AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region
We present position-velocity strip maps of the Galactic Center region in the CO J = 7 → 6 and J = 4 → 3 transitions observed with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) located at Amundsen-Scott South Pole Station. Emission from the two rotational transitions of 12CO w...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.338.1302 2023-05-15T13:24:29+02:00 AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region Sunguen Kim Christopher L. Martin Antony A. Stark Adair P. Lane The Pennsylvania State University CiteSeerX Archives 2002 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.338.1302 http://arxiv.org/pdf/astro-ph/0207586v2.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.338.1302 http://arxiv.org/pdf/astro-ph/0207586v2.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://arxiv.org/pdf/astro-ph/0207586v2.pdf Subject headings Galaxy abundances — Galaxy center — ISM general — text 2002 ftciteseerx 2016-01-07T23:45:21Z We present position-velocity strip maps of the Galactic Center region in the CO J = 7 → 6 and J = 4 → 3 transitions observed with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) located at Amundsen-Scott South Pole Station. Emission from the two rotational transitions of 12CO was mapped at b = 0 ◦ for 3.5 ◦> ℓ> −1.5 ◦ , on a 1 ′ grid with a FWHM beamsize of 58 ′ ′ at 806 GHz and 105 ′ ′ at 461 GHz. Previous observations of CO J = 4 → 3 (Martin et al., in preparation) and [CI] (Ojha et al. 2001) emission from this region show that these lines are distributed in a manner similar to CO J = 1 → 0 (Stark et al. 1987); the (CO J = 4 → 3)/(CO J = 1 → 0) line ratio map is almost featureless across the entire Galactic Center region. In contrast, the CO J = 7 → 6 emission from the Galactic Center is strongly peaked toward the Sgr A and Sgr B molecular complexes. A Large Velocity Gradient (LVG) analysis shows that aside from the two special regions Sgr A and Sgr B, the photon-dominated regions within a few hundred parsecs of the Galactic Center are remarkably uniform in mean density and kinetic temperature at n = 2500 to 4000 cm−3 and T = 30 to 45 K. The (CO J = 7 → 6)/(CO J = 4 → 3) line temperature ratios near Sgr B are a factor of two higher than those observed in the nuclear region of the starburst galaxy M82 (Mao et al. 2000), while the CO(J = 7 → 6)/CO(J = 4 → 3) line temperature ratios around Sgr A are similar to M82. The line ratio on large scales from the Galactic Center region is an order of magnitude less than that from M82. Text Amundsen-Scott Antarc* Antarctic South pole South pole Unknown Antarctic The Antarctic South Pole Amundsen-Scott ENVELOPE(0.000,0.000,-90.000,-90.000) Amundsen Scott South Pole Station ENVELOPE(0.000,0.000,-90.000,-90.000) Amundsen-Scott South Pole Station ENVELOPE(139.273,139.273,-89.998,-89.998) |
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op_collection_id |
ftciteseerx |
language |
English |
topic |
Subject headings Galaxy abundances — Galaxy center — ISM general — |
spellingShingle |
Subject headings Galaxy abundances — Galaxy center — ISM general — Sunguen Kim Christopher L. Martin Antony A. Stark Adair P. Lane AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
topic_facet |
Subject headings Galaxy abundances — Galaxy center — ISM general — |
description |
We present position-velocity strip maps of the Galactic Center region in the CO J = 7 → 6 and J = 4 → 3 transitions observed with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) located at Amundsen-Scott South Pole Station. Emission from the two rotational transitions of 12CO was mapped at b = 0 ◦ for 3.5 ◦> ℓ> −1.5 ◦ , on a 1 ′ grid with a FWHM beamsize of 58 ′ ′ at 806 GHz and 105 ′ ′ at 461 GHz. Previous observations of CO J = 4 → 3 (Martin et al., in preparation) and [CI] (Ojha et al. 2001) emission from this region show that these lines are distributed in a manner similar to CO J = 1 → 0 (Stark et al. 1987); the (CO J = 4 → 3)/(CO J = 1 → 0) line ratio map is almost featureless across the entire Galactic Center region. In contrast, the CO J = 7 → 6 emission from the Galactic Center is strongly peaked toward the Sgr A and Sgr B molecular complexes. A Large Velocity Gradient (LVG) analysis shows that aside from the two special regions Sgr A and Sgr B, the photon-dominated regions within a few hundred parsecs of the Galactic Center are remarkably uniform in mean density and kinetic temperature at n = 2500 to 4000 cm−3 and T = 30 to 45 K. The (CO J = 7 → 6)/(CO J = 4 → 3) line temperature ratios near Sgr B are a factor of two higher than those observed in the nuclear region of the starburst galaxy M82 (Mao et al. 2000), while the CO(J = 7 → 6)/CO(J = 4 → 3) line temperature ratios around Sgr A are similar to M82. The line ratio on large scales from the Galactic Center region is an order of magnitude less than that from M82. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Sunguen Kim Christopher L. Martin Antony A. Stark Adair P. Lane |
author_facet |
Sunguen Kim Christopher L. Martin Antony A. Stark Adair P. Lane |
author_sort |
Sunguen Kim |
title |
AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
title_short |
AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
title_full |
AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
title_fullStr |
AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
title_full_unstemmed |
AST/RO Observations of CO J = 7 → 6 and J = 4 → 3 Emission toward the Galactic Center Region |
title_sort |
ast/ro observations of co j = 7 → 6 and j = 4 → 3 emission toward the galactic center region |
publishDate |
2002 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.338.1302 http://arxiv.org/pdf/astro-ph/0207586v2.pdf |
long_lat |
ENVELOPE(0.000,0.000,-90.000,-90.000) ENVELOPE(0.000,0.000,-90.000,-90.000) ENVELOPE(139.273,139.273,-89.998,-89.998) |
geographic |
Antarctic The Antarctic South Pole Amundsen-Scott Amundsen Scott South Pole Station Amundsen-Scott South Pole Station |
geographic_facet |
Antarctic The Antarctic South Pole Amundsen-Scott Amundsen Scott South Pole Station Amundsen-Scott South Pole Station |
genre |
Amundsen-Scott Antarc* Antarctic South pole South pole |
genre_facet |
Amundsen-Scott Antarc* Antarctic South pole South pole |
op_source |
http://arxiv.org/pdf/astro-ph/0207586v2.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.338.1302 http://arxiv.org/pdf/astro-ph/0207586v2.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766379915462049792 |