text:
\section{Introduction}

The study of the Narrow Line Region (NLR) in Seyfert galaxies is
contributing substantially to the understanding of the central engine
of active galaxies. Of particular interest is the apparent close
association between radio continuum and optical line emission in this
region, which has a typical extent of 0.1-1\,kpc. The link between
optical and radio emission in the NLR manifests itself most
prominently in a positional association between linear radio
structures and optical line emission as well as in a correlation
between line width and radio power (Wilson and Willis 1980, Whittle
1985). It is widely accepted that the radio emission is related to the
outflow of relativistic plasma from the core of the galaxy. As is
found in higher power radio galaxies and quasars, this outflow appears
to be highly collimated into jets. The radio-optical association
suggests that the interaction of the jets with the interstellar medium
(ISM) strongly influences the dynamics of the ionized gas in the
NLR\@. It can be hoped that the study of this interaction will reveal
important information on the physical conditions of the gas in the NLR
and in the plasma jets.

The expansion of the cocoons of large scale extragalactic jets in
radio galaxies has been examined analytically by Scheuer (1974) and
Begelman and Cioffi (1989) and numerically by Cioffi and Blondin
(1992).  Blandford and K\"{o}nigl (1979) first suggested that the
interaction of jets with BLR clouds could cause the radio emission and
the associated kinematics of the BLR\@. The observation of symmetric
double or triple radio sources associated with emission line gas in
the NLR of a number of Seyfert galaxies (in particular in NGC\,5929,
Haniff, Wilson and Ward 1988, Su {et al.\,} 1996, and NGC\,1068, Wilson and
Ulvestad 1987, Gallimore {et al.\,} 1996) led to the development of more
detailed models invoking the interaction of plasmons or jets with the
local ISM\@. Pedlar {et al.\,}\ (1985) proposed an expanding plasmon model
for the NLR\@. They suggested that a high pressure relativistic plasma
bubble expands and drives a shock wave sweeping up the surrounding
ISM.

Whittle {et al.\,}\ (1986) found a spatial separation of
$0.95\pm0.11$\arcsec\ between the peaks of the [O\,{\sc iii}] 5007-\AA\  components in
high dispersion spectroscopic observations. This separation is
significantly smaller than the measured distance between the radio
components. Based on these observations, Pedlar {et al.\,} (1987) proposed
a variant of the plasmon model similar to the radiative
bowshock model suggested earlier by Wilson \& Ulvestad (1987) for the
radio structure observed in NGC\,1068.  This model explains the
difference in the spatial separation between the peaks of the radio
and the optical components. It invokes a supersonic motion of a jet or
plasmon inducing a bowshock in the ambient medium. In the frame of the
head of the bowshock, the shocked ISM gas then moves along its
surface. All the basic properties of an expanding plasmon model are
still applicable, but, in addition, the cooling time of the gas behind
the bowshock allows the gas to flow a significant distance from the
vertex before cooling to a temperature sufficiently low ($\sim 10^4$
K) that optical lines are emitted. Since the radio emission is
expected to peak at the vertex, there will be a difference in the peak
positions of the optical and the radio emission. This model was
further developed by Taylor {et al.\,} (1989, 1992) and Ferruit {et al.\,}
(1996).

Recent Hubble Space Telescope (e.g. Capetti {et al.\,} 1995a,b; Bower {et al.\,}
1994, 1995) and MERLIN observations (Pedlar {et al.\,} 1993; Kukula {et al.\,}
1996) revealed overwhelming new structure in the NLR of several
Seyfert galaxies with radio jets. Discrete clouds and diffuse line
emission are found to be closely aligned with highly structured and
sometimes distorted radio jets.  These observations clearly show that
the idea of a radio jet interacting with the NLR can account for
basic features of these jets. However, the phenomena are far more
complicated than can be accounted for by the simple geometric bowshock
model.  The full non-stationary character of the interaction between a
jet and its environment has to be taken into account to explain the
newly observed features.

In this paper, we therefore apply high resolution axisymmetric
hydrodynamic simulations to explore the time dependent interaction of
Seyfert jets with the NLR\@. We demonstrate that the association
between the radio and optical emission can be explained as a natural
consequence of the expansion of a hot jet cocoon into the interstellar
medium creating an envelope of dense cool gas and discrete emission
line knots which can be associated with the narrow-line clouds
themselves.  We compare our model with observations of the NLR
H$\alpha$\ emission in MKN~1066, which has a similar linear extension
(Bower {et al.\,} 1995).

In Section \ref{analytic.sec} we estimate the properties of our cocoon
shock model analytically.  The numerical procedure of the simulations
is briefly described in Section
\ref{simulation.sec}.  Section \ref{results.sec} contains the results
and their discussion. We summarize our conclusions in Section
\ref{conclusions.sec}.

\section{Analytical estimates}
\label{analytic.sec}

We consider the dense optically emitting envelope of swept-up ISM gas
around the cocoon of a supersonic jet propagating into a uniform,
ionized medium. The ionization is assumed to be due to photoionization
from a UV source at the active nucleus of the galaxy. For a
UV photon rate $S\sim 10^{52}{\rm s^{-1}}$ similar to the one in NGC5929
(Bower {et al.\,} 1995) and an ambient density of 1\,cm$^{-1}$ the radius of
the Str\"omgren sphere is 700\,pc, which is well beyond the distances
we consider in this paper. For an estimate of the initial conditions
in a simulation which can be compared with typical observations, we
assume that the envelope is a thin cylindrical shell of radius $r_{\rm c}
\sim$ 20\,pc, length $l_{\rm c}$ = 150\,pc,
H$\alpha$\ luminosity $L_{\rm H\alpha} = 10^{37}-10^{39}$erg\,s$^{-1}$, and
a thickness $d_{\rm c} \ll r_{\rm c}$. Within our model the spectral line width
in the NLR will be similar to twice the cocoon expansion speed, if
observed from a direction perpendicular to the jet axis. We
therefore have typical shock velocities of 100--200\,{\rm\ km\ s}$^{-1}$
(e.g. MKN\,1066, Bower {et al.\,} 1995).  In the following, we estimate
some characteristic quantities, such as the density $n_0$ of the ambient
ISM, the density $n_{\rm c}$ and thickness $d_{\rm c}$ of the dense cool
envelope, using this range of observed sizes and luminosities.

