of this event, which should happen within a timescale of several hundred thousand years for the WR component (Maeder, 1981; Chiosi & Maeder, 1986) . It is becoming more accepted that all supernova explosions probably exhibit some preferred axis aligned with the progenitor stellar spin. As one of the closest imminent WC-class Wolf-Rayets, an isotropic supernova in WR 104 at kiloparsec scale distances would no doubt put on an impressive show, but any impact on Earth's biosphere is likely to be negligible (Ellis & Schramm, 1995) . However for a highly anisotropic explosion, the most extreme example of which would be a Gamma Ray Burst, effects could be significant if Earth lies within the <∼ 12∘ opening angle (Frail et al., 2001) of the burst, even at 2 kpc distances (Melott et al., 2004; Thomas et al., 2005a, b) .
Could WR 104 produce a GRB? Certainly a case could be made that the OB component of the binary system, which was the recipient of mass and angular-momentum transfer in the prior Roche-lobe overflow event, may meet the requirements for envelope mass and angular momentum for many current models of GRB formation (see Petrovic et al., 2005, for a discussion of WR binaries as GRB progenitors) . The Wolf-Rayet component, with WC spectral type, has arguably the shortest fuse, being in the last known stable phase before supernova. Although prior stripping may have lowered the envelope mass into a regime less favorable for conventional collapsar GRB's, there are also more exotic magnetar (millisec pulsar driven) GRB models which may prove viable (Gaensler et al., 2005; Metzger et al., 2007) . In short, this is a very active and rapidly-evolving field, and the uncertainties outnumber the firm conclusions in arriving at a mass/metallicity/evolutionary portrait of likely GRB progenitors. Whether or not the WR 104 system will play host to a future GRB, it does seem clear that two pole-oriented supernovae will occur, and that energy and matter will be preferentially ejected along this axis (see Fryer & Warren, 2004, for a discussion of the effects of stellar rotation on SN explosions) . Further observations to constrain the inclination of the orbital plane, which should be possible with spectroscopic monitoring, are therefore encouraged.
The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The Authors would like to particularly thank the instrument technicians and engineering crew at the observatory for their help and support of our unorthodox observing techniques. Devinder Sivia kindly provided the maximum entropy mapping program "VLBMEM", which we have used to reconstruct our diffraction limited images. This work has been supported by grants from the National Science Foundation and the Australian Research Council. We thank Charles Townes for his long-standing support of this program, and Bryan Gaensler, Shami Chatterjee and Grant Hill for helpful discussions.
Bethe (1990) Bethe, H. A. 1990, Reviews of Modern Physics, 62, 801
Canto et al. (1996) Canto, J., Raga, A. C., & Wilkin, F. P. 1996, ApJ, 469, 729
Castor et al. (1975) Castor, J. I., Abbott, D. C., & Klein, R. I. 1975, ApJ, 195, 157
Cherchneff et al. (2000) Cherchneff, I., Le Teuff, Y. H., Williams, P. M., & Tielens, A. G. G. M. 2000, A&A, 357, 572
Chiosi et al. (1978) Chiosi, C., Nasi, E., & Sreenivasan, S. R. 1978, A&A, 63, 103
Chiosi & Maeder (1986) Chiosi, C., & Maeder, A. 1986, ARA&A, 24, 329
Crowther (1997) Crowther, P. A. 1997, MNRAS, 290, L59
Crowther (2003) Crowther, P. A. 2003, Ap&SS, 285, 677
Danchi et al. (2001) Danchi, W. C., Tuthill, P. G., & Monnier, J. D. 2001, ApJ, 562, 440
Eichler & Usov (1993) Eichler, D., & Usov, V. 1993, ApJ, 402, 271
Ellis & Schramm (1995) Ellis, J., & Schramm, D. N. 1995, Proceedings of the National Academy of Science, 92, 235
Frail et al. (2001) Frail, D. A., et al. 2001, ApJ, 562, L55
Fryer & Warren (2004) Fryer, C. L., & Warren, M. S. 2004, ApJ, 601, 391
Gaensler et al. (2005) Gaensler, B. M., McClure-Griffiths, N. M., Oey, M. S., Haverkorn, M., Dickey, J. M., & Green, A. J. 2005, ApJ, 620, L95
Gayley et al. (1997) Gayley, K. G., Owocki, S. P., & Cranmer, S. R. 1997, ApJ, 475, 786
