2010A&A...522A..59A


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.23CEST18:56:58

2010A&A...522A..59A - Astronomy and Astrophysics, volume 522, A59-59 (2010/11-1)

13CO 1-0 imaging of the Medusa merger, NGC 4194. Large scale variations in molecular cloud properties.

AALTO S., BESWICK R. and JUETTE E.

Abstract (from CDS):

Studying molecular gas properties in merging galaxies gives important clues to the onset and evolution of interaction-triggered starbursts. The (12CO)/(13CO) line intensity ratio can be used as a tracer of how dynamics and star formation processes impact the gas properties. The Medusa merger (NGC 4194) is particularly interesting to study since its LFIR/LCO ratio rivals that of ultraluminous galaxies (ULIRGs), despite the comparatively modest luminosity, indicating an exceptionally high star formation efficiency (SFE) in the Medusa merger. High resolution OVRO (Owens Valley Radio Observatory) observations of the 13CO 1-0 have been obtained and compared with matched resolution OVRO 12CO 1-0 data to investigate the molecular gas cloud properties in the Medusa merger. Interferometric observations of 12CO and 13CO 1-0 in the Medusa (NGC 4194) merger show the 12CO/13CO 1-0 intensity ratio (R) increases from normal, quiescent values (7-10) in the outer parts (r>2kpc) of the galaxy to high (16 to >40) values in the central (r<1kpc) starburst region. In the central two kpc there is an east-west gradient in R where the line ratio changes by more than a factor of three over 5" (945pc). The integrated 13CO emission peaks in the north-western starburst region while the central 12CO emission is strongly associated with the prominent crossing dust-lane. We discuss the central east-west gradient in R in the context of gas properties in the starburst and the central dust lane. We suggest that the central gradient in R is mainly caused by diffuse gas in the dust lane. In this scenario, the actual molecular mass distribution is better traced by the 13CO 1-0 emission than the 12CO. The possibilities of temperature and abundance gradients are also discussed. We compare the central gas properties of the Medusa to those of other minor mergers and suggest that the extreme and transient phase of the Medusa star formation activity has similar traits to those of high-redshift galaxies.

Abstract Copyright:

Journal keyword(s): galaxies: evolution - galaxies: individual: NGC 4194 - galaxies: starburst - galaxies: active - radio lines: ISM - ISM: molecules

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NGC 1808 Sy2 05 07 42.343 -37 30 46.98 11.05 10.80 9.94 9.36 10.2 ~ 631 3
2 NGC 3256 IG 10 27 51.284 -43 54 13.55   11.83 11.33 10.62 11.9 ~ 733 2
3 NGC 3690 IG 11 28 31.326 +58 33 41.80   13.19 12.86     ~ 864 4
4 LB 2136 QSO 11 53 24.46663282 +49 31 08.8301947   17.94 17.66     ~ 409 1
5 NGC 4194 AGN 12 14 09.615 +54 31 35.93   13.79 13.30     ~ 402 2
6 NGC 4441 GiG 12 27 20.402 +64 48 05.64   13.5       ~ 64 0
7 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 3683 4
8 M 83 SBG 13 37 00.919 -29 51 56.74 8.85 8.11 7.52 7.21   ~ 2161 2
9 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2621 4
10 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2182 2
11 NGC 7479 Sy2 23 04 56.668 +12 19 22.36 11.74 11.60 10.85 10.47 9.66 ~ 651 2

    Equat.    Gal    SGal    Ecl

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2019.10.23-18:56:58

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