J/MNRAS/487/5572 Connecting galaxy structure and star formation (Mishra+, 2019)
Connecting galaxy structure and star formation:
the role of environment in formation of S0 galaxies.
Mishra P.K., Wadadekar Y., Barway S.
<Mon. Not. R. Astron. Soc., 487, 5572-5583 (2019)>
=2019MNRAS.487.5572M 2019MNRAS.487.5572M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Morphology ; Magnitudes ; Optical ; Ultraviolet
Keywords: galaxies: bulges - galaxies: evolution - galaxies: formation
Abstract:
In this work, we investigate the reason behind the increased
occurrence of S0 galaxies in high-density environments. Our sample
comprises of ∼2500 spiral and ∼2000 S0 galaxies spanning a wide range
of environments. Dividing the galaxies into categories of classical
and pseudo-bulge hosting spiral and S0 galaxies, we have studied their
properties as a function of the environment. We find that the fraction
of pseudo-bulge hosting disc galaxies decreases with increase in
density. The classical bulge hosting spirals and S0 galaxies follow a
similar trend in less dense environments but towards higher densities,
we observe an increase in the fraction of classical bulge host S0
galaxies at the expense of spirals. Comparing the structural and the
star formation properties of galaxies on the size-mass and NUV-r
colour-mass planes, respectively, we infer that classical bulge
hosting spirals are likely to get transformed into S0 morphology. We
notice a trend of galaxy structure with environment such that the
fraction of classical bulge hosting spiral galaxies is found to
increase with environment density. We also find that among classical
bulge hosting spirals, the fraction of quenched galaxies increases in
denser environments. We surmise that the existence of more classical
bulge hosting spirals galaxies and more efficient quenching leads to
the observed increased occurrence of S0 galaxies in high-density
environments. The relation between galaxy structure and environment
also exists for the disc galaxies irrespective of their visual
morphology, which is driven mainly by halo mass.
Description:
In order to carry out our study, we wanted to construct a
statistically meaningful sample of galaxies with available information
on morphology, structure, and environment. For this, we used
Nair & Abraham (2010ApJS..186..427N 2010ApJS..186..427N, Cat. J/ApJS/186/427) catalogue,
which provides the visual morphological classification for 14034
spectroscopically targeted galaxies in the SDSS DR4 (Adelman-McCarthy
et al. 2006ApJS..162...38A 2006ApJS..162...38A, Cat. II/267). We obtained structural
information by cross-matching with Simard et al. (2011ApJS..196...11S 2011ApJS..196...11S,
Cat. J/ApJS/196/11), which contains bulge+disc decompositions in the
SDSS g and r bands for a sample of 1123718 galaxies from the SDSS DR 7
(Abazajian et al. 2009ApJS..182..543A 2009ApJS..182..543A, Cat. II/294). The cross-match
between these two catalogues resulted in 12063 galaxies. We then
selected the disc galaxies having reliable bulge+disc fits and we
discarded the galaxies that host a bar. Application of these cuts
leaves us with a sample of 4692 objects (parent sample).
In order to obtain the final sample of disc galaxies, we have applied
three selection cuts on our parent sample: galaxy stellar mass
>108M☉ ; bulge size (=2re) greater than the median PSF of
1.43arcsec of the SDSS imaging ; and 1.75=<log(Σ)=<1.75, where
Σ is the environmental density parameter. The application of all
three selection criteria on the parent sample leaves us with a final
sample of 4573 galaxies, out of which 2541 are spirals and rest 2032
are S0 galaxies.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 118 4573 Galaxies in our final sample and their physical
parameters
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See also:
J/ApJS/186/427 : Detailed morphology of SDSS galaxies (Nair+, 2010)
J/ApJS/196/11 : Bulge+disk decompositions of SDSS galaxies (Simard+, 2011)
II/294 : The SDSS Photometric Catalog, Release 7
(Adelman-McCarthy+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name SDSS galaxy name (JHHMMSS.ss+DDMMSS.ss)
22- 23 I2 --- TType Hubble morphological stage
25- 42 F18.15 mag/arcsec2 mub Bulge surface brightness µb(<re)
44- 48 F5.2 kpc re Bulge half-light radius
50- 55 F6.3 [Mpc-2] logSig ?=0.0 Environmental density parameter (1)
57- 61 F5.2 kpc Rgal Galaxy half-light radius
63- 68 F6.3 [Msun] logM* Galaxy stellar mass
70- 75 F6.3 [Msun] logMhalo ?=0.0 Dark matter halo mass
77- 94 F18.16 mag NUV-r ? NUV-r colour
96-105 F10.7 mag NUVmag ? GALEX NUV magnitude (2)
107-116 F10.7 mag rmag SDSS r-band magnitude (2)
118 I1 --- BulgeType [1/2] Type of the bulge (3)
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Note (1): This environmental density parameter is defined as
ΣN=N/(πdN2), where dN is the distance to the Nth
nearest neighbour. Baldry et al. (2006MNRAS.373..469B 2006MNRAS.373..469B) provides the
best estimate environmental density (Σ) by averaging the
environmental densities Σ4 and Σ5.
Note (2): The SDSS r-band and GALEX NUV magnitude for the galaxies in our final
sample were obtained from the RCSED catalogue (Chilingarian et al.
2017ApJS..228...14C 2017ApJS..228...14C)
Note (3): Bulge type as follows:
1 = Classical bulge (3420/4573)
2 = Pseudo bulge (1153/4573)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 22-Nov-2022