HI Stripping and Galaxy Evolution in the Virgo Cluster
HI Stripping and Galaxy Evolution in the Virgo Cluster
HI Stripping and Galaxy Evolution in the Virgo Cluster
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Galaxies can go through…<br />
Life is Tough!<br />
Environmental effects
Very extended<br />
& vulnerable<br />
Role of <strong>HI</strong><br />
Galaxies can go through…<br />
<strong>HI</strong> Gas, a great tool!<br />
Reservoir of<br />
star formation<br />
Good tracer<br />
of various<br />
effects
Title<br />
<strong>HI</strong> <strong>Stripp<strong>in</strong>g</strong> & <strong>Galaxy</strong> <strong>Evolution</strong> <strong>in</strong> <strong>Virgo</strong><br />
“<strong>Galaxy</strong> <strong>Evolution</strong> & Environment”<br />
Kuala Lumpur, Malaysia Mar 30-Apr 3, 2009<br />
Where <strong>and</strong> how do<br />
galaxies lose <strong>the</strong>ir <strong>HI</strong> GAS <strong>in</strong><br />
<strong>the</strong> cluster environment?<br />
Aeree ChunG<br />
National Radio Astronomy Observatory
Atlas+Legend<br />
M87<br />
M49<br />
M86<br />
M87 M86<br />
M49 D 25 ×10
Outskirts1
Intermediate
Center
Outskirts2
Color-<strong>HI</strong><br />
ISM <strong>Stripp<strong>in</strong>g</strong> & Color <strong>Evolution</strong><br />
RED<br />
Higher fraction of red galaxies <strong>in</strong> high density regions<br />
(Hogg et al. 2004): AGN? Mergers? ISM stripp<strong>in</strong>g?<br />
The VIVA sample is a good sample to <strong>in</strong>spect <strong>the</strong> impact of<br />
gas stripp<strong>in</strong>g on <strong>the</strong> color evolution of galaxies <strong>in</strong> clusters<br />
Any correlation between <strong>the</strong> <strong>HI</strong> properties <strong>and</strong> <strong>the</strong> color?
CMD<br />
Color-Magnitude Diagram of VIVA Sample<br />
t q ~200-300 Myr<br />
t q >400 Myr<br />
t q ~100 Myr<br />
Contour: 140K+ SDSS Galaxies (Blanton et al. 2003) / Cross: VIVA<br />
sample (Crowl, Chung, Schim<strong>in</strong>ovich, et al. 2009 <strong>in</strong> preparation)
CMD<br />
Color-Magnitude Diagram of VIVA Sample<br />
t q ~200-300 Myr<br />
t q >400 Myr<br />
t q ~100 Myr<br />
Contour: 140K+ SDSS Galaxies (Blanton et al. 2003) / Cross: VIVA<br />
sample (Crowl, Chung, Schim<strong>in</strong>ovich, et al. 2009 <strong>in</strong> preparation)
Summary<br />
Summary<br />
1. <strong>HI</strong> rich (extended) galaxies are always found <strong>in</strong> <strong>the</strong> cluster outskirts<br />
2. <strong>HI</strong> disk is always truncated with<strong>in</strong> stellar disk <strong>in</strong> <strong>the</strong> cluster center<br />
3. At <strong>in</strong>termediate distances, we f<strong>in</strong>d a range of <strong>HI</strong> stripp<strong>in</strong>g stages <strong>and</strong><br />
we do see <strong>the</strong> GAS LEAVING <strong>the</strong> disk<br />
Some are at <strong>the</strong> right distance where <strong>the</strong> ICM pressure is<br />
just high enough to strip <strong>the</strong> <strong>HI</strong> <strong>in</strong> <strong>the</strong> outer disk<br />
Even at <strong>the</strong> distance where <strong>the</strong> estimated ICM pressure<br />
(based on <strong>the</strong> smooth ICM distribution) is too low to strip<br />
<strong>the</strong> <strong>HI</strong> gas, a) <strong>the</strong> tidal field due to neighbor<strong>in</strong>g galaxies<br />
or b) non static ICM can accelerate <strong>the</strong> <strong>HI</strong> stripp<strong>in</strong>g<br />
4. We f<strong>in</strong>d star formation quench<strong>in</strong>g time scale to be correlated with <strong>HI</strong><br />
deficiency <strong>and</strong> morphology: evidence that gas stripp<strong>in</strong>g affects color<br />
evolution <strong>in</strong> <strong>the</strong> cluster environment
End<br />
The End
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