\subsection{Non-magnetic case}
\label{non-magnetic.sec}

We first assume that there is no magnetic field in the environment
which could limit the compression at the shock, which is driven
perpendicularly to the jet axis into the ISM by the overpressured
cocoon. We further assume that the shock is isothermal, at the
temperature $T_0 = 10^4$K of the pre-shock gas. This assumption
is justified by estimating the cooling distance $\delta$
behind a shock of speed $v_{\rm s} = $ 150{\rm\ km\ s}$^{-1}$\ in typical environmental gas
with a hydrogen density of $n_0 = $1{\rm\ cm}$^{-3}$, using the adiabatic
compression factor of 4. We then have (Taylor, Dyson and Axon 1992)
\begin{equation}
\label{dcool.eq}
\delta = \frac{\bar{m} v_{\rm s} k T_{\rm s}^{(1-\alpha)}}{4 m_{\rm p} n_0 \Lambda_0},
\end{equation}
where we use a power-law cooling function of the form
\begin{equation}
\label{fcool.eq}
\Lambda (T_{\rm s}) = \Lambda_0 T_{\rm s}^\alpha
\end{equation}
with $\Lambda_0 = 4.6 \cdot 10^{-18} {\rm erg\,s}^{-1}{\rm cm^3}$ and
$\alpha=-0.76$ at $T > 1.5 \cdot 10^5$K.  The
temperature $T_s$ immediately behind the shock is given by
\begin{equation}
\label{shocktemp.eq}
T_{\rm s} = \frac{3}{16} \frac{\bar{m}}{k} v_{\rm s}^2,
\end{equation}
where $\bar{m}$ is the mean molecular weight and $k$ is the Boltzmann
constant (we assume $\bar{m} =0.5 m_{\rm p}$, $m_{\rm p}$ is the proton mass).
The cooling distance perpendicular to the shock is then $\delta =
1.8{\times} 10^{17}$~cm or 0.06~pc with corresponding postshock temperature
of $T_{\rm s} = 2.5{\times} 10^5$~K. For $v_{\rm s}$=100 (200)\,{\rm\ km\ s}$^{-1}$\ the cooling
distance will be 2.2 (3.7) times smaller (larger) than for
$v_{\rm s}$=150\,{\rm\ km\ s}$^{-1}$. All these values are much smaller than the radius
$r_{\rm c}\sim 20$pc of the cocoon, justifying the assumption of an
isothermal shock for the estimates.

We now calculate the density $n_{\rm c}$ and thickness $d_{\rm c}$ of the compressed
postshock layer of gas and the density of the environmental gas $n_0$. We
start with the compression ratio of the isothermal shock, which is
\begin{equation}
\label{f1.eq}
f = \frac{n_{\rm c}}{n_0}
  = \frac{\bar{m} v_{\rm s}^2}{kT_0}
  = 120 \, \frac{\bar{m}}{m_{\rm p}}
        \left(\frac{T_0}{10^4{\rm K}}\right)^{-1}
        \left(\frac{v_{\rm s}}{100\,{\rm km\,s^{-1}}}\right)^2
\end{equation}
In terms of the volumes of the cylindrical cocoon
$V_{\rm z}$ and the cylindrical shell of swept up gas around the cocoon
$V_{\rm c}$ we also have
\begin{equation}
\label{f2.eq}
f = \frac{V_{\rm z}}{V_{\rm c}}
  = \frac{\pi r_{\rm c}^2 l_{\rm c}}{2\pi r_{\rm c} d_{\rm c} l_{\rm c}}
  = \frac{r_{\rm c}}{2 d_{\rm c}}.
\end{equation}
Combining equations (\ref{f1.eq}) and (\ref{f2.eq}) we find the
thickness of the layer of swept up gas to be
\begin{eqnarray}
\label{dc.eq}
d_{\rm c} &=& \frac{r_{\rm c}}{2} \frac{kT_0}{\bar{m} v_{\rm s}^2} \nonumber \\
    &=& 0.083 \,{\rm pc} \,\frac{\bar{m}}{m_{\rm p}}
                     \left(\frac{r_{\rm c}}{{20 \rm pc}}\right)
                     \left(\frac{T_0}{10^4{\rm K}}\right)
        \left(\frac{v_{\rm s}}{100\,{\rm km s^{-1}}}\right)^{-2}
\end{eqnarray}
Assuming pure hydrogen gas of uniform density, the H$\alpha$\ luminosity of this
layer will be
\begin{eqnarray}
L_{\rm H\alpha} &=& n_{\rm c}^2 \epsilon V_{\rm c} \nonumber \\
  &=& 3.7\x10^{38} {\rm erg\,s^{-1}}
      \left(\frac{n_{\rm c}}{100 {\rm cm^{-3}}}\right)^2
      \left(\frac{V_{\rm c}}{10^{59} {\rm cm^3}}\right)
\end{eqnarray}
where $\epsilon=3.8{\times} 10^{-25}{\rm erg cm^3 s^{-1}}$ is the H$\alpha$\
emission coefficient at $T_0$ (see Section \ref{optical.sec}).

The total mass swept up from the environment into the shell is
\begin{equation}
\label{M.eq}
M = n_{\rm c} m_{\rm p} V_{\rm c} = 8300 {\rm M_\odot}
        \left(\frac{n_{\rm c}}{100 {\rm cm^{-3}}}\right)
        \left(\frac{V_{\rm c}}{10^{59} {\rm cm^3}}\right)
\end{equation}
We assume full ionization of the gas in the NLR\@. A column of swept up
hydrogen gas of density $n_{\rm c}$ at a distance $l_{\rm c}$ from the ionizing photon
source with a photon flux $S$ will stay fully ionized up to a thickness \\
\begin{equation}
d_{\rm s} = 1.1{\rm pc}
        \left(\frac{n_{\rm c}}{100 {\rm cm^{-3}}}\right)^{-2}
        \left(\frac{l_{\rm c}}{100 {\rm pc}}\right)^{-2}
        \left(\frac{S}{10^{52} {\rm s^{-1}}}\right)
\label{stroem.eq}
\end{equation}
assuming that no photons are intercepted on their way to the cloud.

In Section \ref{results.sec} we compare
these analytic estimates with the results from our simulation.

\subsection{Magnetic case}
\label{magnetic.sec}

We now consider the case where the undisturbed environment
is threaded by a random magnetic field, assuming
the components in the plane of the shock will be compressed
with the field lines frozen into the gas. The effect of the magnetic
field will be to limit the compression of the shocked gas when the magnetic
pressure equals the thermal pressure. The compression
factor $f_m$ is then given by (e.g. Dopita and Sutherland 1995):
\begin{eqnarray}
f_m &=& \frac{n_{cm}}{n_{0m}}
     =  \frac{(8\pi\bar{m})^{1/2} v_s}{B_{\parallel} n_{0m}^{-1/2}} \nonumber \\
    &=& 64 \frac{\bar{m}}{m_{\rm p}}
           \left(\frac{v_{\rm s}}{100\,{\rm km\,s^{-1}}}\right)
           \left(\frac{B_{\parallel} n_{0m}^{-1/2}}{{\rm \mu G\,cm^{-3/2}}}\right)
\label{fm.eq}
\end{eqnarray}
The thickness of the shocked gas layer is then
\begin{eqnarray}
d_{\rm cm} &=& \frac{r_{\rm c}}{2 v_{\rm c}}\frac{B_{\parallel}
               n_{\rm 0m}^{-1/2}}{(8\pi\bar{m})^{1/2}} \nonumber \\
    &=& 0.15\,{\rm pc} \,\, \bar{m} m_{\rm p}^{-3/2}
        \left(\frac{r_{\rm c}}{{20 \rm pc}}\right)
        \left(\frac{v_{\rm s}}{100\,{\rm km\,s^{-1}}}\right)^{-1} \nonumber\\
    &&\left(\frac{B_{\parallel}
     n_{{\rm 0m}}^{-1/2}}{{\rm \mu G\,cm^{-3/2}}}\right)
.
\label{dcm.eq}
\end{eqnarray}
Values of the magnetic parameter
$(B_{\parallel} n_{{\rm 0m}}^{-1/2})/({\rm \mu G\, cm^{-3/2}})$ are of order 1,
in the range 1-10 (Dopita \& Sutherland, 1995).

