J/MNRAS/471/2687 Massive galaxies environmental density (Bait+, 2017)
On the interdependence of galaxy morphology, star formation and environment in
massive galaxies in the nearby Universe.
Bait O., Barway S., Wadadekar Y.
<Mon. Not. R. Astron. Soc., 471, 2687-2702 (2017)>
=2017MNRAS.471.2687B 2017MNRAS.471.2687B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Redshifts ; Morphology
Keywords: galaxies: evolution - galaxies: general - galaxies: groups: general -
galaxies: star formation - galaxies: statistics - galaxies: structure
Abstract:
Using multiwavelength data, from ultraviolet to optical to
near-infrared to mid-infrared, for ∼6000 galaxies in the local
Universe, we study the dependence of star formation on the
morphological T-types for massive galaxies (logM*/M☉≥10). We
find that, early-type spirals (Sa-Sbc) and S0s predominate in the
green valley, which is a transition zone between the star forming and
quenched regions. Within the early-type spirals, as we move from Sa to
Sbc spirals the fraction of green valley and quenched galaxies
decreases, indicating the important role of the bulge in the quenching
of galaxies. The fraction of early-type spirals decreases as we enter
the green valley from the blue cloud, which coincides with the
increase in the fraction of S0s. These points towards the
morphological transformation of early-type spiral galaxies into S0s,
which can happen due to environmental effects such as ram-pressure
stripping, galaxy harassment or tidal interactions. We also find a
second population of S0s that are actively star forming and are
present in all environments. Since morphological T-type, specific star
formation rate (sSFR), and environmental density are all correlated
with each other, we compute the partial correlation coefficient for
each pair of parameters while keeping the third parameter as a control
variable. We find that morphology most strongly correlates with sSFR,
independent of the environment, while the other two correlations
(morphology-density and sSFR-environment) are weaker. Thus, we
conclude that, for massive galaxies in the local Universe, the
physical processes that shape their morphology are also the ones that
determine their star-forming state.
Description:
The sample is drawn from the Nair & Abraham, 2010ApJS..186..427N 2010ApJS..186..427N, Cat.
J/ApJS/186/427 (hereafter NA10) catalogue of detailed visual
morphological classification of 14034 galaxies. NA10 galaxies were
selected from the SDSS DR4 with spectroscopic redshift in the range
0.01<z<0.1, and extinction corrected apparent magnitude limit of
g<16mag. For galaxies in our sample, we use optical imaging data from
the SDSS DR12 (Alam et al., 2015ApJS..219...12A 2015ApJS..219...12A, Cat. V/147) in the u,
g, r, i and z bands. In order to have a better constraint on recent
star formation, we make use of Galaxy Evolution Explorer (GALEX) data
in the far-UV (FUV) and near-UV (NUV) filters. We use near-IR data
from the Two-Micron All Sky Survey (2MASS) in the J, H and K bands
(Skrutskie et al., 2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233), wherein we use
the model photometry. Mid-IR data are taken from the Wide-Field
Infrared Survey Explorer (WISE; Wright et al., 2010, cat. II/311) in
all four channels - W1, W2, W3 and W4. We construct our sample by
cross-matching the NA10 catalogue with archival data from GALEX, SDSS,
2MASS and WISE, which gives us 7 831 galaxies. Of these, we have flux
measurements in all the 14 bands for 6819 galaxies. For 594 galaxies,
we have flux measurements in 13 bands due to missing flux in the W4
filter, and for 418 galaxies we have flux measurement in 10 bands due
to missing fluxes in all the four WISE filters. For all of these
galaxies, we also have local environmental density information from
Baldry et al. (2006MNRAS.373..469B 2006MNRAS.373..469B).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 174 7831 *Catalogue of the MAGPHYS output parameters and
NA10 morphologies and environmental density
for each galaxy in our sample
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Note on table2.dat: NA10 stands for Nair & Abraham, 2010ApJS..186..427N 2010ApJS..186..427N,
Cat. J/ApJS/186/427.
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam, 2015)
J/ApJS/186/427 : Detailed morphology of SDSS galaxies (Nair+, 2010)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- ObjID Object SDSS name, JHHMMSS.ss+DDMMSS.ss
22- 43 F22.18 deg RAdeg Right ascension (J2000)
45- 66 F22.18 deg DEdeg Declination (J2000)
68- 87 F20.18 --- z Redshift
89-106 F18.15 [Msun] logM* Stellar mass
108-126 F19.15 [yr-2] logsSFR Specific star formation rate
128-129 I2 --- TT Morphological T-Type
131-152 F22.19 [Mpc2] logSIGMA Local environmental density
154-174 F21.17 --- chi2 chi square value
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-May-2020