The SAMI Galaxy Survey: Satellite galaxies undergo little structural change during their quenching phase. (arXiv:1902.05652v1 [astro-ph.GA])

The SAMI Galaxy Survey: Satellite galaxies undergo little structural change during their quenching phase. (arXiv:1902.05652v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Cortese_L/0/1/0/all/0/1">L. Cortese</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sande_J/0/1/0/all/0/1">J. van de Sande</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_C/0/1/0/all/0/1">C. P. Lagos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Catinella_B/0/1/0/all/0/1">B. Catinella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davies_L/0/1/0/all/0/1">L. J. M. Davies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Croom_S/0/1/0/all/0/1">S. .M. Croom</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brough_S/0/1/0/all/0/1">S. Brough</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bryant_J/0/1/0/all/0/1">J. J. Bryant</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lawrence_J/0/1/0/all/0/1">J. S. Lawrence</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Owers_M/0/1/0/all/0/1">M. S. Owers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Richards_S/0/1/0/all/0/1">S. N. Richards</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sweet_S/0/1/0/all/0/1">S. M. Sweet</a>

At fixed stellar mass, satellite galaxies show higher passive fractions than
centrals, suggesting that environment is directly quenching their star
formation. Here, we investigate whether satellite quenching is accompanied by
changes in stellar spin (quantified by the ratio of the rotational to
dispersion velocity V/$sigma$) for a sample of massive ($M_{*}>$10$^{10}$
M$_{odot}$) satellite galaxies extracted from the SAMI Galaxy Survey. These
systems are carefully matched to a control sample of main sequence, high
$V/sigma$ central galaxies. As expected, at fixed stellar mass and
ellipticity, satellites have lower star formation rate (SFR) and spin than the
control centrals. However, most of the difference is in SFR, whereas the spin
decreases significantly only for satellites that have already reached the red
sequence. We perform a similar analysis for galaxies in the EAGLE
hydro-dynamical simulation and recover differences in both SFR and spin similar
to those observed in SAMI. However, when EAGLE satellites are matched to their
`true’ central progenitors, the change in spin is further reduced and galaxies
mainly show a decrease in SFR during their satellite phase. The difference in
spin observed between satellites and centrals at $zsim$0 is primarily due to
the fact that satellites do not grow their angular momentum as fast as centrals
after accreting into bigger halos, not to a reduction of $V/sigma$ due to
environmental effects. Our findings highlight the effect of progenitor bias in
our understanding of galaxy transformation and they suggest that satellites
undergo little structural change before and during their quenching phase.

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