Element Abundances, 100, 132, 210 Angular Momentum Parame
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Fourier Dissection of Early-Type Galaxy Bars R
The Astronomical Journal, 132:1859Y1876, 2006 November # 2006. The American Astronomical Society. All rights reserved. Printed in U.S.A. FOURIER DISSECTION OF EARLY-TYPE GALAXY BARS R. Buta,1 E. Laurikainen,2 H. Salo,2 D. L. Block,3 and J. H. Knapen4 Received 2006 May 4; accepted 2006 July 14 ABSTRACT This paper reports on a near-infrared survey of early-type galaxies designed to provide information on bar strengths, bulges, disks, and bar parameters in a statistically well-defined sample of S0YSa galaxies. Early-type galaxies have the advantage that their bars are relatively free of the effects of dust, star formation, and spiral structure that com- plicate bar studies in later type galaxies. We describe the survey and present results on a detailed analysis of the rela- tive Fourier intensity amplitudes of bars in 26 early-type galaxies. We also evaluate the ‘‘symmetry assumption’’ of these amplitudes with radius, used recently for bar-spiral separation in later type galaxies. The results show a wide variety of radial Fourier profiles of bars, ranging from simple symmetric profiles that can be represented in terms of a single Gaussian component to both symmetric and asymmetric profiles that can be represented by two overlapping Gaussian components. More complicated profiles than these are also found, often due to multiple barlike features including extended ovals or lenses. Based on the gravitational bar torque indicator Qb, double-Gaussian bars are stronger on average than single-Gaussian bars, at least for our small sample. We show that published numerical simulations in which the bar transfers a large amount of angular momentum to the halo can account for many of the observed profiles. -
1 Introduction
Iranian Journal of Astronomy and Astrophysics Iranian Journal of Vol. 1, No. 1, 2013 Astronomy and © Available online at http://journals.du.ac.ir Astrophysics Evaluation of New MOND Interpolating Function with Rotation Curves of Galaxies Hosein Haghi1 ·Hamed Ghasemi2 ·HongSheng Zhao3 1 Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), P.O. Box 11365-9161, Zanjan, Iran; email: [email protected] 2 Department of Physics, Zanjan University, Zanjan, Iran 3 SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS, UK Abstract. The rotation curves of a sample of 46 low- and high-surface brightness galaxies are considered in the context of Milgrom's modified dynamics (MOND) to test a new interpolating function proposed by Zhao et al. (2010) [1] and compare with the results of simple interpolating function. The predicted rotation curves are calculated from the total baryonic matter based on the B-band surface photometry, and the observed distribution of neutral hydrogen, in which the one adjustable parameter is the stellar mass-to-light ratio. The predicted rotation curves generally agree with the observed curves for both interpolating functions. We show that the fitted M=L in the B-band correlates with B-V color in the sense expected from what we know about stellar population synthesis models. Moreover, the mass-to-light ratios of MOND with new interpolating function is in consistent with scaled Salpeter's initial mass function of the SPS scheme, while those of MOND with simple interpolating function favor Kroupa IMF. Keywords: ISM: molecules, ISM: structure, instabilities 1 Introduction The rotation curves of spiral galaxies provide an accurate determination of the radial force distribution in spiral galaxies. -
Infrared Spectroscopy of Nearby Radio Active Elliptical Galaxies
The Astrophysical Journal Supplement Series, 203:14 (11pp), 2012 November doi:10.1088/0067-0049/203/1/14 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. INFRARED SPECTROSCOPY OF NEARBY RADIO ACTIVE ELLIPTICAL GALAXIES Jeremy Mould1,2,9, Tristan Reynolds3, Tony Readhead4, David Floyd5, Buell Jannuzi6, Garret Cotter7, Laura Ferrarese8, Keith Matthews4, David Atlee6, and Michael Brown5 1 Centre for Astrophysics and Supercomputing Swinburne University, Hawthorn, Vic 3122, Australia; [email protected] 2 ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) 3 School of Physics, University of Melbourne, Melbourne, Vic 3100, Australia 4 Palomar Observatory, California Institute of Technology 249-17, Pasadena, CA 91125 5 School of Physics, Monash University, Clayton, Vic 3800, Australia 6 Steward Observatory, University of Arizona (formerly at NOAO), Tucson, AZ 85719 7 Department of Physics, University of Oxford, Denys, Oxford, Keble Road, OX13RH, UK 8 Herzberg Institute of Astrophysics Herzberg, Saanich Road, Victoria V8X4M6, Canada Received 2012 June 6; accepted 2012 September 26; published 2012 November 1 ABSTRACT In preparation for a study of their circumnuclear gas we have surveyed 60% of a complete sample of elliptical galaxies within 75 Mpc that are radio sources. Some 20% of our nuclear spectra have infrared emission lines, mostly Paschen lines, Brackett γ , and [Fe ii]. We consider the influence of radio power and black hole mass in relation to the spectra. Access to the spectra is provided here as a community resource. Key words: galaxies: elliptical and lenticular, cD – galaxies: nuclei – infrared: general – radio continuum: galaxies ∼ 1. INTRODUCTION 30% of the most massive galaxies are radio continuum sources (e.g., Fabbiano et al. -
The Young Nuclear Stellar Disc in the SB0 Galaxy NGC 1023
MNRAS 457, 1198–1207 (2016) doi:10.1093/mnras/stv2864 The young nuclear stellar disc in the SB0 galaxy NGC 1023 E. M. Corsini,1,2‹ L. Morelli,1,2 N. Pastorello,3 E. Dalla Bonta,` 1,2 A. Pizzella1,2 and E. Portaluri2 1Dipartimento di Fisica e Astronomia ‘G. Galilei’, Universita` di Padova, vicolo dell’Osservatorio 3, I-35122 Padova, Italy 2INAF–Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, I-35122 Padova, Italy 3Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia Accepted 2015 December 3. Received 2015 November 5; in original form 2015 September 11 Downloaded from ABSTRACT Small kinematically decoupled stellar discs with scalelengths of a few tens of parsec are known to reside in the centre of galaxies. Different mechanisms have been proposed to explain how they form, including gas dissipation and merging of globular clusters. Using archival Hubble Space Telescope imaging and ground-based integral-field spectroscopy, we investigated the http://mnras.oxfordjournals.org/ structure and stellar populations of the nuclear stellar disc hosted in the interacting SB0 galaxy NGC 1023. The stars of the nuclear disc are remarkably younger and more metal rich with respect to the host bulge. These findings support a scenario in which the nuclear disc is the end result of star formation in metal enriched gas piled up in the galaxy centre. The gas can be of either internal or external origin, i.e. from either the main disc of NGC 1023 or the nearby satellite galaxy NGC 1023A. The dissipationless formation of the nuclear disc from already formed stars, through the migration and accretion of star clusters into the galactic centre, is rejected. -