Low upper limits on the O-2 abundance from the Odin satellite

L  Pagani; A O H  Olofsson; P  Bergman; P  Bernath; J H  Black; R S  Booth; V  Buat; J  Crovisier; C L  Curry; P J  Encrenaz; E  Falgarone; P A  Feldman; M  Fich; H G  Floren; U  Frisk; M  Gerin; E M  Gregersen; J  Harju; T  Hasegawa; A  Hjalmarson; L E B  Johansson; S  Kwok; B  Larsson; A  Lecacheux; T  Liljestrom; M  Lindqvist; R  Liseau; K  Mattila; G F  Mitchell; L H  Nordh; M  Olberg; G  Olofsson; I  Ristorcelli; A  Sandqvist; F  von Scheele; G  Serra; N F  Tothill; K  Volk; T  Wiklind; C D  Wilson

doi:10.1051/0004-6361:20030344

Low upper limits on the O-2 abundance from the Odin satellite

L Pagani, A O H Olofsson, P Bergman, P Bernath, J H Black, R S Booth, V Buat, J Crovisier, C L Curry, P J Encrenaz, E Falgarone, P A Feldman, M Fich, H G Floren, U Frisk, M Gerin, E M Gregersen, J Harju, T Hasegawa, A HjalmarsonL E B Johansson, S Kwok, B Larsson, A Lecacheux, T Liljestrom, M Lindqvist, R Liseau, K Mattila, G F Mitchell, L H Nordh, M Olberg, G Olofsson, I Ristorcelli, A Sandqvist, F von Scheele, G Serra, N F Tothill, K Volk, T Wiklind, C D Wilson

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O-2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (T-sys(SSB) = 600 K), Odin has reached unprecedented upper limits on the abundance of O2, especially in cold dark clouds where the excited state levels involved in the 487 GHz transition are not expected to be significantly populated. Here we report upper limits for a dozen sources. In cold dark clouds we improve upon the published SWAS upper limits by more than an order of magnitude, reaching N(O-2)/N(H-2) less than or equal to 10(-7) in half of the sources. While standard chemical models are definitively ruled out by these new limits, our results are compatible with several recent studies that derive lower O-2 abundances. Goldsmith et al. (2002) recently reported a SWAS tentative detection of the 487 GHz transition of O-2 in an outflow wing towards rho Oph A in a combination of 7 beams covering approximately 10' X 14'. In a brief (1.3 hour integration time) and partial covering of the SWAS region (approximate to65% if we exclude their central position), we did not detect the corresponding 119 GHz line. Our 3 sigma upper limit on the O-2 column density is 7.3 X 10(15) cm(-2). We presently cannot exclude the possibility that the SWAS signal lies mostly outside of the 9' Odin beam and has escaped our sensitive detector.

Original language	English
Pages (from-to)	L77-L81
Number of pages	5
Journal	Astronomy & Astrophysics
Volume	402
Issue number	3
DOIs	https://doi.org/10.1051/0004-6361:20030344
Publication status	Published - May 2003

Keywords

radio lines : ISM
ISM : molecules
Galaxy : abundances
DENSE INTERSTELLAR CLOUDS
INTER-STELLAR CLOUDS
GALACTIC-CENTER REGION
MOLECULAR CLOUD
STAR-FORMATION
SPECTRAL-LINE
(CO)-O-18(J=1->0) SURVEY
CARBON-MONOXIDE
RHO-OPHIUCHI
LARGE-SCALE

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10.1051/0004-6361:20030344

Cite this

Pagani, L., Olofsson, A. O. H., Bergman, P., Bernath, P., Black, J. H., Booth, R. S., Buat, V., Crovisier, J., Curry, C. L., Encrenaz, P. J., Falgarone, E., Feldman, P. A., Fich, M., Floren, H. G., Frisk, U., Gerin, M., Gregersen, E. M., Harju, J., Hasegawa, T., ... Wilson, C. D. (2003). Low upper limits on the O-2 abundance from the Odin satellite. Astronomy & Astrophysics, 402(3), L77-L81. https://doi.org/10.1051/0004-6361:20030344

