text:
\section{Introduction}
\label{sec:intro}
Dual Active Galactic Nuclei (dAGNs) are two accreting massive black
holes (MBHs) residing within a single host galaxy and are expected to
occur following the merger of two massive galaxies. A
population of dAGNs in post-merger galaxies seems to be an unavoidable prediction of hierarchal galaxy
formation models \citep[e.g.][]{Rosa2020}. In some cases, the separation of the two
MBHs that comprise a dAGN will shrink slowly over time as the orbiting
MBHs interact with the gaseous and stellar backgrounds of the galaxy
\citep[e.g.,][]{BBR1980,Volonteri2003, B2012, V2016,Bonetti2019,
  K2019, LBB22a}, eventually leading to the emission of gravitational
waves and the coalescence of the two black holes
\citep[e.g.,][]{LISA2017,KBH2017,Kelley2019}. Therefore,
dAGNs are `tracers' of future MBH mergers and gravitational wave
events. An observed sample of dAGNs, combined with a
model describing their future evolution, can thus provide a prediction of the MBH merger rate, a critical parameter for the
upcoming \textit{Laser Interferometer Space Antenna} (\textit{LISA}) gravitational wave
observatory.

Whether an observable dAGN results in a MBH coalescence depends on the physical
processes within the remnant galaxy that drive the orbital evolution
of the MBHs. When the MBHs are at separations of $\sim 1$~kpc,
dynamical friction (DF) by gas and stars is expected to dominate the
orbital decay \citep{BBR1980}. In this process, gravitational
deflection of gas \citep{O1999,KK2007} or collisionless particles
\citep[e.g., stars and dark matter;][]{C1943,AM2012} causes an
overdense wake to form behind each MBH. The wakes exert a gravitational pull onto the MBHs, which saps their orbital energy. Once
the two MBHs are gravitationally bound (at separations $\sim$~pc)
stellar ``loss-cone"  scattering is expected to dominate the orbital
decay \citep[e.g.,][]{Q1996, QH1997, Y2002}. If the
galaxy is sufficiently gas rich, drag on the binary by the surrounding
circumbinary disk may also affect its orbital evolution at separations
$\la 0.1$~pc \citep[e.g.,][]{A2005, MP2005}. Only when the separation
falls below $\sim 1000$ Schwarzschild radii does gravitational wave
emission begin to dominate the orbital evolution until the MBHs merge
\citep[e.g.,][]{KT1976, BBR1980}. In addition to the the orbital decay, the gas content of the post-merger galaxy will also
  strongly influence the accretion rates onto the MBHs and their subsequent
  properties as dAGNs. As a result, connecting observations of dAGNs to their
  potential future gravitational wave sources will depend on the
  properties of the host galaxy and the orbit of the MBH pair
  \citep[e.g.,][]{LBB21a}.

In Paper I of this series \citep{LBB22a}, we presented the results of
a semi-analytic model that followed the dynamical evolution of
$\approx 8000$ MBH pairs from $\sim 1$~kpc to coalescence accounting for all the
processes described above (DF, loss-cone scattering,
decay in a circumbinary disk, and gravitational wave emission). The host galaxy models in
which the MBH pairs evolved were constructed from the properties of
merger galaxies in the TNG50-3 cosmological
simulation \citep{Nelson2019, TNG50_a, TNG50_b}. Paper I showed that
the DF phase was the most important process in determining if a MBH
pair would coalesce within a Hubble time, and therefore the stellar
and gas content at scales of a few hundreds pc in post-merger galaxies are critical
for the expected \textit{LISA}\ detection rates. Moreover, we found that
radiation feedback effects from the accreting MBHs has the potential
to significantly weaken DF forces in gas-rich galaxies
\citep[e.g.,][]{PB2017,LBB20b}, which could severely reduce the number
of MBH mergers detected by \textit{LISA}. It is crucial, therefore, to find a
method that can test these predictions, especially the potential role
of radiation feedback, and observationally constrain the
\textit{LISA}\ expectations.

Here, we build on the results of Paper I by describing the expected
dAGN properties of MBH pairs as they evolve towards
coalescence. Paper I shows that the galaxy properties at $\sim
1$~kpc scale are often crucial for the overall orbital decay, and so we focus
on the dAGN properties with separations in this range. As our model
follows these MBH pairs through to coalescence, we demonstrate that
observational surveys of dAGNs can provide an estimate of the expected
MBH merger rate. Crucially, we consider the impact of radiation
feedback on both the dynamics and accretion onto the MBHs, allowing
for an observational determination of the magnitude of this effect.

This paper is organized as follows. In \S~\ref{sec:methods} we provide
a brief summary of the main features of the calculation used to evolve the MBHs
and how the TNG50-3 simulation data is used as input to the
model. \S~\ref{sec:AGN_dist_zla} shows how the distributions of
dAGN luminosity and separation change over time.
\S~\ref{sec:AGN_coal} presents the merger fraction of dAGNs at
different redshifts and how this depends on the properties of the host
galaxy and MBH pair.
The impact of radiation
feedback on these results is shown in \S~\ref{sec:RF_AGN_dist}. Finally, we discuss the
implications of our findings in \S~\ref{sec:discuss} and conclude in
\S~\ref{sec:concl}. We assume a cosmology consistent with that used in the TNG50-3 simulation ($\Omega_{\rm \Lambda,\,0}=0.6911$, $\Omega_{\rm m,\, 0}= 0.3089$, $\Omega_{\rm b, \, 0}= 0.0486$, $h=0.6774$), and $t_{\rm Hubble}=14.4$ billion yrs.

\section{Methods}
\label{sec:methods}
A thorough description of the dynamical evolution calculation of MBH
pairs and our use of the TNG50-3 simulation data is found in Paper I (see also
\citealt{LBB20a}). We therefore provide a brief summary of the method
below before describing how we compute the time-dependent accretion
rate and luminosity of each of our model dAGNs.

\subsection{The Dynamical Evolution of MBH Pairs in TNG50-3
  Post-Merger Galaxies}
\label{sec:galaxymodel}
We assume that a galaxy merger produces a single remnant, with a
stellar bulge and gas disk\footnote{We neglect the stellar disk in the
calculation as its impact on the orbital evolution of an MBH is
relatively minor \citep{LBB20a}.}, which includes the MBH pair. The primary MBH (pMBH; with mass $M_{\rm 1}$) is fixed at the center of the galaxy. The non-rotating bulge has a mass $M_{\rm sb}$ and
follows a coreless powerlaw density profile \citep[e.g.,][]{BT1987}, which is cutoff at twice the half-mass radius of the bulge ($2\times$$R_{\mathrm{b,h}}$), with the scale parameters proportional to $\log \,(M_{\rm 1}/10^{\rm 5} M_{\rm \odot})$ kpc. We consider the orbital
evolution of a bare, secondary MBH (sMBH; with mass $M_{\rm 2} < M_{\rm 1}$) which is orbiting in the plane of
the gas disk. The total mass of the MBH pair is $M_{\mathrm{bin}}=M_{\rm 1}+M_{\rm 2}$ and the mass ratio is $q=M_{\rm 2}/M_{\rm 1}$.

The gas fraction of the remnant
galaxy is $f_{\mathrm{g}}=M_{\rm gd}/(M_{\rm gd}+M_{\rm sb})$, where
$M_{\rm gd}$ is the mass of the gas disk within twice the half-mass
radius of the gas disk ($2\times$$R_{\mathrm{g,h}}$). Once $f_{\mathrm{g}}$ is set
the gas densities are determined using an exponential profile with a scale
radius defined as $2 \log\,(M_{\rm 1}/10^{\rm 5}\, M_{\rm
  \odot})$~kpc \citep[e.g.,][]{BT1987}. As a result, galaxies with a
larger pMBH\ have gas densities that decrease more slowly with radius. The
gas disk of each galaxy rotates with a speed drawn from the uniform distribution $0.7-0.9 v_{\rm c}(r)$, where $v_{\rm c}(r)$ is the
local circular velocity.

A list of 1997 galaxy merger events, including redshifts and MBH masses, is
extracted from the catalogs of the TNG50-3 simulation\footnote{See
\url{https://www.tng-project.org/data/docs/specifications
}}. Specifically, the redshifts correspond to when the two MBHs reach
a separation equal to the gravitational softening length of the
collisionless component ($\approx 1$~kpc). The properties of the
remnant galaxy ($M_{\rm sb}$, $M_{\rm gd}$, $R_{\mathrm{b,h}}$, and $R_{\mathrm{g,h}}$) are also
extracted from the TNG50-3 catalogs and are used to construct the
galaxy model within which the MBH pair evolves. The dynamical
evolution of the pair is initialized so that the semi-major axis $a$
is $\approx 1$~kpc. The initial eccentricity of the sMBH\ is set to be
either $e_i < 0.2$ or $0.8 \leq e_i \leq 0.9$, and we consider both
prograde and retrograde orbits \citep{LBB20a}. Thus, we compute four distinct
evolutions of the sMBH\ in each of the 1997 post-merger galaxies. The
results presented below are from the combined dataset of 7988 calculations.

The orbital evolution of the sMBH\ due to DF is computed as described
by \citet{LBB20a, LBB20b}. This process takes the sMBH\ down
to the influence radius of the MBH pair, where the mass enclosed by
the orbit is equal to twice the pair mass. Below this radius, the
orbital decay is due to the combination of loss-cone scattering, drag
from the circumbinary gas disk, and gravitational wave emission. The
calculation ends when the orbital separation is smaller than the
radius of the innermost stable circular orbit (ISCO) of a non-spinning
MBH pair (i.e., $R_{\rm ISCO} = 6 G M_{\rm bin}/
c^{2}$). Paper I provides full details of
how the orbital evolution is computed below the influence radius. The
full decay time of the sMBH\ is tracked and the MBH coalescence
redshift, $z_{\mathrm{coal}}$, is recorded for each calculation that merges within
a Hubble time ($36$\% of the 7988 orbital evolutions do not
successfully merge within this time; see \S~3 of Paper I).

Lastly, for those models which successfully reach coalescence, we
compute the expected \textit{LISA}\ signal-to-noise ratio (SNR) during the
inspiral phase assuming a four-year mission lifetime (Appendix A of
Paper I; \citealt{Bonetti2019}). The detection threshold
for \textit{LISA}\ used in this paper is a SNR$> 8$. This information will
allow us to connect \textit{LISA}-detectable MBH pairs to their earlier dAGN
properties.

\subsection{Accretion Rates and Luminosities}
\label{sub:accretion}
The accretion rates onto both the pMBH\ and sMBH\ are calculated as a
function of time during the DF phase of the calculation. That is, we
compute the dAGN luminosities only when the separations are greater
than the influence radius of the MBH pair ($\sim 1$~pc). For simplicity, we neglect
the mass increase of each MBH due to accretion and consider only
bolometric luminosities (see \S~\ref{sec:discuss}).