Gayley et al. (1996) Gayley, K. G., Owocki, S. P., & Cranmer, S. R. 1996, Workshop on Colliding Winds in Binary Stars to Honor Jorge Sahade, vol. 5, p. 68, 68
Gull & Skilling (1984) Gull, S.F. and Skilling, J. 1984, Proc. IEEE, 131, 6
Haniff & Buscher (1992) Haniff, C. A., & Buscher, D. F. 1992, J. Opt. Soc. Am. A, 9, 203
Harries et al. (2004) Harries, T. J., Monnier, J. D., Symington, N. H., & Kurosawa, R. [HMSK] 2004, MNRAS, 350, 565
Högbom (1974) Högbom, J. 1974, ApJS, 15, 417
Howarth & Schmutz (1992) Howarth, I. D., & Schmutz, W. 1992, A&A, 261, 503
van der Hucht (2001) van der Hucht, K. A. 2001, New Astronomy Review, 45, 135
Ireland et al. (2006) Ireland, M. J., Monnier, J. D., & Thureau, N. 2006, Proc. SPIE, 6268,
Kato et al. (2002) Kato, T., Haseda, K., Yamaoka, H., & Takamizawa, K. 2002, PASJ, 54, L51
Kuiper (1941) Kuiper, G. P. 1941, ApJ, 93, 133
Lemaster et al. (2007) Lemaster, M. N., Stone, J. M., & Gardiner, T. A. 2007, ApJ, 662, 582
Le Teuff (2002) Le Teuff, Y. H. 2002, Interacting Winds from Massive Stars, 260, 223
Lundstrom & Stenholm (1984) Lundstrom, I., & Stenholm, B. 1984, A&AS, 58, 163
Maeder (1981) Maeder, A. 1981, A&A, 99, 97
Marchenko et al. (2002) Marchenko, S. V., Moffat, A. F. J., Vacca, W. D., Côté, S., & Doyon, R. 2002, ApJ, 565, L59
Marchenko & Moffat (2006) Marchenko, S. V., & Moffat, A. F. J. 2006, ArXiv Astrophysics e-prints, arXiv:astro-ph/0610531
Matthews et al. (1996) Matthews, K., Ghez, A. M., Weinberger, A. J., & Neugebauer, G. 1996, PASP, 108, 615
Mauron & Huggins (2006) Mauron, N., & Huggins, P. J. 2006, A&A, 452, 257
Marchenko et al. (2003) Marchenko, S. V., et al. 2003, ApJ, 596, 1295
Melott et al. (2004) Melott, A. L., et al. 2004, International Journal of Astrobiology, 3, 55
Metzger et al. (2007) Metzger, B. D., Thompson, T. A., & Quataert, E. 2007, ArXiv e-prints, 704, arXiv:0704.0675
Mondal & Chandrasekhar (2002) Mondal, S., & Chandrasekhar, T. 2002, MNRAS, 334, 143
Monnier et al. (1999) Monnier, J. D., Tuthill, P. G., & Danchi, W. C. 1999, ApJ, 525, L97
Monnier et al. (2000) Monnier, J. D., Tuthill, P. G., & Danchi, W. C. 2000, ApJ, 545, 957
Monnier et al. (2002) Monnier, J. D., Greenhill, L. J., Tuthill, P. G., & Danchi, W. C. 2002, ApJ, 566, 399
Monnier et al. (2002) Monnier, J. D., Tuthill, P. G., & Danchi, W. C. 2002, ApJ, 567, L137
Monnier et al. (2004) Monnier, J. D., et al. 2004, ApJ, 605, 436
Monnier et al. (2007) Monnier, J. D., Tuthill, P. G., Danchi, W. C., Murphy, N., & Harries, T. J. 2007, ApJ, 655, 1033
Moran & Reichart (2005) Moran, J. A., & Reichart, D. E. 2005, ApJ, 632, 438
Paczyński (1967) Paczyński, B. 1967, Acta Astronomica, 17, 355
Pauls et al. (2005) Pauls, T. A., Young, J. S., Cotton, W. D., & Monnier, J. D. 2005, PASP, 117, 1255
Petrovic et al. (2005) Petrovic, J., Langer, N., Yoon, S.-C., & Heger, A. 2005, A&A, 435, 247
Rajagopal et al. (2004) Rajagopal, J. K., Barry, R., Lopez, B., Danchi, W. C., Monnier, J. D., Tuthill, P. G., & Townes, C. H. 2004, Proc. SPIE, 5491, 1120
Rochowicz & Niedzielski (1995) Rochowicz, K., & Niedzielski, A. 1995, Acta Astronomica, 45, 307
Ryder et al. (2004) Ryder, S. D., Sadler, E. M., Subrahmanyan, R., Weiler, K. W., Panagia, N., & Stockdale, C. 2004, MNRAS, 349, 1093
Sivia (1987) Sivia, D.S. 1987, Ph.D. diss., Cambridge Univ.
Stevens et al. (1992) Stevens, I. R., Blondin, J. M., & Pollock, A. M. T. 1992, ApJ, 386, 265
Struve (1950) Struve, O. 1950, Stellar Evolution, Princeton University Press, NJ.
Tassoul (1987) Tassoul, J.-L. 1987, ApJ, 322, 856
Thomas et al. (2005a) Thomas, B. C., et al. 2005a, ApJ, 634, 509
Thomas et al. (2005b) Thomas, B. C., Jackman, C. H., Melott, A. L., Laird, C. M., Stolarski, R. S., Gehrels, N., Cannizzo, J. K., & Hogan, D. P. 2005b, ApJ, 622, L153
Torres et al. (1986) Torres, A. V., Conti, P. S., & Massey, P. 1986, ApJ, 300, 379
Tuthill et al. (1999) Tuthill, P. G., Monnier, J. D., & Danchi, W. C. 1999, Nature, 398, 487
Tuthill et al. (2000) Tuthill, P. G., Monnier, J. D., Danchi, W. C., Wishnow, E. H., & Haniff, C. A. 2000, PASP, 112, 555
Tuthill et al. (2000) Tuthill, P. G., Danchi, W. C., Hale, D. S., Monnier, J. D., & Townes, C. H. 2000, ApJ, 534, 907
Tuthill et al. (2002) Tuthill, P. G., Monnier, J. D., Danchi, W. C., Hale, D. D. S., & Townes, C. H. 2002, ApJ, 577, 826
