J/MNRAS/493/1686 Structural properties of SDSS central galaxies (Luo+, 2020)
Structural and stellar-population properties versus bulge types in Sloan Digital
Sky Survey central galaxies.
Luo Y., Faber S.M., Rodriguez-Puebla A., Woo J., Guo Y., Koo D.C.,
Primack J.R., Chen Z., Yesuf H.M., Lin L., Barro G., Fang J.J., Pandya V.,
Huertas-Company M., Mao S.
<Mon. Not. R. Astron. Soc., 493, 1686-1707 (2020)>
=2020MNRAS.493.1686L 2020MNRAS.493.1686L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Positional data
Keywords: galaxies: bulges - galaxies: evolution - galaxies: formation -
galaxies: fundamental parameters - galaxies: structure
Abstract:
This paper studies pseudo-bulges (P-bulges) and classical bulges
(C-bulges) in Sloan Digital Sky Survey (SDSS) central galaxies using
the new bulge indicator ΔΣ1, which measures relative
central stellar-mass surface density within 1kpc. We compare
ΔΣ1 to the established bulge-type indicator
Δ<µe> from Gadotti (2009MNRAS.393.1531G 2009MNRAS.393.1531G, Cat.
J/MNRAS/393/1531) and show that classifying by ΔΣ1
agrees well with Δ<µe>. ΔΣ1 requires no
bulge-disc decomposition and can be measured on SDSS images out to
z=0.07. Bulge types using it are mapped on to 20 different structural
and stellar-population properties for 12000 SDSS central galaxies with
masses 10.0<logM*/M☉<10.4. New trends emerge from this large
sample. Structural parameters show fairly linear log-log relations
versus ΔΣ1 and Δ<µe> with only moderate
scatter, while stellar-population parameters show a highly non-linear
'elbow' in which specific star formation rate remains roughly flat
with increasing central density and then falls rapidly at the elbow,
where galaxies begin to quench. P-bulges occupy the low-density end of
the horizontal arm of the elbow and are universally star forming,
while C-bulges occupy the elbow and the vertical branch and exhibit a
wide range of star formation rates at a fixed density. The non-linear
relation between central density and star formation rate has been seen
before, but this mapping on to bulge class is new. The wide range of
star formation rates in C-bulges helps to explain why bulge
classifications using different parameters have sometimes disagreed in
the past. The elbow-shaped relation between density and stellar
indices suggests that central structure and stellar populations evolve
at different rates as galaxies begin to quench.
Description:
We used a large SDSS sample used to study the general properties of
galaxies versus central density. It is selected from the SDSS DR7
catalogue (Abazajian et al. 2009ApJS..182..543A 2009ApJS..182..543A, Cat. II/294). To
avoid seeing degradation, we limit the redshift range to 0.02<z<0.07
(Fang et al. 2013ApJ...776...63F 2013ApJ...776...63F). Besides the redshift cut, galaxies
are limited to logM*/M☉>9.5, axial ratio b/a>0.5, and
single-Sersic index 0.5<n<6. The decision was also made to focus on
central SDSS galaxies for this first analysis. Satellite galaxies are
accordingly excluded based on the group designation (Mrank>1)
according to Yang et al. (2012ApJ...752...41Y 2012ApJ...752...41Y). Merging galaxies are
also excluded for similar reasons, using the classification
(PMG<0.1) from Galaxy Zoo (Lintott et al. 2011MNRAS.410..166L 2011MNRAS.410..166L, Cat.
J/MNRAS/410/166).
Integrated photometry and surface brightness profiles in the ugriz
bands for SDSS galaxies are obtained from the SDSS data base and
corrected for Galactic extinction. We compute the cumulative light
profile and interpolate smoothly in order to calculate the total light
within 1kpc. The stellar mass surface density within 1kpc, Σ1,
is computed using the total light within 1kpc in the i band and
M/Li from Fang et al. (2013ApJ...776...63F 2013ApJ...776...63F). The Σ1 value
for SDSS DR7 galaxies with their SDSS identification can be found in
Table B1.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 47 100022 Sample entries from the Σ1 catalogue for
SDSS DR7 galaxies
--------------------------------------------------------------------------------
See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
11- 19 F9.5 deg DEdeg Declination (J2000)
21- 38 I18 --- ID SDSS unique object identifier (objID)
40- 47 F8.5 [Msun/kpc2] logS1 Logarithm of the stellar mass surface
density within 1 kpc
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 14-Apr-2023