The accretion rate onto the
stationary pMBH\ is computed using the Bondi formula \citep{BH1944,
  Bondi1952} and its luminosity is limited to be no more than $10$\%
of the Eddington luminosity \citep[e.g.,][]{Lusso2012}, i.e.,
\begin{eqnarray}
  \label{eq:L1}
L_{1} =
\begin{cases}
  0.1 \dot{M}_{\rm B1} c^2 & {\rm when} \;\;\; L_{1} < 0.1L_{\rm 1, Edd}, \\
  0.1 L_{\rm 1, Edd} & \mathrm{otherwise},
\end{cases}
\end{eqnarray}
where $\dot{M}_{\rm B1} = \pi\, n_{\rm gd0}\, m_{\rm p}\,(GM_{\rm
  1})^2/c_{\rm s1,\infty}^3$ is the Bondi accretion rate onto the
pMBH\ and $L_{\rm 1, Edd} = 4\pi G M_{\rm 1}m_{\rm p}c / \sigma_{\rm
  T}$ is its Eddington luminosity. In the Bondi formula $n_{\rm gd0}$
is the central gas density and
$c_{\rm s1,\infty}$ is the sound speed at the galactic center. To
determine the sound speed, the temperature profile of the gas disk is
assumed to be $10^4$~K above the minimum Toomre stability temperature
\citep{T1964}.

As the sMBH\ is moving through the post-merger galaxy, its accretion
rate is calculated using the Bondi-Hoyle-Lyttleton model, which accounts
for the drop in accretion due to the relative motion of the MBH \citep{HL1939, BH1944, Bondi1952},
$\dot{M}_{\rm BHL} = \dot{M}_{\rm B2} / (1+\Delta v^2/c_{\rm s2,
  \infty}^2)^{3/2}$. Here, $\dot{M}_{\rm B2}$ represents the regular
Bondi rate of the sMBH, $c_{\rm s2, \infty}$ is the sound speed of the
gas at the same radius as the sMBH, and $\Delta v$ is the velocity of
the sMBH\ relative to the gas disk. The resulting accretion luminosity
of the sMBH\ is
\begin{eqnarray}
  \label{eq:L2}
L_{2} =
\begin{cases}
  0.1 \dot{M}_{\rm BHL} c^2 & {\rm when} \;\;\; L_{2} < L_{\rm 2, Edd}, \\
  L_{\rm 2, Edd} & \mathrm{otherwise},
\end{cases}
\end{eqnarray}
where $L_{\rm 2, Edd} = 4\pi G M_{\rm 2}m_{\rm p}c / \sigma_{\rm T}$
is the Eddington luminosity of the sMBH.

The dependence of $L_2$ on both gas density and relative velocity
means that the AGN luminosity of the sMBH\ may vary significantly
during each orbit and will also show a long-term evolution as the
orbit decays. Therefore, we expect the properties of the dAGN
population to change with redshift as MBH pairs evolve in time (see
also \citealt{LBB21a}). In this paper, we do not consider the instantaneous luminosity of dAGNs, instead, we use the evolution time weighted luminosity, which is calculated by summing the product of the instantaneous luminosity and the time step through the entire evolution, and then divide it by total evolution time.

To summarize, we have computed the full dynamical evolution (from
separations of $\approx 1$~kpc to coalescence) of 7988 MBH pairs
evolving in model post-merger galaxies derived from the TNG50-3
simulation. We also compute the \textit{LISA}\ SNR for those pairs that
successfully merge within a Hubble time. As described above, we also track estimates of the dAGN
luminosities of each pair while their separations are $\ga 1$~pc. In
the rest of the paper, we explore the connections between dAGNs and
MBH merger events. To do so, we define $z_{\mathrm{dAGN}}$\ as the redshift at
which a dAGN is observed and $z_{\mathrm{coal}}$\ as the redshift at which the two
MBHs that comprise the dAGN eventually coalesce (where $z_{\mathrm{coal}}$$ <$
$z_{\mathrm{dAGN}}$). The luminosity of a dAGN is defined as
$L_{\mathrm{bol}}=L_1+L_2$.

\section{The Evolution of Dual Active Galactic
  Nuclei Luminosities and Separations}
\label{sec:AGN_dist_zla}
In this section we provide an overview of the evolving dAGN population
found in our model suite.
TNG50-3 predicts
a small number of galaxy mergers beyond a redshift of $3$ (Fig.~2 in
Paper I), so we limit our analysis of dAGNs to lower redshifts (in
particular, $z_{\mathrm{dAGN}}$$\leq 2$) where the population of dAGNs is largest.

The minimum MBH
mass in the TNG50-3 simulation is $\approx 10^6$~M$_{\odot}$
\citep{TNG50_a}, which means that the lower-limit to the
dAGN luminosity distribution is $L_{\mathrm{bol}} \approx 10^{43}$~erg~s$^{-1}$
(i.e., the maximum allowed luminosity of a pMBH\ with this mass;
Eq.~\ref{eq:L1}). The solid green histogram in Figure~\ref{fig:z_dist}
shows how the total population of model dAGNs with $L_{\mathrm{bol}} >
10^{43}$~erg s$^{-1}$ evolves with $z_{\mathrm{dAGN}}$. Since the orbital evolution time of
a dAGN in the DF phase is frequently $>$Gyr (Paper I), one system can
appear in multiple redshift bins as long as its $L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$ in that redshift range.
\begin{figure}
 \includegraphics[width=0.5\textwidth]{hist_N_AGN_z_tot.pdf}
 \caption{The redshift distribution of all dAGNs with
   total bolometric luminosity larger than $10^{43}$~erg~s$^{-1}$ and
   with separations of $0.7$, $0.4$, and $0.1$~kpc.}
\label{fig:z_dist}
\end{figure}
We find that the largest number of dAGNs are present in the redshift range of
$0.4-0.5$, and the number drops as the redshift increases from $0.5$ to
$3$. The distribution of DF evolution times and galaxy gas fractions combine
to determine this redshift distribution. Paper I showed that the evolution time
for a sMBH\ to reach $a \sim 0.001$~kpc from $a \sim 1$~kpc ranges from $\sim
1$~Gyr (if the stellar bulge dominates) to $\sim 5-10$~Gyr (if the gas
disk dominates) depending on the orbital configuration of the
sMBH. Thus, only the systems containing dAGNs whose orbital evolution is
determined by stellar DF in the bulge and have relatively short
evolution time will evolve to pc-scales at high $z_{\mathrm{dAGN}}$. The dAGNs
whose orbital evolution is determined by the slower gaseous DF process
reaches this separation at lower redshifts.

Fig.~\ref{fig:z_dist} also illustrates the redshift distribution of
dAGNs with separations of $0.7$, $0.4$ and $0.1$~kpc. All three
distributions peak at the smallest redshifts $z_{\mathrm{dAGN}}$\ $\approx
0$--$0.1$, but the peak is flattest and the total number of dAGNs
highest for $a=0.7$~kpc. This is because there are always more
dAGNs with large rather than with small separations. This happens because all
dAGNs with small separations were once dAGNs with large separations in
the past, but not all dAGNs with large separations evolve into dAGNs
with small separations. Taking everything into account, the shape of the redshift distribution of dAGNs is a natural result of DF dominated orbital evolution. This slow evolution means that $z_{\mathrm{dAGN}}$$\la 0.5$ is the
optimal region for observational searches for dAGNs.

Turning now to the 65\% of dAGNs that eventually lead to a
MBH merger, Figure~\ref{fig:al_dist} shows the separation and luminosity
distributions at $z_{\mathrm{dAGN}}$$=0.1$, $1$ and $2$ of all dAGN that will coalesce (solid blue histograms). The total number of dAGNs at $z_{\mathrm{dAGN}}$$=1$
and $2$ that eventually merge is larger than that at $z_{\mathrm{dAGN}}$$=0.1$
because MBH mergers can happen between $z_{\mathrm{dAGN}}$$=1$ and $0.1$ and these
do not appear in the leftmost distribution.
\begin{figure*}
  \centering
	\includegraphics[width=0.9\textwidth]{hist_a_L_tot.pdf}
\caption{The separation and luminosity distributions at $z_{\mathrm{dAGN}}$$=0.1$,
  $1$, and $2$ of dAGNs whose
  MBHs coalesce by $z_{\mathrm{coal}}$$=0$. The blue
  solid histograms show all dAGNs that eventually lead to coalescence by $z_{\mathrm{coal}}$$=0$, and the red hatched histograms show the
  systems in which the MBH merger has a \textit{LISA}\ SNR $>8$. }
\label{fig:al_dist}
\end{figure*}
The top three panels of Fig.~\ref{fig:al_dist} show that most dAGNs at
$z_{\mathrm{dAGN}}$$=1$ and $2$ that eventually merge have separations in the range
of $0.5-1$~kpc. This is because the evolution time from $\sim
1$~kpc to coalescence is often in the range of $5-10$~Gyrs (Paper
I). The separation distribution at $z_{\mathrm{dAGN}}$$=2$ (the rightmost panel)
has a secondary peak at $a\sim 1.2$~kpc. This is because the time
between $z_{\mathrm{dAGN}}$$=2$ and $0$ ($\approx 10$~Gyrs) is long enough to allow
some MBH pairs with separations larger than $1$~kpc to merge within a Hubble time. The peak of the distribution at
$z_{\mathrm{dAGN}}$$=0.1$ is shifted towards $0.2-0.5$~kpc due to the relatively
short evolution time between $z_{\mathrm{dAGN}}$$=0.1$ and $0$ ($\sim 1$~Gyr).

The solid blue histograms in the bottom three panels of Fig.~\ref{fig:al_dist} show the
distribution of $L_{\mathrm{bol}}$ for all dAGNs at $z_{\mathrm{dAGN}}$$=0.1, 1,$ and $2$
whose MBHs merge before $z_{\mathrm{coal}}$$=0$. As expected, there is a sharp
cutoff at $L_{\mathrm{bol}} \approx 10^{43}$~erg~s$^{-1}$ due to the
minimum MBH mass in the TNG50-3 simulation. At all $z_{\mathrm{dAGN}}$\ the
majority of dAGNs that eventually merge have $L_{\mathrm{bol}} \approx
10^{43-45}$~erg~s$^{-1}$.

The hatched red histograms in Fig.~\ref{fig:al_dist} shows the
distributions of dAGNs that lead to \textit{LISA}\ SNR$> 8$. These potential
\textit{LISA}\ sources follow a similar trend in the separation distribution
at all three redshifts. However, at luminosities larger than $\approx
10^{45}$~erg~s$^{-1}$, the fraction of \textit{LISA}\ sources drops
significantly in the lower three panels. This is because the
bolometric luminosity is proportional to the binary mass, so more luminous precursor dAGNs have more massive MBHs and are less likely to be detected by
\textit{LISA}.

\section{The Coalescence Fraction of kpc-scale Dual Active Galactic Nuclei}
\label{sec:AGN_coal}
This section presents the coalescence fraction of dAGNs as a function
of redshift and observable properties of dAGN hosts. These fractions
provide a quantitative relation between the number of dAGNs and
merging MBHs, and can be used to estimate the cosmological
MBH binary coalescence rate and the number of \textit{LISA}\ detections from a sample of
detected dAGNs.

