scholarly journals Spectroscopic Properties of Cool Stars in the Sloan Digital Sky Survey: An Analysis of Magnetic Activity and a Search for Subdwarfs

2004 ◽  
Vol 128 (1) ◽  
pp. 426-436 ◽  
Author(s):  
Andrew A. West ◽  
Suzanne L. Hawley ◽  
Lucianne M. Walkowicz ◽  
Kevin R. Covey ◽  
Nicole M. Silvestri ◽  
...  
2019 ◽  
Vol 15 (S356) ◽  
pp. 358-360
Author(s):  
Dejene Zewdie ◽  
Mirjana Pović ◽  
Manuel Aravena ◽  
Roberto J. Assef ◽  
Asrate Gaulle

AbstractIn this work, we study the properties of galaxies that are showing the inside-out assembly (which we call inside-out assembled galaxies; IOAGs), with the main aim to understand better their properties and morphological transformation. We analysed a sample of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8), with stellar masses in the range log M* = 10.73 – 11.03 M⊙ at at z < 0.1, and analyze their location in the stellar mass-SFR and the color-stellar mass diagram. We found that IOAGs have different spectroscopic properties, most of them being classified either as AGN or composite. We found that the majority of our sources are located below the main sequence of star formation in the SFR-stellar mass diagram, and in the green valley or red sequence in the color-stellar mass diagram. We argue that IOAGs seem to correspond to the transition area where the galaxies are moving from star-forming to quiescent, and from the blue cloud to the red sequence and/or to recently quenched galaxies.


2005 ◽  
Vol 117 (833) ◽  
pp. 706-710 ◽  
Author(s):  
Andrew A. West ◽  
Lucianne M. Walkowicz ◽  
Suzanne L. Hawley

2005 ◽  
Vol 624 (2) ◽  
pp. 571-585 ◽  
Author(s):  
Randall R. Rojas ◽  
Michael S. Vogeley ◽  
Fiona Hoyle ◽  
Jon Brinkmann

2008 ◽  
Vol 135 (3) ◽  
pp. 785-795 ◽  
Author(s):  
Andrew A. West ◽  
Suzanne L. Hawley ◽  
John J. Bochanski ◽  
Kevin R. Covey ◽  
I. Neill Reid ◽  
...  

2014 ◽  
Vol 4 (3) ◽  
pp. 655-661
Author(s):  
Waleed Elsanhoury

Using Sloan Digital Sky Survey SDSS catalog, some intrinsic characteristics of Quasars (10,000 points) are developed of these are the strong correlations between redshifts and other parameters, e.g. combined magnitude, luminosity, and absolute magnitude .Moreover ,the Karlsson peak of our sample is also computed.


2021 ◽  
Vol 504 (1) ◽  
pp. 65-88
Author(s):  
Abhijeet Anand ◽  
Dylan Nelson ◽  
Guinevere Kauffmann

ABSTRACT In order to study the circumgalactic medium (CGM) of galaxies we develop an automated pipeline to estimate the optical continuum of quasars and detect intervening metal absorption line systems with a matched kernel convolution technique and adaptive S/N criteria. We process ∼ one million quasars in the latest Data Release 16 (DR16) of the Sloan Digital Sky Survey (SDSS) and compile a large sample of ∼ 160 000 Mg ii absorbers, together with ∼ 70 000 Fe ii systems, in the redshift range 0.35 &lt; zabs &lt; 2.3. Combining these with the SDSS DR16 spectroscopy of ∼1.1 million luminous red galaxies (LRGs) and ∼200 000 emission line galaxies (ELGs), we investigate the nature of cold gas absorption at 0.5 &lt; z &lt; 1. These large samples allow us to characterize the scale dependence of Mg ii with greater accuracy than in previous work. We find that there is a strong enhancement of Mg ii absorption within ∼50 kpc of ELGs, and the covering fraction within 0.5rvir of ELGs is 2–5 times higher than for LRGs. Beyond 50 kpc, there is a sharp decline in Mg ii for both kinds of galaxies, indicating a transition to the regime where the CGM is tightly linked with the dark matter halo. The Mg ii-covering fraction correlates strongly with stellar mass for LRGs, but weakly for ELGs, where covering fractions increase with star formation rate. Our analysis implies that cool circumgalactic gas has a different physical origin for star-forming versus quiescent galaxies.


2019 ◽  
Vol 15 (S359) ◽  
pp. 441-443
Author(s):  
F. S. Lohmann ◽  
A. Schnorr-Müller ◽  
M. Trevisan ◽  
R. Riffel ◽  
N. Mallmann ◽  
...  

AbstractObservations at high redshift reveal that a population of massive, quiescent galaxies (called red nuggets) already existed 10 Gyr ago. These objects undergo a significant size evolution over time, likely due to minor mergers. In this work we present an analysis of local massive compact galaxies to assess if their properties are consistent with what is expected for unevolved red nuggets (relic galaxies). Using integral field spectroscopy (IFS) data from the MaNGA survey from the Sloan Digital Sky Survey (SDSS), we characterized the kinematics and properties of stellar populations of massive compact galaxies, and find that these objects exhibit, on average, a higher rotational support than a control sample of average sized early-type galaxies. This is in agreement with a scenario in which these objects have a quiet accretion history, rendering them candidates for relic galaxies.


2020 ◽  
Vol 500 (4) ◽  
pp. 4469-4490 ◽  
Author(s):  
James Trussler ◽  
Roberto Maiolino ◽  
Claudia Maraston ◽  
Yingjie Peng ◽  
Daniel Thomas ◽  
...  

ABSTRACT We investigate the environmental dependence of the stellar populations of galaxies in Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Echoing earlier works, we find that satellites are both more metal-rich (&lt;0.1 dex) and older (&lt;2 Gyr) than centrals of the same stellar mass. However, after separating star-forming, green valley, and passive galaxies, we find that the true environmental dependence of both stellar metallicity (&lt;0.03 dex) and age (&lt;0.5 Gyr) is in fact much weaker. We show that the strong environmental effects found when galaxies are not differentiated result from a combination of selection effects brought about by the environmental dependence of the quenched fraction of galaxies, and thus we strongly advocate for the separation of star-forming, green valley, and passive galaxies when the environmental dependence of galaxy properties are investigated. We also study further environmental trends separately for both central and satellite galaxies. We find that star-forming galaxies show no environmental effects, neither for centrals nor for satellites. In contrast, the stellar metallicities of passive and green valley satellites increase weakly (&lt;0.05 and &lt;0.08 dex, respectively) with increasing halo mass, increasing local overdensity and decreasing projected distance from their central; this effect is interpreted in terms of moderate environmental starvation (‘strangulation’) contributing to the quenching of satellite galaxies. Finally, we find a unique feature in the stellar mass–stellar metallicity relation for passive centrals, where galaxies in more massive haloes have larger stellar mass (∼0.1 dex) at constant stellar metallicity; this effect is interpreted in terms of dry merging of passive central galaxies and/or progenitor bias.


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