2010A&A...522A..62M


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.14CEST09:01:31

2010A&A...522A..62M - Astronomy and Astrophysics, volume 522, A62-62 (2010/11-1)

A large 12C/13C isotopic ratio in M 82 and NGC 253.

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

Abstract (from CDS):

Our aim is to derive carbon isotopic ratios from optically thin tracers in the central regions of the starburst galaxies M 82 and NGC 253. We present high-sensitivity observations of CCH and two of its 13C isotopologues, C13CH and 13CCH, as well as the optically thin emission from C18O and 13C18O. We assume the column density ratio between isotopologues is representative of the 12C/13C isotopic ratio. From CCH, lower limits to the 12C/13C isotopic ratio of 138 in M 82, and 81 in NGC 253, are derived. Lower limits to the 12C/13C ratios from CO isotopologues support these. 13C18O is tentatively detected in NGC 253, which is the first reported detection in the extragalactic ISM. Based on these limits, we infer ratios of 16O/18O>350 and >300 in M 82 and NGC 253, respectively, and 32S/34S>16 in NGC 253. The derived CCH fractional abundances toward these galaxies of ≲1.1x10–8 agree well with those of molecular clouds in the Galactic disk. Our lower limits to the 12C/13C ratio from CCH are a factor of 2-3 larger than previous limits. The results are discussed in the context of molecular and nucleo-chemical evolution. The high 12C/13C isotopic ratio of the molecular ISM in these starburst galaxies suggest that the gas has been recently accreted toward their nuclear regions.

Abstract Copyright:

Journal keyword(s): galaxies: abundances - galaxies: individual: NGC 253 - galaxies: individual: M 82 - galaxies: ISM - galaxies: nuclei - galaxies: starburst

Simbad objects: 14

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Number of rows : 14

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 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2855 2
2 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1360 1
3 LDN 1527 DNe 04 39 53 +25 45.0           ~ 467 0
4 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1325 0
5 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14312 1
6 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3887 5
7 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5209 6
8 IC 694 G 11 28 27.312 +58 34 42.29   18.2       ~ 232 2
9 NGC 3690 IG 11 28 31.326 +58 33 41.80   13.19 12.86     ~ 861 4
10 NGC 4195 LSB 12 14 18.054 +59 36 55.06   15.5       ~ 27 0
11 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1226 2
12 QSO J1415+1129 QSO 14 15 46.25 +11 29 43.4   17.63 17.23     ~ 579 1
13 NGC 6240 Sy2 16 52 58.861 +02 24 03.55   14.31 13.37     ~ 1439 2
14 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 10991 0

    Equat.    Gal    SGal    Ecl

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2019.10.14-09:01:31

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