\subsection{The Coalescence Fraction As a Function of Dual AGN Redshift}
\label{sec:coal_z}
In order to quantify the relationship between observable dAGNs and MBH
coalescence, we count the number of dAGNs with $L_{\mathrm{bol}} >
10^{43}$~erg~s$^{-1}$ with MBHs that coalesce before $z_{\mathrm{coal}}$$=0$ and
show the coalescence fraction as a function of $z_{\mathrm{dAGN}}$\ in the left
panel of Figure~\ref{fig:fraction}, grouped by dAGN separation. Almost all dAGNs with $a=0.1$~kpc
at $z_{\mathrm{dAGN}}$$>0.1$ eventually coalesce by $z_{\mathrm{coal}}$$=0$. The evolution time
of these systems is $10^{5-8}$~yrs (Paper I), which is sufficient for
a dAGN with a separation of $a=0.1$~kpc at $z_{\mathrm{dAGN}}$$=0.1$ to coalesce
(the corresponding cosmological time is $\sim 1.3$ Gyr). Thus, if a
dAGN is observed with $a\leq 0.1$~kpc at any redshift larger than $0.1$, then it has
nearly $100\%$ chance to coalescence in a Hubble time.
\begin{figure*}
\centering
	\includegraphics[trim=5 80 5 85,clip,width=0.9\textwidth]{fraction_tot_with_no_RF.pdf}
\caption{The fraction of dAGNs observed at a given redshift whose MBHs
coalesce before $z_{\mathrm{coal}}$$=0$. The red circles show the fraction using
all 7988 dAGNs in the model suite, while the green triangles, blue
squares and cyan stars show how the fraction varies with dAGN
separation. The black '+' symbols indicate
the fraction of all dAGNs that lead to a \textit{LISA}\ SNR$>8$. The
right-hand panel shows how the fractions change when the effects of
radiation feedback (RF) are taken into account (\S~\ref{sec:RF_AGN_dist}).}
\label{fig:fraction}
\end{figure*}

Similarly, all dAGNs with $a=0.4$~kpc at $z_{\mathrm{dAGN}}$$>0.4$ coalesce
before $z_{\mathrm{coal}}$$=0$, but the coalescence fraction between $z_{\mathrm{dAGN}}$$=0$ and
$0.1$ drops to $\sim 0.3$, showing that majority of these systems have
an evolution time longer than $\sim 1.3$~Gyrs. The coalescence
fraction of dAGNs with separations of $0.7$~kpc gradually increases as
redshift grows. This is as expected, since higher
redshift dAGNs that reach separations of $a=0.7$~kpc have a greater
probability to evolve to coalescence prior to
$z_{\mathrm{coal}}$$=0$. Indeed, the left panel of Fig.~\ref{fig:fraction} shows
that nearly $90\%$ of dAGNs with $a=0.7$ kpc at $z_{\mathrm{dAGN}}$$=3$ lead to a
MBH merger. However, this fraction drops to $50\%$ at
$z_{\mathrm{dAGN}}$$=0.3$. The coalescence fraction of dAGNs with separations of
$a=0.7$~kpc is in general lower than those with $a=0.1$ or $0.4$~kpc
because it is easier for the sMBH\ to evolve to coalescence from
$0.1$~kpc than from $0.7$~kpc.

The coalescence fraction of all dAGNs with $L_{\mathrm{bol}}>10^{43}$~erg~s$^{-1}$ is shown as the red circles in
Fig.~\ref{fig:fraction} and is $\sim 70\%$ at $z_{\mathrm{dAGN}}$$=3$ and $\sim
50\%$ at $z_{\mathrm{dAGN}}$$=1$. Thus, given a sample of $z_{\mathrm{dAGN}}$$=1$ dAGNs with
$L_{\mathrm{bol}}>10^{43}$~erg~s$^{-1}$ with separations of
$0.001-2$~kpc, we expect that half of them will coalesce before
$z_{\mathrm{coal}}$$=0$. In order to estimate the number of potential \textit{LISA}\ sources
using the number of observed dAGNs, we also count the number of dAGN
that coalesce before $z_{\mathrm{coal}}$$=0$ with \textit{LISA} SNR$>8$, and show
this fraction as black plus signs in the left panel of
Figure~\ref{fig:fraction}. As expected, the \textit{LISA}\ detectable fraction
is lower than the coalescence fraction at all redshifts, since
\textit{LISA}\ will not be as sensitive to the most massive MBH pairs.

Since the evolution time of the sMBH\ depends on the
properties of the post-merger galaxy and MBH pair
\citep[][Paper I]{LBB20a}, Figure~\ref{fig:fraction_mq} shows how
the coalescence fraction of dAGNs is impacted by the galaxy bulge mass (left
panel) and the MBH binary mass ratio (right panel). We find that the coalescence
fraction of dual AGNs is inversely proportional to
$M_{\mathrm{sb}}$, with the largest fractions in galaxies with bulge
masses of $M_{\mathrm{sb}} \approx 10^9$~M$_{\odot}$ and the lowest
with $M_{\mathrm{sb}} \approx 10^{11}$~M$_{\odot}$. This is a result
of the inverse relationship between $M_{\mathrm{sb}}$ and $f_g$
(\S~\ref{sec:galaxymodel}) so that galaxy models with less massive
bulges have higher gas fraction (and, thus, high gas densities and
sound speeds), where gaseous DF efficiently
decays the orbit of the sMBH\ at large separations (see also Paper I). When $M_{\mathrm{sb}}
> 10^{10}$~M$_{\odot}$, the gas
fraction falls to low enough values that gaseous DF becomes
inefficient, increasing the decay time of the sMBH\ before the stellar DF can takes over.
The coalescence fractions of the entire dAGN population (red circles)
and the population that leads to \textit{LISA}\ SNRs$> 8$ (black plus signs)
closely follow the $M_{\mathrm{sb}} = 10^{10}$~M$_{\odot}$
results. This illustrates that galaxies with $M_{\mathrm{sb}} \approx
10^{10}$~M$_{\odot}$ dominate the sample of post-merger galaxies in
TNG50-3. The right panel of Fig.~\ref{fig:fraction_mq} shows that the
coalescence fraction of dAGNs with $q=0.1$ and $0.5$ have the highest
coalescence fractions because the DF forces are larger (and the
inspiral time shorter) for higher mass sMBHs \citep[][their Figure
  11]{LBB20a}.
\begin{figure*}[t]
\centering
	\includegraphics[trim=5 80 5 85,clip,width=0.9\textwidth]{fraction_tot_m_q.pdf}
\caption{The fraction of dAGNs at a given redshift that coalesce by
  $z_{\mathrm{coal}}$$=0$. Left: the coalescence fraction of dAGNs grouped by the bulge
  mass. Green triangles represent systems with $\log\,(M_{\rm
    sb}/\,M_{\rm \odot})=9$, blue squares represent systems with
  $\log\,(M_{\rm sb}/\,M_{\rm \odot})=10$, and cyan stars represent
  systems with $\log\,(M_{\rm sb}/\,M_{\rm \odot})=11$. Right: the
  coalescence fraction of dAGNs grouped by the mass ratio $q$. Green
  triangles represent systems with $\log\,q=-2$, blue squares
  represent systems with $\log\,q=-1$, and cyan stars represent
  systems with $\log\,q=-0.3$. In both panels, red circles illustrate
  the coalescence fraction of all dAGNs, and the black
  plus signs represent the fraction of all dAGNs that coalesce by
  $z_{\mathrm{coal}}$$=0$ and can be detected by \textit{LISA}.}
\label{fig:fraction_mq}
\end{figure*}

\subsection{The Cumulative Coalescence Fractions of Dual AGNs}
\label{sec:coal_para}
The results above focused on dAGNs that evolve to a MBH merger before
$z_{\mathrm{coal}}$$=0$, but it is also interesting to examine how these mergers
are distributed across redshift $z_{\mathrm{coal}}$.  Figure~\ref{fig:CCF} shows the
cumulative coalescence fractions (CCFs) of dAGNs with
$L_{\mathrm{bol}}  > 10^{43}$~erg~s$^{-1}$ at $z_{\mathrm{dAGN}}$$=1$, $2$ and
$3$.
\begin{figure*}
\centering
\includegraphics[trim=5 90 5 90,clip,width=0.9\textwidth]{CCF_tot.pdf}
\caption{The cumulative coalescence fraction (CCF) of dAGNs with
  $L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$ at $z_{\mathrm{dAGN}}$$=1$, $2$ and $3$.
  The dot-dashed green lines plot the CCFs of dAGNs with separations
  of $a=0.7$~kpc, while the dotted orange lines and
  solid red lines represent dAGNs with separations of $0.4$ and
  $0.1$~kpc, respectively.}
\label{fig:CCF}
\end{figure*}
\begin{figure*}
\centering
	\includegraphics[trim=5 50 5 30,clip,width=0.9\textwidth]{CCF_2.pdf}
\caption{The cumulative coalescence fraction (CCFs) of dAGNs at
  $z_{\mathrm{dAGN}}$$=0.1$, $1$ and $2$ with
  $L_{\rm bol}>10^{\rm 43} {\rm erg\, s^{\rm -1}}$ grouped by the
  stellar bulge mass (top row), and the MBH mass ratio (bottom row). The dashed lines show
  the CCFs of mergers that result in \textit{LISA}\ events with SNR$>8$.}
\label{fig:CCF_2}
\end{figure*}
The three lines in each panel shows the CCFs for dAGNs with different
separations at the starting $z_{\mathrm{dAGN}}$. Unsurprisingly, we see that dAGNs
that start with a separation of only $a=0.1$~kpc evolve to coalescence
efficiently, reaching a 100\% coalescence fraction by $z_{\mathrm{coal}}$$\approx
0.9$, $1.8$, $2.6$, if starting at $z_{\mathrm{dAGN}}$$=1$, $2$ and
$3$, respectively. Similarly, 100\% of the dAGNs with $a=0.4$~kpc in our sample that
are at $z_{\mathrm{dAGN}}$$=2$ or $3$ merge by $z_{\mathrm{coal}}$$\approx 1.2$
and $2.2$. Our calculations suggest that there may still
be a small fraction of the $z_{\mathrm{dAGN}}$$=1$, $a=0.4$~kpc population at low
$z$, but the majority of them would have merged by $z_{\mathrm{coal}}$$\approx
0.8$. In contrast, Fig.~\ref{fig:CCF} shows that dAGNs with separations of
$a=0.7$~kpc at $z_{\mathrm{dAGN}}$$=1$ or $2$ will not all have merged by
$z_{\mathrm{coal}}$$=0$ although the ones starting at $z_{\mathrm{dAGN}}$$=3$ would all have
merged by $z_{\mathrm{coal}}$$\approx 0.4$. Of course, the dAGNs that remain at low
redshifts will be at significantly smaller separations (e.g.,
Fig.~\ref{fig:al_dist}).

As in Fig.~\ref{fig:fraction_mq}, we show in Figure~\ref{fig:CCF_2}
how the CCFs vary with $M_{\mathrm{sb}}$\ (upper panels) and $q$ (lower
panels). dAGNs of all separations are included in each curve, and the
dashed lines show CCFs of those mergers with \textit{LISA}\ SNRs$> 8$. We
replace the $z_{\mathrm{dAGN}}$$=3$ panels with one at $z_{\mathrm{dAGN}}$$=0.1$ to more closely
connect to observational searches for dAGNs.

In the upper-row of the figure, we see the same inverse relationship
between $M_{\mathrm{sb}}$\ and coalescence fractions as seen in
Fig.~\ref{fig:fraction_mq}. For example, $\sim 30$--$40$\% of
$z_{\mathrm{dAGN}}$$=0.1$ dAGNs in galaxies with $M_{\mathrm{sb}} =
10^{9}$~M$_{\odot}$ bulges will have coalesced by $z_{\mathrm{coal}}$$=0$. However,
if the dAGNs reside in post-merger galaxies with $M_{\mathrm{sb}} >
10^{10}$~M$_{\odot}$, then only $\sim 10$\% will merge in a Hubble
time. The fractions increase markedly when considering dual AGNs at higher redshifts, however the
fraction never rises above $40$\% for dAGNs in the most massive
bulges. In the bottom row of Fig.~\ref{fig:CCF_2}, we again see that
MBH pairs with larger values of $q$ will evolve faster and reach
coalescence at higher $z_{\mathrm{coal}}$\ than lower values of $q$. The implication
of this is that the most likely population of dAGNs persisting
to low redshift will be systems with $\log q \la -2$ and in galaxies
with $M_{\mathrm{sb}} \ga 10^{11}$~M$_{\odot}$. However, as shown by
the dashed lines, the strongest \textit{LISA}\ signals will originate from
MBH pairs evolving in lower mass bulges (see also Paper I).

