The Extremely Luminous Quasar Survey in the Pan-STARRS 1 Footprint (PS-ELQS)

Abstract

We present the results of the Extremely Luminous Quasar Survey in the $3\pi$ survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint ($\sim 12,000{\mathrm{deg}}^2$) to a much larger area ($\sim 21486{\mathrm{deg}}^2$). This spectroscopic survey targets the most luminous quasars ($M_{1450}\le -26.5$; $m_i\le 18.5$) at intermediate redshifts ($z\ge 2.8$). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts ($z_{\mathrm{reg}}$) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at $z_{\mathrm{reg}}\ge 2.8$ from a parent sample of 74318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new $z\ge 2.8$ quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at $z\ge 2.8$, our quasar selection method has a selection efficiency of at least $77\%$. At lower declinations $-30\le Decl.\le 0$ we approximately triple the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars ($m_i\le 18.5$, $z\ge 2.8$). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.

34 pages, 10 figures, accepted to ApJS

References in corpus (21)

• A luminous quasar at a redshift of z = 7.085
• Second ROSAT all-sky survey (2RXS) source catalogue
• The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• Physical properties of 15 quasars at $z\gtrsim 6.5$
• Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey
• The 2dF-SDSS LRG and QSO Survey: QSO clustering and the L-z degeneracy
• Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
• A Survey of z~6 Quasars in the SDSS Deep Stripe: I. a Flux-Limited Sample at z_{AB}<21
• Clustering Analyses of 300,000 Photometrically Classified Quasars--I. Luminosity and Redshift Evolution in Quasar Bias
• The Half Million Quasars (HMQ) Catalogue
• Photometric redshift estimation via deep learning
• Discovery of eight z ~ 6 quasars from Pan-STARRS1
• The Subaru high-z quasar survey: discovery of faint z~6 quasars
• Three new VHS-DES Quasars at 6.7 < z < 6.9 and Emission Line Properties at z > 6.5
• Two bright z > 6 quasars from VST ATLAS and a new method of optical plus mid-infra-red colour selection
• The discovery of the first luminous z~6 quasar in the UKIDSS Large Area Survey
• The Extremely Luminous Quasar Survey (ELQS) in the SDSS footprint I.: Infrared Based Candidate Selection
• The Extremely Luminous Quasar Survey in the Sloan Digital Sky Survey footprint. III. The South Galactic Cap Sample and the Quasar Luminosity Function at Cosmic Noon
• A new bright z=6.82 quasar discovered with VISTA: VHS J0411-0907

Cited by in corpus (12)

• The spectroscopic follow-up of the QUBRICS bright quasar survey
• Random Forests as a viable method to select and discover high redshift quasars
• Ultra-luminous quasars at redshift $z>4.5$ from SkyMapper
• Spectroscopy of QUBRICS quasar candidates: 1672 new redshifts and a Golden Sample for the Sandage Test of the Redshift Drift
• A Thirty-Four Billion Solar Mass Black Hole in SMSS J2157-3602, the Most Luminous Known Quasar
• Forecasting cosmic acceleration measurements using the Lyman-$\alpha$ forest
• A Closer Look at Two of the Most Luminous Quasars in the Universe
• Photometric IGM Tomography: Efficiently Mapping Quasar Light Echoes with Deep Narrow Band Imaging
• The probabilistic random forest applied to the QUBRICS survey: improving the selection of high-redshift quasars with synthetic data
• The quasar luminosity function at $z\sim 5$ via deep learning and Bayesian information criterion
• An Extremely Bright QSO at $z=2.89$
• Photometric classification of QSOs from ALHAMBRA survey using random forest