Tuthill et al. (2002) Tuthill, P. G., Monnier, J. D., & Danchi, W. C. 2002, Interacting Winds from Massive Stars, 260, 321
Tuthill et al. (2002) Tuthill, P. G., Men'shchikov, A. B., Schertl, D., Monnier, J. D., Danchi, W. C., & Weigelt, G. 2002, A&A, 389, 889
Tuthill et al. (2003) Tuthill, P. G., Monnier, J. D., Danchi, W. C., & Turner, N. H. 2003, A Massive Star Odyssey: From Main Sequence to Supernova, 212, 121
Tuthill et al. (2006) Tuthill, P., Monnier, J., Tanner, A., Figer, D., Ghez, A., & Danchi, W. 2006, Science, 313, 935
Usov (1991) Usov, V. V. 1991, MNRAS, 252, 49
Walder & Folini (2000) Walder, R., & Folini, D. 2000, Ap&SS, 274, 343
Woosley et al. (2002) Woosley, S. E., Heger, A., & Weaver, T. A. 2002, Reviews of Modern Physics, 74, 1015
Woosley & Bloom (2006) Woosley, S. E., & Bloom, J. S. 2006, ARA&A, 44, 507
Vanbeveren et al. (1998) Vanbeveren, D., De Loore, C., & Van Rensbergen, W. 1998, A&A Rev., 9, 63
Williams et al. (1990) Williams, P. M., van der Hucht, K. A., Pollock, A. M. T., Florkowski, D. R., van der Woerd, H., & Wamsteker, W. M. 1990, MNRAS, 243, 662
Williams (1997) Williams, P. M. 1997, Ap&SS, 251, 321
Williams & van der Hucht (2000) Williams, P. M., & van der Hucht, K. A. 2000, MNRAS, 314, 23
Zahn (1977) Zahn, J.-P. 1977, A&A, 57, 383
Zubko (1998) Zubko, V. G. 1998, MNRAS, 295, 109
Figure 1: Images recovered from data in the CH4 filter over 11 observing epochs. Contour levels are .4, 1, 2, 5, 10, 50 % of the peak. North (Dec.) is up and east (R.A.) to the left with the image scale labelled in millseconds of arc. Images have been centered on the mathematical origin of the best-fit Archimedian spiral model (dashed line: see text for details).
Figure 2: Images recovered from data in the H filter over 11 observing epochs. See caption to Figure 1 for details.
Figure 3: Images recovered from data in the PAHCS filter over 6 observing epochs. Contour levels are 1, 2, 5, 10, 20 % of the peak. Otherwise similar to Figure 1.
Figure 4: Photometry data for WR 104 obtained in our three filter bandpasses (key inset), folded with the 241.5 d period.
Figure 5: Schematic diagram of the key elements in the WR 104 system. The geometry depicted is that of a face-on view onto a 20∘ cone half-angle pinwheel. The axis of the system, and the line of shadow cast at 84∘ to the spiral origin (θ=0), are indicated as dot-dashed lines. Key elements are labeled, and some, such as the binary separation, are not to scale (depicted here about a factor of ten too large).
Figure 6: Average brightness profile of the plume as a function of angular displacement along the spiral model locus. Data for our three filter bandpasses are given (linetypes indicated in the key) together with a profile extracted from the numerical radiative transfer simulations of Harries et al. (2004) specific to our CH4 filter in the K band. Data for H and PAHCS are terminated shortly after the first full turn, at which point the signal-to-noise in the images is insufficient to discern real structure from noise. For convenience, intervals of 1 and 2 complete revolutions are marked.
Figure 7: (Upper panel) The rotation of the pinwheel at each observing epoch from fits to data in Figure 1, plotted as a function of the orbital phase. The dashed line gives a simple model of uniform angular velocity. (Lower panel) the residual between the data and the uniform model. Both panels have overplotted dotted lines giving examples of expected curves for elliptical orbits with eccentricity e=0.1 and 0.2.
Figure 8: Stacked composite image of all epochs of data in the CH4 filter. Contour levels are .1, .2, .5, 1, 2, 5, 10, 20, 30, 70 % of the peak. Individual images have been projected to a face-on viewing angle and derotated to the first Apr98 epoch according to the best-fit Archimedian spiral model prior to coadding.
JD-2450000
1998 Apr 14 918 H,CH4,PAHCS
1998 Jun 04 969 H,CH4,PAHCS
1998 Sep 29 1086 H,CH4,PAHCS
1999 Apr 25 1294 H,CH4,PAHCS
1999 Jul 29 1389 H,CH4,PAHCS
2000 Jun 23 1719 H,CH4,PAHCS
2001 Jun 11 2072 H,CH4
2002 Jul 23 2479 H,CH4
2003 May 12 2772 H,CH4
2004 Sep 03 3154 H,CH4
Table 1: Journal of Interferometric Observations.
(μm)
H 1.656 0.333
CH4 2.269 0.155
PAHCS 3.083 0.101
Table 2: Properties of Filters