Due to the additional magnetic pressure, the thickness of the cold
envelope will be larger and the density lower than in the non-magnetic
case. Since the optical line emission depends on the square of the
density, the emission received from a strongly magnetized envelope
will be considerably lower than  that coming from a non-magnetic envelope.

\section{Numerical simulation}
\label{simulation.sec}

\subsection{Initial conditions}
\label{initcond.sec}

The determination of jet parameters like plasma speed and density is a
classical and basically unsolved problem in extragalactic
astrophysics. For the purpose of simulating the the expanding
envelope, the exact values of the jet speed and density input
parameters are not important.  The expansion of the cocoon shock is
principally determined by the cocoon pressure, and a given pressure
can be obtained from a range of jet parameters. For practical purposes
this range of parameters is also somewhat restricted by the available
computing resources. We therefore performed a small series of test
runs varying the particle density in the ISM around 1{\rm\ cm}$^{-3}$, jet
velocities around 10$^4$\,{\rm\ km\ s}$^{-1}$ (Bicknell {et al.\,} 1990) and Mach
numbers around 10. A Mach number higher than 5 is required for a jet
with a noticeable cocoon (Norman, Smarr and Winkler 1985). From these
tests we chose a set of parameters which compares well with the
observations of Seyfert galaxies given in Section
\ref{analytic.sec} (in particular MKN\,1066) and which illustrates
best the qualitative features of the formation and structure of the
dense cocoon envelope. A more detailed account on the influence of
varying the parameters will be given in a forthcoming paper (Steffen
{et al.\,}, in preparation). The chosen parameters are:

\begin{eqnarray}
n_0 &=& 1.5 {\rm\ cm}^{-3} \nonumber\\
T_0 &=& 10^4 {\rm K} \nonumber\\
n_j &=& 0.18 {\rm\ cm}^{-3} \nonumber\\
M_j &=& 8.3 \nonumber\\
v_j &=& 6.8{\times} 10^8 {\rm\ cm~s}^{-1} \nonumber\\
r_j &=& 5.3{\times} 10^{18} {\rm cm} \nonumber
\end{eqnarray}

This yields a jet mechanical luminosity of $L_j = 2\times 10^{39}
{\rm erg\,s^{-1}}$.

\subsection{Scaling and similarity}
\label{scaling}

In the absence of cooling, the jet will be evolve in a self-similar
fashion
\begin{equation}
l_c = {\cal A}\left(L_j t^3\over\bar{m} n_0\right)^{1/5}
\label{e:self}
\end{equation}
with ${\cal A} \simeq 1$, once $l_c \gg (n_j/n_e)^{1/2} r_j =
2\ee{18}{\rm\,cm}$ (Falle 1991).

Cooling will begin to have an effect when the advance speed of the
outer shock at the base of the jet is roughly $100{\rm\,km\,s^{-1}}$
(Dyson 1984), that is roughly when $l_c = l_{\rm cool} =
6\ee{19}{\rm\,cm}$, if the aspect ratio of the jet is ${\cal R} =
l_c/r_c = 5$.  Thus, for our typical parameters, the jet will be self
similar before cooling becomes important (neglecting the effects of
turbulence in the jet).

Once cooling becomes non-negligible, self-similarity no longer holds
but the evolution of jets with different parameters will be similar to
each other, if times are scaled to the time at which the gas begins to
cool, and distances are scaled to the length of the jet at this time.
For the cooling law, equation (2), the lengths will scale as
\begin{eqnarray}
l_{\rm cool} &\simeq& 6\ee{19}{\rm\,cm}
\left(L_j\over2\ee{39}{\rm\,erg\,s^{-1}}\right)^{(3-2\alpha)/(9-4\alpha)}
\nonumber \\
&&\cdot \left(n_0\over1.5{\rm\,cm^{-3}}\right)^{-(6-2\alpha)/(9-4\alpha)}
\end{eqnarray}
and the times as
\begin{eqnarray}
t_{\rm cool} &\simeq& 6\ee{11}{\rm\,s}
\left(L_j\over2\ee{39}{\rm\,erg\,s^{-1}}\right)^{(2-2\alpha)/(9-4\alpha)}
\nonumber \\
&&\cdot \left(n_0\over1.5{\rm\,cm^{-3}}\right)^{-(7-2\alpha)/(9-4\alpha)}.
\end{eqnarray}
If the jet power is doubled, the timescales will increase by 22 per
cent and the lengthscales by 30 per cent, while if the ambient density
is doubled the lengthscales will decrease by 35 percent and the
timescales by nearly 40 per cent.

Once the cooling becomes rapid at the head of the jet, when $l_c
\simeq {\cal R}^{3/2} l_{\rm cool}$, the global evolution of the jet
will enter a second self-similar regime with its evolution varying
according to equation~(\ref{e:self}), only with a rather smaller
constant of proportionality.

\subsection{The hydrodynamic code}
\label{code}

We used the adaptive grid hydrodynamic code described by Biro {et al.\,}
(1995) in axisymmetric mode.  It solves the equations of mass,
momentum and energy conservation using a flux-vector-splitting
scheme. The computation was carried out in a 5-level, binary adaptive
grid. In our simulations we assume full ionization of the jet and
ambient medium due to photoionization from the central
UV source. We use the non-equilibrium cooling function described by
Biro {et al.\,} (1995) with an additional term taking into account
bremsstrahlung losses, $L_b$, given by
\begin{equation}
\label{bems.eq}
L_b = 2.29\x10^{-27} n_e n_p T_e^{\frac{1}{2}}\ {\rm erg\,s^{-1}~cm^{-3}}
\end{equation}
where $n_e$ and $n_p$ are the electron and proton densities in
particles per cm$^{3}$, respectively, and $T_e$ is the electron
temperature in Kelvin (Cox \& Tucker 1969).
We do not allow the gas temperature to drop below $10^4$~K, where we
assume it is maintained by the thermostat effect of [O\,{\sc iii}] 5007-\AA\  emission.

The computational domain was set to be 513x1025 computational cells
and $5{\times} 1.25$ times $10^{20}$cm. The grid cells are smaller in radial
direction than in axial direction for better resolution of the small
distance scales of the radially expanding envelope. The initial jet
radius was covered by 27 cells in the axisymmetric simulation. The
cooling distance $\delta$ was marginally resolved for $v_s = 150${\rm\ km\ s}$^{-1}$.
The thickness $d_{\rm c}$ of the cold envelope of swept up gas was near the
resolution limit and was smeared out artificially over 2-3 cells at
shock speeds higher than 150{\rm\ km\ s}$^{-1}$.  This artificially limits the
compression with effects similar to those expected if magnetic fields
in the ISM were present (with a magnetic parameter of the order of 5,
although magnetic fields were not taken into account
explicitly). However, increasing the resolution further would lead to
prohibitively large computing times for these initial
studies. Quantitative results will therefore be only order of
magnitude estimates, but the qualitative results, as discussed in this
paper, will not be significantly altered. The boundary conditions are
reflective on the axis and on the left side of the computational
domain (except for the inflow condition where the jet is injected, see
Fig.\,\ref{dp.fig}). The top and right boundaries have outflow
conditions.

\subsection{Emission maps}
\label{emission.sec}

\subsubsection{Optical emission}
\label{optical.sec}

We calculate the H$\alpha$\ emissivity $\epsilon$ using radiative
recombination (Case B) following Aller (1984).  In the temperature
regime of our simulations ($T>10^4$K) only recombination contributes
considerably to the emissivity.
We assume full ionization of the
hydrogen, which would mainly be due to photoionization from the UV
source at the centre of the galaxy and, to some extend, from shock
ionization in the bowshock region.
\begin{equation}
\epsilon = 4.16\times 10^{-25} {\rm erg\,cm^3\,s^{-1}}
           (T_4^{0.983} 10^{0.0424/T_4})^{-1}
\end{equation}
where $T_4$ is the temperature in units of $10^4$K.

\subsubsection{Radio emission}
\label{radio.sec}

  Only relativistic electrons (and perhaps positrons) contribute
significantly to the radio emission of jets. Since it is still unclear
how these high energy electrons are generated (most probably through
re-acceleration in shocks), we assume that this population of fast
electrons shares the same hydrodynamics as the non-relativistic fluid
of electrons and protons. A more detailed description would require
the consideration of two jet populations to account for the
non-relativistic gas (electrons and protons) with ratio of specific
heats of 5/3, and the ultrarelativistic electrons with ratio of 4/3.
Duncan, Hughes, Opperman (1996) have performed preliminary simulations
of highly relativisitic jets using a variable adiabatic index and
found that the rest frame variables vary smoother along the jet axis,
with smaller amplitude maxima at the bowshock, and in the vecinity of
the contact surface. We ignore these effects in the present simulations.

  In order to calculate the synchrotron emission from the jet whose
hydrodynamics is modeled as above, we need to establish how the internal
energy is distributed among the relativistic electrons. Observations suggest
that this distribution follows the usual power law $N(E) \, {\rm d}E = N_o
E^{-p} {\rm d}E$, with spectral index $p$, and energies above a minimum value
$E_{\rm min}$. Assuming that the relativistic electron energy density ${\cal
U}$, and number density ${\cal N}$ are proportional to their corresponding
thermal quantities calculated by the hydrodynamical code as a function of
position in the jet, the previous power law is determined by the equations
(G\'omez et al. 1995)
\begin{equation}
\label{ncero}
N_o = \left[{\cal U} \:
(p\!-\!2)\right]^{p-1}
\left[{\cal N}\:(p\!-\!1)\right]^{p-2}
\end{equation}
and
\begin{equation}
\label{emin}
E_{\rm min} = \frac{\cal U}{\cal N}\:\:
\frac{p\!-\!2}{p\!-\!1} ,
\end{equation}

The synchrotron emission is also determined by the magnetic field, and since
we are neglecting its influence on the fluid dynamics, we assume that the
magnetic energy density remains a fixed fraction of the particle energy
density, which leads to a field of magnitude proportional to ${\cal U}^{1/2}$.
We refer the reader to G\'omez et al. (1993, 1995) for a detailed
discussion of the radio emission calculations.

\section{Results and Discussion}
\label{results.sec}

\subsection{Structure}
\label{structure.sec}

We show the results of our simulation at a time when the jet has
reached a distance of approximately 150~pc from the injection point.
This is 127\,000 years after the jet switched on.

Fig.\,\ref{dp.fig} shows the density (top) and the pressure (bottom)
distribution on a logarithmic scale.  We can identify several
characteristic features which are marked in the schematic view shown
in Fig.\,\ref{jetscheme.fig}. The jet itself shows several
recollimation shocks on the axis, best seen in the pressure image. At
the tip of the jet, the termination shock generates high pressure
and high temperature jet plasma. This plasma flows back into the hot
jet cocoon, which surrounds the high speed jet. The jet cocoon is
surrounded by a thick layer of hot gas from the
interstellar medium which has passed through the bowshock. Near the head
of the jet we find a thin layer of hot shocked gas from the ISM which
further back turns into an even thinner, but cold and very dense
envelope of the jet cocoon.  This envelope is what distinguishes the
NLR jet from adiabatic high power extragalactic jets.
The fact that this envelope starts at a significant distance from the front
of the bowshock distinguishes NLR jets from the regime of strongly
cooling galactic jets (e.g. Blondin, Fryxell and K\"onigl 1990).

We find that the radius of the cold envelope in the simulation is
approximately $7.8\times 10^{19}{\rm cm}$ and the expansion speed of
the cocoon is somewhat above 100~{\rm\ km\ s}$^{-1}$. The peak density in the
envelope varies from values between 30 to 40 cm$^{-3}$ over most of
its extent, up to 100 cm$^{-3}$ in the dense clouds. This
corresponds to compression factor of 30 and 70, respectively. This is
factors of 2 too low compared to Eq.\,(\ref{f1.eq}), which is
probably due to numerical smearing. This effect
mimics a magnetic parameter of the order of 5 (see Eq.\,\ref{dcm.eq}),
which corresponds to a ambient magnetic field near $5\mu G$.  The
integrated H$\alpha$\ luminosity at this timestep is $5.8{\times} 10^{37} {\rm erg\,
s^{-1}}$ and the envelope has a thickness of $d_{\rm c} \sim 1-2\x10^{18}$\,cm
and volume of $V_{\rm c} \sim 2{\times} 10^{59} {\rm cm^3}$.  These values are
in good agreement with our analytical estimates and the results from
optical observations of Seyfert galaxies with associated NLR radio
jets.

We find that the non-stationary dynamics of jet propagation
through interstellar medium have a strong influence on the structure
of the cold shell. The quasi-periodic recollimations of the jet cause
the advance speed of the jet head to oscillate, thereby accumulating
jet material in a restricted nose region for some period of time. It
is then released into the cocoon almost explosively, when the jet
expands and slows down again.  This imposes a characteristic arc
structure onto the bowshock and the cold shell of swept up gas. These
arcs cool almost as a unity once catastrophic cooling sets in. This
can be seen in Fig.\ref{collapse.fig}, where the density is shown at
three different times with the same separation between them. While the
head of the jet has advanced considerably between the first and second
panel, the point where the cold dense envelope starts has not advanced
appreciably. However, later, after the same timestep, the full arc has
cooled. Therefore, a cooling distance for the bowshock measured
from the head of the jet, as  discussed by Taylor {et al.\,} (1989, 1992),
can at best be only an average property.

At the positions where neighbouring arcs meet, the two shock waves
cross at an angle near 90$^\circ$. This interaction will produce a Mach
shock at the vertex with an effective speed of
$\sqrt{2}$ times the speeds of the incident shocks (supposing that
they are the same). Correspondingly, the compression and the
emissivity of the gas increase by factors of $\sim 2$ and $\sim 4$,
respectively.  As a result of the radiative nature of the crossing
shocks they merge to form short high density filaments and clouds,
marked as ``high density spots'' and ``intruding dense filaments'' in
Fig.\,\ref{jetscheme.fig}. In the simulation the spots have peak
densities between 80 and 100{\rm\ cm}$^{-3}$, consistent with the previously
estimated additional compression by factors around 2. We suggest that
these spots could be identified with the brightest discrete clouds in
the NLR of some Seyfert galaxies. Note that the spacing between these
spots is directly related to the time dependent quasi-periodic
recollimation of the jet and therefore contains information about the
history of the interaction between the jet and its
environment. Several Seyfert galaxies show a knotty NLR structure and
the distances between the strongest emission line clouds is indeed
similar but rather smaller than the distances between the radio knots
(e.g. MKN~3, Capetti {et al.\,} 1995a; MKN~6, Capetti {et al.\,} 1995b;
NGC~4151, Boksenberg {et al.\,} 1995).

At some distance from the jet head the arc structure in the
envelope is lost and it becomes roughly cylindrical justifying the
approximations of Section \ref{analytic.sec}
(Fig.\ref{dp.fig}). However, the high density clouds and filaments
created at the intersection points of these arcs are retained. When
the envelope fragments (as can be expected in a full three dimensional
simulation) these regions will be seen as discrete NLR clouds and
filaments. Since the creation of these arcs and clouds is related to
the recollimations of the jet, we have found a direct relation between
the optical structure of the NLR and the internal non-stationary shock
structure of the jet.

The expansion of the overpressured jet cocoon into the undisturbed
interstellar medium is similar to a supernova explosion. Some
theoretical aspects can therefore be treated in an analogous
fashion. This applies in particular to the stability of the shock and
the postshock layer of swept up gas. The stability of radiative shock
wave has been considered by a number authors with varying emphasis
(e.g. Vishniac 1983, Bertschinger 1986).  The radiative shock
instabilities discussed by Bertschinger (1986) are present in our
simulations and produce the pressure variations near the cold
envelope. These are likely to be disruptive and thus contribute to the
formation of NLR clouds and filaments. From the results presented by
Jun, Norman and Stone (1995) it can be expected that the shock region
in our simulation is also Rayleigh-Taylor (R-T) unstable, with fastest
growth of features on the scale of the thickness of the cold layer of
swept up gas.The onset of these instabilities can be observed as
pressure variations and small ripples in some sections of the cold
envelope (Fig.\ref{dp.fig}). As these instabilities grow, they might
contribute to the fragmentation process of the envelope and form
further NLR clouds, in addition to the high density clouds produce at
the intersection of the arcs discussed in the previous
section. However, magnetic fields have a stabilizing effect and
therefore different combinations of ambient magnetic parameters and
jet powers might lead to two categories of evolved cocoon envelopes:
R-T stable narrow line regions with fewer small clouds and R-T
unstable ones with a high number of small NLR clouds with separations
of a few times the thickness of the cold layer (i.e.  $\sim$
1\,pc). More detailed investigations of this process will have to be
carried out to quantify this prediction over a range of parameters in
order to compare it with recent and future high resolution
observations of the NLR in Seyfert galaxies.

The Str\"omgren column given by Eq.(\ref{stroem.eq}) is similar to the
thickness of the cocoon envelope and the size of the clouds. It may
well be that the highest density clouds can develope neutral cloud cores.
As a result, NLR clouds could be sites of jet induced star formation
(Van Breugel and Dey 1993, Tresch-Fienberg {et al.\,}\ 1987).

\subsection{Emission}
\label{emission_res.sec}

In Fig.\ref{ha.fig} the H$\alpha$\ emissivity distribution is displayed on a
logarithmic along with the radio
emission superimposed as contours in the lower panel.  As expected,
most of the optical line emission comes from the thin envelope of cold
postshock material. The H$\alpha$\ luminosity obtained from this
axisymmetric simulation is $5.8\times10^{37} {\rm erg\,s^{-1}}$. This
is well within our expectations considering the simplicity of our
analytical estimates. The length of the NLR jet in MKN~1066 is similar
to that in our simulation, although the transverse extent
could be 2-3 times smaller. From observations by Bower {et al.\,}
(1995) we determined the H$\alpha$\ flux coming from the area covered by the
NE jet in MKN~1066 to be $3.3\times10^{37} {\rm erg\, s^{-1}}$, which
is in excellent agreement with our simulation, taking into account the
the simplifications of the model and the smaller radius of the cocoon
in MKN~1066.

>From our model it can be expected that higher power radio jets yield
faster cocoon shocks, producing broader emission lines. This will
result in a correlation between line width and radio power, which is
consistent with the observed correlation between these quantities
(Wilson and Willis 1980, Whittle 1985). Our initial study does,
however, not allow a more quantitative conclusion about the
correlation. An extensive survey of the parameter space and other
factors which influence the line width, like galaxy rotation, is
needed for a detailed theoretical study of this correlation in terms
of our model.

The calculated line spectrum is shown in Fig.\ref{spec.fig} for three
different viewing angles. In the spectrum, emission from the
background has not been included in order to focus on the expanding
envelope. Inclusion of the background would produce a narrow peak at zero
velocity.  Within the volume of this simulation the background
emission amounts to $4.8\times 10^{36} {\rm erg\,s^{-1}}$, an order of
magnitude less than contained in the envelope. The strength of this
central peak, compared to the broader contribution from the
envelope, is a measure of the ratio of disturbed and
undisturbed gas.  Because of the cylindrical shape of the expanding
envelope and the small velocity of the gas along the shell, the line
shape of the envelope is double peaked for viewing angles far from the
axis but becomes almost rectangular if the line of sight is near the
jet axis. The line width of the expanding cylindrical shell is, of
course, not only a function of the expansion speed (which is
approximately the same as the shock speed), but depends also on the
angle between the symmetry axis and the line of sight. This is in
apparent disagreement with results from Whittle (1985), which suggest
that there is no strong correlation between the orientation of the
galaxy and the NLR line width, assuming that the jet follows the
rotation axis of the galaxy.  However, observations of radiation cones
(e.g. Wilson and Tsvetanov 1994), which at least can be expected to
have a closer link to the radio jets, and point symmetric bending of
jets in Seyferts (presumably as a result of the interaction with the
rotating environment, Wilson and Ulvestad 1982, Steffen {et al.\,}\ 1996)
suggest that the jets often are not aligned with the rotational axis
of the galaxies. This would strongly weaken any correlation between
line width and galaxy rotation.

The contours in Fig.\ref{ha.fig} show the radio emission at 10~GHz as
calculated from our model described in Section \ref{radio.sec}. A
spectral index in the power law energy distribution of the electrons
of 2.4, and magnetic field strength at the jet inlet of 100$\mu{\rm
G}$ have been used. A total flux for the jet of 4 mJy is obtained. As
expected, most of the radio emission comes from the hotspot region
near the head of the jet, with some low brightness emission from the
recollimation shocks. There are a number of Seyfert jets in which the
the head of the jet is dominant at radio wavelength. However, in most
cases there are a number of strong radio knots along the jet. More so
in the case of NGC~1066, which has rather continuous emission along
the jet (at the resolution of the VLA) and no hot spot near the
head. This highlights the problem of the nature of the knots seen
along radio jets in general. Internal shocks can produce this kind of
knots. In our simulations we find two different types of internal
shocks: the recollimation shocks and the shocks produced by the
interaction with the turbulent cocoon near the head of the jet. From
our simulations and our model for the synchrotron emission we find
that these are not strong enough to explain the radio emission knots
seen in most of the Seyfert jets. One possible solution are time
variations of the ejection parameters at the base of the jet. G\'omez
et al (1996), Hughes, Duncan, and Mioduszewski (1996) and Komissarov
and Falle (1996) have shown that variations of the ejection velocity
can produce strong internal working surfaces which visible as strong
radio knots in the jet. Such variations in the jet properties possibly
have some influence on the structure of the cold cocoon envelope and thus
on the NLR. In a forthcoming paper we will investigate the effects of
variable jet properties on the NLR in more detail
(Steffen et al, in preparation).

