Sign on

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0810.1291)
· On-line Data
· References in the article
· Citations to the Article (15) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (13)
· Associated Articles
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
The Planetary Nebula Spectrograph elliptical galaxy survey: the dark matter in NGC 4494
Authors:
Napolitano, N. R.; Romanowsky, A. J.; Coccato, L.; Capaccioli, M.; Douglas, N. G.; Noordermeer, E.; Gerhard, O.; Arnaboldi, M.; de Lorenzi, F.; Kuijken, K.; Merrifield, M. R.; O'Sullivan, E.; Cortesi, A.; Das, P.; Freeman, K. C.
Affiliation:
AA(INAF-Observatory of Capodimonte, Salita Moiariello, 16, 80131, Naples, Italy), AB(UCO/Lick Observatory, University of California, Santa Cruz, CA 95064, USA; Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción, Chile), AC(Max-Planck-Institut für Extraterrestriche Physik, Giessenbachstrasse, D-85748 Garching b. München, Germany), AD(Dipartimento di Scienze Fisiche, Universit'a Federico II, Via Cinthia, 80126, Naples, Italy; INAF - VSTceN, Salita Moiariello, 16, 80131, Naples, Italy), AE(Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen, the Netherlands), AF(School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD), AG(Max-Planck-Institut für Extraterrestriche Physik, Giessenbachstrasse, D-85748 Garching b. München, Germany), AH(European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany; INAF, Osservatorio Astronomico di Pino Torinese, I-10025 Pino Torinese, Italy), AI(Max-Planck-Institut für Extraterrestriche Physik, Giessenbachstrasse, D-85748 Garching b. München, Germany), AJ(Leiden Observatory, Leiden University, PO Box 9513, 2300RA Leiden, the Netherlands), AK(School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD), AL(Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA), AM(School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD), AN(Max-Planck-Institut für Extraterrestriche Physik, Giessenbachstrasse, D-85748 Garching b. München, Germany), AO(Research School of Astronomy & Astrophysics, ANU, Canberra, Australia)
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 393, Issue 2, pp. 329-353. (MNRAS Homepage)
Publication Date:
02/2009
Origin:
MNRAS
MNRAS Keywords:
planetary nebulae: general , galaxies: elliptical and lenticular, cD , galaxies: individual: NGC 4494 , galaxies: kinematics and dynamics , galaxies: structure , dark matter
DOI:
10.1111/j.1365-2966.2008.14053.x
Bibliographic Code:
2009MNRAS.393..329N

Abstract

We present new Planetary Nebula Spectrograph observations of the ordinary elliptical galaxy NGC 4494, resulting in positions and velocities of 255 planetary nebulae out to seven effective radii (25 kpc). We also present new wide-field surface photometry from MMT/Megacam, and long-slit stellar kinematics from VLT/FORS2. The spatial and kinematical distributions of the planetary nebulae agree with the field stars in the region of overlap. The mean rotation is relatively low, with a possible kinematic axis twist outside 1Re. The velocity dispersion profile declines with radius, though not very steeply, down to ~70kms-1 at the last data point.

We have constructed spherical dynamical models of the system, including Jeans analyses with multi-component Λ cold dark matter (CDM) motivated galaxies as well as logarithmic potentials. These models include special attention to orbital anisotropy, which we constrain using fourth-order velocity moments. Given several different sets of modelling methods and assumptions, we find consistent results for the mass profile within the radial range constrained by the data. Some dark matter (DM) is required by the data; our best-fitting solution has a radially anisotropic stellar halo, a plausible stellar mass-to-light ratio and a DM halo with an unexpectedly low central density. We find that this result does not substantially change with a flattened axisymmetric model.

Taken together with other results for galaxy halo masses, we find suggestions for a puzzling pattern wherein most intermediate-luminosity galaxies have very low concentration haloes, while some high-mass ellipticals have very high concentrations. We discuss some possible implications of these results for DM and galaxy formation.


Associated Articles

Source Paper     Catalog Description    


Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints