Andrew Wetzel edited quenching_time.tex  about 9 years ago

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%Thus, the left panel of Figure~\ref{fig:quench_times} uses time since infall into the MW/M31 halos, ignoring group preprocessing, while the right panel uses time since infall into \emph{any} host halo, including group preprocessing.  The latter results in longer quenching timescales, though it primarily shifts the upper 16\% of the distribution.  Both panels show shorter median quenching timescales for less massive satellites: $\sim5\gyr$ at $\mstar=10^{8-9}\msun$, $2-3\gyr$ at $\mstar=10^{7-8}\msun$, and replace_contentlt;1.5\gyr$ $ < 1.5\gyr$  at $\mstar<10^7\msun$, depending on the inclusion of group preprocessing. Moreover, the median timescale for two of the lowest $\mstar$ bins is $0\gyr$ because 100\% of those satellites are quiescent, which implies extremely rapid quenching after infall.  This mass trend is broadly consistent the results of \citep{Weisz2015} that more massive dwarf galaxies in the LG quenched more recently. 

Altogether, Figure~\ref{fig:quench_times} indicates a complex dependence of the environmental quenching timescale on satellite $\mstar$.  The typical timescale for the low-mass satellites in the MW/M31 halos increases with $\mstar$, from $\lesssim1\gyr$ at $\mstar<10^7\msun$ to $\sim5\gyr$ at $\mstar\approx10^{8.5}\msun$.  \citet{Wheeler2014} indicate that this mass dependence continues, though with a rapid increase ($\sim2\times$) to $\approx9.5\gyr$, and no change from $\mstar\approx10^{8.5}$ to $10^{9.5}\msun$.  This rapid increase implies some tension with our results based on the two quiescent satellites of M31, NGC 205 and M32 ($\mstar\approx10^{8.5}\msun$), unless both experienced unusually early infall $> replace_contentgt;  9.5\gyr$ ago or M31 quenched its satellites much more rapidly than the (more massive) hosts in \citet{Wheeler2014}. %(\citeauthor{Wheeler2014}'s results are consistent with the star-forming LMC/SMC of the MW.)  At higher $\mstar$, \citet{Wetzel2013} indicate that the quenching timescale rapidly \emph{decreases} by $5\times10^9\msun$, and it continues to decline with increasing $\mstar$.