J/MNRAS/484/5192 Molecular gas distribution and star formation (Chown+, 2019)
Linking bar- and interaction-driven molecular gas concentration with centrally
enhanced star formation in EDGE-CALIFA galaxies.
Chown R., Li C., Athanassoula E., Li N., Wilson C.D., Lin L., Mo H.,
Parker L.C., Xiao T.
<Mon. Not. R. Astron. Soc., 484, 5192-5211 (2019)>
=2019MNRAS.484.5192C 2019MNRAS.484.5192C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Molecular data ; Star Forming Region ;
Equivalent widths ; Carbon monoxide
Keywords: galaxies: bulges - galaxies: evolution - galaxies: interactions -
galaxies: spiral - galaxies: star formation
Abstract:
We study the spatially resolved star formation history (SFH) and
molecular gas distribution of 58 nearby galaxies, using integral field
spectroscopy from the CALIFA survey and CO J=1-0 intensity mapping
from the CARMA EDGE survey. We use the 4000Å break (Dn(4000)),
the equivalent width (EW) of the Hδ absorption line
(EW(HδA)), and the EW of the Hα emission line
(EW(Hα)) to measure the recent SFH of these galaxies. We measure
radial profiles of the three SFH indicators and molecular gas mass
surface density, from which we measure the level of centrally enhanced
star formation and the molecular gas concentration. When we separate
our galaxies into categories of barred (17 galaxies), unbarred (24
galaxies), and merging/paired (17 galaxies), we find that the galaxies
that have centrally enhanced star formation (19/58) are either barred
(13/19) or in mergers/pairs (6/19) with relatively high molecular gas
concentrations. A comparison between our barred galaxies and a
snapshot of a hydrodynamic N-body simulation of a barred galaxy shows
that the current theory of bar formation and evolution can
qualitatively reproduce the main features of the observed galaxies in
our sample, including both the sharp decrease of stellar age in the
galactic centre and the gradual decrease of age with increasing
distance from centre. These findings provide substantial evidence for
a picture in which cold gas is transported inwards by a bar or tidal
interaction, which leads to the growth and rejuvenation of star
formation in the central region.
Description:
CARMA EDGE (Bolatto et al. 2017ApJ...846..159B 2017ApJ...846..159B, Cat. J/ApJ/846/159) is
a survey of CO emission in 126 nearby galaxies carried out using the
CARMA interferometer (Bock et al. 2006SPIE.6267E..13B 2006SPIE.6267E..13B). The CARMA EDGE
sample was selected from the CALIFA sample with high fluxes in the
22um band from the Wide-field Spectroscopic Explorer (WISE) survey.
The requirement for high mid-infrared flux means that the sample is
mainly gas-rich and actively star-forming, given the correlation
between the mid-infrared luminosities from WISE and the molecular gas
mass (e.g. Jiang et al. 2015ApJ...799...92J 2015ApJ...799...92J). The sample consists of
galaxies imaged in 12CO and 13CO with sensitivity. We use the publicly
available 12CO J=1-0 integrated flux maps from CARMA EDGE.
We use optical IFU data from the 3rd data release (DR3) of the CALIFA
survey (Sanchez et al. 2012A&A...538A...8S 2012A&A...538A...8S). The CALIFA survey
consists of about 600 galaxies observed with the PMAS/PPak
integral-field spectrograph at the Calar Alto Observatory (Roth et al.
2005PASP..117..620R 2005PASP..117..620R; Kelz et al. 2006PASP..118..129K 2006PASP..118..129K). The CALIFA
datacubes are available in three spectral setups: (1) a low-resolution
setup with 6Å spectral resolution (V500), (2) a medium-resolution
setup with 2.3Å resolution (V1200), and (3) the combination of V500
and V1200 cubes (called COMBO). We used the COMBO data cubes from
CALIFA DR3 where available.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 84 58 Basic properties of the galaxies in our sample
tablea2.dat 101 58 Quantities derived from spatially resolved
optical IFU and molecular gas maps
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Galaxy name
14 A1 --- f_Name [ABM] Flag on Name (1)
16- 17 I2 --- Number [1/58] Index of each galaxy in our sample
19- 26 F8.4 deg RAdeg Right ascension (J2000)
28- 34 F7.4 deg DEdeg Declination (J2000)
36- 41 F6.4 --- z Raw redshift measured from the CALIFA
datacubes
43- 49 F7.4 [Msun] logMstar Stellar mass from CALIFA DR3 reanalysis of
SDSS DR7 ugriz growth curves
(Walcher et al. 2014A&A...569A...1W 2014A&A...569A...1W)
51- 53 F3.1 mag NUV-r ? NUV-r magnitude from the NASA-Sloan Atlas
55- 61 F7.4 arcsec r50 r-band half-light radius r50 from the NSA
63- 66 F4.1 [Msun] logMHI ? Neutral hydrogen mass from ALFALFA 100%
catalogue (Haynes et al. 2018ApJ...861...49H 2018ApJ...861...49H,
Cat. J/ApJ/861/49) where available, or from
the HyperLeda data base
68- 73 F6.4 [Msun] logMH2 The total detected H2 mass in the whole CO
image
75- 80 F6.4 [Msun] e_logMH2 Error on logMH2
82- 84 A3 --- Type The morphological type (RC3) provided in
CALIFA DR3
--------------------------------------------------------------------------------
Note (1): Flag as follows:
B = Barred galaxy
A = Unbarred galaxy
M = Merger/pair galaxy
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Galaxy name
14 A1 --- f_Name [ABM] Flag on Name (1)
16 A1 --- Upturn [Y/N] Indicates if this galaxy has an upturn
in logEW(Hα)
18- 24 F7.4 --- DDn4000 Dn(4000) turnover strength (2)
26- 32 F7.4 0.1nm DEWHd EW(HδA) upturn strength (3)
34- 40 F7.4 --- DEWHa EW(Hα) upturn strength (3)
42- 48 F7.4 arcsec r50mol Molecular gas half-mass radius
50 A1 --- l_logcmol Limit flag on logcmol
52- 58 F7.4 [-] logcmol Molecular gas concentration index (4)
60- 65 F6.4 yr logtdepc ? Molecular gas depletion time in the
'centre' (0.5kpc semimajor axis)
67- 72 F6.4 yr e_logtdepc ? Error on logtdepc
74- 79 F6.4 yr logtdepd ? Molecular gas depletion time in the 'disc'
(between 0.5kpc and r50)
81- 86 F6.4 yr e_logtdepd ? Error on logtdepd
88- 94 F7.4 [-] logtc/td ? Centre-to-disc depletion time ratio
96-101 F6.4 [-] e_logtc/td ? Error on logtc/td
--------------------------------------------------------------------------------
Note (1): Flag as follows:
B = Barred galaxy
A = Unbarred galaxy
M = Merger/pair galaxy
Note (2): For Dn(4000) (the 4000Å-break), the turnover strength is defined
as ΔDn(4000)=Dn(4000)extrap(r=0)-Dn(4000)(r=0).
Note (3): The upturn/turnover strength of each galaxy, for each of the SFH
indicators, is quantified by the difference between the observed and
extrapolated value in the central region. Specifically, for
logEW(Hα) and logEW(HδA), the upturn strength is defined
as ΔY=Y(r=0)-Yextrap(r=0).
Note (4): We measure a molecular gas concentration index cmol defined as the
ratio of the optical half-light radius to the molecular gas half-mass
radius r50 measured from radial profiles of the publicly available
EDGE CO J=1-0 maps
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 06-Sep-2022