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Based on the Sloan Digital Sky Survey Data Release 5 Galaxy Sample, we explore photometric morphology classification and redshift estimation of galaxies using photometric data and known spectroscopic redshifts. An unsupervised method,…

Astrophysics · Physics 2009-11-13 Yanxia Zhang , Lili Li , Yongheng Zhao

This paper presents a morphology classification catalog of spiral and ring features of 59,854 magnitude-limited galaxies ($r<17.8$ mag, and additional 628,005 subsamples down to $r=20$ mag) at $z=0.01-0.3$ based on the Third Public Data…

Astrophysics of Galaxies · Physics 2024-01-05 Rhythm Shimakawa , Masayuki Tanaka , Kei Ito , Makoto Ando

We present the largest, most homogeneous catalogue of merging galaxies in the nearby universe obtained through the Galaxy Zoo project - an interface on the world-wide web enabling large-scale morphological classification of galaxies through…

We devise improved photometric parameters for the morphological classification of galaxies using a bright sample from the First Data Release of the Sloan Digital Sky Survey. In addition to using an elliptical aperture concentration index…

A photometric method for quantifying deviations from axisymmetry in optical images of disk galaxies is applied to a sample of 32 face-on and nearly face-on spirals. The method involves comparing the relative fluxes contained within…

Astrophysics · Physics 2009-10-30 David A. Kornreich , Martha P. Haynes , Richard V. E. Lovelace

We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 minutes per galaxy, assuming at least 8…

Globular clusters (GCs) exhibit varying degrees of flattening (ellipticity), which may provide insight into their internal dynamics and evolution histories. Commonly used methods to measure ellipticity, such as ellipse fitting of density…

Astrophysics of Galaxies · Physics 2026-04-22 Laurane Fréour , Ellen Leitinger , Elena Pancino , Alice Zocchi , Glenn van de Ven

The results of morphological galaxy classifications performed by humans and by automated methods are compared. In particular, a comparison is made between the eyeball classifications of 454 galaxies in the Sloan Digital Sky Survey (SDSS)…

Astrophysics · Physics 2007-05-23 Nicholas M. Ball

In this article I extend an earlier study of spiral galaxies in the Sloan Digital Sky Survey (SDSS) to investigate whether the universe has an overall handedness. A preference for spiral galaxies in one sector of the sky to be left-handed…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-17 Michael J. Longo

We present a statistical study of optical warps in a sample of 540 galaxies, about five times larger than previous samples. About 40% of all late-type galaxies reveal S-shaped warping of their planes in the outer parts. Given the…

Astrophysics · Physics 2007-05-23 Vladimir Reshetnikov , Francoise Combes

We study the ellipticity of galaxy cluster halos as characterized by the distribution of cluster galaxies and as measured with weak lensing. We use monte-carlo simulations of elliptical cluster density profiles to estimate and correct for…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-12 Tae-hyeon Shin , Joseph Clampitt , Bhuvnesh Jain , Gary Bernstein , Andrew Neil , Eduardo Rozo , Eli Rykoff

We present the morphological catalog of galaxies in nearby clusters of the WINGS survey (Fasano et al. 2006). The catalog contains a total number of 39923 galaxies, for which we provide the automatic estimates of the morphological type…

We present central velocity dispersions and Mg$_2$ line indices for an all-sky sample of $\sim$ 1178 elliptical and S0 galaxies, of which 984 had no previous measures. This sample contains the largest set of homogeneous spectroscopic data…

We have reanalyzed a data set of 99 low redshift ($ z < 0.1 $) Abell clusters and determined their shapes. For this, three different measures are used. We use Monte-Carlo simulations to investigate the errors in the methods. The corrected…

Astrophysics · Physics 2015-06-24 P. A. M. de Theije , P. Katgert , E. van Kampen

The halo masses of nearby individual elliptical galaxies can be estimated by using the kinematics of their stars, planetary nebulae, and globular clusters -- ideally in combination. With currently improving coverage of galaxies of ordinary…

Astrophysics · Physics 2009-11-11 Aaron J. Romanowsky

We present radial tracks for four early-type galaxies with embedded intermediate-scale discs in a modified spin-ellipticity diagram. Here, each galaxy's spin and ellipticity profiles are shown as a radial track, as opposed to a single,…

Astrophysics of Galaxies · Physics 2017-06-07 Sabine Bellstedt , Alister W. Graham , Duncan A. Forbes , Aaron J. Romanowsky , Jean P. Brodie , Jay Strader

The accuracy and robustness of a simple method to estimate the total mass profile of a galaxy is tested using a sample of 65 cosmological zoom-simulations of individual galaxies. The method only requires information on the optical surface…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 N. Lyskova , E. Churazov , I. Zhuravleva , T. Naab , L. Oser , O. Gerhard , X. Wu

Whether the spiral structure of galaxies is trailing or leading has been a subject of debate. We present a new spin parity catalog of 146 spiral galaxies that lists the following three pieces of information: whether the spiral structure…

Astrophysics of Galaxies · Physics 2020-01-08 Masanori Iye , Kenichi Tadaki , Hideya Fukumoto

We describe a non-parametric method for determining both the anisotropy and mass profiles of elliptical galaxies from velocity dispersions and velocity profile shapes along the line of sight. In this way, mass-to-light ratios out to 2-3…

Astrophysics · Physics 2007-05-23 Andi Kronawitter , Ortwin E. Gerhard , R. P. Saglia , Ralf Bender