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A crucial test of any cosmological model is the distribution of distant objects such as quasars. Because of well defined selection criteria quasars found by a ultraviolet excess (UVX) survey are ideal candidates for testing the model out to…

Astrophysics · Physics 2009-10-22 David F. Crawford

We apply a convolutional neural network (CNN) to classify and detect quasars in the Sloan Digital Sky Survey Stripe 82 and also to predict the photometric redshifts of quasars. The network takes the variability of objects into account by…

Instrumentation and Methods for Astrophysics · Physics 2018-04-11 Johanna Pasquet-Itam , Jérôme Pasquet

We present a probabilistic autoencoder (PAE) framework for galaxy spectral energy distribution (SED) modeling and redshift estimation, applied to synthetic SPHEREx 102-band spectrophotometry. Our PAE learns a compact latent representation…

Instrumentation and Methods for Astrophysics · Physics 2026-03-27 Richard M. Feder , Liam Parker , Uroš Seljak

This study presents a coupled physical statistical framework for retrieving snow water equivalent (SWE) in forested areas using dual frequency X and Ku band SAR observations. The method combines a multilayer snow hydrology model (MSHM) with…

Geophysics · Physics 2025-11-25 Siddharth Singh , Carrie Vuyovich , Ana P. Barros

Accurate photometric redshifts are a lynchpin for many future experiments to pin down the cosmological model and for studies of galaxy evolution. In this study, a novel sparse regression framework for photometric redshift estimation is…

Instrumentation and Methods for Astrophysics · Physics 2025-06-03 Ibrahim A. Almosallam , Sam N. Lindsay , Matt J. Jarvis , Stephen J. Roberts

In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-$z$) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the $\sigma_{68}$ scatter…

We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift universe with VLT/XSHOOTER" (hereafter `XQ-100'). XQ-100 has…

SubHalo Abundance Matching (SHAM) is an empirical method for constructing galaxy catalogues based on high-resolution $N$-body simulations. We apply SHAM on the UNIT simulation to simulate SDSS BOSS/eBOSS Luminous Red Galaxies (LRGs) within…

The two currently largest all-sky photometric datasets, WISE and SuperCOSMOS, were cross-matched by Bilicki et al. (2016) (B16) to construct a novel photometric redshift catalogue on 70% of the sky. Galaxies were therein separated from…

Astrophysics of Galaxies · Physics 2016-11-30 T. Krakowski , K. Małek , M. Bilicki , A. Pollo , M. Krupa , A. Kurcz

Photometric galaxy surveys are an essential tool to further our understanding of the large-scale structure of the universe, its matter and energy content and its evolution. These surveys necessitate the determination of the galaxy redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-06 Pol Martí , Ramon Miquel , Anne Bauer , Enrique Gaztañaga

We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-15 B. Hoyle , D. Gruen , G. M. Bernstein , M. M. Rau , J. De Vicente , W. G. Hartley , E. Gaztanaga , J. DeRose , M. A. Troxel , C. Davis , A. Alarcon , N. MacCrann , J. Prat , C. Sánchez , E. Sheldon , R. H. Wechsler , J. Asorey , M. R. Becker , C. Bonnett , A. Carnero Rosell , D. Carollo , M. Carrasco Kind , F. J. Castander , R. Cawthon , C. Chang , M. Childress , T. M. Davis , A. Drlica-Wagner , M. Gatti , K. Glazebrook , J. Gschwend , S. R. Hinton , J. K. Hoormann , A. G. Kim , A. King , K. Kuehn , G. Lewis , C. Lidman , H. Lin , E. Macaulay , M. A. G. Maia , P. Martini , D. Mudd , A. Möller , R. C. Nichol , R. L. C. Ogando , R. P. Rollins , A. Roodman , A. J. Ross , E. Rozo , E. S. Rykoff , S. Samuroff , I. Sevilla-Noarbe , R. Sharp , N. E. Sommer , B. E. Tucker , S. A. Uddin , T. N. Varga , P. Vielzeuf , F. Yuan , B. Zhang , 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 , M. T. Busha , D. Capozzi , J. Carretero , M. Crocce , C. B. D'Andrea , L. N. da Costa , D. L. DePoy , S. Desai , H. T. Diehl , P. Doel , T. F. Eifler , J. Estrada , A. E. Evrard , E. Fernandez , B. Flaugher , P. Fosalba , J. Frieman , J. García-Bellido , D. W. Gerdes , T. Giannantonio , D. A. Goldstein , R. A. Gruendl , G. Gutierrez , K. Honscheid , D. J. James , M. Jarvis , T. Jeltema , M. W. G. Johnson , M. D. Johnson , D. Kirk , E. Krause , S. Kuhlmann , N. Kuropatkin , O. Lahav , T. S. Li , M. Lima , M. March , J. L. Marshall , P. Melchior , F. Menanteau , R. Miquel , B. Nord , C. R. O'Neill , A. A. Plazas , A. K. Romer , M. Sako , E. Sanchez , B. Santiago , 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 , W. Wester , R. C. Wolf , B. Yanny , J. Zuntz

