scholarly journals Structural and stellar-population properties versus bulge types in Sloan Digital Sky Survey central galaxies

2020 ◽  
Vol 493 (2) ◽  
pp. 1686-1707 ◽  
Author(s):  
Yifei Luo ◽  
S M Faber ◽  
Aldo Rodríguez-Puebla ◽  
Joanna Woo ◽  
Yicheng Guo ◽  
...  

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 1 kpc. We compare ΔΣ1 to the established bulge-type indicator Δ〈μe〉 from Gadotti (2009) 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 12 000 SDSS central galaxies with masses 10.0 < log M*/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.

2003 ◽  
Vol 599 (2) ◽  
pp. 971-991 ◽  
Author(s):  
A. M. Hopkins ◽  
C. J. Miller ◽  
R. C. Nichol ◽  
A. J. Connolly ◽  
M. Bernardi ◽  
...  

2015 ◽  
Vol 449 (4) ◽  
pp. 3719-3740 ◽  
Author(s):  
Jillian M. Scudder ◽  
Sara L. Ellison ◽  
Emmanuel Momjian ◽  
Jessica L. Rosenberg ◽  
Paul Torrey ◽  
...  

2021 ◽  
Vol 923 (2) ◽  
pp. 205
Author(s):  
Hassen M. Yesuf ◽  
Luis C. Ho ◽  
S. M. Faber

Abstract The morphology and structure of galaxies reflect their star formation and assembly histories. We use the framework of mutual information (MI) to quantify the interdependence among several structural variables and to rank them according to their relevance for predicting the specific star formation rate (SSFR) by comparing the MI of the predictor variables with the SSFR and penalizing variables that are redundant. We apply this framework to study ∼3700 face-on star-forming galaxies (SFGs) with varying degrees of bulge dominance and central concentration and with stellar mass M ⋆ ≈ 109 M ⊙−5 × 1011 M ⊙ at redshift z = 0.02–0.12. We use the Sloan Digital Sky Survey (SDSS) Stripe 82 deep i-band imaging data, which improve measurements of asymmetry and bulge dominance indicators. We find that star-forming galaxies are a multiparameter family. In addition to M ⋆, asymmetry emerges as the most powerful predictor of SSFR residuals of SFGs, followed by bulge prominence/concentration. Star-forming galaxies with higher asymmetry and stronger bulges have higher SSFR at a given M ⋆. The asymmetry reflects both irregular spiral arms and lopsidedness in seemingly isolated SFGs and structural perturbations by galaxy interactions or mergers.


2013 ◽  
Vol 91 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Xin-Fa Deng

The primary goal of this study is to explore the dependence of the clustering properties of galaxies on star formation rate (SFR) and specific star formation rate (SSFR). From the main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct two volume-limited samples with absolute magnitudes above and below [Formula: see text], and then divide each volume-limited main galaxy sample into two subsamples with low SFRs and high SFRs or low SSFRs and high SSFRs. A strong dependence of the clustering properties on SFR and SSFR is found: high SFR and SSFR galaxies are preferentially isolated or found in close pairs and small groups, whereas low SFR and SSFR galaxies preferentially inhabit dense groups and clusters.


2013 ◽  
Vol 91 (4) ◽  
pp. 337-342
Author(s):  
Xin-Fa Deng

From each of two volume-limited main galaxy samples of the Sloan Digital Sky Survey data release 7, a paired galaxy sample and an isolated galaxy sample are constructed and comparative studies between the star formation of galaxies in pairs and isolated are performed to explore influences of galaxy interactions on star formation. It is found that isolated galaxies have an enhancement of the star formation rate and the specific star formation rate, which suggests that interactions between galaxies are not the trigger of enhanced star formation.


2016 ◽  
Vol 12 (S323) ◽  
pp. 392-393
Author(s):  
Zhimin Zhou

AbstractStar formation rate (SFR) is one of the most important diagnostics in understanding the evolution of galaxies across cosmic times. In order to explore the possibility of using the optical u-band luminosities to estimate SFRs of galaxies, we show the correlations between u band, Hα and infrared luminosities by combing the data from the South Galactic Cap u band Sky Survey (SCUSS) with the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We derive the u versus Hα relation and the u and 12 μm relations to calibrate the u-band luminosity as an SFR indicator.


2020 ◽  
Vol 501 (1) ◽  
pp. 1046-1058
Author(s):  
Valeria Mesa ◽  
Sol Alonso ◽  
Georgina Coldwell ◽  
Diego García Lambas ◽  
J L Nilo Castellon

ABSTRACT We use SDSS-DR14 to construct a sample of galaxy systems consisting of a central object and two satellites. We adopt projected distance and radial velocity difference criteria and impose an isolation criterion to avoid membership in larger structures. We also classify the interaction between the members of each system through a visual inspection of galaxy images, finding ${\sim}80{{\ \rm per\ cent}}$ of the systems lack evidence of interactions whilst the remaining ${\sim}20{{\ \rm per\ cent}}$ involve some kind of interaction, as inferred from their observed distorted morphology. We have considered separately, samples of satellites and central galaxies, and each of these samples were tested against suitable control sets to analyse the results. We find that central galaxies showing signs of interactions present evidence of enhanced star formation activity and younger stellar populations. As a counterpart, satellite samples show these galaxies presenting older stellar populations with a lower star formation rate than the control sample. The observed trends correlate with the stellar mass content of the galaxies and with the projected distance between the members involved in the interaction. The most massive systems are less affected since they show no star formation excess, possibly due to their more evolved stage and less gas available to form new stars. Our results suggest that it is arguably a transfer of material during interactions, with satellites acting as donors to the central galaxy. As a consequence of the interactions, satellite stellar population ages rapidly and new bursts of star formation may frequently occur in the central galaxy.


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