We use the combined data from the COS-GASS and COS-Halos surveys to
characterize the Circum-Galactic Medium (CGM) surrounding typical low-redshift
galaxies in the mass range $\rm~M_*\sim~10^9.5-11.5~M_ødot $, and over a
range of impact parameters extending to just beyond the halo virial radius
($\rm~R_vir$). We find the radial scale length of the distributions of the
equivalent widths of the Lyman~$\alpha$ and Si III absorbers to be 0.9 and 0.4
$\rm~R_vir$, respectively. The radial distribution of equivalent widths is
relatively uniform for the blue galaxies, but highly patchy (low covering
fraction) for the red galaxies. We also find that the Lyman~$\alpha$ and Si III
equivalent widths show significant positive correlations with the specific
star-formation rate (sSFR) of the galaxy. We find a surprising lack of
correlations between the halo mass (virial velocity) and either the velocity
dispersions or velocity offsets of the Lyman~$\alpha$ lines. The ratio of the
velocity offset to the velocity dispersion for the Lyman~$\alpha$ absorbers has
a mean value of $\sim$ 4, suggesting that a given the line-of-sight is
intersecting a dynamically coherent structure in the CGM rather than a sea of
orbiting clouds. The kinematic properties of the CGM are similar in the blue
and red galaxies, although we find that a significantly larger fraction of the
blue galaxies have large Lyman~$\alpha$ velocity offsets (>200 km s$^-1$). We
show that - if the CGM clouds represent future fuel for star-formation - our
new results could imply a large drop in the specific star-formation rate across
the galaxy mass-range we probe.
Description
[1609.06308] The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results from the COS-GASS+COS-Halos Surveys
%0 Generic
%1 borthakur2016properties
%A Borthakur, Sanchayeeta
%A Heckman, Timothy
%A Tumlinson, Jason
%A Bordoloi, Rongmon
%A Kauffmann, Guinevere
%A Catinella, Barbara
%A Schiminovich, David
%A Dave, Romeel
%A Moran, Sean M.
%A Saintonge, Amelie
%D 2016
%K cgm galaxies local
%T The Properties of the Circumgalactic Medium in Red and Blue Galaxies:
Results from the COS-GASS+COS-Halos Surveys
%U http://arxiv.org/abs/1609.06308
%X We use the combined data from the COS-GASS and COS-Halos surveys to
characterize the Circum-Galactic Medium (CGM) surrounding typical low-redshift
galaxies in the mass range $\rm~M_*\sim~10^9.5-11.5~M_ødot $, and over a
range of impact parameters extending to just beyond the halo virial radius
($\rm~R_vir$). We find the radial scale length of the distributions of the
equivalent widths of the Lyman~$\alpha$ and Si III absorbers to be 0.9 and 0.4
$\rm~R_vir$, respectively. The radial distribution of equivalent widths is
relatively uniform for the blue galaxies, but highly patchy (low covering
fraction) for the red galaxies. We also find that the Lyman~$\alpha$ and Si III
equivalent widths show significant positive correlations with the specific
star-formation rate (sSFR) of the galaxy. We find a surprising lack of
correlations between the halo mass (virial velocity) and either the velocity
dispersions or velocity offsets of the Lyman~$\alpha$ lines. The ratio of the
velocity offset to the velocity dispersion for the Lyman~$\alpha$ absorbers has
a mean value of $\sim$ 4, suggesting that a given the line-of-sight is
intersecting a dynamically coherent structure in the CGM rather than a sea of
orbiting clouds. The kinematic properties of the CGM are similar in the blue
and red galaxies, although we find that a significantly larger fraction of the
blue galaxies have large Lyman~$\alpha$ velocity offsets (>200 km s$^-1$). We
show that - if the CGM clouds represent future fuel for star-formation - our
new results could imply a large drop in the specific star-formation rate across
the galaxy mass-range we probe.
@misc{borthakur2016properties,
abstract = {We use the combined data from the COS-GASS and COS-Halos surveys to
characterize the Circum-Galactic Medium (CGM) surrounding typical low-redshift
galaxies in the mass range $\rm~M_*\sim~10^{9.5-11.5}~M_{\odot} $, and over a
range of impact parameters extending to just beyond the halo virial radius
($\rm~R_{vir}$). We find the radial scale length of the distributions of the
equivalent widths of the Lyman~$\alpha$ and Si III absorbers to be 0.9 and 0.4
$\rm~R_{vir}$, respectively. The radial distribution of equivalent widths is
relatively uniform for the blue galaxies, but highly patchy (low covering
fraction) for the red galaxies. We also find that the Lyman~$\alpha$ and Si III
equivalent widths show significant positive correlations with the specific
star-formation rate (sSFR) of the galaxy. We find a surprising lack of
correlations between the halo mass (virial velocity) and either the velocity
dispersions or velocity offsets of the Lyman~$\alpha$ lines. The ratio of the
velocity offset to the velocity dispersion for the Lyman~$\alpha$ absorbers has
a mean value of $\sim$ 4, suggesting that a given the line-of-sight is
intersecting a dynamically coherent structure in the CGM rather than a sea of
orbiting clouds. The kinematic properties of the CGM are similar in the blue
and red galaxies, although we find that a significantly larger fraction of the
blue galaxies have large Lyman~$\alpha$ velocity offsets (>200 km s$^{-1}$). We
show that - if the CGM clouds represent future fuel for star-formation - our
new results could imply a large drop in the specific star-formation rate across
the galaxy mass-range we probe.},
added-at = {2016-09-22T10:05:03.000+0200},
author = {Borthakur, Sanchayeeta and Heckman, Timothy and Tumlinson, Jason and Bordoloi, Rongmon and Kauffmann, Guinevere and Catinella, Barbara and Schiminovich, David and Dave, Romeel and Moran, Sean M. and Saintonge, Amelie},
biburl = {https://www.bibsonomy.org/bibtex/2da5c2800a2d661b2ec4cf0871c7b69e7/miki},
description = {[1609.06308] The Properties of the Circumgalactic Medium in Red and Blue Galaxies: Results from the COS-GASS+COS-Halos Surveys},
interhash = {ef37ec1e78b700741de46e0b157befa8},
intrahash = {da5c2800a2d661b2ec4cf0871c7b69e7},
keywords = {cgm galaxies local},
note = {cite arxiv:1609.06308Comment: 18 pages, 18 figures, 2 tables. Accepted for publication in ApJ},
timestamp = {2016-09-22T10:05:03.000+0200},
title = {The Properties of the Circumgalactic Medium in Red and Blue Galaxies:
Results from the COS-GASS+COS-Halos Surveys},
url = {http://arxiv.org/abs/1609.06308},
year = 2016
}