Albany Mall offers an EXCITinG OPPORTUNITY for a new career!
Select any of the links below of current merchants who are accepting applications to view their job descriptions and how to apply.
Bath & Body Works is HIRING!
Who wouldn't love to sell lotion for a living??Come grow with this company!
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Go to careers.booksamillion.com to join!!!
Now Hiring qualified 16 year olds. Open interviews are Mondays at 4 pm sharp.
Holiday Portraits at Albany Mall is currently excepting applications for the Easter Season at the Albany Mall. The Easter Season starts March 30th and continues until April 20th. Working hours are Monday - Thursday 11 am - 8 pm, Friday and Saturday 10 am - 8 pm and Sunday 1 pm - 5 pm.
For more information please contact David Hagood at 334-410-0746 or Katie Hagood at 334-380-1706.
Reed's Jewelers is currently seeking a Full Time Sales Associate. Hours are flexible. Please see store to apply.


text:
Death toll from China landslides rises
duration 14 July 2010
image captionBuildings were buried and vehicles turned over in the Xiaohe landslide
Heavy rain is continuing to cause havoc across southern and central China, triggering landslides which have left dozens of people dead or missing.
The death toll from five landslides, in Yunnan, Sichuan and Hunan provinces, rose to 37, with another 40 people missing, Xinhua news agency said.
Elsewhere, villagers were evacuated as reservoirs overflowed and troops blew up a dyke to prevent further flooding.
China experiences seasonal rains but they have been severe this year.
Meteorologists say more rain is expected in central and southern China, potentially exacerbating flood problems.
Dyke blasted
In worst-hit Xiaohe, in Yunnan province, 13 people were confirmed dead after the side of a mountain collapsed before dawn on Tuesday, burying houses.
image captionHeavy rain caused flooding in Anhui province
Thirty-two others were missing, a local government spokesman said.
Images from the scene showed overturned cars and toppled houses in a landscape strewn with rocks and mud.
Relief supplies were being sent to the area, state media said.
Landslides also hit rural communities in Sichuan and Hunan, killing a total of 24 people.
Flooding has also affected vast areas. In Jiangxi province, 10,000 people were evacuated from villages in the north after rain triggered flashfloods and caused three reservoirs to overflow.
In Anhui province, troops blew up part of a dyke on a swollen branch of the Yangtze to prevent floodwaters flowing into riverside villages.
But there was some good news. Officials said troops had finished digging a drainage channel from an overflowing reservoir in Qinghai and the water level was beginning to subside.
More than 10,000 people had been evacuated from the area, and there were fears that flooding could knock out power in the nearby city of Golmud.
In pictures: China floods

