scholarly journals Transformations from WISE to 2MASS, SDSS and BVI Photometric Systems: II. Transformation Equations for Red-Clump Stars

2012 ◽  
Vol 29 (2) ◽  
pp. 121-131 ◽  
Author(s):  
S. Bilir ◽  
S. Karaali ◽  
N. D. Dağtekin ◽  
Ö. Önal ◽  
S. Ak ◽  
...  
Keyword(s):  
Field Survey ◽  
Sloan Digital Sky Survey ◽  
Wide Field ◽  
Experiment Data ◽  
The Third ◽  
Final Sample ◽  
Sky Survey ◽  
Data Release ◽  
Red Clump ◽  
Absolute Magnitudes

AbstractWe present colour transformations for the conversion of Wide-Field Survey Explorer W1, W2, and W3 magnitudes to the Johnson–Cousins BVIc, Sloan Digital Sky Survey gri, and Two Micron All Sky Survey JHKs photometric systems, for red clump (RC) stars. RC stars were selected from the Third Radial Velocity Experiment Data Release. The apparent magnitudes were collected by matching the coordinates of this sample with different photometric catalogues. The final sample (355 RC stars) was used to obtain metallicitydependent and free-of-metallicity transformations. These transformations combined with known absolute magnitudes at shorter wavelengths can be used in space density determinations for the Galactic (thin and thick) discs at distances larger than the ones evaluated with JHKs photometry alone, hence providing a powerful tool in the analysis of Galactic structure.

scholarly journals The optical luminosity function of LOFAR radio-selected quasars at 1.4 ≤ z ≤ 5.0 in the NDWFS-Boötes field

2020 ◽  
Vol 636 ◽  
pp. A12
Author(s):  
E. Retana-Montenegro ◽  
H. J. A. Röttgering
Keyword(s):  
Radio Emission ◽  
Luminosity Function ◽  
Field Survey ◽  
Sloan Digital Sky Survey ◽  
Spatial Density ◽  
Spectral Energy ◽  
Wide Field ◽  
Infrared Photometry ◽  
Mid Infrared ◽  
Sky Survey

We present an estimate of the optical luminosity function (OLF) of LOFAR radio-selected quasars (RSQs) at 1.4 <  z <  5.0 in the 9.3 deg2 NOAO Deep Wide-field survey (NDWFS) of the Boötes field. The selection was based on optical and mid-infrared photometry used to train three different machine learning (ML) algorithms (Random forest, SVM, Bootstrap aggregation). Objects taken as quasars by the ML algorithms are required to be detected at ≥5σ significance in deep radio maps to be classified as candidate quasars. The optical imaging came from the Sloan Digital Sky Survey and the Pan-STARRS1 3π survey; mid-infrared photometry was taken from the Spitzer Deep, Wide-Field Survey; and radio data was obtained from deep LOFAR imaging of the NDWFS-Boötes field. The requirement of a 5σ LOFAR detection allowed us to reduce the stellar contamination in our sample by two orders of magnitude. The sample comprises 130 objects, including both photometrically selected candidate quasars (47) and spectroscopically confirmed quasars (83). The spectral energy distributions calculated using deep photometry available for the NDWFS-Boötes field confirm the validity of the photometrically selected quasars using the ML algorithms as robust candidate quasars. The depth of our LOFAR observations allowed us to detect the radio-emission of quasars that would be otherwise classified as radio-quiet. Around 65% of the quasars in the sample are fainter than M1450 = −24.0, a regime where the OLF of quasars selected through their radio emission, has not been investigated in detail. It has been demonstrated that in cases where mid-infrared wedge-based AGN selection is not possible due to a lack of appropriate data, the selection of quasars using ML algorithms trained with optical and infrared photometry in combination with LOFAR data provides an excellent approach for obtaining samples of quasars. The OLF of RSQs can be described by pure luminosity evolution at z <  2.4, and a combined luminosity and density evolution at z >  2.4. The faint-end slope, α, becomes steeper with increasing redshift. This trend is consistent with previous studies of faint quasars (M1450 ≤ −22.0). We demonstrate that RSQs show an evolution that is very similar to that exhibited by faint quasars. By comparing the spatial density of RSQs with that of the total (radio-detected plus radio-undetected) faint quasar population at similar redshifts, we find that RSQs may compose up to ∼20% of the whole faint quasar population. This fraction, within uncertainties, is constant with redshift. Finally, we discuss how the compactness of the RSQs radio-morphologies and their steep spectral indices could provide valuable insights into how quasar and radio activity are triggered in these systems.

