The consequences of ram pressure stripping on the Virgo cluster spiral galaxy NGC 4522

Citation
B. Vollmer et al., The consequences of ram pressure stripping on the Virgo cluster spiral galaxy NGC 4522, ASTRON ASTR, 364(2), 2000, pp. 532-542
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
0004-6361 → ACNP
Volume
364
Issue
2
Year of publication
2000
Pages
532 - 542
Database
ISI
SICI code
0004-6361(200012)364:2<532:TCORPS>2.0.ZU;2-2
Abstract
New H alpha Fabry-Perot interferometer observations of the Virgo cluster sp iral galaxy NGC 4522 are presented. A velocity field up to a radius of 60 " was obtained. The observed rotation curve is symmetric. It is not perturbe d in the inner disk. For radii > 50 " it shows a solid body rotation. We co mpare these data with a numerical model which includes the effects of ram p ressure stripping. The model can reproduce the main characteristics of the H alpha emission distribution and velocity field. We therefore conclude tha t the stripping event which caused the HI deficiency and the distorted H al pha distribution and velocity field has been due to ram pressure. The close st passage of the galaxy to the cluster center is estimated to be similar t o6.5 10(8) yr ago. The observed recent star formation is due to the re-accr etion of gas clouds which were accelerated to velocities below the escape v elocity during the stripping event. Furthermore, the gas which is located a t radii > 60 " is part of an asymmetric expanding ring of gas clouds. A sub stantial part of these clouds is located above the disk plane. We predict t he HI gas distribution and velocity field as it would be observed by deep 2 1 cm observations.