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We have undertaken a pilot survey for faint QSOs in the UKIDSS Ultra Deep Survey Field using the KX selection technique. These observations exploit the very deep near-infrared and optical imaging of this field from UKIRT and Subaru to…

天体物理学 · 物理学 2009-11-13 Ian Smail , Rob Sharp , A. M. Swinbank , M. Akiyama , Y. Ueda , S. Foucaud , O. Almaini , S. Croom

We obtain a sample of 87 radio-loud QSOs in the redshift range 3.6<z<4.4 by cross-correlating sources in the FIRST radio survey S{1.4GHz} > 1 mJy with star-like objects having r <20.2 in SDSS Data Release 7. Of these 87 QSOs, 80 are…

星系天体物理 · 物理学 2015-06-23 D. Tuccillo , J. I. Gonzalez-Serrano , C. R. Benn

Understanding the formation and evolution of the cosmic web of galaxies is a fundamental goal of cosmology, using various tracers of the cosmic large-scale structure at an ever wider range of redshifts. Our principal aim is to advance the…

With the aim of using machine learning techniques to obtain photometric redshifts based upon a source's radio spectrum alone, we have extracted the radio sources from the Million Quasars Catalogue. Of these, 44,119 have a spectroscopic…

宇宙学与河外天体物理 · 物理学 2022-05-25 S. J. Curran , J. P. Moss , Y. C. Perrott

The Beijing-Arizona Sky Survey (BASS) Data Release 3 (DR3) catalogue was released in 2019, which contains the data from all BASS and the Mosaic z-band Legacy Survey (MzLS) observations during 2015 January and 2019 March, about 200 million…

We have studied the distribution of $B_J<20.5$ galaxies from the ROE/NRL COSMOS/UKST catalogue around two samples of $z>0.3$ QSOs with similar redshift distributions. The first sample is formed by 144 radio-loud QSOs from the Parkes…

天体物理学 · 物理学 2016-08-30 N. Benitez , E. Martinez-Gonzalez , IFCA

Future photometric supernova surveys will produce vastly more candidates than can be followed up spectroscopically, highlighting the need for effective classification methods based on lightcurves alone. Here we introduce boosting and kernel…

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…

星系天体物理 · 物理学 2015-08-06 M. A. DiPompeo , J. Bovy , A. D. Myers , D. Lang

Gravitational clustering broadens the count-in-cells distribution of galaxies for surveys along uncorrelated (well-separated) lines of sight beyond Poisson noise. A number of methods have proposed to measure this excess "cosmic" variance to…

星系天体物理 · 物理学 2018-11-28 Alex Cameron , Michele Trenti , Rachael Livermore , Cameron van der Velden

In order to answer the open questions of modern cosmology and galaxy evolution theory, robust algorithms for calculating photometric redshifts (photo-z) for very large samples of galaxies are needed. Correct estimation of the various…

天体物理仪器与方法 · 物理学 2021-08-25 Oleksandra Razim , Stefano Cavuoti , Massimo Brescia , Giuseppe Riccio , Mara Salvato , Giuseppe Longo

Around $10^5$ strongly lensed galaxies are expected to be discovered with Euclid and the LSST. Utilising these large samples to study the inner structure of lens galaxies requires source redshifts, to turn lens models into mass…

宇宙学与河外天体物理 · 物理学 2023-02-01 Danial Langeroodi , Alessandro Sonnenfeld , Henk Hoekstra , Adriano Agnello

The distinction between stars and galaxies is a fundamental problem in the field of celestial classification. This issue has become challenging for these ongoing and upcoming digital surveys, which will produce terabytes and even petabytes…

天体物理仪器与方法 · 物理学 2026-04-14 Zhuoming Han , Tianmeng Zhang , Chao Liu , Chenxiaoji Ling

We develop and demonstrate a classification system constituted by several Support Vector Machines (SVM) classifiers, which can be applied to select quasar candidates from large sky survey projects, such as SDSS, UKIDSS, GALEX. How to…

天体物理仪器与方法 · 物理学 2015-06-04 Nanbo Peng , Yanxia Zhang , Yongheng Zhao , Xuebing Wu

The accurate estimation of photometric redshifts plays a crucial role in accomplishing science objectives of the large survey projects. The template-fitting and machine learning are the two main types of methods applied currently. Based on…

We have revised the SWIRE Photometric Redshift Catalogue to take account of new optical photometry in several of the SWIRE areas, and incorporating 2MASS and UKIDSS near infrared data. Aperture matching is an important issue for combining…

宇宙学与河外天体物理 · 物理学 2015-08-03 Michael Rowan-Robinson , Eduardo Gonzalez-Solares , Mattia Vaccari , Lucia Marchetti

We present a description of the observations and data reduction procedures for an extensive spectroscopic and multi-band photometric study of nine high redshift, optically-selected cluster candidates. The primary goal of the survey is to…

天体物理学 · 物理学 2009-10-30 J. B. Oke , Marc Postman , Lori Lubin

We consider the problem of determining the host galaxies of radio sources by cross-identification. This has traditionally been done manually, which will be intractable for wide-area radio surveys like the Evolutionary Map of the Universe…

天体物理仪器与方法 · 物理学 2018-05-18 M. J. Alger , J. K. Banfield , C. S. Ong , L. Rudnick , O. I. Wong , C. Wolf , H. Andernach , R. P. Norris , S. S. Shabala

Artificial intelligence methods are indispensable to identifying pulsars from large amounts of candidates. We develop a new pulsar identification system that utilizes the CoAtNet to score two-dimensional features of candidates, uses a…

天体物理仪器与方法 · 物理学 2023-04-25 NanNan Cai , JinLin Han , WeiCong Jing , ZeKai Zhang , DeJiang Zhou , Xue Chen

Clusters of galaxies as gravitational lenses allow to study the stellar content and properties of high-z galaxies much fainter than the usual spectroscopic field surveys. We review the recent results obtained on the identification and study…

天体物理学 · 物理学 2009-10-31 Roser Pello

We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that…

天体物理学 · 物理学 2008-11-26 Nicholas M. Ball , Robert J. Brunner , Adam D. Myers , David Tcheng