scholarly journals A phylogenetic analysis of galaxies in the Coma Cluster and the field: a new approach to galaxy evolution

2020 ◽  
Vol 499 (4) ◽  
pp. 5607-5622
Author(s):  
M Martínez-Marín ◽  
R Demarco ◽  
G Cabrera-Vives ◽  
P Cerulo ◽  
N W C Leigh ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Galaxy Evolution ◽  
Principal Component ◽  
Sloan Digital Sky Survey ◽  
Chemical Variation ◽  
Coma Cluster ◽  
New Approach ◽  
Sky Survey ◽  
Abundance Indices ◽  
Galaxy Populations

ABSTRACT We propose a phylogenetic approach (PA) as a novel and robust tool to detect galaxy populations (GPs) based on their chemical composition. The branches of the tree are interpreted as different GPs and the length between nodes as the internal chemical variation along a branch. We apply the PA using 30 abundance indices from the Sloan Digital Sky Survey to 475 galaxies in the Coma Cluster and 438 galaxies in the field. We find that a dense environment, such as Coma, shows several GPs, which indicates that the environment is promoting galaxy evolution. Each population shares common properties that can be identified in colour–magnitude space, in addition to minor structures inside the red sequence. The field is more homogeneous, presenting one main GP. We also apply a principal component analysis (PCA) to both samples, and find that the PCA does not have the same power in identifying GPs.

scholarly journals A Principle Component Analysis of Galaxy Properties from a Large, Gas-Selected Sample

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
Yu-Yen Chang ◽  
Rikon Chao ◽  
Wei-Hao Wang ◽  
Pisin Chen
Keyword(s):  
Principal Component Analysis ◽  
Near Infrared ◽  
Principal Component ◽  
Theoretical Work ◽  
Component Analysis ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Larger Sample ◽  
Global Parameters ◽  
Infrared Data

Disney et al. (2008) have found a striking correlation among global parameters of Hi-selected galaxies and concluded that this is in conflict with the CDM model. Considering the importance of the issue, we reinvestigate the problem using the principal component analysis on a fivefold larger sample and additional near-infrared data. We use databases from the Arecibo Legacy Fast AreciboL-band Feed Array Survey for the gas properties, the Sloan Digital Sky Survey for the optical properties, and the Two Micron All Sky Survey for the near-infrared properties. We confirm that the parameters are indeed correlated where a single physical parameter can explain 83% of the variations. When color (g-i) is included, the first component still dominates but it develops a second principal component. In addition, the near-infrared color (i-J) shows an obvious second principal component that might provide evidence of the complex old star formation. Based on our data, we suggest that it is premature to pronounce the failure of the CDM model and it motivates more theoretical work.

Estimation of Alpha-Element Abundance Ratios Based on Gaussian Process Regression

2014 ◽  
Vol 543-547 ◽  
pp. 1685-1688
Author(s):  
Yu De Bu ◽  
Jing Chang Pan ◽  
Jie Wang
Keyword(s):  
Principal Component Analysis ◽  
Gaussian Process ◽  
Gaussian Process Regression ◽  
Principal Component ◽  
Component Analysis ◽  
Sloan Digital Sky Survey ◽  
Estimation Accuracy ◽  
Element Abundance ◽  
Sky Survey ◽  
Data Release

In this paper, we present a method to estimate the [α/Fe ]using the spectra from ninth data release of Sloan Digital Sky Survey (SDSS). We first use principal component analysis (PCA) to reduce the dimension of the spectra, and then use Gaussian process regression (GPR) to estimate the [α/Fe ]ratios. The results show that GPR is accurate and efficient in estimating the [α/Fe]ratios. Further analysis shows that using PCA can improve the estimation accuracy of GPR.

scholarly journals The Mass of the Coma Cluster from Weak Lensing in the Sloan Digital Sky Survey

2007 ◽  
Vol 671 (2) ◽  
pp. 1466-1470 ◽  
Author(s):  
Jeffrey M. Kubo ◽  
Albert Stebbins ◽  
James Annis ◽  
Ian P. Dell’Antonio ◽  
Huan Lin ◽  
...  
Keyword(s):  
Sloan Digital Sky Survey ◽  
Weak Lensing ◽  
Coma Cluster ◽  
Sky Survey

scholarly journals Effect of bars on evolution of SDSS spiral galaxies

2020 ◽  
Vol 494 (4) ◽  
pp. 5839-5850
Author(s):  
Minbae Kim ◽  
Yun-Young Choi ◽  
Sungsoo S Kim
Keyword(s):  
Galaxy Evolution ◽  
Velocity Dispersion ◽  
Sufficient Conditions ◽  
Central Star ◽  
Sloan Digital Sky Survey ◽  
Causal Connection ◽  
Limited Sample ◽  
Massive Black Hole ◽  
Barred Galaxies ◽  
Sky Survey

ABSTRACT We explore the significance of bars in triggering central star formation (SF) and active galactic nucleus (AGN) activity for spiral galaxy evolution using a volume-limited sample with 0.020 < z < 0.055, Mr < −19.5, and σ > 70 km s−1 selected from Sloan Digital Sky Survey Data Release 7. On a central SF rate–σ plane, we measure the fraction of galaxies with strong bars in our sample and also the AGN fractions for barred and non-barred galaxies, respectively. The comparison between the bar and AGN fractions reveals a causal connection between the two phenomena of SF quenching and AGN activity. A massive black hole and abundant gas fuels are sufficient conditions to trigger AGNs. We infer that the AGNs triggered by satisfying the two conditions drive the strong AGN feedback, suddenly suppressing the central SF and leaving the SF sequence. We find that in galaxies where either of the two conditions is not sufficient, bars are a great help for the AGN triggering, accelerating the entire process of evolution, which is particularly evident in pseudo-bulge galaxies. All of our findings are obtained only when plotted in terms of their central velocity dispersion and central SFR (not galactic scale SFR), indicating that the AGN-driven SF quenching is confined in the central kpc region.

scholarly journals Radio Star Candidates from FIRST and 2MASS Databases

2008 ◽  
Vol 4 (S252) ◽  
pp. 129-130
Author(s):  
Yanxia Zhang ◽  
Yongheng Zhao
Keyword(s):  
Principal Component Analysis ◽  
Near Infrared ◽  
Principal Component ◽  
Component Analysis ◽  
Infrared Band ◽  
Source Database ◽  
Sky Survey ◽  
Radio Band ◽  
Radio Stars

AbstractWe positionally cross-identified FIRST (the Faint Images of the Radio Sky at Twenty centimeters) catalogue with 2MASS (the Two Micron All Sky Survey) pointed-source database and collected the data from radio band and near infrared band. Then the data were cross-matched with the Véron-Cetty & Véron 2006 catalog and the Tycho-2 catalog, respectively. Therefore the known samples of quasars and stars are obtained. We applied principal component analysis (PCA) on the known sample. The overall sample may be projected in the principal component space. From the space, we can easily locate the area that radio stars occupy, and select out radio star candidates. With the follow-up observation of these candidates, the properties of radio stars may be studied.

Sign in / Sign up

Export Citation Format

Share Document