\section{Conclusions}
\label{conclusions.sec}

Using hydrodynamic simulations with radiative cooling we confirm the
basic structure of the interaction between a jet and the NLR in
Seyfert galaxies as obtained in a geometric model by Taylor {et al.\,}
(1989).  However, we find new features of the interaction, like the
formation of NLR clouds and a larger extent of the cold cocoon
envelope.  Due to the time-dependent propagation speed of the jet into
the ISM, the cooling distance of the bowshock material as measured
from the head the jet varies episodically with time.  Our simulations show
that there might be a link between the time-dependent internal
recollimation structure of the radio jets and the narrow line
clouds. We expect that the distances between particularly bright knots
along the symmetry axis are similar to the separation between the
radio knots behind the main hotspot (assuming that the latter are due
to internal recollimation shocks). Estimates of the Str\"omgren column
show that the dense clouds produced in this simulation could be
partially neutral. They might represent cores for jet induced star
formation in the NLR of Seyfert galaxies.

\section{Acknowledgements}
We thank F. Kahn, J.E. Dyson, J. Meaburn, and D.J. Axon for useful
discussions. We also thank the referee S.A.E.G. Falle for useful
suggestions. WS, JLG and RJRW acknowledge the receipt of a PPARC
associateship. JLG also gratefully acknowledges a ``Contrato de
Reincorporaci\'on'' by the Spanish Ministry of Education.

redpajama_set_name: RedPajamaArXiv


Florida has been called the land of "newlyweds and nearly deads." The same has been applied to Hawaii, California, Atlantic City, and other places.
Far from being the land of the "newly wed and the nearly dead" as many comedians have described the state, Florida's immaculate climate has persuaded people from all over the US and the rest of the world to arrive in search of a subtropical paradise.
QUIET, PLEASE. By James Branch Cabell. 105 pp. A University of Florida Press Book. New York: Farrar, Straus & Young. $3.
Here is the home of newlyweds and the nearly-deads.
For some time there has been a local joke that Santa Monica is a city of the newly wed and nearly dead—and there appears to be more than a shred of truth in it.


text:
Collins told WKBW-TV that he has a concealed carry permit and will carry a firearm "from this day forward" when he's "out and about."
"On a rare occasion, I would have my gun in a glove box or something," Collins told the television station. "But it's going to be in my pocket from this day forward."
► Suspect killed after Scalise, others shot
► Alleged Scalise shooter raged on Facebook
► 'Like I was back in Iraq,' Ohio congressman says after colleague shot
A New York concealed carry permit holder would not be able to carry their firearm in Washington D.C., which does not recognize permits from other jurisdictions.
Five people were transported to a local hospital following the early Wednesday shooting, according to police in Alexandria, Virginia.
The suspected shooter ultimately died from his injuries, according to President Donald Trump.
No members of New York's Republican congressional delegation were believed to be at the baseball field at the time of the shooting. None of the state's nine Republican representatives is listed on the roster for the GOP team, which was practicing ahead of an annual charity game Thursday against Democrats.
A spokeswoman for Collins confirmed he was not at the field.
Collins is a strong supporter of Trump, often acting as a surrogate on national television to defend the president and his administration. He hails from one of the state's most conservative districts, which is home to counties in the rural areas between Rochester and Buffalo.
In a statement, Collins called Wednesday's attack "absolutely devastating."
"While it is apparent that the shooter was a zealot with an intention to cause harm, it is important that we all be cognizant that our words have strong meaning," he said. "It's time for all of us, including myself, to tone down our rhetoric and recognize that we are all of one country and all proud Americans."

redpajama_set_name: RedPajamaCommonCrawl


text:
Welcoming Groupon to the U.S. Pizza Team
Welcoming Groupon to the Team
Here at PMQ, we talk and think and write a lot about the U.S. Pizza Team. For us, it represents everything we love about pizzaioli and the pizza industry—the energy, the big-hearted warmth and earthy humor, the flair for innovation and, paradoxically, the passion for tradition. And the pizzas themselves—mamma mia, those pizzas!
For a decade and a half, team members have spread goodwill and scrumptiousness around the world, appearing on national TV, slinging dough for Regis and Kelly, marching in the Macy's Thanksgiving Day Parade. Little kids stop in their tracks and marvel, slack-jawed, at our dough spinners' deft moves. Members of the press can't get enough of their exquisitely tasty artisan pizzas prepared with black truffles, sopressata, quail eggs—I could go on and on, but I'm making myself hungry, and it's only 10 a.m.
Over the years, many wonderful sponsors have given generously to support the team in its endeavors, and we owe them a huge debt of gratitude. Now we're thrilled to welcome our first title sponsor, Groupon, whose name will heretofore grace the team's logo and whose support, we believe, will help raise the team's public profile and carry it to an entirely new level.
With the backing of this highly respected global brand, the Groupon U.S. Pizza Team will soon become a name that will resonate with the public. We also intend to expand our membership and attract even more talented pizza makers and dough spinning "pizzathletes" to qualifying events and international competitions.
We hope you'll join us in welcoming Groupon to the PMQ pizza family. You'll be hearing a lot about the Groupon U.S. Pizza Team in the next year! Come and take part in this new era, and help us make positive headlines in your town and all over the nation!
US Pizza Team
The U.S. Pizza Team Sweeps Spanish Pizza Championship
Simone Pizzuto Wins Gold in Sweden With Asian-Italian Inspired Pizza
Breaking News: U.S. Pizza Team's Scott Volpe Wins Gold Medal at World Pizza Championship
France's Top 10 Most Beautiful Pizzas
U.S. Pizza Team Winter Acrobatic Trials
PMQ International
Alfonso Monaco Takes First at the 4th Pizza d'Autores


