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Related papers: Quantifying the Poor Purity and Completeness of Mo…

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We show that the Halpha line (6563 Angstrom) alone is an extremely effective criterion for identifying galaxies that are uniform in color (red), luminosity-weighted age (old), and morphology (bulge-dominated). By combining the Sloan Digital…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Willy D. Kranz , Kim-Vy H. Tran , Lea Giordano , Amelie Saintonge

The two-step galaxy morphology classification framework {\tt USmorph} successfully combines unsupervised machine learning (UML) with supervised machine learning (SML) methods. To enhance the UML step, we employed a dual-encoder architecture…

Astrophysics of Galaxies · Physics 2025-12-22 Xiaolei Yin , Guanwen Fang , Shiying Lu , Zesen Lin , Yao Dai , Chichun Zhou

We present a classification of galaxies in the Pan-STARRS1 (PS1) 3$\pi$ survey based on their recent star formation history and morphology. Specifically, we train and test two Random Forest (RF) classifiers using photometric features…

High Energy Astrophysical Phenomena · Physics 2020-10-21 A. Baldeschi , A. Miller , M. Stroh , R. Margutti , D. L. Coppejans

Growth curves of the near-infrared (NIR) magnitude as a function of the aperture have been built and used to derive NIR total magnitudes from aperture data taken from the literature. By cross-correlating with optical and redshift data,…

Astrophysics · Physics 2007-05-23 Michel Fioc , Brigitte Rocca-Volmerange

We present a quantitative study of the far-ultraviolet (FUV) and optical morphology in 32 nearby galaxies and estimate the ``morphological k-correction'' expected if these objects were observed unevolved at high redshift. Using the common…

Astrophysics · Physics 2009-11-06 L. E. Kuchinski , Barry F. Madore , Wendy L. Freedman , M. Trewella

We present results from an optical-IR photometric study of early-type galaxies in 19 galaxy clusters out to z=0.9. The galaxy sample is selected on the basis of morphologies determined from HST WFPC2 images, and is photometrically defined…

Astrophysics · Physics 2009-10-30 S. A. Stanford , Peter R. Eisenhardt , Mark Dickinson

We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to…

(Abridged) We explore the evolution of field early-type galaxies on a sample extracted from GOODS/CDFS. The galaxies are selected by means of a non-parametric analysis followed by visual inspection. We exclude those galaxies which are not…

Astrophysics · Physics 2009-11-10 I. Ferreras , T. Lisker , C. M. Carollo , S. J. Lilly , B. Mobasher , .

(Abridged) Luminous Compact Galaxies (LCGs) (M_B < -20, R_{1/2} < 4.5kpc and EW_{0}(OII) >15\AA) constitute one of the most rapidly evolving galaxy populations over the last ~8 Gyr history of the universe. Due to their inherently compact…

Astrophysics · Physics 2009-11-13 A. Rawat , A. K. Kembhavi , F. Hammer , H. Flores , S. Barway

We used ultraviolet (200 nm) images of the local spiral galaxies M33, M51, M81, M100, M101 to compute morphological parameters of galactic disks at this wavelength : half-light radius $r_{hl}$, surface brightness distributions, asymmetries…

Astrophysics · Physics 2009-11-06 Denis Burgarella , Veronique Buat , Jose Donas , Bruno Milliard , Sandra Chapelon

Morphological classification is a key piece of information to define samples of galaxies aiming to study the large-scale structure of the universe. In essence, the challenge is to build up a robust methodology to perform a reliable…

Instrumentation and Methods for Astrophysics · Physics 2019-11-05 P. H. Barchi , R. R. de Carvalho , R. R. Rosa , R. Sautter , M. Soares-Santos , B. A. D. Marques , E. Clua , T. S. Gonçalves , C. de Sá-Freitas , T. C. Moura

Determining the redshift distribution $n(z)$ of galaxy samples is essential for several cosmological probes including weak lensing. For imaging surveys, this is usually done using photometric redshifts estimated on an object-by-object…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-31 Jörg Herbel , Tomasz Kacprzak , Adam Amara , Alexandre Refregier , Claudio Bruderer , Andrina Nicola

This is the first in a series of papers describing the {\it Optical Redshift Survey} (ORS), a redshift survey of optically selected galaxies covering 98\% of the sky above $|b| = 20^\circ$ (8.09 ster). The survey is drawn from the UGC, ESO,…

Astrophysics · Physics 2009-10-22 B. X. Santiago , M. A. Strauss , O. Lahav , M. Davis , A. Dressler , J. Huchra

Aims. This work investigates the potential of using the wavelength-dependence of galaxy structural parameters (S\'ersic index, n, and effective radius, Re) to separate galaxies into distinct types. Methods. A sample of nearby galaxies with…

Astrophysics of Galaxies · Physics 2015-05-13 M. Vika , B. Vulcani , S. P. Bamford , B. Häußler , A. L. Rojas

We investigate the properties of bright galaxies with various morphological types in Abell 1139 and Abell 2589, using the pixel color-magnitude diagram (pCMD) analysis technique. The sample is 32 galaxies brighter than Mr = -21.3 mag with…

Astrophysics of Galaxies · Physics 2018-05-02 Joon Hyeop Lee , Mina Pak , Hye-Ran Lee , Sree Oh

We present a method to refine photometric redshift galaxy catalogs by comparing their color-space matching with overlapping spectroscopic calibration data. We focus on cases where photometric redshifts (photo-$z$) are estimated empirically.…

We present an analysis of bar length measurements of 3150 local galaxies in a volume limited sample of low redshift (z < 0.06) disk galaxies. Barred galaxies were initially selected from the Galaxy Zoo 2 project, and the lengths and widths…

Using the galaxy data of the Sloan Digital Sky Survey Data Release 8 (SDSS DR8), I explore whether the concentration index is a good morphological classification tool and find that a reasonably pure late-type galaxy sample can be…

Astrophysics of Galaxies · Physics 2015-06-12 Xin-Fa Deng

We present ultraviolet photometry for a sample of morphologically early-type galaxies selected by matching the Sloan Digital Sky Survey Data Release 1 with the GALEX Medium and All-sky Imaging Surveys. We obtain a working sample of 1032…

We have measured the clustering of z<0.9 red galaxies and constrained models of the evolution of large-scale structure using the initial 1.2 sq. degree data release of the NOAO Deep Wide-Field Survey (NDWFS). The area and BwRI passbands of…

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