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The opacity of spiral galaxy disks, from counts of distant galaxies, is compared to HI column densities. The opacity measurements are calibrated using the ``Synthetic Field Method'' from Gonzalez et al (1998) and Holwerda et al. (2005a).…

Astrophysics · Physics 2009-11-11 B. W. Holwerda , R. A. González , Ronald J. Allen , P. C. van der Kruit

The aim of this study is to determine the fractions of different spiral galaxy types, especially bulgeless disks, from a complete and homogeneous sample of 15127 edge-on disk galaxies extracted from the sixth data release from the Sloan…

Astrophysics of Galaxies · Physics 2010-11-11 S. J. Kautsch

We present a method for measuring small deviations from axisymmetry of the potential of a filled gas disk. The method is based on a higher order harmonic expansion of the full velocity field of the disk. This expansion is made by first…

Astrophysics · Physics 2015-06-24 R. H. M. Schoenmakers , M. Franx , P. T. de Zeeuw

We propose a novel statistical method to measure cosmic birefringence and demonstrate its power in probing parity violation due to axions. Exploiting an empirical correlation between the integrated radio polarization direction of a spiral…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-09 Weichen Winston Yin , Liang Dai , Junwu Huang , Lingyuan Ji , Simone Ferraro

A logarithmic spiral is a prominent feature appearing in a majority of observed galaxies. This feature has long been associated with the traditional Hubble classification scheme, but historical quotes of pitch angle of spiral galaxies have…

We investigate the impact of nonaxisymmetric structure on estimates of galaxy inclinations and position angles. A new minimization technique is used to obtain estimates of inclination and position angle from a global fit to either…

Astrophysics · Physics 2009-11-07 Eric I. Barnes , J. A. Sellwood

FITS images in the B, V, R, I, H and K passbands are presented of a sample of 86 face-on spiral galaxies. The galaxies were selected from the UGC to have a diameter of at least 2 arcmin and a minor over major axis ratio larger than 0.625.…

Astrophysics · Physics 2007-05-23 Roelof S. de Jong

We present optical (B & R) and infrared (K_s) images and photometry for a sample of 49 extremely late-type, edge-on disk galaxies selected from the Flat Galaxy Catalog of Karenchentsev et al. (1993). Our sample was selected to include…

Astrophysics · Physics 2009-10-31 Julianne J. Dalcanton , Rebecca A. Bernstein

An asymmetry index is derived from ellipse-fitting to galaxy images, that gives weight to faint outer features and is not strongly redshift-dependent. These measures are made on a sample of 13 2MASS QSOs and their neighbour galaxies, and a…

Astrophysics · Physics 2009-11-13 J. B. Hutchings , C. Proulx

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

I summarize a series of studies where the underlying theme is to exploit non-axisymmetry disk structures such as bars and spiral arms. By measuring the strength of gravitational forces from these structures we can measure the mass in them.…

Astrophysics · Physics 2007-05-23 A. C. Quillen

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…

The structural symmetry of forty-three face-on galaxy images in the R(65 0 nm) and J(450 nm) bands are measured to determine the usefulness of symmetry a s a morphological parameter. Each galaxy image is rotated by $180$\deg and subtr acted…

Astrophysics · Physics 2009-10-30 Christopher J. Conselice

We suggest a set of morphological measures that we believe can help in quantifying the shapes of two-dimensional cosmological images such as galaxies, clusters, and superclusters of galaxies. The method employs non-parametric morphological…

Astrophysics · Physics 2009-07-30 Nurur Rahman , Sergei F. Shandarin

This paper is the first part in our series on the influence of tidal interactions and minor mergers on the radial and vertical disk structure of spiral galaxies. We report on the sample selection, our observations, and data reduction.…

Astrophysics · Physics 2010-01-25 U. Schwarzkopf , R. -J. Dettmar

We present integrated polarization properties of nearby spiral galaxies at 4.8 GHz, and models for the integrated polarization of spiral galaxy disks as a function of inclination. Spiral galaxies in our sample have observed integrated…

Astrophysics · Physics 2011-02-11 Jeroen M. Stil , Marita Krause , Rainer Beck , A. Russell Taylor

We present results of surface photometry for eleven edge-on galaxies observed with the 6-m telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences. The photometric scale length, the scale height, and the…

Astrophysics · Physics 2007-05-23 Dmitry Bizyaev , Serafim Kajsin

Astrometry covers a parameter space that cannot be reached by RV or transit methods to detect terrestrial planets on wide orbits. In addition, high accuracy astrometric measurements are necessary to measure the inclination of the planet's…

Earth and Planetary Astrophysics · Physics 2016-07-20 Quentin Kral , Jean Schneider , Grant Kennedy , Damya Souami

Traditional photometric redshift methods use only color information about the objects in question to estimate their redshifts. This paper introduces a new method utilizing colors, luminosity, surface brightness, and radial light profile to…

Astrophysics · Physics 2008-11-26 James J. Wray , James E. Gunn

Using a large sample of galaxies from the SDSS-DR7, we have analysed the alignment of disk galaxies around cosmic voids. We have constructed a complete sample of cosmic voids (devoid of galaxies brighter than M_r-5 log(h) =-20.17) with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Jesús Varela , Juan Betancort-Rijo , Ignacio Trujillo , Elena Ricciardelli