scholarly journals Cross-correlation of the 2XMMi catalogue with Data Release 7 of the Sloan Digital Sky Survey

2011 ◽  
Vol 527 ◽  
pp. A126 ◽  
Author(s):  
F.-X. Pineau ◽  
C. Motch ◽  
F. Carrera ◽  
R. Della Ceca ◽  
S. Derrière ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Data Release

scholarly journals Constraints on running of non-Gaussianity from large-scale structure probes

2019 ◽  
Vol 491 (1) ◽  
pp. L61-L65 ◽  
Author(s):  
Ji-Ping Dai ◽  
Jun-Qing Xia
Keyword(s):  
Spectral Index ◽  
Large Scale ◽  
Cross Correlation ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Sloan Digital Sky Survey ◽  
Microwave Background ◽  
Sky Survey ◽  
Data Release ◽  
Clustering Data

ABSTRACT In this letter, we present constraints on the scale-dependent ‘local’-type primordial non-Gaussianity, which is described by non-Gaussianity’s spectral index nNG, from the NRAO VLA Sky Survey and the quasar catalogue of the Sloan Digital Sky Survey (SDSS) Data Release 6, together with the SDSS Data Release 12 photo-z sample. Here, we use the autocorrelation analyses of these three probes and their cross-correlation analyses with the cosmic microwave background (CMB) temperature map, and obtain the tight constraint on the spectral index: $n_{\rm NG}=0.2 ^{+0.7}_{-1.0}$ ($1\sigma$ C.L.), which shows the first competitive constraint on the running of non-Gaussianity from current large-scale structure clustering data. Furthermore, we also perform the forecast calculations and improve the limit of nNG using the future Euclid mission, and obtain the standard deviation at a 68 per cent confidence level: ΔnNG = 1.74 when considering the fiducial value fNL = 3, which provides the complementary constraining power to those from the CMB bispectrum information.

scholarly journals Statistical analysis of cross-correlation sample of 3XMM-DR4 with SDSS-DR10 and UKIDSS-DR9

2014 ◽  
Vol 10 (S306) ◽  
pp. 372-374
Author(s):  
Yan-Xia Zhang ◽  
Yong-Heng Zhao ◽  
Xue-Bing Wu ◽  
Hai-Jun Tian
Keyword(s):  
Cross Correlation ◽  
Sloan Digital Sky Survey ◽  
Infrared Band ◽  
Classification Result ◽  
X Ray ◽  
The United Kingdom ◽  
Sky Survey ◽  
Distribution Rule ◽  
Data Release ◽  
Multidimensional Parameter

AbstractWe match the XMM-Newton 3XMMi-DR4 catalog with the Sloan Digital Sky Survey (SDSS) Data Release 10 and the United Kingdom Infrared Deep Sky Survey (UKIDSS) Data Release 9. Based on this X-ray/optical/infrared catalog, we probe the distribution of various types of X-ray emitters in the multidimensional parameter space. It is found that quasars, galaxies and stars have some kind distribution rule, especially for stars. The result shows that only using the X-ray/optical features, stars are difficult to discriminate from galaxies and quasars, the added information from infrared band is very helpful to improve the classification result of any classifier. Comparing the classification accuracy of random forests with that of rotation forests, rotation forests show better performance.

scholarly journals A New Catalog of Isolated Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 464-464
Author(s):  
J. A. Vázquez-Mata ◽  
H. M. Hernández-Toledo ◽  
Changbom Park ◽  
Yun-Young Choi
Keyword(s):  
Galaxy Formation ◽  
Environmental Effects ◽  
Comparative Studies ◽  
Sloan Digital Sky Survey ◽  
Selection Algorithm ◽  
Isolated Galaxies ◽  
Galaxy Formation And Evolution ◽  
Sky Survey ◽  
Data Release ◽  
Formation And Evolution

We present a new catalog of isolated galaxies (coined as UNAM–KIAS) obtained through an automated systematic search. The 1520 isolated galaxies were found in ~ 1.4 steradians of the sky in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) photometry. The selection algorithm was implemented from a variation of the criteria developed by Karachentseva (1973), with full redshift information. This new catalog is aimed to carry out comparative studies of environmental effects and constraining the currently competing scenarios of galaxy formation and evolution.

scholarly journals Clustering and Halo Occupation Distribution of Active Galactic Nuclei

2013 ◽  
Vol 9 (S304) ◽  
pp. 243-243
Author(s):  
Takamitsu Miyaji ◽  
M. Krumpe ◽  
A. Coil ◽  
H. Aceves ◽  
B. Husemann
Keyword(s):  
Cross Correlation ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Sloan Digital Sky Survey ◽  
Dark Matter Halo ◽  
Bias Parameter ◽  
X Ray ◽  
Sky Survey ◽  
Galaxy Population ◽  
Halo Occupation Distribution

