Related papers: Target Selection and Validation of DESI Quasars

Photometric Redshifts of Quasars

We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts (``photo-z''s) of quasars. Using a sample…

Astrophysics · Physics 2009-11-06 Gordon T. Richards , Michael A. Weinstein , Donald P. Schneider , Xiaohui Fan , Michael A. Strauss , Daniel E. Vanden Berk

QSO Selection and Photometric Redshifts with Neural Networks

Baryonic Acoustic Oscillations (BAO) and their effects on the matter power spectrum can be studied by using the Lyman-alpha absorption signature of the matter density field along quasar (QSO) lines of sight. A measurement sufficiently…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-21 Ch. Yeche , P. Petitjean , J. Rich , E. Aubourg , N. Busca , J. -Ch. Hamilton , J. -M. Le Goff , I. Paris , S. Peirani , Ch. Pichon , E. Rollinde , M. Vargas-Magana

Reddening Independent Quasar Selection from a Wide Field Optical and Near-IR Imaging Survey

We present preliminary results from a wide field near-IR imaging survey that uses the Cambridge InfraRed Survey Instrument (CIRSI) on the 2.5m Isaac Newton Telescope (INT). CIRSI is a JH-band mosaic imager that contains 4 Rockwell…

Astrophysics · Physics 2007-05-23 C. N. Sabbey , R. G. Sharp , A. K. Vivas , S. T. Hodgkin , P. S. Coppi , R. G. McMahon

Impact and mitigation of spectroscopic systematics on DESI DR1 clustering measurements

The large scale structure catalogs within DESI Data Release 1 (DR1) use nearly 6 million galaxies and quasars as tracers of the large-scale structure of the universe to measure the expansion history with baryon acoustic oscillations and the…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-04 A. Krolewski , J. Yu , A. J. Ross , S. Penmetsa , W. J. Percival , R. Zhou , J. Hou , J. Aguilar , S. Ahlen , D. Brooks , E. Chaussidon , T. Claybaugh , A. de la Macorra , Biprateep Dey , J. E. Forero-Romero , S. Gontcho A Gontcho , J. Guy , K. Honscheid , S. Juneau , D. Kirkby , T. Kisner , A. Kremin , A. Lambert , L. Le-Guillou , M. E. Levi , P. Martini , A. Meisner , R. Miquel , J. Moustakas , A. D. Myers , J. A. Newman , G. Niz , N. Palanque-Delabrouille , G. Rossi , E. Sanchez , E. F. Schlafly , D. Schlegel , M. Schubnell , H. Seo , D. Sprayberry , G. Tarlé , B. A. Weaver , C. Zhao

The Composite Spectrum of QSO Absorption Line Systems in DESI DR2

We present details regarding the construction of a composite spectrum of quasar (QSO) absorption line systems. In this composite spectrum we identify more than 70 absorption lines, and observe oxygen and hydrogen emission features at a…

Astrophysics of Galaxies · Physics 2025-12-03 Lucas Napolitano , Adam D. Myers , Adam Tedeschi , Abhijeet Anand , Hiram K. Herrera-Alcantar , Jessica Aguilar , Steven Ahlen , Stephen Bailey , Segev BenZvi , Davide Bianchi , David Brooks , Todd Claybaugh , Andrei Cuceu , Axel de la Macorra , Arjun Dey , Biprateep Dey , Peter Doel , Andreu Font-Ribera , Jaime E. Forero-Romero , Enrique Gaztanaga , Satya Gontcho A Gontcho , Gaston Gutierrez , Julien Guy , Dick Joyce , Anthony Kremin , Martin Landriau , Laurent Le Guillou , Marc Manera , Aaron Meisner , Ramon Miquel , John Moustakas , Seshadri Nadathur , Nathalie Palanque-Delabrouille , Will Percival , Francisco Prada , Ignasi Perez-Rafols , Graziano Rossi , Eusebio Sanchez , David Schlegel , Michael Schubnell , Joesph Harry Silber , David Sprayberry , Gregory Tarle , Benjamin Alan Weaver , Rongpu Zhou , Hu Zou

