Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample

Richards, Gordon T.; Fan, Xiaohui; Newberg, Heidi Jo; Strauss, Michael A.; Berk, D. E. vanden; Schneider, Donald P.; Yanny, B.; Boucher, Andrew; Burles, Scott; Frieman, Joshua A.; Gunn, James E.; Hall, Patrick B.; Ivezić, Željko; Kent, Stephen M.; Loveday, Jon; Lupton, Robert H.; Rockosi, Constance M.; Schlegel, David J.; Stoughton, Chris; SubbaRao, Mark; York, Donald G.

doi:10.1086/340187

Cited by 919 publications

(949 citation statements)

References 35 publications

Supporting

Mentioning

927

Contrasting

Order By: Relevance

“…The QSOs selected for this study lie amongst the brightest values of M i (z = 2) compared to the spectroscopically confirmed SDSS QSOs (Shen et al 2011), which are uniformly selected to ∼90 percent completeness (Richards et al 2002a;Vanden Berk et al 2005). It is clear that the sample presented here represents some of the brightest quasars existing between redshift 1 and 2.…”

Section: Comparison To Global Populationmentioning

confidence: 93%

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

Selsing

Fynbo

Christensen

et al. 2015

A&A

159

180

View full text Add to dashboard Cite

Quasi-stellar object (QSO) spectral templates are important both to QSO physics and for investigations that use QSOs as probes of intervening gas and dust. However, combinations of various QSO samples obtained at different times and with different instruments so as to expand a composite and to cover a wider rest frame wavelength region may create systematic effects, and the contribution from QSO hosts may contaminate the composite. We have constructed a composite spectrum from luminous blue QSOs at 1 < z < 2.1 selected from the Sloan Digital Sky Survey (SDSS). The observations with X-Shooter simultaneously cover ultraviolet (UV) to nearinfrared (NIR) light, which ensures that the composite spectrum covers the full rest-frame range from Lyβ to 11 350 Å without any significant host contamination. Assuming a power-law continuum for the composite we find a spectral slope of α λ = 1.70 ± 0.01, which is steeper than previously found in the literature. We attribute the differences to our broader spectral wavelength coverage, which allows us to effectively avoid fitting any regions that are affected either by strong QSO emissions lines (e.g., Balmer lines and complex [Fe II] blends) or by intrinsic host galaxy emission. Finally, we demonstrate the application of the QSO composite spectrum for evaluating the reddening in other QSOs.

show abstract

Section: Comparison To Global Populationmentioning

confidence: 93%

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

Selsing

Fynbo

Christensen

et al. 2015

A&A

159

180

View full text Add to dashboard Cite

show abstract

“…We start from the SDSS DR7 QSO sample (Schneider et al 2010), consisting of 105 783 QSOs. We restrict this sample to the subset that has been selected by a uniform target selection algorithm (Richards et al 2002) and thus form a well-defined broad line AGN sample (Richards et al 2006a;Shen & Kelly 2012). The sample is magnitude limited to 15.0 < i < 19.1 below z = 2.9 and the target selection is based on multicolour information.…”

Section: Sdssmentioning

confidence: 99%

The cosmic growth of the active black hole population at 1 <z <2 in zCOSMOS, VVDS and SDSS

Schulze

Bongiorno

Gavignaud

et al. 2015

Monthly Notices of the Royal Astronomical Society

159

View full text Add to dashboard Cite

We present a census of the active black hole population at 1 < z < 2, by constructing the bivariate distribution function of black hole mass and Eddington ratio, employing a maximum likelihood fitting technique. The study of the active black hole mass function (BHMF) and the Eddington ratio distribution function (ERDF) allows us to clearly disentangle the active galactic nuclei (AGN) downsizing phenomenon, present in the AGN luminosity function, into its physical processes of black hole mass downsizing and accretion rate evolution. We are utilizing type-1 AGN samples from three optical surveys (VVDS, zCOSMOS and SDSS), that cover a wide range of 3 dex in luminosity over our redshift interval of interest. We investigate the cosmic evolution of the AGN population as a function of AGN luminosity, black hole mass and accretion rate. Compared to z = 0, we find a distinct change in the shape of the BHMF and the ERDF, consistent with downsizing in black hole mass. The active fraction or duty cycle of type-1 AGN at z ∼ 1.5 is almost flat as a function of black hole mass, while it shows a strong decrease with increasing mass at z = 0. We are witnessing a phase of intense black hole growth, which is largely driven by the onset of AGN activity in massive black holes towards z = 2. We finally compare our results to numerical simulations and semi-empirical models and while we find reasonable agreement over certain parameter ranges, we highlight the need to refine these models in order to match our observations.