text:
Terms: petrology -- equipment
Terms: Scientific Instruments -- Catalogue
Henry Wild, Ld., Heerbrugg, Switzerland (12)
Henry Wild Surveying Instruments Supply Co., Ltd., Heerbrugg, Sw (9)
E. Ducretet et Cie, Paris (7)
Cooke, Troughton & Simms Ltd., London (6)
Keuffel & Esser Co., New York and Hoboken, NJ (6)
Léon Laurent, Paris (5)
Elliott Brothers, London (4)
Aug. Bel & Co., London (3)
Daniel Davis, Boston (3)
The Ealing Corporation, Cambridge, MA (3)
Astronomical Observatory Prague - Podolf, Czechoslovakia (2)
C. L. Berger & Sons, Inc., Boston (2)
C. L. Berger and Sons, Boston (2)
Eingetragene Schutzmarke, Gehlberg, Germany (2)
Fauth & Co., Washington, DC (2)
Harvard University Library, Cambridge MA (2)
James J. Hicks, London (2)
New York University Press, New York (2)
Regal Art Press, Troy, NY (2)
T. S. & J. D. Negus, New York (2)
The Astragal Press, Mendham, NJ (2)
Troughton and Simms, London (2)
American institute of Mining Engineers, NY (1)
Annals of Science (1)
Anton Dohrn, Naples, Italy (1)
Apps, London (1)
Arthur C. Cole & Son (1)
B. L. Makepeace, Inc., Boston (1)
C3-D3 (103)
Scientific Instruments (35)
Scientific Instruments -- Catalogue (32)
Surveying Instruments (25)
Henry Wild Ld., Heerbrugg (22)
scientific instruments -- surveying (14)
surveying -- instruments (10)
E. Ducretet et Cie. (8)
Theodolites (7)
Telegraphs (6)
Keuffel & Esser Co. (6)
Engineering Instruments (5)
Léon Laurent (5)
Mathematical Instruments (4)
C. F. Casella & Co. Ltd. (4)
Astronomical Instruments (3)
Sextants (3)
Scientific Apparatus (3)
Scientific Instrument Makers (3)
1951 Solar Ephemeris and Other Data
1961 Solar Ephemeris and Surveying Instrument Manual
Accurate Speed, Frequency and Acceleration Measurements
American Practical Navigator: An Epitome of Navigation and Nautical Astronomy
The Aniline Colours of the Badische Anilin- & Soda- Fabrik Ludwigshafen o/Rhine and their Application on Wool, Cotton, Silk and other Textile Fibres
The Annals of Electricity, Magnetism, and Chemistry; and Guarduan of Experimental Science
Apparate zur Elektrizitätslehre
As in a Glass: Souvenir Catalogue
Astronomical and Engineering Instruments
The Averaging Machine
Bausch & Lomb: Portrait Lenses for the Professional Photographer
Berger: Precision Instruments of Proven Accuracy for Engineering and Surveying


text:
Indian Army: Army Logo, Army Information, Army Day, Indian Army Artillery, Indian Army Training, Army Intelligence
Aftab Dawa	0 Comments Army Day, Army Information, Army Intelligence, Indian Army Artillery, Indian Army Training, Indian Army: Army Logo
The Indian Army is the land based branch and the largest part of the Indian armed forces. The President of India is the Supreme Commander of the Indian Army, and it's commanded by the Chief of Army staff (COAS), who may be a four-star general. 2 officers are given with the rank of Marshall, a five-star rank, that may be a ceremonial position of great honour.
The Indian Army originated from the armies of the East India Company, that eventually became the british Indian Army, and therefore the armies of the princely states, that finally became the national army after independence. The units and regiments of the Indian Army have numerous histories and have participated in a number of battles and campaigns across the world, earning an oversized number of battle and theatre honours before and after Independence.
The primary mission of the Indian Army is to make sure national security and national unity, defending the nation from external aggression and internal threats, and maintaining peace and security among its borders. It conducts humanitarian rescue operations throughout natural calamities and different disturbances, like Operation Surya Hope, and may even be requisitioned by the govt. to deal with internal threats. It's a major component of national power alongside the Indian Navy and the Indian Air Force.
Indian Army Logo:
Indian Army Information:
The Indian Army has been concerned in four wars with neighbouring Pakistan and one with China. Different major operations undertaken by the army include: Operation Vijay, Operation Meghdoot and Operation cactus. Aside from conflicts, the army has conducted large peace time exercises like Operation Brasstacks and Exercise Shoorveer, and it's conjointly been an active participant in various UN peace keeping missions as well as those in: Cyprus, Lebanon, Congo, Angola, Cambodia, Vietnam, Namibia, El Salvador, Liberia, Mozambique and Somalia.
The Indian Army contains a regimental system, however is operationally and geographically divided into seven commands, with the essential field formation being a division. It's an all-volunteer force and contains over eightieth of the country's active defence personnel. It's the second largest standing army within the world, with 1,237,117 active troops and 960,000 reserve troops. The military has embarked on an infantry modernisation program called futuristic infantry Soldier As a System (F-INSAS), and is additionally upgrading and acquiring new assets for its armoured, artillery and aviation branches.
ALSO READ: INDIAN CYBER ARMY
British Indian Army:
A Military Department was created within the govt. of the East India Company at Kolkata within the year 1776. Its main function was to sift and record orders concerning the army that were issued by numerous Departments of the East India Company for the territories underneath its management.
With the Charter Act of 1833, the Secretariat of the govt. of the East India Company was reorganized into four Departments, together with a Military Department. The Army within the Presidencies of Bengal, Bombay and Madras functioned as individual Presidency Armies till one Apr 1895 when they were unified into one Indian Army. For administrative convenience, it absolutely was divided into four commands at that point, particularly Punjab (including the North West Frontier), Bengal, Madras (including Burma) and Bombay (including Sind, Quetta and Aden).
Indian Army Independence Day:
Upon independence and the subsequent Partition of India in 1947, four of the 10 Gurkha regiments were transferred to the British Army. The rest of the British Indian Army was divided between the new created nations of India and Pakistan. The Punjab Boundary Force, that had been formed to assist police the Punjab during the partition period, was disbanded, and Headquarters Delhi and East Punjab Command was formed to administer the area.
The departure of nearly all senior British officers following independence and their replacement by Indian officers meant several of the latter held acting ranks many ranks higher than their substantive ones. For instance, S. M. Shrinagesh, the ground forces commander of Indian forces throughout initial Indo-Pak War of 1947-49 (and the future third COAS) was first an acting major-general then an acting lieutenant-general throughout the conflict whereas holding the substantive rank of major, and solely received a substantive promotion to lieutenant-colonel in August 1949. Gopal Gurunath Bewoor, the future ninth COAS, was an acting colonel at his promotion to substantive major from substantive captain in 1949, whereas future lieutenant-general K. P. Candeth was an acting general officer (substantive captain) at a similar time.
Indian Army Day:
Indian Army Day is celebrated on fifteen Jan each year in India, in recognition of lieutenant general K. M. Cariappa's absorbing as the 1st Commander-in-Chief of the Indian Army from General Sir Francis Butcher, the last British Commander-in-Chief of India, on fifteen Jan 1949. With result from twenty six Jan 1950, the date India became a republic, all active-duty Indian Army officers formerly holding the King's Commission were recommissioned and confirmed in their substantive ranks.
Indian Army Artillery:
The Regiment of Artillery is the second largest arm of the Indian Army, constituting nearly one sixth of the Army's total strength. Originally raised in 1935 as a part of the Royal Indian Artillery of British Indian Army, the Regiment is currently tasked with providing the Army's towed and self-propelled field artillery, as well as guns, howitzers, heavy mortars, rockets and missiles.
As an integral part of nearly all combat operations conducted by the Indian Army, the Regiment of Artillery features a history of being a serious contributor to Indian military success. Throughout the Kargil War, it had been the Indian Artillery that inflicted the foremost damage. Over the years, 5 artillery officers have gone on to the Army's highest post as Chief of Army Staff of the Indian Army. For some time, the Regiment of Artillery commanded a significantly larger share of the Army's personnel than it does currently, because it was conjointly responsible for air defense artillery and a few aviation assets.
Indian Army Regiment of Artillery:
The 1990s saw the formation of the Corps of Army Air Defence and therefore the coalescing of all aviation assets into the military Aviation Corps. The arm is currently focused on field artillery, and provides regiments and batteries to every of the operational commands. The house of the Regiment is in Nashik, geographical region, wherever their headquarters is found along side the service's museum. The college of Artillery of the Indian Army is located nearby in Devlali.
After undergoing consistent failures to import or produce modern artillery for 3 decades, the Regiment of Artillery is finally going ahead with procurement of brand new 130-mm and 150-mm artillery guns. The army is additionally putting massive numbers of rocket launchers into service, with the indigenously-developed Pinaka multi barrel rocket launcher to equip twenty two regiments by the tip of the next decade.
Indian Army Training:
Pre-commission coaching of Gentlemen Cadets is allotted at the Indian military academy at Dehradun and therefore the Officers Coaching Academy at Chennai. There are also specialised coaching institutions like the Army War college, at Mhow, Madhya Pradesh, the High Altitude Warfare School (HAWS), at Gulmarg, Jammu and Kashmir, the Counter insurgency and Jungle Warfare School (CIJW), in Vairengte, Mizoram, and the College of Military Engineering (CME), in Pune. There's a military training Command (ARTRAC) at Shimla, whose main aim is to maximise the effectiveness of the coaching of personnel.
Indian Army Intelligence:
The Directorate of Military Intelligence (DMI) is the Intelligence arm of the Indian Army. The MI (as it's commonly referred to) was constituted in 1941 and was initially created to examine corruption within the Army's own ranks. With time, its role has evolved into cross border intelligence, intelligence sharing with friendly nations, infiltrating insurgent teams and counter-terrorism. Within the late 1970s, the MI was embroiled within the Samba spy scandal whereby 3 Indian Army officers were incorrectly involved as Pakistani spies.
The organisation has since emerged from the scandal as a prime Intelligence organisation of the Indian Army. As of 2012, the MI has seen several of its roles taken away during a struggle with the newly created National Technical Research Organisation and therefore the Defence Intelligence Agency. Since it had been set up in 2004 as a premier apex scientific agency underneath the National Security adviser within the Prime Minister's office, it conjointly includes the National Institute of cryptology research and Development (NICRD), that is the first of its kind in Asia.
← Indian Army Weapons, Modern Indian Army Guns, Most Powerful Weapons Photos
Join Indian Army: How to Join Indian Army after 10th, 12th & Graduation, Check Complete Procedure Here →
Joining Indian Army Using NCC Certificate
Retirement age Indian army officers
10+2 TES 28 Merit List By Indian Army