Photometric redshift analysis in the Dark Energy Survey Science Verification data

We present results from a study of the photometric redshift performance of the Dark Energy Survey (DES), using the early data from a Science Verification (SV) period of observations in late 2012 and early 2013 that provided science-quality…

Instrumentation and Methods for Astrophysics · Physics 2014-10-15 C. Sánchez , M. Carrasco Kind , H. Lin , R. Miquel , F. B. Abdalla , A. Amara , M. Banerji , C. Bonnett , R. Brunner , D. Capozzi , A. Carnero , F. J. Castander , L. A. N. da Costa , C. Cunha , A. Fausti , D. Gerdes , N. Greisel , J. Gschwend , W. Hartley , S. Jouvel , O. Lahav , M. Lima , M. A. G. Maia , P. Martí , R. L. C. Ogando , F. Ostrovski , P. Pellegrini , M. M. Rau , I. Sadeh , S. Seitz , I. Sevilla-Noarbe , A. Sypniewski , J. de Vicente , T. Abbot , S. S. Allam , D. Atlee , G. Bernstein , J. P. Bernstein , E. Buckley-Geer , D. Burke , M. J. Childress , T. Davis , D. L. DePoy , A. Dey , S. Desai , H. T. Diehl , P. Doel , J. Estrada , A. Evrard , E. Fernández , D. Finley , B. Flaugher , E. Gaztanaga , K. Glazebrook , K. Honscheid , A. Kim , K. Kuehn , N. Kuropatkin , C. Lidman , M. Makler , J. L. Marshall , R. C. Nichol , A. Roodman , E. Sánchez , B. X. Santiago , M. Sako , R. Scalzo , R. C. Smith , M. E. C. Swanson , G. Tarle , D. Thomas , D. L. Tucker , S. A. Uddin , F. Valdés , A. Walker , F. Yuan , J. Zuntz

The Feasibility and Flexibility of Selecting Quasars by Variability Using Ensemble Machine Learning Algorithms

In this work we train three decision-tree based ensemble machine learning algorithms (Random Forest Classifier, Adaptive Boosting and Gradient Boosting Decision Tree respectively) to study quasar selection in the variable source catalog in…

Astrophysics of Galaxies · Physics 2021-06-02 Da-Ming Yang , Zhang-Liang Xie , Jun-Xian Wang

Discovering New Strong Gravitational Lenses in the DESI Legacy Imaging Surveys

We have conducted a search for new strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys' Data Release 8. We use deep residual neural networks, building on previous work presented in Huang…

Instrumentation and Methods for Astrophysics · Physics 2021-03-10 X. Huang , C. Storfer , A. Gu , V. Ravi , A. Pilon , W. Sheu , R. Venguswamy , S. Banka , A. Dey , M. Landriau , D. Lang , A. Meisner , J. Moustakas , A. D. Myers , R. Sajith , E. F. Schlafly , D. J. Schlegel

Optical selection of quasars: SDSS and LSST

Over the last decade, quasar sample sizes have increased from several thousand to several hundred thousand, thanks mostly to SDSS imaging and spectroscopic surveys. LSST, the next-generation optical imaging survey, will provide hundreds of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Zeljko Ivezic , W. Niel Brandt , Xiaohui Fan , Chelsea L. MacLeod , Gordon T. Richards , Peter Yoachim

The FIRST-2MASS Red Quasar Survey

Combining radio observations with optical and infrared color selection -- demonstrated in our pilot study to be an efficient selection algorithm for finding red quasars -- we have obtained optical and infrared spectroscopy for 120 objects…

Astrophysics · Physics 2009-11-13 Eilat Glikman , David J. Helfand , Richard L. White , Robert H. Becker , Michael D. Gregg , Mark Lacy

The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign. I. Overview and classification of candidates selected by two techniques