\section{The Impact of Radiation Feedback Effects}
\label{sec:RF_AGN_dist}
The thermal pressure of the ionized bubble surrounding an accreting
MBH regulates its accretion rate \citep[e.g.][]{Ostriker1976,
  B1985, Ric2008, Park2011, Park2012} and suppresses its luminosity. The
magnitude of this effect depends on the motion of the MBH relative to
its gas environment, the gas density, and the temperature of
surrounding gas \citep{Park2013}. Meanwhile, the ionized bubble can
also reduce the DF force on MBHs moving in gas-rich hosts \citep{PB2017,
  G2020,T2020}, an effect known as ``negative DF''. In several previous papers we showed that these
radiation feedback (RF) effects may impact both the dAGN
luminosities and the overall dynamical evolution of the sMBH\ \citep[][Paper
  I]{LBB20b,LBB21a}. In particular, Paper I showed that the negative
DF effect increases the orbital decay timescale of sMBHs in gas-rich
hosts, which could, in
principle, severely reduce the expected \textit{LISA}\ detection rates. In
this section, we explore how RF will impact the evolution of the dAGN
population. As the reduction in $L_{\mathrm{bol}}$ is relatively
modest (RF does not typically impact the luminosity of the pMBH;
\citealt{LBB21a}), we focus here on the RF effects on the orbital
decay of the sMBH. Details on how we implement RF in the calculation
of the DF force can
be found in the paper by \citet{LBB20b}. We note that the RF effects are only
computed during the DF phase of the MBH evolution, but, as seen Paper
I, this phase dominates the overall timescale of a MBH merger.

Figure~\ref{fig:z_dist_RF} shows the redshift distribution of all
dAGNs in our model suite with $L_{\rm bol} >10^{43}$~erg~s$^{-1}$ when
the RF effects are included in the calculations. This plot should be
compared to Fig.~\ref{fig:z_dist} which shows the results in the
absence of RF.
\begin{figure}
  \centering
  \includegraphics[trim=5 40 5 40,clip,width=0.45\textwidth]{hist_N_AGN_z_tot_RF.pdf}
\caption{As Figure~\ref{fig:z_dist}, but now showing the redshift
  distributions when including the effects of radiation feedback (RF). }
\label{fig:z_dist_RF}
\end{figure}
The green histogram shows the redshift distribution of all dAGNs and
is similar to the one in Fig.~\ref{fig:z_dist}, except that there are
more dAGNs at $z \approx 0-0.4$ when RF effects are included. This is
because negative DF slows the orbital decay, which results in longer
evolution time and more dAGNs at low
redshifts. Figure~\ref{fig:z_dist_RF} also illustrates the redshift
distribution of dAGNs with separations of $a=0.7, 0.4$ and $0.1$~kpc
in the presence of RF. dAGNs separated by $a=0.7$~kpc still dominate
the population as in Fig.~\ref{fig:z_dist}. However, when RF effects
are included there are fewer
dAGNs with separations of $0.4$ and $a=0.1$~kpc, especially at large
redshifts. This is because negative DF increases the evolution time of
most systems with gas fractions larger than $0.1$
\citep{LBB20b}. Thus, it takes longer for most systems to reach smaller separations in the presence of RF, and thus, there are fewer dAGNs with separations $<0.4$ kpc at high redshifts when RF is taken into account.

The impact of RF on the separation and luminosity
distributions of all dAGNs that evolve to coalescence is shown in
Figure~\ref{fig:al_dist_RF} and should be compared to
Fig.~\ref{fig:al_dist}. Critically, the total number of systems that
reach coalescence decreases in all panels when RF effects are
included, with largest drop when $z_{\mathrm{dAGN}}$$=2$. This is a result of the
increase in evolution time caused by RF effects (see Paper I).
\begin{figure*}[t]
\centering
	\includegraphics[trim=5 40 5 40,clip,width=0.9\textwidth]{hist_a_L_tot_RF.pdf}
\caption{As Figure~\ref{fig:al_dist}, but now showing the separation
  and luminosity distributions when RF effects are included.}
\label{fig:al_dist_RF}
\end{figure*}
The shape of the separation distributions are largely similar between
the two cases except for the one at $z_{\mathrm{dAGN}}$$=2$ which
remains bimodal in the presence of RF, but
the left peak at $a=0.6-0.7$~kpc is now lower than the right peak at
$a=1.2-1.3$~kpc, contrary to the outcome in the absence of RF. Dual
AGNs with a separation of $0.6-0.7$~kpc at $z_{\mathrm{dAGN}}$$=2$ tend to have
smaller binary masses and higher gas fractions compared to those dAGNs
with the same separation but observed at $z_{\mathrm{dAGN}}$$=1$. Although the
separation is the same, dAGNs at $z_{\mathrm{dAGN}}$$=2$ are more likely to stall
in the presence of RF than those at $z_{\mathrm{dAGN}}$$=1$. So the left peak at
$a=0.6-0.7$~kpc is visibly reduced. The right peak at $a=1.2-1.3$~kpc
is largely due to dAGNs whose orbital evolution is determined by
stellar DF in the bulge, which are also the ones that are least
affected by RF, so the right peak is only slightly reduced in the
presence of RF.

The bottom row of Figure~\ref{fig:al_dist_RF} shows the bolometric
luminosity distribution of all dAGNs that eventually coalesce in the
presence of RF. Comparing this bottom row to the one in
Fig.~\ref{fig:al_dist} we find that most dAGNs that evolve to mergers
continue to have $L_{\mathrm{bol}}=10^{43-44}$~erg~s$^{-1}$ at all
$z_{\mathrm{dAGN}}$\ in the presence of RF, but the total number of such systems
has decreased significantly. However, the peak at
$L_{\mathrm{bol}}=10^{\rm 45-46}$~erg~s$^{-1}$ is barely affected by
RF. This is because $L_{\mathrm{bol}}$ is proportional to the MBH pair
mass, so the higher luminosity peak is composed of more massive dAGNs
whose orbital evolution is determined by stellar DF in the bulge and
is least affected by RF. Thus, the more luminous dAGNs are barely
affected by RF. The red-hatched histograms indicates systems that
evolve to MBH mergers with \textit{LISA}\ SNR$> 8$. As these are concentrated
in the lower mass, lower $L_{\mathrm{bol}}$, systems, RF effects
significantly decrease the number of these events (see also Paper I).

The impact of RF on the evolution of dAGNs is clearly seen in the
right panel of Fig.~\ref{fig:fraction} which shows the coalescence
fraction of dAGNs with $L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$ as a
function of $z_{\mathrm{dAGN}}$\ in the presence of RF. Almost all dAGNs with
separations of $a=0.1$~kpc at $z_{\mathrm{dAGN}}$$>0.1$ coalesce before $z_{\mathrm{coal}}$$=0$,
similar to the case in the absence of RF (the left panel of
Fig.~\ref{fig:fraction}). However, there are no $a=0.1$~kpc data
points at $z_{\mathrm{dAGN}}$$>1.8$, since negative DF increases the evolution
time, and none of our systems reaches $a=0.1$~kpc at these
redshifts. The square and star markers show the coalescence fraction
of dAGNs with
$a=0.4$ and $0.7$~kpc, respectively. Comparing to the coalescence fraction in the absence
of RF as shown in the left panel of Fig.~\ref{fig:fraction}, at $z_{\mathrm{dAGN}}$$<1.8$, the coalescence fractions are in general
reduced by $10$--$20$\% for $a=0.4$~kpc dAGNs in the presence of RF,
while for $a=0.7$~kpc dAGNs the coalescence fraction is reduced by
$30$--$50$\%. At $z_{\mathrm{dAGN}}$$>1.8$, the coalescence fractions
are reduced significantly to $0.2$--$0.3$ no matter the dAGN
separation. This is because negative DF reduces the coalescence fraction.

Lastly, the red circles in the right panel of Fig.~\ref{fig:fraction}
represent the coalescence fraction of all dAGNs with $L_{\rm bol}>
10^{\rm 43} {\rm erg\, s^{\rm -1}} $ in the presence of RF. The
coalescence fraction at $z_{\mathrm{dAGN}}$$>0.7$ is nearly flat, and corresponds
to $0.2$--$0.25$. Thus, in the presence of RF, if dAGNs are observed
at $z_{\mathrm{dAGN}}$$>0.7$, then we expect $20$--$25$\% of them to coalesce by
$z_{\mathrm{coal}}$$=0$. The black plus signs in this plot illustrate the the
fraction of \textit{LISA}\ GW sources in the presence of RF. Similar to the
case in the absence of RF, the \textit{LISA}\ detectable fraction of dAGNs is
in general $\sim5$--$10$\% lower than the total coalescence fraction.

\section{Discussion}
\label{sec:discuss}

\subsection{Predicting the MBH Merger Rate from Dual AGN
  Surveys}
\label{sec:method}
The results presented above allow an estimate of the MBH merger rate,
and the subsequent \textit{LISA}\ detection rate,
to be derived from an observational survey of kpc-scale
dAGNs. Predictions can be calculated either in the presence or in the
absence of RF effects.
Given a survey of dAGNs with $L_{\mathrm{bol}} >
10^{43}$~erg~s$^{-1}$ at $z_{\mathrm{dAGN}}$$\pm \Delta z$, the rate at which the MBHs in these systems
merge before $z_{\mathrm{coal}}$$=0$ is
\begin{equation}
  \label{eq:dAGN_rate}
  {dN_{\mathrm{coal}} \over dt}(z_{\mathrm{dAGN}}) =
  f_{\mathrm{coal}}\, n \,
  {4\pi c d^2_{L} \over (1+z_{\mathrm{dAGN}})^2},
\end{equation}
where $f_{\mathrm{coal}}$ is the coalescence
fraction at $z_{\mathrm{dAGN}}$\ from Fig.~\ref{fig:fraction}, $d_L$ is
the luminosity distance to $z_{\mathrm{dAGN}}$, and
$n$ is the observed dAGN comoving number density at $z_{\mathrm{dAGN}}$.

As an example, consider an all-sky survey that detected $400$
kpc-scale dAGNs with $L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$ at
$z_{\mathrm{dAGN}}$$=1\pm0.01$. Then
\begin{enumerate}
  \item the dAGN comoving number density is $n=400/4\pi d_L^2c
    dt$. The time interval $dt$ is the cosmological time across
    $z_{\mathrm{dAGN}}$$=1\pm0.01$ which is $0.081$~Gyr in our adopted cosmology (see \S~1).
  \item According to the left panel of Fig.~\ref{fig:fraction} the
    coalescence rate for dAGNs at $z_{\mathrm{dAGN}}$$=1$ in the absence of RF
    effects is $f_{\mathrm{coal}}\approx 0.45$. The fraction of dAGNs
    that lead to a merger with a \textit{LISA}\ SNR$>8$ is $\approx 0.35$.
  \item The coalescence rate of these dAGNs at $z_{\mathrm{dAGN}}$$=1$ is found
    from Eq.~\ref{eq:dAGN_rate}: $dN_{\mathrm{coal}}/dt \sim 6\times
    10^{-7}$~yr$^{-1}$. The rate of mergers with a \textit{LISA}\ SNR$>8$ is
    $\sim 5\times 10^{-7}$~yr$^{-1}$.
\end{enumerate}
To include the effects of RF, the calculation can be repeated using
the values of $f_{\mathrm{coal}}$ from the right-hand panel of
Fig.~\ref{fig:fraction}. In the example above, RF reduces the
predicted merger rates to $3\times 10^{-7}$~yr$^{-1}$ (all systems) and $2\times
10^{-7}$~yr$^{-1}$ (those with \textit{LISA}\ SNR$>8$).

