Kinematic properties of the field elliptical NGC7507

The dark matter (DM) halos of field elliptical galaxies have not been well-studied and their properties appear controversial in the literature. While some galaxies appear to be nearly devoid of DM, others show clear evidence of its presence. Furthermore, modified Newtonian dynamics (MOND), which has...

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Autores principales: Salinas, R., Richtler, T., Bassino, Lilia Patricia, Romanowsky, A. J., Schuberth, Y.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2012
Materias:
Ciencias Astronómicas
galaxies: individual: NGC 7507
Galaxy: kinematics and dynamics
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84664
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-84664
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
galaxies: individual: NGC 7507
Galaxy: kinematics and dynamics
spellingShingle Ciencias Astronómicas
galaxies: individual: NGC 7507
Galaxy: kinematics and dynamics
Salinas, R.
Richtler, T.
Bassino, Lilia Patricia
Romanowsky, A. J.
Schuberth, Y.
Kinematic properties of the field elliptical NGC7507
topic_facet Ciencias Astronómicas
galaxies: individual: NGC 7507
Galaxy: kinematics and dynamics
description The dark matter (DM) halos of field elliptical galaxies have not been well-studied and their properties appear controversial in the literature. While some galaxies appear to be nearly devoid of DM, others show clear evidence of its presence. Furthermore, modified Newtonian dynamics (MOND), which has been found to have predictive power in the domain of disk galaxies, has not yet been investigated for isolated elliptical galaxies. We study the kinematics of the isolated elliptical NGC 7507, which has been claimed as a clear example of DM presence in early-type galaxies. We obtained major and minor axis long-slit spectroscopy of NGC 7507 using the Gemini South telescope and deep imaging in Kron-Cousins R and Washington C using the CTIO/MOSAIC camera. Mean velocities, velocity dispersion and higher order moments of the velocity distribution are measured out to ∼90′′. The galaxy, although almost circular, has significant rotation along the minor axis and a rapidly declining velocity dispersion along both axes. The velocity dispersion profile is modeled in the context of a spherical Jeans analysis. Models without DM provide an excellent representation of the data with a mass-to-light ratio (M/L) of 3.1 (R-band). The most massive Navarro-Frenk-White (NFW) halo the data allow has a virial mass of only 3.9 -2.1 +3.1×10 11 M ⊙, although the data are more consistent with models that have a slight radial anisotropy, which implies the galaxy has an even lower DM halo mass of 2.2 -1.2 +2.0×10 11 M ⊙. Modeling of the h 4 Gauss-Hermite coefficient is inconclusive but seems to be consistent with mild radial anisotropy. A cored logarithmic DM halo with parameters r 0⊙l = 7 kpc and v 0 = 100 km s -1 can also reproduce the observed velocity dispersion profile. The MOND predictions overestimate the velocity dispersion. In conclusion, we cannot easily reproduce the previous findings of a predominance of DM in NGC 7507 within a simple spherical model. DM may be present, but only in conjunction with a strong radial anisotropy, for which there are some indications.
format Articulo
Articulo
author Salinas, R.
Richtler, T.
Bassino, Lilia Patricia
Romanowsky, A. J.
Schuberth, Y.
author_facet Salinas, R.
Richtler, T.
Bassino, Lilia Patricia
Romanowsky, A. J.
Schuberth, Y.
author_sort Salinas, R.
title Kinematic properties of the field elliptical NGC7507
title_short Kinematic properties of the field elliptical NGC7507
title_full Kinematic properties of the field elliptical NGC7507
title_fullStr Kinematic properties of the field elliptical NGC7507
title_full_unstemmed Kinematic properties of the field elliptical NGC7507
title_sort kinematic properties of the field elliptical ngc7507
publishDate 2012
url http://sedici.unlp.edu.ar/handle/10915/84664
work_keys_str_mv AT salinasr kinematicpropertiesofthefieldellipticalngc7507
AT richtlert kinematicpropertiesofthefieldellipticalngc7507
AT bassinoliliapatricia kinematicpropertiesofthefieldellipticalngc7507
AT romanowskyaj kinematicpropertiesofthefieldellipticalngc7507
AT schuberthy kinematicpropertiesofthefieldellipticalngc7507
bdutipo_str Repositorios
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