AbstractWe present the results of our series of studies on correlation function and halo occupation distribution of AGNs utilizing data the ROSAT All-Sky Survey (RASS) and the Sloan Digital Sky Survey (SDSS) in the redshift range of 0.07<z<0.36. In order to improve the signal-to-noise ratio, we take cross-correlation approach, where cross-correlation functions (CCF) between AGNs and much more numerous AGNs are analyzed. The calculated CCFs are analyzed using the Halo Occupation Distribution (HOD) model, where the CCFs are divided into the term contributed by the AGN-galaxy pairs that reside in one dark matter halo (DMH), (the 1-halo term) and those from two different DMHs (the 2-halo term). The 2-halo term is the indicator of the bias parameter, which is a function of the typical mass of the DMHs in which AGNs reside. The combination of the 1-halo and 2-halo terms gives, not only the typical DMH mass, but also how the AGNs are distributed among the DMHs as a function of mass separately for those at the center of the DMHs and satellites. The main results are as follows: (1) the range of typical mass of the DMHs in various sub-samples of AGNs log (MDMH/h−1MΘ) ~ 12.4–13.4, (2) we found a dependence of the AGN bias parameter on the X-ray luminosity of AGNs, while the optical luminosity dependence is not significant probably due to smaller dynamic range in luminosity for the optically-selected sample, and (3) the growth of the number of AGNs per DMH (N (MDMH)) with MDMH is shallow, or even may be flat, contrary to that of the galaxy population in general, which grows with MDMH proportionally, suggesting a suppression of AGN triggering in denser environment. In order to investigate the origin of the X-ray luminosity dependence, we are also investigating the dependence of clustering on the black hole mass and the Eddington ratio, we also present the results of this investigation.

scholarly journals Nitrogen-Enriched Quasars in the Sloan Digital Sky Survey First Data Release

2004 ◽  
Vol 128 (2) ◽  
pp. 561-568 ◽  
Author(s):  
Misty C. Bentz ◽  
Patrick B. Hall ◽  
Patrick S. Osmer
Keyword(s):  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Data Release

scholarly journals White Dwarf Stars

2017 ◽  
Vol 45 ◽  
pp. 1760023
Author(s):  
S. O. Kepler ◽  
Alejandra Daniela Romero ◽  
Ingrid Pelisoli ◽  
Gustavo Ourique
Keyword(s):  
White Dwarf ◽  
Final Stage ◽  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Dwarf Stars ◽  
Multiple Systems ◽  
White Dwarf Stars ◽  
Sky Survey ◽  
Data Release ◽  
Low Mass

White dwarf stars are the final stage of most stars, born single or in multiple systems. We discuss the identification, magnetic fields, and mass distribution for white dwarfs detected from spectra obtained by the Sloan Digital Sky Survey up to Data Release 13 in 2016, which lead to the increase in the number of spectroscopically identified white dwarf stars from 5[Formula: see text]000 to 39[Formula: see text]000. This number includes only white dwarf stars with [Formula: see text], i.e., excluding the Extremely Low Mass white dwarfs, which are necessarily the byproduct of stellar interaction.

scholarly journals Influences of Galaxy Interactions on AGN Activity

2013 ◽  
Vol 30 ◽  
Author(s):  
Xin-Fa Deng ◽  
Guisheng Yu ◽  
Peng Jiang
Keyword(s):  
Survey Data ◽  
Strong Evidence ◽  
Sloan Digital Sky Survey ◽  
Limited Sample ◽  
Galaxy Interactions ◽  
Opposite Trend ◽  
Main Galaxy ◽  
Isolated Galaxies ◽  
Sky Survey ◽  
Data Release

AbstractUsing two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 7 , we explore influences of galaxy interactions on AGN activity. It is found that in the faint volume-limited sample, paired galaxies have a slightly higher AGN fraction than isolated galaxies, whereas in the luminous volume-limited sample, an opposite trend can be observed. The significance is <1σ. Thus, we do not observe strong evidence that interactions or mergers likely trigger the AGN activity.

The Mass Function of Void Galaxies in the Sloan Digital Sky Survey Data Release 2

2005 ◽  
Vol 621 (2) ◽  
pp. 643-650 ◽  
Author(s):  
David M. Goldberg ◽  
Timothy D. Jones ◽  
Fiona Hoyle ◽  
Randall R. Rojas ◽  
Michael S. Vogeley ◽  
...  
Keyword(s):  
Survey Data ◽  
Mass Function ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Void Galaxies ◽  
Data Release

scholarly journals The Sub-Eddington Boundary for the Quasar Mass–Luminosity Plane: A Theoretical Perspective

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 145 ◽  
Author(s):  
David Garofalo ◽  
Damian J. Christian ◽  
Andrew M. Jones
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Survey Data ◽  
Theoretical Perspective ◽  
Sloan Digital Sky Survey ◽  
Black Hole Mass ◽  
Massive Black Holes ◽  
Sky Survey ◽  
Data Release ◽  
Gap Paradigm

By exploring more than sixty thousand quasars from the Sloan Digital Sky Survey Data Release 5, Steinhardt & Elvis discovered a sub-Eddington boundary and a redshift-dependent drop-off at higher black hole mass, possible clues to the growth history of massive black holes. Our contribution to this special issue of Universe amounts to an application of a model for black hole accretion and jet formation to these observations. For illustrative purposes, we include ~100,000 data points from the Sloan Digital Sky Survey Data Release 7 where the sub-Eddington boundary is also visible and propose a theoretical picture that explains these features. By appealing to thin disk theory and both the lower accretion efficiency and the time evolution of jetted quasars compared to non-jetted quasars in our “gap paradigm”, we explain two features of the sub-Eddington boundary. First, we show that a drop-off on the quasar mass-luminosity plane for larger black hole mass occurs at all redshifts. But the fraction of jetted quasars is directly related to the merger function in this paradigm, which means the jetted quasar fraction drops with decrease in redshift, which allows us to explain a second feature of the sub-Eddington boundary, namely a redshift dependence of the slope of the quasar mass–luminosity boundary at high black hole mass stemming from a change in radiative efficiency with time. We are able to reproduce the mass dependence of, as well as the oscillating behavior in, the slope of the sub-Eddington boundary as a function of time. The basic physical idea involves retrograde accretion occurring only for a subset of the more massive black holes, which implies that most spinning black holes in our model are prograde accretors. In short, this paper amounts to a qualitative overview of how a sub-Eddington boundary naturally emerges in the gap paradigm.

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