show abstract

“…The resulting imaging provides photometric observations in five bands: u, g, r, i, and z (Fukugita et al 1996). The selection for spectroscopic followup for the quasars at low redshift (z ≤ 3) is done in the ugri color space with a limiting magnitude of i ≤ 19.1 (Richards et al 2002). At high-redshift (z ≥ 3), the selection is performed in griz color space with i < 20.2.…”

Section: Sloan Digital Sky Surveymentioning

confidence: 99%

“…We select a flux limited i = 19.1 sample of 48338 quasars with 0.3 ≤ z ≤ 2.3 from the Shen et al (2011) catalog with the flag uniform_target= 1. This sample includes both RLQs and RQQs selected uniformly by the quasar target selection algorithm presented in Richards et al (2002). For quasar clustering studies, it is critical to use statistical samples that have been constructed using only one target selection algorithm.…”

Section: Sloan Digital Sky Surveymentioning

confidence: 99%

Probing the radio loud/quiet AGN dichotomy with quasar clustering

Retana-Montenegro

Röttgering

2017

A&A

View full text Add to dashboard Cite

We investigate the clustering properties of 45441 radio-quiet quasars (RQQs) and 3493 radio-loud quasars (RLQs) drawn from a joint use of the Sloan Digital Sky Survey (SDSS) and Faint Images of the Radio Sky at 20 cm (FIRST) surveys in the range 0.3 < z < 2.3. This large spectroscopic quasar sample allow us to investigate the clustering signal dependence on radio-loudness and black hole (BH) virial mass. We find that RLQs are clustered more strongly than RQQs in all the redshift bins considered. We find a real-space correlation length of r 0 = 6.59 +0.33 −0.24 h −1 Mpc and r 0 = 10.95 +1.22 −1.58 h −1 Mpc for RQQs and RLQs, respectively, for the full redshift range. This implies that RLQs are found in more massive host haloes than RQQs in our samples, with mean host halo masses of ∼ 4.9 × 10 13 h −1 M and ∼ 1.9 × 10 12 h −1 M , respectively. Comparison with clustering studies of different radio source samples indicates that this mass scale of 1 × 10 13 h −1 M is characteristic for the bright radio-population, which corresponds to the typical mass of galaxy groups and galaxy clusters. The similarity we find in correlation lengths and host halo masses for RLQs, radio galaxies and flat-spectrum radio quasars agrees with orientation-driven unification models. Additionally, the clustering signal shows a dependence on black hole (BH) mass, with the quasars powered by the most massive BHs clustering more strongly than quasars having less massive BHs. We suggest that the current virial BH mass estimates may be a valid BH proxies for studying quasar clustering. We compare our results to a previous theoretical model that assumes that quasar activity is driven by cold accretion via mergers of gas-rich galaxies. While the model can explain the bias and halo masses for RQQs, it cannot reproduce the higher bias and host halo masses for RLQs. We argue that other BH properties such as BH spin, environment, magnetic field configuration, and accretion physics must be considered to fully understand the origin of radio-emission in quasars and its relation to the higher clustering.

show abstract

Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample

Cited by 919 publications

References 35 publications

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

An X-Shooter composite of bright 1 <z< 2 quasars from UV to infrared

The cosmic growth of the active black hole population at 1 <z <2 in zCOSMOS, VVDS and SDSS

Probing the radio loud/quiet AGN dichotomy with quasar clustering

Contact Info

Product

Resources

About