redpajama_set_name: RedPajamaCommonCrawl


How to Win with People - and Understand why some Relationships just don't Work. Can't get on with the boss? Keep picking the wrong man, time after time? You love the girl, but can't stand her attitude? Never fear, the answer's here. Bernard Fitzwalter has twice been President of the Astrological Lodge of London, and for over 10 years, has been a tutor for the Faculty of Astrological Studies in London. His columns have been published worldwide, in magazines such as Chat and Elle.


Large santoku knife in steel AISI 420, mat.
Forged AISI 420 steel, mat.
Stefano Giovannoni was born in La Spezia in 1954, architect and designer. His explosive talent, able to embody the complex system of "affective codes" in his projects, is winning him the title of best "Super & Popular" designer of the years 2000.


Apps that store data need access to database tables. It's best, if at all possible, to create these tables seamlessly without requiring the user to go through an installation procedure. We call the process of setting up your tables and any other related stuff your app needs to do in order to operate activation.
Activation happens inside perch/addons/apps/my_app/activate.php. This script should create your tables, do what it needs to do, and then return true if it worked or false if it didn't.
If you've built your classes on top of PerchAPI_Factory, the activation process is kicked off with a call to PerchAPI_Factory::attempt_install(). This checks for the existence of the table named in PerchAPI_Factory::table, and if it's not there, runs your activation script.
You need to figure out the logic on when to attempt installation, as it would be wasteful to check on every page load. Usually, the front page of an app is a listing page. It's our recommendation that if this listing returns no results, that would be the best time to attempt to install. Once the user has added data, then it's clear everything is set up and there's no need to try again.
The official Perch apps all contain activation scripts. These can be used as a template for your own.


Manufactured from fabric in mokka colour.
On both sides of the saddlecloth a vertical stripe with dots print. On one side a gold label with our logo- engraved and lacquered.
You're reviewing: Saddlecloth "Mokka Dots"


text:
Home Entertainment Among Us: Gray Will Be The Newest Color To Be Introduced
Among Us: Gray Will Be The Newest Color To Be Introduced
Among Us Updates: For the past year or so, players have adored Among Us to the point that the devs never imagined the game would achieve such acclaim. And now, for the gamers, a new hue is on the way.
Gray will be included in Among Us, according to Innersloth. The feature would be included in the huge 15-player upgrade scheduled for 2021. This would offer gamers more options. The release date for this upgrade is set for late 2021.
The lockout proved to be a blessing in disguise for Innersloth. During the COVID-19 blackout, the game swiftly gained popularity. Since 2018, the game has been available. Many people have been drawn to the game's format, which is both easy and exciting at the same time.
The game's developers have now devoted themselves to keeping it up to date. They do, however, want to make a sequel out of the film.
While it is true that Among Us resembles Mafia, the inclusion of modifications has given the latter an advantage over Mafia. With all of the modifications available for Among Us, adding new hues has become a no-brainer.
Among Us Gray Color
The new hue will be accessible when the 15-player update goes live, according to Innersloth. In addition, a new Rose hue will be added to Among Us. In June, this will be accessible. More details will be revealed at this year's Summer Game Fest, according to the tweet.
Among Us may soon be accessible to play on consoles in addition to PC and mobile. With new console editions, the game's reach is being expanded. These would arrive in the second half of 2021.
Though modifications may not be supported in console versions, which would undoubtedly detract from the game's attractiveness. For those who are unaware, the game's Nintendo Switch version was launched in December 2020.
According to some estimations, Between the PC, Switch, and mobile versions of the game, Among Us might have about 500 million users.
The game is truly one-of-a-kind. It allows people to connect and play party games without having to be in the same room, which is ideal in a circumstance like the COVID-19 epidemic. Let's hope that the new changes and colours add to the game's enjoyment and bring it closer to the outstanding hacked versions.
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We offer a number of guided tours of the Museum.
Docent-led group tours of The Dream of America: Swedish Immigration to Chicago exhibit are held once a month. These tours are best for people aged 12 and up and focus on the immigration from Sweden to Chicago. For dates please check our calendar. This tour is free with admission.
Docent-led Family Tours are also held once a month. The tour follow the CPS immigration curriculum and is the same tour that we offer for school groups. The tour focuses on immigration to the USA in general with Sweden used as an example. The tour is aimed at the whole family and best suited for people aged 6 and up. This is a family tour so parents need to stay with their children at all times. For dates please check our calendar. This tour is free with admission.
It is possible to schedule a private group tour. These guided tours must be pre-scheduled to ensure the availability of a docent to guide your group. We can accommodate groups of up to 60 people for a docent-led tour. The tour is included in the admission price with a minimum of 6 participants in the group tour (it is possible to book a tour for less people but minimum payment is $24 for an adult tour and $18 for a family or senior tour). To book a private group tour please fill out the form below. Please include the number of people in your group.
We also offer school tours. For more information on those please click here.