Eq.~\ref{eq:dAGN_rate} gives the expected rate of MBH mergers from a
population of dAGNs at a particular $z_{\mathrm{dAGN}}$. If this estimate can be
made at multiple $z_{\mathrm{dAGN}}$\, the results can be integrated to yield the
total MBH merger rate. In Paper I we found that the overall MBH
coalescence rate is $\sim 0.45$~yr$^{-1}$ in the absence of RF
effects, while the rate of sources with a \textit{LISA}\ SNR$>8$ is $\sim
0.34$~yr$^{-1}$.  Comparing the merger rates derived from dAGN
observations and Eq.~\ref{eq:dAGN_rate} with future
\textit{LISA}\ measurements will provide important constraints on the
efficiency of DF forces and RF effects in the orbital evolution of MBH pairs.

\subsection{Comparison to Results from Literature}
\label{sub:comparison}
In the paper by \citet{Marta2021}, dAGNs in the cosmological
simulation $\textit{Horizon-AGN}$ are identified and related to the
corresponding MBH binary mergers from the same simulation
\citep{Marta2020}, and the numerical relation between the dAGNs and
MBHB mergers is studied. The right column of their Figure~11
illustrates the CCFs of dAGNs with $5\sim 10$ kpc
separations. According to their results, $30-60\%$ of these dAGNs
observed at $z_{\rm dAGN}\sim1- 3$ coalesce before $z_{\mathrm{coal}}$$=0$,
increasing with decreasing $z_{\rm dAGN}$. This is due to the long
evolution time of dAGNs with small mass ratios at high
redshifts. These high redshift dAGNs with small mass ratios are formed
in \textit{Horizon-AGN} simulation because the criterion for MBH
formation is based only on gas properties. Thus, at high redshifts,
when the gas reservoir is rich, some MBHs form in gas clouds that are too small to be identified as galaxies ('intergalactic' MBHs). These small 'intergalactic' MBHs can be captured by galaxies later on and shine as dAGNs if some stochastic accretion occurs \citep{Marta2021}. According to the left column of Figure~11 of \citet{Marta2021}, dAGNs with one 'intergalactic' MBH have small mass ratios and occur frequently at high redshifts ($20\sim 30\%$ of all dAGNs at $z=2, 3$). The evolution time of these systems is long and the resulting coalescence fractions are low due to the small mass ratios, which leads to low coalescence fractions of dAGNs at high redshifts as shown in the right column of their Figure~11.

In comparison with Figure~\ref{fig:CCF} of this paper, the CCFs in \citet{Marta2021} are in general lower at all $z_{\rm dAGN}$. This is because the initial dAGN separations considered in \citet[][$30-50$\,kpc]{Marta2021} are larger than that considered in this work ($\sim $ kpc), so the evolution time is longer and CCFs are lower in their case. As shown in Figure~\ref{fig:CCF}, the CCFs increase with increasing $z_{\rm dAGN}$, contrary to the results of \citet{Marta2021}. This is because we do not include those  systems comprising one 'intergalactic' MBH in the analysis of this work (see \S~3 of paper I). Overall, the results of \citet{Marta2021} indicate dAGNs that are identified at small separations are generally indicators of effective mergers, which is in agreement with our results.

\subsection{Impact of Simplifying Assumptions}
\label{sub:assumptions}

The advantage of our semi-analytic model is its ability to provide calculations over a wide range of galaxy and MBH orbital properties at the cost of making some simplifying assumptions. The potential impact
of our assumptions on the dynamical evolution of MBH pairs is
discussed by \citet[][Paper I]{LBB20a,LBB20b}. In this section, we
consider the possible effects of these assumptions on the dAGN
properties and their connection to MBH mergers.

We assume that the pMBH\ is fixed at the center of the host galaxy. If
the motion of the pMBH\ and its corresponding Bondi-Hoyle-Lyttleton
accretion rate are accounted for in the calculations, the resulting
bolometric luminosity would be lower and the evolution time would be
shorter. In this case, there would be fewer dAGNs with
$L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$ and more MBH mergers at
higher redshift, resulting in a larger coalescence fraction of
dAGNs. Consequently, including the motion of the pMBH\ would increase
the \textit{LISA}\ detection rate. This effect would be strongest in
comparable mass MBH pairs and weaker in those with small $q$. It would
be manifested as an increase in the number of high redshift
\textit{LISA}\ detections, since MBH pairs at high redshifts tend to have
larger mass ratios.

The orbit of the sMBH is assumed to always reside in the midplane
of the model remnant galaxy. If an inclined orbit takes the
sMBH\ outside of the galactic gas disk, the evolution time would
increase and $L_{\mathrm{bol}}$ would decrease. We also assume that
the sMBHs do not grow in mass during their orbital evolution from kpc
scales toward coalescence. Had they been able to do so, the increase
in the total mass of the binary would render the inspiral time shorter
and their bolometric luminosity higher.

As mentioned in \S~\ref{sec:RF_AGN_dist}, we considered the effect
of RF only during the DF phase. Some studies have shown that RF can
also affect the orbital evolution of sMBHs in circumbinary
disks if there is no gap formed. Especially when sMBHs accrete at high rates, the radiation leads to strong
winds pushing against the gas disk, blowing the gas
away from the binary which stalls the binary hardening in the circumbinary disks \citep{RF1pc, William22}. On the contrary, when there is a gap in the disk, RF does not affect the evolution time of sMBHs \citep{RF1pc}. Our model assumes the gap-opening
regime (Paper I), so taking into account RF in circumbinary disks should not significantly affect the dAGN coalescence fraction and the $\textit{LISA}$ detection fraction predicted in this work.

Triplets of MBHs are likely to form at high redshifts, when the merger rate of galaxies is high. MBHs in these triplets may undergo the Kozai-Lidov oscillations which may increase the eccentricity of the central MBHBs  \citep{Kozai1962} and increase the dAGN coalescence rate. Besides the Kozai-Lidov oscillations, the chaotic three-body interactions can also boost the coalescence rate \citep{Bla2002,Hoffman2007, Amaro2010, Kul2012, Bonetti2016, Ryu2018}. If triplets and the three-body interactions were included in our model, the dAGN coalescence fractions and the $\textit{LISA}$ detection fraction would be higher.

We do not take into account gas consumption and star formation in the
merger remnant galaxies. This means that during the orbital evolution
from $\sim$~kpc to coalescence, the gas fraction of a host remains at
the same value inherited from TNG50-3 data file. This assumption
potentially increases the number of dAGNs with
$L_{\mathrm{bol}}>10^{43}$~erg~s$^{-1}$, since in reality at least a
fraction of the gas reservoir turns into stars. This reduces the gas
fraction and increases the stellar density in the host galaxies. In the
presence of RF, higher stellar densities result in more efficient
orbital evolution of MBH pairs and more MBH mergers. Thus, in the
presence of RF the coalescence fraction of dAGNs would be higher than
determined here. In the absence of RF, the effect of this assumption
can not be easily predicted due to the complicated interplay of DF and
the galactic parameters \citep{LBB20a}. The host galaxies with high gas
fraction are affected most by this assumption.

\section{Conclusions}
\label{sec:concl}
dAGNs are a product of galaxy mergers and trace
the population of future MBH coalescences. In this paper, we combined the
MBH dynamical evolution calculations from Paper I with estimates of
AGN luminosity to explore how the luminosities and
separations of dAGNs change as the MBH pair evolves in its
host galaxy. In addition, we were able to calculate the fraction of the
dAGN population at a redshift $z_{\mathrm{dAGN}}$\ that lead to a MBH merger at
redshift $z_{\mathrm{coal}}$, including determining the fraction that lead to a
\textit{LISA}\ SNR$> 8$.

We find that, in the absence of RF effects, the dAGN population in our model, with total
bolometric luminosity $L_{\mathrm{bol}} > 10^{43}$~erg~s$^{-1}$, peaks at
$z_{\mathrm{dAGN}}$$\approx 0.4$ and is dominated by systems with separations $a \ga 0.7$~kpc (Fig.~\ref{fig:z_dist}). However, a majority of
these dAGNs will not lead to MBH mergers before $z_{\mathrm{coal}}$$=0$
(Fig.~\ref{fig:fraction}). In fact, the majority of low-$z_{\mathrm{dAGN}}$\ dAGNs that
are precursors to MBH mergers are separated by $\la 0.5$~kpc
(Fig.~\ref{fig:al_dist}). This is a result of the orbital decay times
of the sMBH -- there is simply not enough time for most $a\sim 0.7$~kpc
dAGNs at $z_{\mathrm{dAGN}}$$\approx 0.4$ to evolve through to coalescence before
$z_{\mathrm{coal}}$$=0$. Therefore, a closer connection between dAGNs and MBH
mergers can be most easily obtained by detecting dAGNs at $z_{\mathrm{dAGN}}$$\ga
1$, where the coalescence fraction exceeds $0.5$. The separation of
dAGNs at $z_{\mathrm{dAGN}}$$\ga1$ is $\sim 0.7$--$1$~kpc and the total
$L_{\mathrm{bol}}\approx 10^{43-46}$~erg~s$^{-1}$.

The orbital evolution of the sMBH\ depends on the properties of the
post-merger galaxy and MBH pair \citep[e.g.,][Paper I]{LBB20a}, so
these conditions also impact the coalescence fractions of dAGNs. We
find that dAGNs in post-merger galaxies with bulge masses
$M_{\mathrm{sb}} \la 10^{10}$~M$_{\odot}$ and with MBH mass ratios of
$q \approx 0.5$ have the highest coalescence fractions. The fractions increase with $z$, observational searches for dAGNs that
lead to MBH mergers may consider prioritizing galaxies with less
massive stellar bulges.

In Paper I we found the radiation feedback effects can significantly
increase the evolution timescales for MBH pairs, in particular in high
gas fraction galaxies. This phenomenon (``negative DF'') leads to a
drop in the expected MBH coalescence rate and is seen in the dAGN
properties when we include this effect (Fig.~\ref{fig:fraction}
and~\ref{fig:al_dist_RF}). A signature of RF effects is in a
larger than expected number of dAGNs with wide separations, as this
would indicate slow orbital decay predicted by negative DF.

The coalescence fractions shown in Fig.~\ref{fig:fraction} can be
combined with the results of dAGN surveys to predict both the MBH
merger rate and the rate of \textit{LISA}\ signals with SNR$> 8$. We provide a
recipe in \S~\ref{sec:method} that can be followed to calculate
these rates (either with or without RF effects) from observations of
dAGNs. Comparing these predicted rates to \textit{LISA}\ measurements can be used to test our understanding of DF, including the importance of RF effects. The results like the ones presented here, in combination with the next-generation of dAGN
surveys, will thus be crucial in testing the physical models of MBH
evolution at sub-kpc scales.

