Issue |
A&A
Volume 462, Number 1, January IV 2007
|
|
---|---|---|
Page(s) | 93 - 99 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20066302 | |
Published online | 02 November 2006 |
Deep H I observations of the surroundings of ram pressure stripped Virgo spiral galaxies*
Where is the stripped gas?
1
CDS, Observatoire astronomique de Strasbourg, UMR 7550, 11 rue de l'université, 67000 Strasbourg, France e-mail: bvollmer@astro.u-strasbg.fr
2
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Received:
28
August
2006
Accepted:
23
October
2006
Deep Effelsberg 100-m Hi observations of 5 Hi deficient Virgo spiral
galaxies are presented. No new extended Hi tail is found in these galaxies.
The already known Hi tail north of NGC 4388 does not significantly extend further
than a WSRT image has shown.
Based on the absence of Hi tails in a sample of 6 Virgo spiral galaxies and a
balance of previous
detections of extraplanar gas in the targeted galaxies we propose a global picture
where the outer gas disk (beyond the optical radius R25) is removed
much earlier than expected by the classical ram pressure criterion. Based on the two-phase
nature of atomic hydrogen located in a galactic disk, we argue that the warm diffuse
Hi in the outer galactic disk is evaporated much more rapidly than the cold
dense Hi. Therefore,
after a ram pressure stripping event we can only observe atomic hydrogen
which was cold and dense before it was removed from the galactic disk.
This global picture is consistent with all available observations.
We detect between 0.3% and 20% of the stripped mass assuming an initially
non-deficient galaxy and between 3% and 70% of the stripped mass assuming an
initially Hi deficient galaxy (). Under the latter assumption we estimate
an evaporation rate by dividing the missing mass by the estimated time
to peak ram pressure from dynamical simulations. We find evaporation rates
between 10 and 100
yr-1.
Key words: galaxies: evolution / galaxies: interactions / galaxies: ISM / galaxies: intergalactic medium
© ESO, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.