TY - JOUR
T1 - The AMIGA sample of isolated galaxies. IX. Molecular gas properties
AU - Lisenfeld, U.
AU - Espada, D.
AU - Verdes-Montenegro, L.
AU - Kuno, N.
AU - Leon, S.
AU - Sabater, J.
AU - Sato, N.
AU - Sulentic, J.
AU - Verley, S.
AU - Yun, M. S.
PY - 2011/10/1
Y1 - 2011/10/1
N2 - Aims: We characterize the molecular gas content (ISM cold phase)
using CO emission of a redshift-limited subsample of isolated galaxies
from the AMIGA (Analysis of the interstellar Medium of Isolated
GAlaxies) project in order to provide a comparison sample for studies of
galaxies in different environments. Methods: We present the
12CO(1-0) data for 273 AMIGA galaxies, most of them (n = 186)
from our own observations with the IRAM 30 m and the FCRAO 14 m
telescopes and the rest from the literature. We constructed a
redshift-limited sample containing galaxies with 1500 km s-1
<v <5000 km s-1 and excluded objects with
morphological evidence of possible interaction. This sample (n = 173) is
the basis for our statistical analysis. It contains galaxies with
molecular gas masses, MH2, in the range of
~108 - 1010 M&sun;. It is dominated,
both in absolute number and in detection rate, by spiral galaxies of
type T = 3-5 (Sb-Sc). Most galaxies were observed with a single pointing
towards their centers. Therefore, we performed an extrapolation to the
total molecular gas mass expected in the entire disk based on the
assumption of an exponential distribution. We then studied the
relationships between MH2 and other galactic
properties (LB, D_25^2, LK, LFIR, and
MHI). Results: We find correlations between
MH2 and LB, D_25^2, LK, and
LFIR. The tightest correlation of MH2
holds with LFIR and, for T = 3-5, with LK, and the
poorest with D_25^2. The correlations with LFIR and
LK are very close to linearity. The correlation with
LB is nonlinear so that
MH2/LB increases with LB.
The molecular and the atomic gas masses of our sample show no strong
correlation. We find a low mean value,
log(MH2/MHI) = -0.7 (for T = 3-5), and
a strong decrease in this ratio with morphological type. The molecular
gas column density and the surface density of the star formation rate
(the Kennicutt-Schmidt law) show a tight correlation with a rough unity
slope. We compare the relations of MH2 with
LB and LK found for AMIGA galaxies to samples of
interacting galaxies from the literature and find an indication for an
enhancement of the molecular gas in interacting galaxies of up to
0.2-0.3 dex.
Full Tables 1, 4 and 5 are only available at the CDS via anonymous ftp
to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A102Appendix
is available in electronic form at http://www.aanda.org
AB - Aims: We characterize the molecular gas content (ISM cold phase)
using CO emission of a redshift-limited subsample of isolated galaxies
from the AMIGA (Analysis of the interstellar Medium of Isolated
GAlaxies) project in order to provide a comparison sample for studies of
galaxies in different environments. Methods: We present the
12CO(1-0) data for 273 AMIGA galaxies, most of them (n = 186)
from our own observations with the IRAM 30 m and the FCRAO 14 m
telescopes and the rest from the literature. We constructed a
redshift-limited sample containing galaxies with 1500 km s-1
<v <5000 km s-1 and excluded objects with
morphological evidence of possible interaction. This sample (n = 173) is
the basis for our statistical analysis. It contains galaxies with
molecular gas masses, MH2, in the range of
~108 - 1010 M&sun;. It is dominated,
both in absolute number and in detection rate, by spiral galaxies of
type T = 3-5 (Sb-Sc). Most galaxies were observed with a single pointing
towards their centers. Therefore, we performed an extrapolation to the
total molecular gas mass expected in the entire disk based on the
assumption of an exponential distribution. We then studied the
relationships between MH2 and other galactic
properties (LB, D_25^2, LK, LFIR, and
MHI). Results: We find correlations between
MH2 and LB, D_25^2, LK, and
LFIR. The tightest correlation of MH2
holds with LFIR and, for T = 3-5, with LK, and the
poorest with D_25^2. The correlations with LFIR and
LK are very close to linearity. The correlation with
LB is nonlinear so that
MH2/LB increases with LB.
The molecular and the atomic gas masses of our sample show no strong
correlation. We find a low mean value,
log(MH2/MHI) = -0.7 (for T = 3-5), and
a strong decrease in this ratio with morphological type. The molecular
gas column density and the surface density of the star formation rate
(the Kennicutt-Schmidt law) show a tight correlation with a rough unity
slope. We compare the relations of MH2 with
LB and LK found for AMIGA galaxies to samples of
interacting galaxies from the literature and find an indication for an
enhancement of the molecular gas in interacting galaxies of up to
0.2-0.3 dex.
Full Tables 1, 4 and 5 are only available at the CDS via anonymous ftp
to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A102Appendix
is available in electronic form at http://www.aanda.org
UR - http://www.scopus.com/inward/record.url?scp=80055011850&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201117056
DO - 10.1051/0004-6361/201117056
M3 - Article
SN - 1432-0746
VL - 534
SP - 102
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
ER -