2001A&A...374..824V


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.01CET10:01:13

2001A&A...374..824V - Astronomy and Astrophysics, volume 374, 824-838 (2001/8-2)

12CO(1-0) observations of NGC 4848: A Coma galaxy after stripping.

VOLLMER B., BRAINE J., BALKOWSKI C., CAYATTE V. and DUSCHL W.J.

Abstract (from CDS):

We study the molecular gas content and distribution in the Coma cluster spiral galaxy NGC 4848 which is HI deficient and where the remaining atomic gas is on one side of the galaxy, presumably because of the strong ram-pressure in the rich Coma cluster. Plateau de Bure interferometric CO(1-0) observations reveal a lopsided H2 distribution with an off-center secondary maximum coincident with the inner part of the HI. NGC 4848 is not at all deficient in molecular gas as it contains MH2∼4x109M in the central and inner disk regions. As predicted by earlier calculations, ram-pressure has little influence on the dense molecular gas in the inner disk, which appears dynamically normal at our 2kpc resolution. At the interface between the CO and HI emission regions, about 8kpc NW of the center, however, strong star formation is present as witnessed by Hα and radio continuum emission. From the radio and Hα fluxes we estimate the star formation rate in the northern emission region to be close to 0.3M/yr, nearly that of an average quiescent spiral. This is the region in which earlier Fabry-Perot observations revealed a double-peaked Hα line, indicating gas at two different velocities at the same sky position. In order to understand these observations, we present the results of numerical simulations of the galaxy-cluster ICM interaction. We suggest that NGC 4848 already passed through the center of the cluster about 4x108 years ago. At the observed stage ram pressure has no more direct dynamical influence on the galaxy's ISM. We observe the galaxy when a fraction of the stripped gas is falling back onto the galaxy. Ram pressure is thus a short-lived event with longer-lasting consequences. The combination of ram-pressure and rotation results in gas at different velocities colliding where the double-peaked Hα line is observed. Ram-pressure can thus result, after re-accretion, in displaced molecular gas without the H2 itself being pushed efficiently by the intracluster medium. This process, however, requires strong stripping, such that only galaxies with radial orbits can be affected as much as NGC 4848. A scenario where two interactions take place simultaneously is also consistent with the available data but less probable on the basis of our numerical simulations.

Abstract Copyright:

Journal keyword(s): galaxies: individual: NGC 4848 - galaxies: interactions - galaxies: ISM - galaxies: kinematics and dynamics

Simbad objects: 10

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Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 ICRF J092703.0+390220 Sy1 09 27 03.0139516273 +39 02 20.847968628   17.17 17.00 16.486   ~ 937 1
2 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5980 0
3 NGC 4419 LIN 12 26 56.433 +15 02 50.72 12.42 12.08 11.16     ~ 372 1
4 3C 273 BLL 12 29 06.6996828061 +02 03 08.598846466   13.05 14.830 14.11   ~ 5404 1
5 NGC 4522 GiG 12 33 39.657 +09 10 29.54   13.6       ~ 334 0
6 3C 277.3 BLL 12 54 12.052 +27 37 34.15   15.94       ~ 346 1
7 NGC 4848 AGN 12 58 05.5774186519 +28 14 33.264194270   14.2   13.53   ~ 175 0
8 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4317 2
9 7C 1308+3236 BLL 13 10 28.66387 +32 20 43.7831   15.61 15.24 17.91   ~ 760 1
10 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3839 2

    Equat.    Gal    SGal    Ecl

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2021.03.01-10:01:13

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