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In the gravitational lens system Q2237+0305 the cruciform quasar image geometry is twisted by ten degrees by the lens effect of a bar in the lensing galaxy. This effect can be used to measure the mass of the bar. We construct a new lensing…

Astrophysics · Physics 2009-10-30 Robert Schmidt , Rachel L. Webster , Geraint F. Lewis

We have measured a velocity dispersion for the foreground galaxy in this gravitationally lensed system. Our dispersion confirms the prediction from lens models, provided that the source is distant enough ($z_{_S}>0.2$). Current…

Astrophysics · Physics 2009-10-28 J. Lehar , A. J. Cooke , C. R. Lawrence , A. D. Silber , G. I. Langston

We have compiled a sample of 2728 nearby ($z<0.08$) elliptical galaxies with photometry in the $g,r,i,z$ bands from the Sloan Digital Sky Survey (SDSS) and $J,H,K$ photometry from the Two Micron All Sky Survey (2MASS). Stellar masses,…

Context. Stellar shells, which form axially symmetric systems of arcs in some elliptical galaxies, are most likely remnants of radial minor mergers. They are observed up a radius of $\sim$100 kpc. The stars in them oscillate in radial…

Astrophysics of Galaxies · Physics 2015-06-19 M. Bílek , K. Bartošková , I. Ebrová , B. Jungwiert

We review the theory of how the shapes of the X-ray isophotes probe both the shape and radial distribution of gravitating matter in elliptical galaxies in a way that is more robust than the traditional spherical approach. We summarize and…

Astrophysics · Physics 2007-05-23 David A. Buote , Claude R. Canizares

We present high-resolution two-dimensional velocity fields in Halpha and CO of the nearby dwarf galaxy NGC 2976. Our observations were made at both higher spatial resolution (~75 pc) and higher velocity resolution (13 km/s in Halpha and 2…

Astrophysics · Physics 2007-05-23 Joshua D. Simon , Alberto D. Bolatto , Adam Leroy , Leo Blitz

(Abridged) We present an analysis of a Chandra ACIS-S observation of the elliptical galaxy NGC 720 to verify the existence of a dark matter (DM) halo and to measure its ellipticity. The ACIS-S3 image reveals over 60 point sources. For…

Astrophysics · Physics 2009-11-07 David A. Buote , Tesla E. Jeltema , Claude R. Canizares , Gordon P. Garmire

We measure the alignment of galaxy ellipticities in the local universe over a range of scales using digitized photographic data from the SuperCOSMOS Sky Survey. We find for a magnitude cut of b_J < 20.5, corresponding to a median galaxy…

Astrophysics · Physics 2009-10-31 M. L. Brown , A. N. Taylor , N. C. Hambly , S. Dye

We present a new approach to measure the shapes of galaxies, a fundamental task in observational astronomy. This approach is based on the decomposition of a galaxy image into a series of orthogonal basis functions, or `shapelets'. Our…

Astrophysics · Physics 2017-08-23 Alexandre Refregier , Tzu-Ching Chang , David Bacon

We report a detailed modeling of a mass profile of a $z = 0.2999$ massive elliptical galaxy using 30 milli-arcsecond resolution 1-mm Atacama Large Millimeter/submillimeter Array (ALMA) images of the galaxy-galaxy lensing system SDP.81. The…

Astrophysics of Galaxies · Physics 2015-04-17 Yoichi Tamura , Masamune Oguri , Daisuke Iono , Bunyo Hatsukade , Yuichi Matsuda , Masao Hayashi

We investigate how strong gravitational lensing can test contemporary models of massive elliptical (ME) galaxy formation, by combining a traditional decomposition of their visible stellar distribution with a lensing analysis of their mass…

High angular resolution images of the complex gravitational lens system RXS J1131-1231 (a quadruply imaged AGN with a bright Einstein ring) obtained with the Advanced Camera for Surveys and NICMOS instruments onboard the Hubble Space…

Astrophysics · Physics 2009-11-11 J. -F. Claeskens , D. Sluse , P. Riaud , J. Surdej

Orbit superposition models are a non-parametric dynamical modelling technique to determine the mass of a galaxy's central supermassive black hole (SMBH), its stars, or its dark-matter halo. One of the main problems is how to decide which…

Astrophysics of Galaxies · Physics 2021-04-28 Mathias Lipka , Jens Thomas

We study the transition from regular to chaotic motion in a prolate elliptical galaxy dynamical model with a bulge and a dense nucleus. Our numerical investigation shows that stars with angular momentum Lz less than or equal to a critical…

Astrophysics of Galaxies · Physics 2012-04-06 Nicolaos D. Caranicolas , Euaggelos E. Zotos

The statistical properties of the ellipticities of galaxy images depend on how galaxies form and evolve, and therefore constrain models of galaxy morphology, which are key to the removal of the intrinsic alignment contamination of…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-28 B. Joachimi , E. Semboloni , P. E. Bett , J. Hartlap , S. Hilbert , H. Hoekstra , P. Schneider , T. Schrabback

An exquisite gravitational arc with a radius of 2.1" has been discovered around the z = 0.938 field elliptical galaxy CFRS03.1077 during HST observations of Canada-France Redshift Survey (CFRS) fields. Spectroscopic observations of the arc…

Astrophysics · Physics 2009-11-07 David Crampton , David Schade , F. Hammer , A. Matzkin , S. J. Lilly , O. LeFevre

This is the fourth paper of our series investigating the effects of active galactic nucleus (AGN) feedback in the evolution of an elliptical galaxy using the {\it MACER} framework. While previous works considered only AGN radiation and…

Astrophysics of Galaxies · Physics 2026-05-01 Minhang Guo , Feng Yuan , Suoqing Ji , Bocheng Zhu

The nearby lenticular galaxy NGC 1277 is thought to host one of the largest black holes known, however the black hole mass measurement is based on low spatial resolution spectroscopy. In this paper, we present Gemini Near-infrared Integral…

Recent studies have shown that massive elliptical galaxies have total mass density profiles within an effective radius that can be approximated as \rho_{tot}\propto r^{-\gamma'}, with mean slope <\gamma'>=2.08 \pm 0.03 and scatter…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Aaron A. Dutton , Tommaso Treu

Recent results from gravitational lensing are combined with new modeling of the stellar velocity distributions in nearby galaxies to probe the connection between the luminous and the dark matter in elliptical galaxies. From analysing a…

Astrophysics · Physics 2007-05-23 H. -W. Rix