text:
Hungover God Can't Remember Where He Parked Universe
Staggering out of His celestial bed with bloodshot eyes, a miserably hungover God couldn't remember where He parked the Universe last night.
"Damn, that party was off the hook," recalled the Almighty as he popped three asteroid-sized ibuprofen. "How the Hell did we even get back to Heaven?"
While He was able to retrace His steps from happy hour at Sully's to two-for-one margaritas at Tacos Locos, He said it "all becomes a blur" after that.
"That dude is crazy," said friend Peter in hush tones so that the Lord would not overhear and smite him. "He blew, like, a galaxy's worth of stardust off an angel's wings and then drove to Krysti's party."
"Typical God," added wingman Michael with disapproval.
Friends say God has been living the partying lifestyle too much lately. Just last weekend, they say, he consumed three solar systems in a blackout rage and drunk sexted multiple ex-girlfriends.
God, on the other hand, said he has no plans to slow down his bacchanalian ways, and is not even too concerned about finding the Universe.
"I'm riding this booze train straight to Apocalypse-town. Gimme another shot," said the All-Knowing Father. "The Universe will be okay on its own for a while."
Couple Starves to Death Trying to Decide What to Have for Dinner Tonight
Philadelphia Sports Fan Perplexingly Not an Asshole


text:
package eu.agilejava.javaonedemo.service;

import eu.agilejava.javaonedemo.entities.Recipe;
import java.util.List;

/**
 *
 * @author ivar
 */
public interface RecipeService {

   int count();

   void create(Recipe recipe);

   void edit(Recipe recipe);

   Recipe find(Object id);

   List<Recipe> findAll();

   void remove(Recipe recipe);

}

redpajama_set_name: RedPajamaGithub


At some point in your learning curve for Clay Shooting you may have considered getting some formal coaching, I recently had a lesson with John King, and thought I would write-up the experience to outline how the session went – and what I learnt.
John King has been a good friend to ShootClay since we started – his shooting DVD and Book package was one of the first things that we reviewed – he has a wealth of experience and is an ideal candidate for a coach. His guide to choosing a shooting coach is an excellent starting point if you are trying to find someone local to you. My lesson was at the fantastic Barbury Shooting School – you can read our review of the facilities here.
Background – I'm a fairly new shooter breaking about 60 or 65% of clays in front of me. I shoot gun-up, am left-eye dominant and right-handed. I have always struggled with gun mount, never feeling that I have a consistent mount. I've never had any coaching before – I often struggle with loopers, high driven birds and rabbits. I hope that sets the scene of what John had to work with.
So – onto the lesson. After a short chat and a check that I had all the necessary safety gear – we headed out to a quiet part of the Barbury school. John showed me a gentle right to left crossing bird and after a short pep talk (about not being nervous) asked me to shoot it. I took about 5 shots, and I could sense that John was observing my gun mount and movement throughout.
After those first few birds – John asked me to go through the basics of 'the method' – establishing the correct position for my feet, the kill point, the pick-up point and the kill picture. His final words of advice were that the ONLY thing I should be seeing before calling 'pull' is that kill picture – getting my mind to focus on that would help my body remember it, he emphasised the key point of 'PUSH'ing away from the bird to make that kill picture and then pulling the trigger.
Then in some subtle coaching he talked about locking the gun in position, my head has always been quite scrunched over – but John asked me to make some minor adjustments to where I held the gun and to ensure that I locked it tight in position, THROUGH the shot (my head was apparently lifting as I pulled the trigger). This was a major development – my next ten/fifteen birds were much better.
Now comes the magic – in my review of Johns book I mentioned that I didn't understand the point he made about using your left hand. John asked me (as an aside) why I shot 'gun-up'. I mentioned that I had never been taught any other method. He gave me a fantastic metaphor for using my left hand to point more directly at the clay as I shoot – and then told me not to pre-mount my gun. Bingo – a completely different experience. I could immediately feel an improvement in how I picked up the bird – I still need more practice here, but the principle was already engrained, and we were only half way through our lesson.
As an aside – I went away from the lesson thinking about how I could improve the reaction and feel of my left-hand (it has always been a useless limb), one technique has been to move my computer mouse to my left hand… my motor skills on my left side have improved significantly in the weeks since my lesson.
For the second part of my lesson – we walked to another area at Barbury and John picked out a looper. This is often a bogey bird for me, ruining a number of scorecards. John talked me through 'the method' again – but focusing on how I should adjust my pick-up point and kill-point for the right to left looper. He explained the principle of 'removing the loop' from the process and finding your kill picture. I managed to hit a few of these and then John paired that up with a quick left-right crosser to get all of the things I'd learnt working together.
By the end of the lesson – I was feeling much more confident in the basics, it felt like I had added a lot of theory that I hadn't really learnt before. I'm already shooting a lot more confidently and thinking about my other tricky targets before I see John for my next lesson. It was an excellent session – and I highly recommend spending time with John King, or another established coach if you want to introduce a step change to your game.