The primary goals of the STRong lensing Insights into the Dark Energy Survey (STRIDES) collaboration are to measure the dark energy equation of state parameter and the free streaming length of dark matter. To this aim, STRIDES is…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-07 T. Treu , A. Agnello , M. A. Baumer , S. Birrer , E. J. Buckley-Geer , F. Courbin , Y. J. Kim , H. Lim , P. J. Marshall , B. Nord , P. L. Schechter , P. R. Sivakumar , L. E. Abramson , T. Anguita , Y. Apostolovski , M. W. Auger , J. H. H. Chan , G. C. F. Chen , T. E. Collett , C. D. Fassnacht , J. -W. Hsueh , C. Lemon , R. G. McMahon , V. Motta , F. Ostrovski , K. Rojas , C. E. Rusu , P. Williams , J. Frieman , G. Meylan , S. H. Suyu , T. M. C. Abbott , F. B. Abdalla , S. Allam , J. Annis , S. Avila , M. Banerji , D. Brooks , A. Carnero Rosell , M. Carrasco Kind , J. Carretero , F. J. Castander , C. B. D'Andrea , L. N. da Costa , J. De Vicente , P. Doel , T. F. Eifler , B. Flaugher , P. Fosalba , J. García-Bellido , D. A. Goldstein , D. Gruen , R. A. Gruendl , G. Gutierrez , W. G. Hartley , D. Hollowood , K. Honscheid , D. J. James , K. Kuehn , N. Kuropatkin , M. Lima , M. A. G. Maia , P. Martini , F. Menanteau , R. Miquel , A. A. Plazas , A. K. Romer , E. Sanchez , V. Scarpine , R. Schindler , M. Schubnell , I. Sevilla-Noarbe , M. Smith , R. C. Smith , M. Soares-Santos , F. Sobreira , E. Suchyta , M. E. C. Swanson , G. Tarle , D. Thomas , D. L. Tucker , A. R. Walker

Constraints on the spacetime variation of the fine-structure constant using DESI emission-line galaxies

We present strong constraints on the spacetime variation of the fine-structure constant $\alpha$ using the Dark Energy Spectroscopic Instrument (DESI). In this pilot work, we utilize $\sim110,000$ galaxies with strong and narrow O III…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Linhua Jiang , Zhiwei Pan , Jessica Nicole Aguilar , Steven Ahlen , Robert Blum , David Brooks , Todd Claybaugh , Axel de la Macorra , Arjun Dey , Peter Doel , Kevin Fanning , Simone Ferraro , Jaime E. Forero-Romero , Enrique Gaztanaga , Satya Gontcho A Gontcho , Gaston Gutierrez , Klaus Honscheid , Stephanie Juneau , Martin Landriau , Laurent Le Guillou , Michael Levi , Marc Manera , Ramon Miquel , John Moustakas , Eva-Maria Mueller , Andrea Munoz-Gutierrez , Adam Myers , Jundan Nie , Gustavo Niz , Claire Poppett , Francisco Prada , Mehdi Rezaie , Graziano Rossi , Eusebio Sanchez , Edward Schlafly , Michael Schubnell , Hee-Jong Seo , David Sprayberry , Gregory Tarle , Benjamin Alan Weaver , Hu Zou

Forecasting the Detection of Lyman-Alpha Forest Weak Lensing from the Dark Energy Spectroscopic Instrument and Other Future Surveys

The apparent angular positions of quasars are deflected on the sky by the gravitational field sourced by foreground matter. This weak lensing effect is measurable through the distortions it introduces in the lensed quasar spectra.…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 Patrick Shaw , Rupert A. C. Croft , R. Benton Metcalf

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope Quasar Survey: Quasar Properties from First Data Release

We present preliminary results of the quasar survey in Large Sky Area Multi- Object Fiber Spectroscopic Telescope (LAMOST) first data release (DR1), which includes pilot survey and the first year regular survey. There are 3921 quasars…