scholarly journals THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. III. CONSTRAINTS ON DARK ENERGY FROM THE THIRD DATA RELEASE QUASAR LENS CATALOG

2008 ◽  
Vol 135 (2) ◽  
pp. 512-519 ◽  
Author(s):  
Masamune Oguri ◽  
Naohisa Inada ◽  
Michael A. Strauss ◽  
Christopher S. Kochanek ◽  
Gordon T. Richards ◽  
...  
Keyword(s):  
Dark Energy ◽  
Sloan Digital Sky Survey ◽  
The Third ◽  
Sky Survey ◽  
Data Release

scholarly journals THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. II. STATISTICAL LENS SAMPLE FROM THE THIRD DATA RELEASE

2008 ◽  
Vol 135 (2) ◽  
pp. 496-511 ◽  
Author(s):  
Naohisa Inada ◽  
Masamune Oguri ◽  
Robert H. Becker ◽  
Min-Su Shin ◽  
Gordon T. Richards ◽  
...  
Keyword(s):  
Sloan Digital Sky Survey ◽  
The Third ◽  
Sky Survey ◽  
Data Release

scholarly journals A Census of the Stellar Populations in the Sco-Cen Complex*

2021 ◽  
Vol 163 (1) ◽  
pp. 24
Author(s):  
K. L. Luhman
Keyword(s):  
High Precision ◽  
Stellar Populations ◽  
Young Stars ◽  
Initial Mass ◽  
Wide Field ◽  
The Third ◽  
Sky Survey ◽  
Data Release ◽  
Mass Functions ◽  
Infrared Survey

Abstract I have used high-precision photometry and astrometry from the early installment of the third data release of Gaia (EDR3) to perform a survey for members of the stellar populations within the Sco-Cen complex, which consist of Upper Sco, UCL/LCC, the V1062 Sco group, Ophiuchus, and Lupus. Among Gaia sources with σ π < 1 mas, I have identified 10,509 candidate members of those populations. I have compiled previous measurements of spectral types, Li equivalent widths, and radial velocities for the candidates, which are available for 3169, 1420, and 1740 objects, respectively. In a subset of candidates selected to minimize field star contamination, I estimate that the contamination is ≲1% and the completeness is ∼90% at spectral types of ≲M6–M7 for the populations with low extinction (Upper Sco, V1062 Sco, UCL/LCC). I have used that cleaner sample to characterize the stellar populations in Sco-Cen in terms of their initial mass functions, ages, and space velocities. For instance, all of the populations in Sco-Cen have histograms of spectral types that peak near M4–M5, which indicates that they share similar characteristic masses for their initial mass functions (∼0.15–0.2 M ⊙). After accounting for incompleteness, I estimate that the Sco-Cen complex contains nearly 10,000 members with masses above ∼0.01 M ⊙. Finally, I also present new estimates for the intrinsic colors of young stars and brown dwarfs (≲20 Myr) in bands from Gaia EDR3, the Two Micron All Sky Survey, the Wide-field Infrared Survey Explorer, and the Spitzer Space Telescope.

scholarly journals The Third Data Release of the Sloan Digital Sky Survey

2005 ◽  
Vol 129 (3) ◽  
pp. 1755-1759 ◽  
Author(s):  
Kevork Abazajian ◽  
Jennifer K. Adelman-McCarthy ◽  
Marcel A. Agüeros ◽  
Sahar S. Allam ◽  
Kurt S. J. Anderson ◽  
...  
Keyword(s):  
Sloan Digital Sky Survey ◽  
The Third ◽  
Sky Survey ◽  
Data Release

scholarly journals Galaxy Groups in the Third Data Release of the Sloan Digital Sky Survey

2005 ◽  
Vol 630 (2) ◽  
pp. 759-763 ◽  
Author(s):  
Manuel E. Merchan ◽  
Ariel Zandivarez
Keyword(s):  
Sloan Digital Sky Survey ◽  
Galaxy Groups ◽  
The Third ◽  
Sky Survey ◽  
Data Release

scholarly journals A Spectroscopic Study of the Ancient Milky Way: F‐ and G‐Type Stars in the Third Data Release of the Sloan Digital Sky Survey

2006 ◽  
Vol 636 (2) ◽  
pp. 804-820 ◽  
Author(s):  
Carlos Allende Prieto ◽  
Timothy C. Beers ◽  
Ronald Wilhelm ◽  
Heidi Jo Newberg ◽  
Constance M. Rockosi ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Milky Way ◽  
Sloan Digital Sky Survey ◽  
The Third ◽  
Sky Survey ◽  
Data Release

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 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
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