@article{3d93d62f6aaa413b8d0c0f4157aad6cf,

title = "Low upper limits on the O-2 abundance from the Odin satellite",

abstract = "For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O-2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (T-sys(SSB) = 600 K), Odin has reached unprecedented upper limits on the abundance of O2, especially in cold dark clouds where the excited state levels involved in the 487 GHz transition are not expected to be significantly populated. Here we report upper limits for a dozen sources. In cold dark clouds we improve upon the published SWAS upper limits by more than an order of magnitude, reaching N(O-2)/N(H-2) less than or equal to 10(-7) in half of the sources. While standard chemical models are definitively ruled out by these new limits, our results are compatible with several recent studies that derive lower O-2 abundances. Goldsmith et al. (2002) recently reported a SWAS tentative detection of the 487 GHz transition of O-2 in an outflow wing towards rho Oph A in a combination of 7 beams covering approximately 10' X 14'. In a brief (1.3 hour integration time) and partial covering of the SWAS region (approximate to65% if we exclude their central position), we did not detect the corresponding 119 GHz line. Our 3 sigma upper limit on the O-2 column density is 7.3 X 10(15) cm(-2). We presently cannot exclude the possibility that the SWAS signal lies mostly outside of the 9' Odin beam and has escaped our sensitive detector.",

keywords = "radio lines : ISM, ISM : molecules, Galaxy : abundances, DENSE INTERSTELLAR CLOUDS, INTER-STELLAR CLOUDS, GALACTIC-CENTER REGION, MOLECULAR CLOUD, STAR-FORMATION, SPECTRAL-LINE, (CO)-O-18(J=1->0) SURVEY, CARBON-MONOXIDE, RHO-OPHIUCHI, LARGE-SCALE",

author = "L Pagani and Olofsson, {A O H} and P Bergman and P Bernath and Black, {J H} and Booth, {R S} and V Buat and J Crovisier and Curry, {C L} and Encrenaz, {P J} and E Falgarone and Feldman, {P A} and M Fich and Floren, {H G} and U Frisk and M Gerin and Gregersen, {E M} and J Harju and T Hasegawa and A Hjalmarson and Johansson, {L E B} and S Kwok and B Larsson and A Lecacheux and T Liljestrom and M Lindqvist and R Liseau and K Mattila and Mitchell, {G F} and Nordh, {L H} and M Olberg and G Olofsson and I Ristorcelli and A Sandqvist and {von Scheele}, F and G Serra and Tothill, {N F} and K Volk and T Wiklind and Wilson, {C D}",

year = "2003",

month = may,

doi = "10.1051/0004-6361:20030344",

language = "English",

volume = "402",

pages = "L77--L81",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

number = "3",

}

Pagani, L, Olofsson, AOH, Bergman, P, Bernath, P, Black, JH, Booth, RS, Buat, V, Crovisier, J, Curry, CL, Encrenaz, PJ, Falgarone, E, Feldman, PA, Fich, M, Floren, HG, Frisk, U, Gerin, M, Gregersen, EM, Harju, J, Hasegawa, T, Hjalmarson, A, Johansson, LEB, Kwok, S, Larsson, B, Lecacheux, A, Liljestrom, T, Lindqvist, M, Liseau, R, Mattila, K, Mitchell, GF, Nordh, LH, Olberg, M, Olofsson, G, Ristorcelli, I, Sandqvist, A, von Scheele, F, Serra, G, Tothill, NF, Volk, K, Wiklind, T & Wilson, CD 2003, 'Low upper limits on the O-2 abundance from the Odin satellite', Astronomy & Astrophysics, vol. 402, no. 3, pp. L77-L81. https://doi.org/10.1051/0004-6361:20030344