Protesters gathered at a local Wendy's this weekend to protest the restaurant for not participating in the Fair Food Program. Photo by Sierra Mannie.
Wendy's on High Street got traffic from more than just the lunch crowd this week. The Mississippi Sustainable Agriculture Network and the Florida-based Coalition for Immokalee Workers brought dozens of activists from around Mississippi and as far away as Florida together at the Mississippi Farmers Market Saturday at the biannual Mississippi Food Summit and Agricultural Revival, and then marched to the nearby fast-food restaurant. The march was in protest of the world's third-largest fast food chain's refusal to participate in the Fair Food Program.
"We're here in Mississippi today joined by dozens of allies here locally to educate people about the conditions in which Wendy's brings the tomatoes that it sells to its customers," said Lupe Gonzalo, a member of the Coalition of Immokalee Workers.
Founded in 1993 and led by farm workers, the human-rights organization spearheaded the Fair Food Program in 2011, which asks corporations to buy "exclusively from suppliers who meet a worker-driven code of conduct, which includes a zero-tolerance policy for forced labor and sexual harassment," a Mississippi Sustainable Agriculture Network press release says. Corporations must also pay a penny more per pound of tomatoes they purchase from their suppliers, which helps pay workers better wages.
Since 2011, buyers have paid more than $22 million into the program.
Gonzalo said Wendy's participation would show commitment not only to better wages for workers, but also respect for the people who farm their tomatoes.
"(Joining means) committing to a code of conduct in which the workers' rights are respected and which has zero tolerance for the worst of abuses including sexual harassment and modern-day slavery, and that the voice of the worker is respected throughout the supply chain, she said at the Jackson protest. She added that farm workers must have the right to speak out against abuses they face without fear of retaliation.
Fourteen major corporations, including Walmart and McDonald's, participate in the program; Wendy's, however, hasn't yet budged, which the CIW says creates a market for less reputable growers. Instead of joining the Fair Food Program, Wendy's left the Florida tomato industry after it signed a Fair Food Agreement, and drafted its own code of conduct for protecting workers that the Alliance for Fair Food called "completely void of effective enforcement mechanisms to protect farmworkers' human rights."
Harper's Magazine wrote this year that Wendy's purchases from Mexican agribusiness giant Bioparques de Occidente, which was the subject of a slavery prosecution in 2013. The magazine reported that workers worked in deplorable conditions without pay, and were "beaten when they tried to quit."
Farm workers are vulnerable to a variety of injustices, especially if they are immigrants, some of whom may not be legally authorized to work. Farmworkers make very low wages; many of them live in poverty. Women, especially, are subject to sexual harassment, but may be too intimidated to stand up for themselves.
"Wendy's is being targeted by an activist group called the Coalition of Immokalee Workers (CIW) and its allies at other activist organizations.
CIW demands we make payments to employees of the companies who supply our tomatoes from the Immokalee area in Florida — even though they are not Wendy's employees. CIW is demanding an added fee on top of the price we pay our suppliers. However, because of our high standards, we already pay a premium to our Florida tomato suppliers.
We believe it's inappropriate to demand that one company pay another company's employees. America doesn't work that way.
Our responsibility to Wendy's customers is to negotiate directly with our suppliers - not third-party organizations — to ensure our product specifications are met at a competitive price. If our suppliers incur additional labor costs, we would expect them to pass them on to us over time."
Agreed to a worker education program conducted on company premises and company time Wendy's supports ongoing efforts by Florida tomato growers to improve working conditions for their workers."


text:
Vehicles Watch These People Play a Car Balancing Game on a Giant Seesaw
Entertainment Guy Makes a Thumb Piano Using Strategically Placed Popsicle Sticks
Innovation YouTubers Attempt to Spray-paint a Hyper Shift over the World's Blackest Paint
Entertainment Why You Should Not Shoot a Gun With a Really Bent Barrel, YouTuber Demonstrates
Entertainment YouTuber Develops Sand Machine That Erases Everything It Creates
Architecture North Korea's Capital Pyongyang's Architecture Explained
Transportation How Large Ships Survive Huge Storms at Sea
Entertainment This is How Boston Dynamics' Robots Learned to Dance
How-to Building Your Own Drone Hovercraft With a Plate
Entertainment Guy Paints Room With World's Blackest Paint and Turns the Light On
Man Brings Back to Life an Old and Dirty Apple IIc
By Trevor English
Even though old computers aren't really capable of doing anything practical nowadays, they can often be major points of nostalgia to collectors and computer lovers. Built in 1984, the Apple IIc has 128K of RAM and a hard drive that was driven by a belt. Of the few that have survived, many don't work anymore, but this guy got his hands on one that did, and he brought it back to its former glory.
With a lot of cleaning using hydrogen peroxide and other chemicals, he was able to remove the yellow tint on the plastic and clean off all of the gunk collected over the last 30 years. He had to fix a few minor issues on the internals, but other than that the old thing worked good as new!
Apple Debuts M1, Apple Silicon MacBook Air, Pro, Big Sur, and Much More
The Life and Times of the Famous Astrophysicist Neil deGrasse Tyson
California Academy of Science Added 213 New Plant and Animal Species to the Tree of Life


