SIMBAD references

2005A&A...433L...5W - Astronomy and Astrophysics, volume 433, L5-8 (2005/4-1)

Searching for O2 in the SMC: Constraints on oxygen chemistry at low metallicities.

WILSON C.D., OLOFSSON A.O.H., PAGANI L., BOOTH R.S., FRISK U., HJALMARSON A., OLBERG M. and SANDQVIST A.

Abstract (from CDS):

We present a 39h integration with the Odin satellite on the ground-state 118.75 GHz line of O2 towards the region of strongest molecular emission in the Small Magellanic Cloud. Our 3σ upper limit to the O2 integrated intensity of <0.049K.km/s in a 9' (160pc) diameter beam corresponds to an upper limit on the O2/H2 abundance ratio of <1.3x10–6. Although a factor of 20 above the best limit on the O2 abundance obtained for a Galactic source, our result has interesting implications for understanding oxygen chemistry at sub-solar metal abundances. We compare our abundance limit to a variety of astrochemical models and find that, at low metallicities, the low O2 abundance is most likely produced by the effects of photo-dissociation on molecular cloud structure. Freeze-out of molecules onto dust grains may also be consistent with the observed abundance limit, although such models have not yet been run at sub-solar initial metallicities.

Abstract Copyright:

Journal keyword(s): galaxies: individual: SMC - ISM: molecules - astrochemistry

CDS comments: p.L5 radio source B0218+357 = QSO B0218+357, p.L6 SMC SW-1 = [RGM91] SW-1, p.L7 L 134N = LDN 134N

Simbad objects: 7

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2019.12.14-22:14:29

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