\acknowledgments

T.B. acknowledges the support by the National Aeronautics and Space Administration (NASA) under award No. 80NSSC19K0319 and by the National Science Foundation (NSF) under award No. 1908042.

redpajama_set_name: RedPajamaArXiv


The summer has begun out here on Maui and Trilogy is gearing up for our snorkeling trips around Maui and Lana'i. With weather typically in the mid 70's F and intense sunshine, sunscreen comes to mind. There are many options out there for you to choose from and it can get overwhelming: all natural, biodegradable, eco-friendly, organic, reef safe, waterproof, creams, gels, spray....the list goes on. When traveling to the Hawaiian Islands and other tropical locations, there's a good chance you will jump into the big blue. Even if you have no plans to snorkel around coral reefs, you still make an impact on marine ecosystems. At a time when these fragile systems are experiencing one of the worst coral bleaching events on record, one of the most important thing to consider when choosing a sunscreen is, "Is it reef safe?"
In general, any natural sunscreen (organic, biodegradable etc.) is better for the environment than a conventional one. Look for a brand that uses physical sunblocks such as titanium or zinc oxide instead of chemical ones. The jury is still out as to whether titanium and zinc oxide are truly reef safe. Both are mineral powders that some scientists claim settle on the ocean floor and block sunlight, but this belief does not seem to be widely accepted. If you want to decide between the two, zinc oxide is proven to block both UVA and UVB rays whereas titanium oxide primarily only blocks UVB rays.
So what can you do? Make sure to apply sunscreen at least 10-15 minutes before going in the water so that the lotion absorbs into your skin. You can also wear an SPF rash guard top and leggings to reduce the amount of sunscreen you put on your skin. Trilogy sells both long and short sleeve rash guards with UPF sun protection.
You can gather additional information from the National Park Service.
Downs, C. A., Kramarsky-Winter, E., Segal, R., Fauth, J., Knutson, S., Bronstien, O., Ciner, F. R., Jeger, R., Lichtenfeld, Y., Woodley, C. M., Pennington, P., Cadenas, K., Kushmara, A., Loya, Y. 2015. Toxicological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Arch. Environ. Contam. Toxicol.


text:
What Are the Disadvantages of SATA?
Basics of Running a Business
By Dan Stone
Information About the Softv92 Data Fax Modem
Comparison of the MacBook Pro With the HP Pavilion Laptop
Laptop Vs. PC Power Consumption
The Best Ways to Build a Fast Computer
What Are PCI Slots?
The widespread adoption of the Serial ATA device connection standard may leave you wondering if you have other options. SATA has a few disadvantages when compared to the Serial Attached Small Computer System Interface standard; however, the SATA standard is considered sufficient for most user-end computer purposes. According to The Serial ATA International Organization, the SATA standard is available in 99 percent of all new computers. SATA's disadvantages come into play in servers and high-end workstations. SATA's major advantage is its lower cost.
Speed and Performance
SATA has a speed disadvantage against SAS. Third generation SATA and second generation SAS match each other with a maximum bandwidth of 6 Gbps. Both standards can send up to 6 Gb of data to the system motherboard per second, which is faster than a typical hard drive's maximum bandwidth; high-end hard drives and solid state disk drives in a can push that connection. The third-generation SAS connection standard features a maximum-bandwidth of 12Gbps, offering twice as fast of a data transfer as SATA. Additionally, SATA hard drives are capped at a 10,000RPM speed while SAS drives can reach speeds of up to 15,000RPM, which makes the SAS hard drives potentially faster.
Mass Connectivity
SATA is at a disadvantage against SAS when it comes to the total number of devices you can connect to the system. SATA and SAS connectable devices include hard drives and optical drives. With SATA, every device needs its own SATA port on the motherboard or an expansion card attached to the motherboard. This means that a SATA-supporting computer can have maximum of about a dozen connectable devices in practice. That number can be increased, but it is still limited by the motherboard. On the other hand, SAS-supporting computers can connect up to 128 devices with expansion cards.
Clean Cables
SAS devices can be daisy-chained to each other so they can share ports, whereas SATA devices need their own ports. This system makes it so SAS computers tend to have less cable clutter when compared to SATA computers. Sequencing cable connections to devices in a row organization uses less cable length than connecting each individual device to the motherboard.
Server Use and Workstation Use
SATA is at a disadvantage against SAS when being used in servers and workstations. It is common for servers to feature dozens of hard drives and SATA support for that many hard drives requires substantial expansion planning if it's possible at all. The servers can also take advantage of the speed boost because they handle requests from multiple computers at the same time. High-end workstations can also be at a disadvantage with SATA because they can take advantage of SAS's faster performance. However, SATA is a sufficient solution for consumer-end devices and won't be at a noticeable disadvantage in typical situations.
The Serial ATA International Organization: SATA FAQ
Thinkmate: SATA vs. SCSI vs. SAS
Network World: Comparing SAS, SATA and Fibre Channel
PCMag.com: Definition of: SATA
PCMag.com: Definition of: SAS
PCMag.com: Definition of: SCSI
Dan Stone started writing professionally in 2006, specializing in education, technology and music. He is a web developer for a communications company and previously worked in television. Stone received a Bachelor of Arts in journalism and a Master of Arts in communication studies from Northern Illinois University.
What Is the Difference Between Powered & Non-Powered USB Hubs?
What Is LAN Used For?
Difference Between SAS & Ultra SCSI
What Are Characteristics of a Hard Drive?
What Is the Difference Between DDR1 & DDR2 RAM?
What Are the Disadvantages of Using Hubs?
Ethernet Networks Involving Hubs or Repeaters
Differences Between Coaxial & Optical
What Is the Purpose of Adding an Expansion Card to the Motherboard?
1 What Is the Difference Between Powered & Non-Powered USB Hubs?
2 What Is LAN Used For?
3 Difference Between SAS & Ultra SCSI
4 What Are Characteristics of a Hard Drive?

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text:
A Short History of The Telegoons...
Prev. Chapter Home Next Chapter
Contents of this Chapter:
Radio's Crazy Gang-- "The Goons" (...includes a list of the BBC Goon CDs)
Goon Shows Preserved While You Wait...
The Wonder of Ultra-Kendall-Vision...
Running Jumping & Standing Still...
Let's See Them Do That On Television!
Telegoon Toon Time...
Voice Actors, Puppeteers & Producers
Go Ask Eccles & Bluebottle
The Persistence of Goon Memory...
Neddie Seagoon Puppet Restoration Fund...
Radio's Crazy Gang--"The Goons"...
Initially billed (against the Goons' wishes) as CRAZY PEOPLE, featuring Radio's Crazy Gang--"The Goons", The Goon Show first aired 28th May, 1951, and revolved around the voice talents of Peter Sellers, Harry Secombe, Spike Milligan, and (briefly) Michael Bentine. Musical breaks were provided by The Ray Ellington Quartet, The Stargazers (who left after the first six shows), and Max Geldray. The Wally Stott Orchestra performed the signature tune, and did the various musical link passages, assisted by the Ray Ellington Quartet in the rhythm section. Grams and Spot sound effects were provided by various people, including John P. Hamilton who has shared his experiences extensively with the GSPS (See newsletters: #81, #82, #83, #84, #85, #86, #92, #94, and the following GSPS video recordings: An evening with John P. Hamilton, 1995; A weekend called Fred, 1995; An Evening with Fred, 1996; Son of a weekend called Fred, 1997).
In the wake of the post-war euphoria that swept Britain in the late 1940s, the '50s provided a fertile ground for new ideas, including new ideas for comedy. Besides, the BBC had been losing some of its top comedians to the private sector and needed to bolster up its offerings. Emerging from this environment, The Goon Show struck a deep chord, particularly in the younger segment of the radio audience, and quickly developed a large following that today, 50 years later, is still extremely loyal. A large part of the show's continued success resides in its ability to take the listener out of this world, stretching the imagination way beyond the normal limits of common sense and logic. As Peter Sellers recalled (TIME, March 3, 1980), "Our premise was taking serious ideas--or any idea at all--to their illogical conclusion." In discussing the origins of The Goon Show, Spike Milligan (Australian PIX, June 6, 1964) said that the show was conceived "as a means of lampooning everything ridiculous about modern living." In his introduction to The Book of The Goons (Elizabeth Rose, ed.), long-time producer of the shows, Peter Eton, put it this way: "Unlike any other radio programme of its time, The Goon Show was less a criticism of any social system than a bold and melodramatic rearrangement of all of life." Nowhere is this more apparent than in the diverse personalities of the eccentric but likeable characters that populate the Goon world. It is these same larger-than-life characters and their human foibles that give the show much of its enduring appeal.
No other radio comedy show has had the lasting impact of The Goon Show, an impact that continues to be felt, even by television. Just as The Goon Show turned British radio comedy on its ear, another comedy show, Monty Python's Flying Circus, in turn, revolutionized British TV comedy. The Pythons have, however, given much of the credit to Spike Milligan, and on many occasions have said that without The Goon Show, and Spike's Q television series, there would be no Monty Python show. As Python co-founder Terry Jones recalled in a recent radio interview, "I thought...what can we do to Python to make it different...hoping to make it ground breaking the way that the Goons...was ground breaking on radio...then seeing Q5, and suddenly thinking, Uh Oh! Milligan's done it already." As put by David Morgan, author of Monty Python Speaks (see Bibliography section), "If there is a progenitor to credit (or blame!) for Monty Python, the innovative and surreal comedy group that turned the BBC and cinema screens on their ends, one need look no further than a tall, undisciplined, manic-depressive Irishman..." Spike's comedic genius was further acclaimed by the readers of BBC News Online, who voted him the funniest person of the millennium, ahead of Monty Python's John Cleese, and such luminaries as Charlie Chaplin, Stan Laurel and Oliver Hardy (September 1999).
The audience size for the original Goon Show broadcasts in the UK grew rapidly, and by the 6th series (September 1955 through March 1956) had reached 7,000,000 for some shows (see table). The figures after this declined somewhat, due to the increasing impact of television. Considering that in March 1955 there were 9,414,224 radio licenses and 4,503,766 combined radio and television licenses, the 5th series Goon Show audience was a significant proportion of the radio audience. By the middle of the 6th series (end of November, 1955), radio licenses had decreased by 458,600, and combined radio and television licenses had increased by 757,933. Obviously a lot of the UK radio audience were starting to spend time in front of the television set, rather than listen to the radio!
Although Goon Show repeats have been somewhat thin on the ground in the UK since the series ended in 1960 (despite Milligan's efforts with the BBC), outside the UK the situation has been quite different. By 1967, the list of countries still enjoying regular radio broadcasts of the Goon Show included New Zealand, Australia, Canada, USA (Public Broadcasting Service), Bermuda, Hong Kong (to the British Forces community), and Aden (ditto). Thirty five years later the list is a lot shorter, and apart from Australia, which seems to be a special case (see below), regular radio broadcasts seem to be a thing of the past. One good, but erratic, source of information is the Internet newsgroup alt.fan.goons, which has carried occasional reports of broadcasts in New Zealand, Canada, and the USA.
During all of the 1960s, 70s, and most of the 80s, New Zealand's National Radio programme (stations 1YA, 2YA, 3YA, and 4YA) repeated the shows every Sunday at 9:00 p.m. More recently, starting May 1999, Radio New Zealand broadcast, at 3:30 p.m. on Saturday afternoons, a series of six of the finest Goon Shows. The aim was not to satisfy any pent-up thirst for more shows. Instead it was to find out "what the 1999 audience makes of Bluebottle" (NZ Listener, May 1st, 1999). I have yet to find out what was the outcome of this research.
The country that ranks as number one in Goon Show popularity outside the UK is not the land of the kiwi, but instead the land of the kangaroo...where the Goons became one of the most revered national institutions, and also where (is there a connection here?) many of the Milligans made their home. As of mid 2000, The Goon Show is still repeated twice-weekly by the Australian Broadcasting Commission (ABC). Interestingly, although transcription discs were available much earlier, ABC Radio did not actually start broadcasting The Goon Show until 1956 (6th Series).
A total of more than 240 Goon Show scripts were written, mainly by Spike Milligan, but more often than not assisted by professional script-writer Larry Stephens. Significant script contributions were also made by Jimmy Grafton, Eric Sykes, Maurice Wiltshire (more about him later), and John Antrobus. In the first three series, it was Jimmy Grafton's editorial hand that helped moderate Spike's extreme flights of imagination, making the shows more comprehensible to the average listener. The shows were rehearsed on Sunday afternoons, and then were recorded in front of a live studio audience the same evening. The venue was the BBC's London studios. The show's main characters were provided by the voices of Spike Milligan (Eccles the original Goon, Miss Minnie Bannister, Moriarty), Sir Harry Secombe (Neddie Seagoon, in various guises as Inspector~, Chief Commissioner~, Dr~, Lieutenant~, Hairy Seagoon, Ned of Wales, Gas Meter Inspector Ned Seagoon, etc., etc.), and Peter Sellers (Bluebottle, Mr. Henry Crun, Major Dennis Bloodnok, Grytpype-Thynne).
"The Goon Show was a phenomenon whose overall influence was greater than the sum of its individual programs. And its legacy has spread to generations who never heard the original broadcasts," said the great English humourist Frank Muir (1920-1998), as presenter of the BBC radio documentary A Sound of Goons. "Even to those who've never heard the repeats. There are schoolchildren now who imitate their parents' imitations of Bluebottle, who say 'He's fallen in the water', who tell each other to 'Shut up, Eccles!', who call each other 'dirty rotten swine', 'silly twisted boy', or even just 'Jim'. They may not be aware of their debt, but they owe it all to The Goon Show--a highly combustible mixture of volatile elements which managed--that difficult task--to make people laugh."
THE GOONS
Harry Secombe
Michael Bentine
These images originally appeared as numbers 10, 29, 41, and 33, respectively, in a set of 48 Telegum TV Stars bubblegum cards published by Merrysweets, London, UK, in the late 1950s.
BBC Home Service Audience Numbers
The Goon Show
Beginning of 1st series 370,000
End of 1st series 1,800,000
Some shows in 2nd series 3,000,000
Some shows in 4th series 3,000,000
The 7th through 10th series
Goon Shows were familiar fare for the British Forces community in Aden, of all places. The RAF's Aden Forces Broadcasting Association presented The Goon Show featuring Harry Secombe, Peter Sellers, and Spike Milligan, every Saturday evening at 8:30 p.m., on 1241 kHz AM. The AFBA masthead lists Flying Officer R.J.D. Wheeler as Chief Director. Little did the Chief Director know that eight years later he would be helping produce the puppet version of The Goon Show for BBC television!
You may click the CD or cassette icons below to buy the BBC Radio Collection Goon Shows. These are genuine BBC originals. Please note that the BBC has been redesigning some of the covers, so they may differ from those shown. Shipping is available to most parts of the planet.
Unsure of what to do? Click here for assistance.
Goon Show -
Celebrity Pick Of The Goons
CD boxed set.
Due Nov.1 2005
(Apparently is on hold)
Further details as & when
they come to hand.
(a.k.a. The Ultimate Collector's Set vol.1?)
The first 94 Goon Shows in the BBC Radio Collection
(Hover mouse over titles for track list. Note: Mozilla unfortunately
truncates these. Use IE6 for best results!)
Next section in this chapter: Goon Shows Preserved While You Wait...
Prev. Chapter Home Top of Page Next Chapter


