J/MNRAS/493/3238 Properties of ETGs in compact groups of galaxies (Moura+, 2020)
Stellar population properties of ETGs in compact groups of galaxies.
Moura T.C., de Carvalho R.R., Rembold S.B., Trevisan M., Ribeiro A.L.B.,
Perez-Villegas A., La Barbera F., Stalder D.H., Rosa R.R.
<Mon. Not. R. Astron. Soc., 493, 3238-3254 (2020)>
=2020MNRAS.493.3238M 2020MNRAS.493.3238M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Galaxies, group ; Morphology ; Velocity dispersion ;
Optical
Keywords: galaxies: active - galaxies: evolution - galaxies: groups: general -
galaxies: interactions - galaxies: stellar content
Abstract:
We present results on the study of the stellar population in
early-type galaxies (ETGs) belonging to 151 compact groups (CGs). We
also selected a field sample composed of 846 ETGs to investigate
environmental effects on galaxy evolution. We find that the
dependences of mean stellar ages, [Z/H] and [α/Fe] on central
stellar velocity dispersion are similar, regardless where the ETG
resides, CGs or field. When compared to the sample of centrals and
satellites from the literature, we find that ETGs in CGs behave
similarly to centrals, especially those embedded in low-mass haloes
(Mh<1012.5M☉). Except for the low-mass limit, where field
galaxies present a star-forming signature, not seen in CGs, the
ionization agent of the gas in CG and field galaxies seem to be
similar due to hot, evolved low-mass stars. However, field ETGs
present an excess of Hα emission relative to ETGs in CGs.
Additionally, we performed a dynamical analysis, which shows that CGs
present a bimodality in the group velocity dispersion distribution - a
high- and low-σ mode. Our results indicate that high-σ
groups have a smaller fraction of spirals, shorter crossing times, and
a more luminous population of galaxies than the low-σ groups. It
is important to emphasize that our findings point to a small
environmental impact on galaxies located in CGs. The only evidence we
find is the change in gas content, suggesting environmentally driven
gas loss.
Description:
The focus of this study is the ETGs belonging to CGs. For the
definition of the sample, we choose the extensive catalogue of bright
galaxies in CGs defined by McConnachie et al. (2009MNRAS.395..255M 2009MNRAS.395..255M,
Cat. J/MNRAS/395/255). This catalogue includes objects classified as
galaxies and with magnitude in the r band brighter than mr=18 in the
data base of the sixth release of the Sloan Sky Digital Survey (SDSS
DR6 - Adelman-McCarth et al. 2009ApJS..182..543A 2009ApJS..182..543A). After the
selection, we performed a visual classification to select the
elliptical galaxies belonging to CGs. For this, we mimic the same
scheme applied in the second version of 'The Galaxy Zoo Project'
(Willett et al. 2013MNRAS.435.2835W 2013MNRAS.435.2835W, Cat. J/MNRAS/435/2835). We also
defined a control sample, constituted of ETGs in the low-density
environment (field).
To increase the spectroscopic data available, we have searched in the
data base of the twelfth release of SDSS (DR12) (Alam et al.
2015ApJS..219...12A 2015ApJS..219...12A, Cat. V/147). Our final sample of CGs is composed
by 629 galaxies distributed in 151 CGs.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 34 629 The morphological classification of the galaxies
belonging to our MC09 sample
tablea2.dat 66 151 Dynamical parameters for the CGs of the sample
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See also:
J/MNRAS/395/255 : Compact groups of galaxies in SDSS DR6 (McConnachie+, 2009)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/MNRAS/435/2835 : Morphological types from Galaxy Zoo 2 (Willett+, 2013)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- GroupID Number of the group given in McConnachie et al.
(2009MNRAS.395..255M 2009MNRAS.395..255M, Cat. J/MNRAS/395/255)
6 I1 --- GalID Position of the galaxy in order of brightness
in the group
8- 26 I19 --- ObjID Object identification in the SDSS DR12 database
28- 30 A3 --- Class Morphological classification (1)
32- 34 A3 --- Feature Any 'odd' additional feature (2)
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Note (1): We adopted the same nomenclature from the Galaxy Zoo 2 Project.
Classification as follows:
A = Star or artifact (1/629)
E = Elliptical (1/629)
Ec = Elliptical with cigar shape (48/629)
Ei = Elliptical with shape between round and cigar (230/629)
Er = Elliptical completely round (182/629)
S = Spherical (25/629)
SBa = Barred spiral with dominant bulge (1/629)
SBb = Barred spiral with obvious bulge (12/629)
SBc = Barred spiral with just noticeable bulge (8/629)
Sa = Spiral with dominant bulge (1/629)
Sb = Spiral with obvious bulge (36/629)
Sc = Spiral with noticeable bulge (40/629)
Sd = Spiral with no bulge (20/629)
Se = Edge-on spiral (2/629)
Seb = Edge-on spiral with boxy shape bulge (2/629)
Sen = Edge-on spiral with no bulge (5/629)
Ser = Edge-on spiral with round bulge (15/629)
Note (2): Features following the Galaxy Zoo 2 nomenclature as follows:
(i) = irregular (7/629)
(d) = disturbed (24/629)
(l) = lens/arc (1/629)
(m) = merger (25/629)
(r) = rings (14/629)
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- GroupID Number of the group given in McConnachie et al.
(2009MNRAS.395..255M 2009MNRAS.395..255M, Cat. J/MNRAS/395/255)
6 I1 --- Nmemb Number of members in the group
8- 16 F9.5 mag rMAG Total absolute magnitude of the group in the
r-band
18- 26 F9.5 km/s vdisp Velocity dispersion of the group σ
28- 34 F7.5 Mpc Rharm Harmonic radius
36- 43 F8.5 Msun logM Logarithm of the dynamical mass
45- 51 F7.5 --- tc Crossing time (in H0-1)
53- 59 F7.5 --- logrho Logarithm of the spatial density
61- 64 F4.2 --- fsp Spiral fraction
66 A1 --- Class [L/H] Dynamical class (L: Low σ,
H: High σ)
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 20-Apr-2023