Andrew Wetzel edited observations.tex  about 9 years ago

Commit id: ed62e85cbba2ca1c19e482fc45fd7af8ecb6e1b3

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In addition to the data in \citet{McConnachie2012}, we also include the more recent measurements or upper limits of cold atomic gas mass from \citet{Spekkens2014}.  We do not include the recently discovered ultra-faint satellites of the MW from the Dark Energy Survey \citep{Koposov2015, DES2015}, though if they are all quiescent galaxies, their inclusion would not change our results.  Observed dwarf galaxies show a tight correlation between their morphology, star formation, and cold gas content, such that all dwarf spheroidals have little-to-no detectable gas or ongoing star formation, and most of the dwarf irregulars have a significant fraction of their baryonic mass in cold gas and ongoing star formation \textbf{XXX stochastic sampling of the IMF at low SFRs makes this statement a little tricky XXX}. tricky. AW - how should we word it? they are both populations are *consistent* with these trends? maybe instead say signs of recent star formation (from SFHs)?}.  Thus, we define ``quiescent'' satellites as those that have $\mgas/\mstar<0.1$ or are classified as having spheroidal morphology if they have no cold gas constraints.  Thus, by this definition, the only star-forming, gas-rich satellites in the LG are: LMC ($\mstar=1.5\times10^9\msun$, $\mgas/\mstar\approx0.3$) and SMC ($\mstar=4.6\times10^8\msun$, $\mgas/\mstar\sim1$) around the MW, and LGS 3 ($\mstar=9.6\times10^5\msun$, $\mgas/\mstar\approx0.4$) and IC 10 ($\mstar=9\times10^7$, $\mgas/\mstar\approx0.6$) around M31.  %(While Sculptor has $\mgas / \mstar \approx 0.096$, we consider it quiescent based on its morphology and lack of recent star formation \citep{Weisz2014a}).