I have actually only had the chance of wagering with John Morrison's Sports Betting Champ system given that March 2009 as well as I've made 19 wagers so far.
I got the system at a somewhat bad time since it was the very end of the NBA betting period, and also prior to the MLB season began, so I had to wait for a long time to earn any type of bets. I desire I would certainly have located this chance faster, since the NBA season was UNDEFEATED at 79 wins as well as no losses!
Despite the fact that I enjoy the Pistons, I was suggested to wager on the Lakers to win the video game, and naturally they did and also I won the wager.
It was Video game 3 of the NBA Finals and also even though the Magic shot over 62% for the video game, and also 75% in the very first half, they barely squeaked by with a win 108-104. I actually thought Kobe would certainly be his common self as well as draw it out with a win at the end, however he missed some free tosses to the end and also the Magic went on to win the video game, for their first win of the series, as well as in franchise business history.
I was informed to bank on the Sports in this video game at +1.5 and I rejoice I did due to the fact that despite the fact that the A's were ahead a lot of the game, the Mariners came back at completion as well as won the game in the 9th inning by one run 8-7. I of program, won this wager.
The Rangers were the underdog at +1.5 in this game and also they ended up shedding by 1 run. The Rangers tracked the whole video game practically, up until the 8th inning when they locked up at 3-3. The Tigers went on to win in the nine by a score of 4-3. I won another one.
I truly thought the Phillies would win this game since they seem to be the far better group, nevertheless I was recommended to bet on the Marlins +1.5 and also the Marlins won 5-3, although Ryan Howard hit 2 homers. One more win for me.
This game was a bottles duel between the Cardinals Chris Carpenter as well as the Makers Yovani Gallardo. There was no score after 9 innings, so it went into bonus. In the 10th inning, an error by the Cardinals came back to haunt them when the Brewers Expense Hall drove in the winning run, making the last score 1-0. I was told to bet on the Cardinals +1.5, and also because they lost by 1 run, I still won the bet.
Heaven Jays pitcher Casey Janssen threw 7 good innings as well as the Blue Jays defeated the Sox 6-3. Heaven Jays were underdogs at +1.5, so I won once more.
The Red Sox stayed perfect against the Yankees this season, as well as took over very first area in the American League East. They edged out the Yankees with a 6-5 win. I selected the Yankees at +1.5 as well as since the Yankees only lost by one run, I won a wager when again.
I was told to bank on the New York Mets at -1.5 to win this wager. This indicates the Mets have to win the game, by at least 2 runs for me to win the wager. The Mets were in advance the majority of the game, however to the end their lead was only one run. In all-time low of the 8th, Luis Castillo of the New York Mets racked up on a ground ball up the middle to put the Mets ahead 6-4. The Mets closer was available in in the 9th inning, as well as closed the door as well as the Mets wound up winning 6-4, so I won another wager with this system.
Before we could enter into a further conversation on exactly how you can get a complimentary sporting activities wager online, it could be a smart idea to acquaint ourselves with the suggestion of a what a 'sports wager' is, to begin with. This would certainly be for the advantage of those who may be finding as term for the initial time.
And also as it ends up, a sporting activities wager is simply a bet that is positioned for or versus a certain showing off event occurring. If, for circumstances, 2 boxers are soon mosting likely to battle, you may determine to place a bet against boxer A winning the fight, while your good friend places a bet for fighter A winning the fight. The setup, in the simplest terms, is that if fighter A loses the battle, you offer your buddy some some loan, state $100 - as well as on the other hand, if boxer A wins the battle, your pal offers you some cash, most likely a similar $100.
So with this background info, we could return into our discussion on how you can get a totally free sporting activities bet.
Certainly, the idea of getting a cost-free sports-bet noises instead counter-intuitive, due to the fact that wagering is supposed to be regarding money; so that when someone talks about totally free sporting activities betting, you are most likely to locate on your own wondering exactly what they are actually speaking about.
In order to remain in a position to comprehend just how a cost-free sports-bet transpires, you need some insight right into the workings of on the internet sporting activities wagering.
Exactly what the people looking to participate in this online sports wagering demand to do is sign up with the sites where the wagering takes area, develop accounts there, down payment the money they would certainly be making use of to make the bets there, and then proceed to make the wagers utilizing that money. In some of these websites, a bulk in fact, the wagering quantities are standardized; so that for $5, you could 'buy' a bet, with which you could after that decide what to bet on.
So when someone informs you that they can give you a complimentary sporting activities wager, exactly what they indicate is that they will load your online betting account with cash that can acquire one such standard wager.