TY - JOUR

T1 - Low upper limits on the O-2 abundance from the Odin satellite

AU - Pagani, L

AU - Olofsson, A O H

AU - Bergman, P

AU - Bernath, P

AU - Black, J H

AU - Booth, R S

AU - Buat, V

AU - Crovisier, J

AU - Curry, C L

AU - Encrenaz, P J

AU - Falgarone, E

AU - Feldman, P A

AU - Fich, M

AU - Floren, H G

AU - Frisk, U

AU - Gerin, M

AU - Gregersen, E M

AU - Harju, J

AU - Hasegawa, T

AU - Hjalmarson, A

AU - Johansson, L E B

AU - Kwok, S

AU - Larsson, B

AU - Lecacheux, A

AU - Liljestrom, T

AU - Lindqvist, M

AU - Liseau, R

AU - Mattila, K

AU - Mitchell, G F

AU - Nordh, L H

AU - Olberg, M

AU - Olofsson, G

AU - Ristorcelli, I

AU - Sandqvist, A

AU - von Scheele, F

AU - Serra, G

AU - Tothill, N F

AU - Volk, K

AU - Wiklind, T

AU - Wilson, C D

PY - 2003/5

Y1 - 2003/5

N2 - For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O-2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (T-sys(SSB) = 600 K), Odin has reached unprecedented upper limits on the abundance of O2, especially in cold dark clouds where the excited state levels involved in the 487 GHz transition are not expected to be significantly populated. Here we report upper limits for a dozen sources. In cold dark clouds we improve upon the published SWAS upper limits by more than an order of magnitude, reaching N(O-2)/N(H-2) less than or equal to 10(-7) in half of the sources. While standard chemical models are definitively ruled out by these new limits, our results are compatible with several recent studies that derive lower O-2 abundances. Goldsmith et al. (2002) recently reported a SWAS tentative detection of the 487 GHz transition of O-2 in an outflow wing towards rho Oph A in a combination of 7 beams covering approximately 10' X 14'. In a brief (1.3 hour integration time) and partial covering of the SWAS region (approximate to65% if we exclude their central position), we did not detect the corresponding 119 GHz line. Our 3 sigma upper limit on the O-2 column density is 7.3 X 10(15) cm(-2). We presently cannot exclude the possibility that the SWAS signal lies mostly outside of the 9' Odin beam and has escaped our sensitive detector.

AB - For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O-2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (T-sys(SSB) = 600 K), Odin has reached unprecedented upper limits on the abundance of O2, especially in cold dark clouds where the excited state levels involved in the 487 GHz transition are not expected to be significantly populated. Here we report upper limits for a dozen sources. In cold dark clouds we improve upon the published SWAS upper limits by more than an order of magnitude, reaching N(O-2)/N(H-2) less than or equal to 10(-7) in half of the sources. While standard chemical models are definitively ruled out by these new limits, our results are compatible with several recent studies that derive lower O-2 abundances. Goldsmith et al. (2002) recently reported a SWAS tentative detection of the 487 GHz transition of O-2 in an outflow wing towards rho Oph A in a combination of 7 beams covering approximately 10' X 14'. In a brief (1.3 hour integration time) and partial covering of the SWAS region (approximate to65% if we exclude their central position), we did not detect the corresponding 119 GHz line. Our 3 sigma upper limit on the O-2 column density is 7.3 X 10(15) cm(-2). We presently cannot exclude the possibility that the SWAS signal lies mostly outside of the 9' Odin beam and has escaped our sensitive detector.

KW - radio lines : ISM

KW - ISM : molecules

KW - Galaxy : abundances

KW - DENSE INTERSTELLAR CLOUDS

KW - INTER-STELLAR CLOUDS

KW - GALACTIC-CENTER REGION

KW - MOLECULAR CLOUD

KW - STAR-FORMATION

KW - SPECTRAL-LINE

KW - (CO)-O-18(J=1->0) SURVEY

KW - CARBON-MONOXIDE

KW - RHO-OPHIUCHI

KW - LARGE-SCALE

U2 - 10.1051/0004-6361:20030344

DO - 10.1051/0004-6361:20030344

M3 - Article

SN - 0004-6361

VL - 402

SP - L77-L81

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

IS - 3

ER -