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We analyzed the spatial distribution of 28500 photometrically selected galaxies with AB magnitude 23.5<R<25.5 and redshift 1.4<z<3.5 in 21 fields with a total area of 0.81 square degrees. The galaxies were divided into three subsamples,…

Astrophysics · Physics 2009-11-10 K. L. Adelberger , C. C. Steidel , M. Pettini , A. E. Shapley , N. A. Reddy , D. K. Erb

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will produce several billion photometric redshifts (photo-$z$'s), enabling cosmological analyses to select a subset of galaxies with the most accurate photo-$z$. We…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Adam Broussard , Eric Gawiser

We investigate and demonstrate the use of convolutional neural networks (CNNs) for the task of distinguishing between merging and non-merging galaxies in simulated images, and for the first time at high redshifts (i.e. $z=2$). We extract…

Astrophysics of Galaxies · Physics 2020-04-28 A. Ćiprijanović , G. F. Snyder , B. Nord , J. E. G. Peek

We use machine learning to identify in color images of high-redshift galaxies an astrophysical phenomenon predicted by cosmological simulations. This phenomenon, called the blue nugget (BN) phase, is the compact star-forming phase in the…

We present the analysis of the emission line galaxies members of 46 low redshift (0.04 < z < 0.07) clusters observed by WINGS (WIde-field Nearby Galaxy cluster Survey, Fasano et al. 2006). Emission line galaxies were identified following…

Astrophysics of Galaxies · Physics 2017-03-15 P. Marziani , M. D'Onofrio , D. Bettoni , B. M. Poggianti , A. Moretti , G. Fasano , J. Fritz , A. Cava , J. Varela , A. Omizzolo

Line intensity mapping is emerging as a novel method that can measure the collective intensity fluctuations of atomic/molecular line emission from distant galaxies. Several observational programs with various wavelengths are ongoing and…

Astrophysics of Galaxies · Physics 2021-12-15 Kana Moriwaki , Naoki Yoshida

We present a machine learning model to classify Active Galactic Nuclei (AGN) and galaxies (AGN-galaxy classifier) and a model to identify type 1 (optically unabsorbed) and type 2 (optically absorbed) AGN (type 1/2 classifier). We test…

Astrophysics of Galaxies · Physics 2021-12-08 Serena Falocco , Francisco J. Carrera , Josefin Larsson

We present a catalogue of photometric redshifts for galaxies from DESI Legacy Imaging Surveys, which includes $\sim0.18$ billion sources covering 14,000 ${\rm deg}^2$. The photometric redshifts, along with their uncertainties, are estimated…

Astrophysics of Galaxies · Physics 2025-02-25 Xingchen Zhou , Nan Li , Hu Zou , Yan Gong , Furen Deng , Xuelei Chen , Qian Yu , Zizhao He , Boyi Ding

Identifying the dominant ionizing sources in galaxies is essential for understanding their formation and evolution. Traditionally, spectra are classified based on their dominant ionizing source using strong emission lines and Baldwin,…

Astrophysics of Galaxies · Physics 2024-10-29 Ahmad Nemer , Ivan Katkov , Jospeh Gelfand , Changhyun Cho

Although the optical colour-magnitude diagram of galaxies allows one to select red sequence objects, neither can it be used for galaxy classification without additional observational data such as spectra or high-resolution images, nor to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Igor Chilingarian , Ivan Zolotukhin

Using deep narrow-band (NB) imaging and optical spectroscopy from the Keck telescope and MMT, we identify a sample of 20 emission-line galaxies (ELGs) at z=0.065-0.90 where the weak auroral emission line, [OIII]4363, is detected at…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Chun Ly , Matthew A. Malkan , Tohru Nagao , Nobunari Kashikawa , Kazuhiro Shimasaku , Masao Hayashi

We introduce the Mass-Excitation (MEx) diagnostic to identify active galactic nuclei (AGN) in galaxies at intermediate redshift. In the absence of near-infrared spectroscopy, necessary to use traditional nebular line diagrams at z>0.4, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Stéphanie Juneau , Mark Dickinson , David M. Alexander , Samir Salim

We present the results of a photometric redshift analysis designed to identify z>6 galaxies from the near-IR HST imaging in three deep fields (HUDF, HUDF09-2 & ERS). By adopting a rigorous set of criteria for rejecting low-z interlopers,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 R. J. McLure , J. S. Dunlop , L. de Ravel , M. Cirasuolo , R. S. Ellis , M. Schenker , B. E. Robertson , A. M. Koekemoer , D. P. Stark , R. A. A. Bowler

We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO -- Special Astrophysical Observatory, Russia). The list is a result of follow-up spectroscopy conducted with the 2.2m CAHA and 4m…

We present a systematic search for wide-separation (Einstein radius >1.5"), galaxy-scale strong lenses in the 30 000 sq.deg of the Pan-STARRS 3pi survey on the Northern sky. With long time delays of a few days to weeks, such systems are…

Astrophysics of Galaxies · Physics 2021-04-08 R. Canameras , S. Schuldt , S. H. Suyu , S. Taubenberger , T. Meinhardt , L. Leal-Taixe , C. Lemon , K. Rojas , E. Savary

We have used FMOS on Subaru to obtain near-infrared spectroscopy of 123 far-infrared selected galaxies in COSMOS and obtain the key rest-frame optical emission lines. This is the largest sample of infrared galaxies with near-infrared…

Rest-frame UV spectral lines of star-forming galaxies are systematically offset from the galaxies' systemic redshifts, probably because of large-scale outflows. We calibrate galaxy redshifts measured from rest-frame UV lines by utilizing…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Olivera Rakic , Joop Schaye , Charles C. Steidel , Gwen C. Rudie

We propose near-infrared colour selection criteria to extract Active Galactic Nuclei (AGNs) using the near-infrared Colour-Colour Diagram (CCD) and predict near-infrared colour evolution with respect to redshift. First, we cross-identify…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Shinjirou Kouzuma , Hitoshi Yamaoka