The DESI survey will measure large-scale structure using quasars as direct tracers of dark matter in the redshift range $0.9<z<2.1$ and using quasar Ly-$\alpha$ forests at $z>2.1$. We present two methods to select candidate quasars for DESI…

We used 3.1 million spectroscopically labelled sources from the Sloan Digital Sky Survey (SDSS) to train an optimised random forest classifier using photometry from the SDSS and the Widefield Infrared Survey Explorer (WISE). We applied this…

Astrophysics of Galaxies · Physics 2020-07-15 A. O. Clarke , A. M. M. Scaife , R. Greenhalgh , V. Griguta

The accurate estimation of photometric redshifts is crucial to many upcoming galaxy surveys, for example the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). Almost all Rubin extragalactic and cosmological science requires…

Instrumentation and Methods for Astrophysics · Physics 2022-05-04 Natalia Stylianou , Alex I. Malz , Peter Hatfield , John Franklin Crenshaw , Julia Gschwend

The Dark Energy Spectroscopic Instrument (DESI) survey will provide optical spectra for $\sim 3$ million quasars. Accurate redshifts for these quasars will facilitate a broad range of science applications. Here we provide improved systemic…

Astrophysics of Galaxies · Physics 2023-08-31 Qiaoya Wu , Yue Shen

We present the results of a pilot survey to find dust-reddened quasars by matching the FIRST radio catalog to the UKIDSS near-infrared survey, and using optical data from SDSS to select objects with very red colors. The deep K-band limit…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Eilat Glikman , Tanya Urrutia , Mark Lacy , S. G. Djorgovski , Meg Urry , Scott Croom , Donald P. Schneider , Ashish Mahabal , Matthew Graham , Jian Ge

Cosmological constraints from key probes of the Euclid imaging survey rely critically on the accurate determination of the true redshift distributions, $n(z)$, of tomographic redshift bins. We determine whether the mean redshift, $<z>$, of…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-27 K. Naidoo , H. Johnston , B. Joachimi , J. L. van den Busch , H. Hildebrandt , O. Ilbert , O. Lahav , N. Aghanim , B. Altieri , A. Amara , M. Baldi , R. Bender , C. Bodendorf , E. Branchini , M. Brescia , J. Brinchmann , S. Camera , V. Capobianco , C. Carbone , J. Carretero , F. J. Castander , M. Castellano , S. Cavuoti , A. Cimatti , R. Cledassou , G. Congedo , C. J. Conselice , L. Conversi , Y. Copin , L. Corcione , F. Courbin , M. Cropper , A. Da Silva , H. Degaudenzi , J. Dinis , F. Dubath , X. Dupac , S. Dusini , S. Farrens , S. Ferriol , P. Fosalba , M. Frailis , E. Franceschi , P. Franzetti , M. Fumana , S. Galeotta , B. Garilli , W. Gillard , B. Gillis , C. Giocoli , A. Grazian , F. Grupp , S. V. H. Haugan , W. Holmes , F. Hormuth , A. Hornstrup , K. Jahnke , M. Kümmel , A. Kiessling , M. Kilbinger , T. Kitching , R. Kohley , H. Kurki-Suonio , S. Ligori , P. B. Lilje , I. Lloro , E. Maiorano , O. Mansutti , O. Marggraf , K. Markovic , F. Marulli , R. Massey , S. Maurogordato , M. Meneghetti , E. Merlin , G. Meylan , M. Moresco , L. Moscardini , E. Munari , R. Nakajima , S. M. Niemi , C. Padilla , S. Paltani , F. Pasian , K. Pedersen , W. J. Percival , V. Pettorino , S. Pires , G. Polenta , M. Poncet , L. Popa , L. Pozzetti , F. Raison , R. Rebolo , A. Renzi , J. Rhodes , G. Riccio , E. Romelli , C. Rosset , E. Rossetti , R. Saglia , D. Sapone , B. Sartoris , P. Schneider , A. Secroun , G. Seidel , C. Sirignano , G. Sirri , J. -L. Starck , C. Surace , P. Tallada-Crespí , A. N. Taylor , I. Tereno , R. Toledo-Moreo , F. Torradeflot , I. Tutusaus , E. A. Valentijn , L. Valenziano , T. Vassallo , Y. Wang , J. Weller , M. Wetzstein , A. Zacchei , G. Zamorani , J. Zoubian , S. Andreon , D. Maino , V. Scottez , A. H. Wright