Astrophysics of Galaxies · Physics 2016-01-27 Y. L. Ai , Xue-Bing Wu , Jinyi Yang , Qian Yang , Feige Wang , Rui Guo , Wenwen Zuo , Xiaoyi Dong , Y. -X. Zhang , H. -L. Yuan , Y. -H. Song , Jianguo Wang , Xiaobo Dong , M. Yang , H. Wu , S. -Y. Shen , J. -R. Shi , B. -L. He , Y. -J. Lei , Y. -B. Li , A. -L. Luo , Y. -H. Zhao , Hao-Tong Zhang

Combining Dark Energy Survey Science Verification Data with Near Infrared Data from the ESO VISTA Hemisphere Survey

We present the combination of optical data from the Science Verification phase of the Dark Energy Survey (DES) with near infrared data from the ESO VISTA Hemisphere Survey (VHS). The deep optical detections from DES are used to extract…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Manda Banerji , S. Jouvel , H. Lin , R. G. McMahon , O. Lahav , F. J. Castander , F. B. Abdalla , E. Bertin , S. E. Bosman , A. Carnero , M. Carrasco Kind , L. N. da Costa , D. Gerdes , J. Gschwend , M. Lima , M. A. G. Maia , A. Merson , C. Miller , R. Ogando , P. Pellegrini , S. Reed , R. Saglia , C. Sanchez , S. Allam J. Annis , G. Bernstein , J. Bernstein , R. Bernstein , D. Capozzi , M. Childress , Carlos E. Cunha , T. M. Davis , D. L. DePoy , S. Desai , H. T. Diehl , P. Doel , J. Findlay , D. A. Finley , B. Flaugher , J. Frieman , E. Gaztanaga , K. Glazebrook , C. Gonzalez-Fernandez , E. Gonzalez-Solares , K. Honscheid , M. J. Irwin , M. J. Jarvis , A. Kim , S. Koposov , K. Kuehn , A. Kupcu-Yoldas , D. Lagattuta , J. R. Lewis , C. Lidman , M. Makler , J. Marriner , Jennifer L. Marshall , R. Miquel , Joseph J. Mohr , E. Neilsen , J. Peoples , M. Sako , E. Sanchez , V. Scarpine , R. Schindler , M. Schubnell , I. Sevilla , R. Sharp , M. Soares-Santos , M. E. C. Swanson , G. Tarle , J. Thaler , D. Tucker , S. A. Uddin , R. Wechsler , W. Wester , F. Yuan , J. Zuntz

Dark Energy Survey Year 1 Results: Cosmological Constraints from Cosmic Shear

We use 26 million galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg$^2$ of the sky to produce the most significant measurement of cosmic shear in a galaxy survey to date. We constrain cosmological parameters in…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-12 M. A. Troxel , N. MacCrann , J. Zuntz , T. F. Eifler , E. Krause , S. Dodelson , D. Gruen , J. Blazek , O. Friedrich , S. Samuroff , J. Prat , L. F. Secco , C. Davis , A. Ferté , J. DeRose , A. Alarcon , A. Amara , E. Baxter , M. R. Becker , G. M. Bernstein , S. L. Bridle , R. Cawthon , C. Chang , A. Choi , J. De Vicente , A. Drlica-Wagner , J. Elvin-Poole , J. Frieman , M. Gatti , W. G. Hartley , K. Honscheid , B. Hoyle , E. M. Huff , D. Huterer , B. Jain , M. Jarvis , T. Kacprzak , D. Kirk , N. Kokron , C. Krawiec , O. Lahav , A. R. Liddle , J. Peacock , M. M. Rau , A. Refregier , R. P. Rollins , E. Rozo , E. S. Rykoff , C. Sánchez , I. Sevilla-Noarbe , E. Sheldon , A. Stebbins , T. N. Varga , P. Vielzeuf , M. Wang , R. H. Wechsler , B. Yanny , T. M. C. Abbott , F. B. Abdalla , S. Allam , J. Annis , K. Bechtol , A. Benoit-Lévy , E. Bertin , D. Brooks , E. Buckley-Geer , D. L. Burke , A. Carnero Rosell , M. Carrasco Kind , J. Carretero , F. J. Castander , M. Crocce , C. E. Cunha , C. B. D'Andrea , L. N. da Costa , D. L. DePoy , S. Desai , H. T. Diehl , J. P. Dietrich , P. Doel , E. Fernandez , B. Flaugher , P. Fosalba , J. García-Bellido , E. Gaztanaga , D. W. Gerdes , T. Giannantonio , D. A. Goldstein , R. A. Gruendl , J. Gschwend , G. Gutierrez , D. J. James , T. Jeltema , M. W. G. Johnson , M. D. Johnson , S. Kent , K. Kuehn , S. Kuhlmann , N. Kuropatkin , T. S. Li , M. Lima , H. Lin , M. A. G. Maia , M. March , J. L. Marshall , P. Martini , P. Melchior , F. Menanteau , R. Miquel , J. J. Mohr , E. Neilsen , R. C. Nichol , B. Nord , D. Petravick , A. A. Plazas , A. K. Romer , A. Roodman , M. Sako , E. Sanchez , V. Scarpine , R. Schindler , M. Schubnell , M. Smith , R. C. Smith , M. Soares-Santos , F. Sobreira , E. Suchyta , M. E. C. Swanson , G. Tarle , D. Thomas , D. L. Tucker , V. Vikram , A. R. Walker , J. Weller , Y. Zhang

ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spectra of 35 million galaxies and quasars over 14,000 square…

Instrumentation and Methods for Astrophysics · Physics 2018-05-04 Parker Fagrelius , Behzad Abareshi , Lori Allen , Otger Ballester , Charles Baltay , Robert Besuner , Elizabeth Buckley-Geer , Karen Butler , Laia Cardiel , Arjun Dey , Ann Elliott , William Emmet , Irena Gershkovich , Klaus Honscheid , Jose M. Illa , Jorge Jimenez , Michael Levi , Christopher Manser , Robert Marshall , Paul Martini , Anthony Paat , Ronald Probst , David Rabinowitz , Kevin Reil , Amy Robertson , Connie Rockosi , David Schlegel , Michael Schubnell , Santiago Serrano , Joseph Silber , Christian Soto , David Sprayberry , David Summers , Greg Tarle , Benjamin A. Weaver , Y. T. Duan

Quasar Probabilities and Redshifts from WISE mid-IR through GALEX UV Photometry

Extreme deconvolution (XD) of broad-band photometric data can both separate stars from quasars and generate probability density functions for quasar redshifts, while incorporating flux uncertainties and missing data. Mid-infrared…

Astrophysics of Galaxies · Physics 2015-08-06 M. A. DiPompeo , J. Bovy , A. D. Myers , D. Lang

Luminosity Function from dedicated SDSS-III and MMT data of quasars in 0.7<z<4.0 selected with a new approach

We present a measurement of the quasar luminosity function in the range 0.68<z<4 down to extinction corrected magnitude g_dered=22.5, using a simple and well understood target selection technique based on the time-variability of quasars.…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-15 N. Palanque-Delabrouille , Ch. Magneville , Ch. Yeche , S. Eftekharzadeh , A. D. Myers , P. Petitjean , I. Paris , E. Aubourg , I. McGreer , X. Fan , A. Dey , D. Schlegel , S . Bailey , D. Bizayev , A. Bolton , K. Dawson , G. Ebelke , E. Malanushenko , V. Malanushenko , D. Oravetz , K. Pan , N. P. Ross , D. P. Schneider , E. Sheldon , A. Simmons , J. Tinker , M. White , Ch. Willmer

Strong Lens Discoveries in DESI Legacy Imaging Surveys DR10 with Two Deep Learning Architectures

We have conducted a search for strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release 10 (DR10). This paper is the fourth in a series of searches (following Huang et al.…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-28 Jose Carlos Inchausti , Christopher J. Storfer , Xiaosheng Huang , Yuan-Ming Hsu , Brandt Kaufmann , Chaitanya Pasupala , S. Banka , A. Dey , D. Lang , A. Meisner , J. Moustakas , A. D. Myers , E. F. Schlafly , D. J. Schlegel