I'm tryna figure out if these images in the new "OCR" video complement the mood OR the art of what Alex Gray brings in his D/P/I project. The aesthetic of "on the fly" with these images is definitely on par with his sound structuring. And for the most part, I've always considered D/P/I (and most of Gray's music) to be location-less. As if it comes from nowhere, but pure entity. Though, this aesthetic of "Chance Images" is ULTRA fun! MOST of these pictures here in "OCR" are not very a-typical to certain destinations, and not having direction in D/P/I is like… well, what it's all about, right?
ANYHOW, fools!!! D/P/I is releasing a total tease on Leaving Records next Tuesday called RICO EP, which is VERY MUCH worth the listen, but definitely leaves you wanting more. More to come, though? MAYBE! Keep on your location-less game, continue checking back in, but in the mean-time, ride every D/P/I wave you can to remain!


Scandal-hit interest rate benchmark Libor will be phased out as the main index in the market by the end of 2021, the Financial Conduct Authority's chief Andrew Bailey has announced.
Libor is supposed to indicate the prevailing interest rate at which banks will lend to each other in different currencies and over varying time periods.
In practice, however, few banks lend to other banks for long periods of time and so the index is made up of hypothetical numbers proposed by the participating banks, with an oversight panel checking up on their estimates.


I am a Payoneer Card and Virtual US Account holder and get payments from some websites and also from my clients using private payments.
I am also working with Chitika.com. Chitika is a famous Ad serving company for website publishers and have a huge network of members. Currently Chitika is only offering PAYPAL and CHECK option.
I have also requested Chitika to contact with you. They said that they will look into this matter. But I cannot see any progress in this matter.
Thanks for posting! We'll certainly reach out to them and see if we can establish a partnership in the future.
I would love to see Chitika payment method via Payoneer. Please contact chitika payment department and establish a partnership ASAP.


text:
'Slow and painful contraction' forecast for UK jobs market
By Maximilian Clarke
The UK jobs market is heading for a "slow and painful contraction", the Chartered Institute of Personnel Development (CIPD) concluded in their latest jobs report.
Organisations are planning to scale back all employment-related operations, including hiring, redundancies, offshoring and overseas recruitment as UK's employment situation deteriorates further in 2011.
The CIPD's Labour Market Outlook employment index - which measures the difference between the number of employers intending to increase total staffing levels and the proportion planning to decrease them — fell to -3 from -1 in the past three months. This was the second successive quarterly fall and the lowest net balance since last winter.
The private-sector looked set to grow in the next three months (+20), but at a slower pace than in recent quarters, found the study. Confidence in the public-sector remained low (-50) for the next three months, and was even more subdued for the year ahead (-57). Meanwhile, the voluntary sector saw no movement in net employment intentions for the fourth quarter of 2011, remaining at +7.
The CIPD said employers appeared to be "hedging their bets" on all employment-related decisions in response to the current economic uncertainty, with both hiring intentions and redundancy intentions down across all sectors compared with recent previous reports.
Gerwyn Davies, public policy adviser at the CIPD, said there was no immediate sign of UK labour market conditions improving in the short or medium term.
"The figures point to a slow, painful contraction in the jobs market," warned Davies. "Many firms appear to be locked in 'wait and see' mode, with some companies scaling back on all employment decisions against a backdrop of increasing uncertainty as a result of the eurozone crisis and wider global economic turmoil.
"The good news resulting from this lull in business activity is that fewer employers are looking to relocate abroad or make redundancies," he continued. "The downside is that recruitment intentions are falling, which will make further rises in unemployment therefore seem inevitable given that public-sector job losses are outpacing the predictions made by the Office for Budget Responsibility."
The proportion of firms intending to hire migrant workers - which has risen steadily in recent consecutive quarters - also fell to 19 per cent from 25 per cent during the past three months.
The number of firms planning to offshore jobs to other parts of the world also decreased to 6 per cent from 10 per cent in the past year. India remained the most popular destination for offshoring, with half of the employers surveyed by YouGov planning to locate some or all of their operations in India. The functions most likely to be offshored were finance and accounts and IT support.


There are 107 Contractors in Kokomo, IN. Below is a list of the 10 most popular Contractors on All contractors & builders. Are you looking for a Contractor specialized in a specific contractor job? Refine your search by selecting a contractor job.
All contractors & builders is one of the worlds largest Contractor directories listing a total of 107 Contractors in Kokomo, Indiana.
Each Kokomo Contractor profile covers office location, office hours, contact details, area of practice, education, client recommendations, Contractor biography and more.
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