2006A&A...450L..13M


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.29CET09:26:42

2006A&A...450L..13M - Astronomy and Astrophysics, volume 450, L13-16 (2006/4-4)

Methanol detection in M82.

MARTIN S., MARTIN-PINTADO J. and MAUERSBERGER R.

Abstract (from CDS):

The nuclear starburst region in M 82 shows systematical low abundances of some complex molecules when compared with other starburst galaxies. This is likely related to a presumably photodissociation dominated environment. In particular, methanol is known to show relatively low abundance because it is easily photodissociated. We present a multilevel study of the emission of methanol, detected for the first time in this galaxy, and discuss the origin of its emission. Observations of three transitions of CH3OH towards the center and two positions around the nucleus of M 82 are presented. Two different components are found, one with high excitation (n(H2)∼106cm–3, Trot∼20K) and the other with low excitation (n(H2)∼104cm–3, Trot∼5K). The high observed methanol abundance of a few 10–9 can only be explained if injection of methanol from dust grains is taken into account. While the overall [CH3OH]/[NH3] ratio is much larger than observed towards other starbursts, the dense high excitation component shows a similar value to that found in NGC253 and Maffei2. Our observations suggest the molecular material in M 82 to be formed by dense warm cores, shielded from the UV radiation and similar to the molecular clouds in other starbursts, surrounded by a less dense photodissociated halo. The dense warm cores are likely the location of recent and future star formation within M 82.

Abstract Copyright:

Journal keyword(s): ISM: molecules - galaxies: abundances - galaxies: individual: M 82 - galaxies: ISM - galaxies: starburst

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2882 2
2 UGCA 39 GiG 02 41 55.092 +59 36 14.73   16       ~ 318 1
3 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1369 1
4 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 701 0
5 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5258 6
6 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1238 2

    Equat.    Gal    SGal    Ecl

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2020.01.29-09:26:42

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