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The Mandalorian Season 2 Showrunner Compares Game of Thrones to Star Wars Shows' 'Larger Story'
By: Pierre Chanliau
The upcoming season 2 of The Mandalorian, if rumors are true, will be adding a lot of new characters, all of whom should be very familiar to Star Wars fans. The biggest rumored additions to the cast are Ahsoka Tano and Boba Fett, two characters that span decades apart from one another and who represent the new and old eras of Star Wars.
While the first season was largely self-contained and small in scale, it got fans enamored with Mando and his new adoptee, The Child, or as the internet has dubbed them, Baby Yoda. So, it should excite fans to know that this next season will be expanding beyond the storyline of those two characters and exploring new ones separate from them to form a larger story.
In an extensive interview with The Mandalorian showrunner Jon Favreau and various others working on the show, Entertainment Weekly was able to get a plethora of information. But, what stuck out the most was that this season would see the exploration of storylines unrelated to Mando or The Child.
"The new season is about introducing a larger story in the world," Favreau said, who EW notes says that the show will move beyond stories focused on the titular character. "The stories become less isolated, yet each episode has its own flavor, and hopefully we're bringing a lot more scope to the show."
Adding to this discussion, Filoni says that "Everything gets bigger, the stakes get higher, but also the personal story between the Child and the Mandalorian develops in a way I think people will enjoy."
And while the first season's episodes were strictly focused on Mando, this next season will add new storytelling angles. Favreau said "As we introduce other characters, there are opportunities to follow different storylines," while making a comparison with "...Game of Thrones and how that evolved as the characters followed different storylines — that's very appealing to me as an audience member."
This larger scope and moving beyond the two main characters was aided by having fewer start-up costs for the second season, which meant a greater percentage of the show's big budget, estimated at $100M for the first season, could be used for these new additions.
Despite the bigger scope, the episode count will be the same as the first season with eight episodes of various lengths, with Jon Favreau noting that "There's probably even variation [in episode lengths] this year."
It's a bit mind boggling to imagine all these characters, if true, being introduced in live-action for the second season of The Mandalorian, on top of them potentially having their own storylines largely separate from Mando and Baby Yoda. It's likely that these storylines could crossover into one another.
The most blatant storyline of the bunch is Moff Gideon wielding the Darksaber, which was previously in possession of Bo-Katan Kryze and given to her by Sabine. This makes it entirely possible that Ahsoka, Sabine, and Bo-Katan will have a storyline separate from Mando, pursuing Gideon, who will himself be in pursuit of The Child for his blood and connection to the Force. This could all then merge into one storyline as all their paths with one another collide.
Whatever kind of stories emerge from this new season, it'll be great to see the scope of the universe expand and new and familiar characters return in live-action, some for the first time.
The Mandalorian Characters, Including Ahsoka, Rumored To Join Disney Parks
The Mandalorian (Series) , The Mandalorian (Character) , Baby Yoda
WandaVision Video Reveals Family Dog, Sparky, Coming Soon To Marvel Series
Tom Holland's Spider-Man 3: Set Video References Avengers: Infinity War's Thanos Snap
Thor 4: Matt Damon Reportedly Cast In Marvel Sequel
Tom Holland's Spider-Man 3: Mysterio Reference Spotted In Set Photos
The Direct Podcast: WandaVision Review, Brandon Davis of Comicbook.com
Spider-Man 3: Set Photos Show Zendaya & Tom Holland's Marvel Characters Together
The Direct Podcast: 2020 Awards, Joseph Gordon-Levitt MCU Rumors, SnyderVerse Movement
Spoiler Review - The Mandalorian: Season 2, Chapter 15: A Question of Faith
The Direct Podcast: Loki Season 2 Update, Robert Downey Jr. & Star Wars, MCU Scores Draft
The Direct Podcast: The Mandalorian Season 2 Finale, Marvel Studios' Fantastic Four Fancast
Copyright © 2020 The Direct Media Group LLC.


text:
School History and Highlights
Community Partnerships and Resources
Contact JQUS
International Baccalaureate (IB) Program
Hybrid & Remote Learning 2020-2021
Announcement & News
Fall Resources & Opportunities
Graduation Requirements, GPA, College Acceptances
From the Nurses
Absence Report Form
Wayfair Employees Welcome Little Sisters With Open Arms
JQUS Students at Wayfair
JQUS Partnership with Boston University Engineering
The College of Engineering has received a $145,000 contribution from AT&T to create a two-year engineering and technology program for an urban high school population, and to document its impact on high school graduation rates. The funding from AT&T will enable undergraduate Inspiration Ambassadors from the College's Technology Innovation Scholars Program (TISP) to deliver classroom and after-school engineering activities at the Josiah Quincy Upper School (JQUS) in Boston beginning in September.
JQUS Class of 2016 Emily Ta blazes her own path
Josiah Quincy Upper School (JQUS) senior Emily Ta, 17, knows what she wants. "Since the eighth grade, I knew I wanted to be in the business field," Emily said. "I've always been interested in the economy, international trade and international affairs." Emily will be attending Boston College in the fall, with 90 percent of her tuition covered by financial aid. She was also accepted to eight other schools: Boston University, Northeastern University, College of the Holy Cross, St. John's University, Mount Holyoke College, Framingham State University, UMass Amherst and UMass Lowell.


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Home Dayton Philharmonic Orchestra About Dayton Philharmonic
Neal Gittleman, Artistic Director and Conductor
Founded in 1933, the Dayton Philharmonic Orchestra has a distinguished place in the Gem City's history as one of the Miami Valley's oldest and longest-standing cultural institutions. A regional orchestra with 83 contracted musicians and rich in artistic tradition, the Philharmonic is proud to call the Benjamin and Marian Schuster Performing Arts Center its home. The Schuster Center is a world-class, state-of-the-art performance hall that attracts arts aficionados from all corners of Ohio and around the nation. In addition, the Philharmonic also performs at Westminster Presbyterian Church and the Dayton Masonic Center. Since July 1, 2012, the DPO has been part of the Dayton Performing Arts Alliance along with Dayton Ballet and Dayton Opera.
Artistic Director and Conductor Neal Gittleman inspires each listener's imagination with his unique programming, in-depth comments, easygoing style and infectious enthusiasm for music. His focus is to make symphonic music readily available, as well as appreciated, by all musical tastes. Under his direction, the Orchestra has received the American Society of Composers, Authors and Publishers (ASCAP) award for Adventurous Programming of Contemporary Music nine times. Neal Gittleman will celebrate his 25th season with the DPO in the 2019–2020 concert season.
Gittleman's mission naturally carries on the dream of the Orchestra's founding Music Director, Dr. Paul Katz.
The Dayton Philharmonic Orchestra tradition began in June 1933 when the then-young conductor and violinist, Katz, and his 26 professional area musicians performed Dayton's very first symphonic concert. They called themselves the Dayton Chamber Orchestra, but from the start, Katz had his musicians performing regular orchestral repertoire he had rescored for the chamber-size ensemble. At the end of the inaugural four-concert season, Daytonians were so enthusiastic that it was obvious another season must be planned. Community volunteers joined together to incorporate the budding nonprofit Dayton Chamber Orchestra Society, in addition to selling subscriptions for the second season.
In April 1934, the Chamber Orchestra Society changed its name to the Dayton Philharmonic Orchestra. A key contributor to the success of the Dayton Philharmonic Orchestra was Miriam Rosenthal, an influential businesswoman in the community, who worked side by side with Katz to build his dream. Rosenthal became the Orchestra's Executive Director during its third season. She remained in that post for three decades until her death in 1965. The financial support, guidance and devotion she brought to the organization marked her tenure. Orchestra historians have singled out Katz and Rosenthal as the two most indispensable and important persons in building the Dayton Philharmonic into the community treasure that it is today.
In November 1934, Katz introduced the first Young People's Concert to Dayton. The success of these concerts continues today, attracting audiences of more than 8,000 schoolchildren each year. The early Young People's Concerts spawned what has evolved into a full-scale, award-winning education program that has been an integral part of education in the Miami Valley ever since.
Realizing how much choral music would enhance the Orchestra's concert programming, in 1935 Katz founded the original all-volunteer Dayton Philharmonic Chorus. Currently, the 140-plus members, who are residents of the Miami Valley, join the Orchestra in concert several times a season to perform some of the most challenging and beautiful choral music. Weekly rehearsals are mandatory for membership and Chorus members attend them with pride.
In 1937, the Dayton Philharmonic Training Orchestra was formed to give young area musicians an opportunity to study challenging orchestral music and to sharpen their cultural awareness and appreciation of music. Another Katz first, the former Training Orchestra later became the Dayton Philharmonic Youth Orchestra, which today is well into its ninth decade with its primary goals unchanged.
Katz was so enthusiastic about satisfying everyone's musical taste that in 1945, he introduced the first Pops Concerts to Dayton. The new concept in musical entertainment was quick to catch on in the Gem City. At the end of the 1974–1975 season, Katz retired as the Orchestra's founding Music Director. He had been on the podium for 42 years.
Charles Wendelken-Wilson began his 12-year tenure as the Dayton Philharmonic's second Music Director in the 1975–1976 season. He continued to bring in world-class guest artists and to fine-tune the musicians' artistic talents. Under him, the Orchestra grew dramatically, in both innovative programming and in ticket sales. While Katz may have introduced individual pops concerts to the community, Wendelken-Wilson started a subscription Pops series in 1978–1979. He expanded the Pops series to two nights and added a second night to the classical series. His artistic leadership through twelve seasons continued to assure the Dayton Philharmonic's prominence as it neared its half-century mark.
Isaiah Jackson served as the Orchestra's third Music Director from 1987 to 1994. Drawing on his experiences as a guest conductor of some of the world's major orchestras, he introduced subscribers to such programming highlights as Dayton's first-ever performance of Mahler's Symphony No. 8, Symphony of a Thousand, a true tour de force for the more than one hundred performers on stage.
The Dayton Philharmonic is a fully professional, unionized orchestra comprising musicians who also teach in area high schools and universities and privately. In addition to a full symphony orchestra, the Dayton Philharmonic family includes five chamber ensembles, a professional concert band, a 140-voice all-volunteer Chorus and three youth orchestras.
Over the years, the Orchestra has continued to build upon its outreach programs. In 1998, a historic Concert for Peace joined together the Dayton Philharmonic Orchestra and the Sarajevo Philharmonic in celebration of the fourth anniversary of the signing of the Dayton Peace Accords. The concert symbolized the partnerships of the people of Dayton and Sarajevo in the building of lasting peace in Bosnia. The program had an international flavor, with music by Bosnian, French, German, American and English composers.
Locally the Dayton Philharmonic has joined performance forces with the Boonshoft Museum of Discovery, the Wright State University Collegiate Chorale, Central State University Chorus, Dayton Art Institute, Dayton Bach Society, Dayton Ballet, Dayton Contemporary Dance Company, Kettering Children's Choir, The Human Race Theatre Company, Muse Machine and The Puerto Rican Cultural Society, among many others. Dayton's public radio stations WDPR/WDPG-FM broadcast all of the Orchestra's classical concerts and interview many of its guest artists, thus making the Dayton Philharmonic's programs available to a wide range of Miami Valley residents. In addition, many concert rebroadcasts and simulcasts take place on Discover Classical 88.1 WDPR and 89.9 WDPG. Year after year, the Dayton Philharmonic continues to offer its patrons unique, challenging programming that stimulates and inspires the imagination.


The Hagerstown Civil War Round Table will be featuring a talk on Robert E. Lee's famous Special Order 191, the Lost Order, by Tom Clemens. Robert E. Lee issued Special Order 191 during the Maryland campaign, before the Battle of Antietam. A copy of the order having been lost, was recovered by Union soldiers of the 27th Indiana on the Best Farm near Frederick, Maryland. The order provided the Union Army with valuable information concerning the Army of Northern Virginia's movements and campaign plans. Upon receiving Lee's "Lost Order", Maj. Gen. George B. McClellan, leading the Union Army of the Potomac, would exclaim "Here is a paper with which, if I cannot whip Bobby Lee, I will be willing to go home." The practical value of this intelligence, which was quickly growing obsolescent, continues to be the subject of much debate. The event is at 7:30 pm on Thursday, January 24, 2019 at Homewood Suites, 1650 Pullman Lane Hagerstown, MD. Dinner at 6:30 pm, open to non-members as well as members, is $22 (reservations required) and the talk at 7:30 pm is $5 for non-members, both payable at the meeting. For more information visit https://sites.google.com/view/hagerstowncwrt/home, search for: Hagerstown Civil War Round Table, email hagerstowncwrt@gmail.com, or call Dennis Graham at 301 766 9516. Dr. Tom Clemens is a history professor emeritus at Hagerstown Community College and a longtime NPS volunteer interpreter and living history presenter. He is a founding member of Save Historic Antietam Foundation, has been its President since 1989, and is eternally grateful for the generosity and dedication of our members. He is the editor of Ezra Carman's The Maryland Campaign of September, 1862: Volume I, South Mountain, Volume II, Antietam, and Volume III, Shepherdstown Ford and the End of the Campaign. Mr. Clemens earned his doctoral degree at George Mason University, where he studied under Maryland Campaign historian Dr. Joseph L. Harsh. He has published a wide variety of magazine articles and book reviews, has appeared in several documentary programs, and is a licensed tour guide at Antietam National Battlefield.


We have included a fair amount of information on this site to do with setting up and running your service using PowerPoint. Although the actual operation of our system is very simply there are a few things to set up. Once this is accomplished the system is easy to manage and looks very professional. It is even possible to set up an entire service an hour before it starts.
Below you will find a list of things you will need accomplish to get your church up and running with a projector, computer and the Using PowerPoint in church system.
After the setup up is done, and most of your songs are entered operating is a simple process. You can train people to use the system by working with them in a few services.


While every care has been taken to ensure the prices and availability of this tour is locked in, we do sometimes experience fluctuations and changes from our suppliers and ground operators. While every effort will be made to ensure this has no impact on the overall cost of your trip, if this can not be done, you will be notified immediately with options.
Please note that we are working in remote destinations and sometimes changes to the itinerary are unavoidable. While we endeavour to ensure we stick to the set itinerary, changes may occur prior to travel and while on location.
Also note that wildlife is never guaranteed nor predictable. We are travelling during times of high probability of wildlife experiences, however this is never 100% guaranteed.
Flights are NOT included with this package. Please discuss with us the timing requirements for arrival and departure from Johannesburg if you are organising your own flights. If you wish us to book flights, we are able to arrange this also.
All prices are quoted in Australian Dollars. Typically, prices are based on two passengers travelling together. Solo traveller supplements may be applicable. Special offer pricing has already been applied to the website pricing displayed, unless it is stated otherwise.
Passports must have a validity of at least 6 months or longer than your intended stay overseas. Visas to some countries are required for Australian Passport holders. Visas can be purchased on arrival in most countries, but please note, for entry into certain countries a visa must be applied for online prior to travel. Some visa fees are payable in US Dollars cash only. Some countries have a requirement making it necessary to have a certain number of blank pages in your passport. Please check with us regarding visa requirements.
Travelling with children under 18 years of age through certain countries may require further documentation in addition to their valid passport. As requirements can change, please check with us.
Please consult your GP or Travel Doctor for up-to-date medical advice. A minimum level of fitness is required to be able to participate on a Where Wild Things Roam Travel tour. In addition, some tours may require you to disclose your body weight. Please check with us to ensure that you can meet the relevant requirements.
Luggage restrictions may apply to your tour where safari vehicles or light aircrafts are utilised. Please check your trip dossier for detail on this and what is suggested to pack.
A non-refundable deposit of 25% per person is required within seven days of booking confirmation along with a signed Booking Form. Some tours and arrangements may impose a higher non-refundable deposit – please check at time of booking. Payment of deposit and a signed Booking Form represents acceptance of Where Wild Things Roam Travel Terms & Conditions by the client. Final balance of payment must be received no later than 60 days prior to departure.
Bookings made within 30 days of travel from Australia will require full payment immediately.
An amendment fee of AU$50 will be levied to cover communication and administration costs for any changes to bookings. This is in addition to any airline and operator fees.
We can organise additional arrangements such as hotels and car hire not forming part of a package. Just ask us at the time of booking.
Cancellations must be received in writing and will take effect from the date received by Where Wild Things Roam Travel. The following cancellation charges will apply to the tour costs.
These charges can vary subject to the trading terms of our suppliers as some do impose higher cancellation fees on certain tours. The non-issuing of an invoice or non-payment of deposit will not exempt clients from these cancellation and administration fees. We regret we can make no exception to the charges and strongly recommend that comprehensive travel insurance is taken out at time of booking to cover cancellation fees.
We strongly recommend that a comprehensive travel insurance policy be taken out at time of paying the deposit. Where Wild Things Roam Travel will NOT accept responsibility for loss of deposit/full payment, loss or damage to baggage and personal items, personal illness or injury, medical expenses, cancellation or curtailment of your trip.
Much care has gone into the composition of itineraries and prices, however circumstances beyond our control such as currency devaluation, fuel or air fare surcharges, imposition of new or amended Government charges (i.e VAT) may necessitate an increase in cost. Where Wild Things Roam Travel cannot be held responsible for these changes. Should this occur at any time until departure date, you will be notified as soon as possible, and regardless of deposit or total payment having been made, any increase is to be paid by the client. If such increase is unacceptable, the client may cancel the booking, though, in so doing, is still liable to pay any cancellation charges imposed by our suppliers. While every effort has been made to ensure prices are accurate, please use the brochure as a guideline only, as rates are subject to change.
Where Wild Things Roam Travel uses local ground operators in Africa. The standards of accommodation and other services are based on various factors, which are generally accepted as indicated as a certain class. However, we do not represent or guarantee that standard, class or fitness for purpose of the accommodation or service. Where Wild Things Roam Travel does not accept any liability of whatever nature for the acts, omissions or default, whether negligent or otherwise, of those airlines, local operators, shipping companies, hoteliers or other persons providing services in connection with your tour pursuant to a contract between them and yourselves and over whom we have no direct and exclusive control. We do not accept liability for any injury, damage, loss, delay, change of itinerary when required, additional expense or inconvenience caused directly or indirectly by events which are beyond our control, or which are not preventable by reasonable diligence on our part including, but not limited to war, civil disturbances, fire, floods, unusually severe weather, acts of God, acts of Government or of any other authorities, accidents to, or failure of, machinery or equipment, or industrial action (whether or not involving our employees and even though such actions may be settled by acceding to demands of a labour group).
© Copyright 2019 Where Wild Things Roam Travel.


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