2001A&A...365..174R


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.09CEST05:29:10

2001A&A...365..174R - Astronomy and Astrophysics, volume 365, 174-185 (2001/1-2)

Warm H2 in the Galactic Center region.

RODRIGUEZ-FERNANDEZ N.J., MARTIN-PINTADO J., FUENTE A., DE VICENTE P., WILSON T.L. and HUETTEMEISTER S.

Abstract (from CDS):

We present ISO observations of several H2 pure-rotational lines (from S(0) to S(5)) towards a sample of 16 molecular clouds distributed along the central ∼500pc of the Galaxy. We also present C18 O and 13CO J=1->0 and J=2 ->1 observations of these sources made with the IRAM-30 m telescope. With the CO data we derive H2 densities of 103.5–4.0cm–3 and H2 column densities of a few 1022cm–2. We have corrected the H2 data for ∼30 magnitudes of visual extinction using a self-consistent method. In every source, we find that the H2 emission exhibits a large temperature gradient. The S(0) and S(1) lines trace temperatures (T) of ∼150K while the S(4) and S(5) lines indicate temperatures of ∼600K. The warm H2 column density is typically ∼1-2x1022cm–2, and is predominantly gas with T=150K. This is the first direct estimate of the total column density of the warm molecular gas in the Galactic center region. These warm H2 column densities represent a fraction of ∼30% of the gas traced by the CO isotopes emission. The cooling by H2 in the warm component is comparable to that by CO. Comparing our H2 and CO data with available ammonia (NH3) observations from literature one obtains relatively high NH3 abundances of a few 10–7 in both the warm and the cold gas. A single shock or Photo-Dissociation Region (PDR) cannot explain all the observed H2 lines. Alternatives for the heating mechanisms are discussed.

Abstract Copyright:

Journal keyword(s): ISM: clouds - ISM: molecules - ISM: dust, extinction - galaxy: center - infrared: ISM: continuum - infrared: ISM: lines and bands

Nomenclature: Table 1: GCM +LL.ll+BB.bb N=8 added.

Simbad objects: 26

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Number of rows : 26

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 PKS 1613-50 Rad 16 17 33.000 -51 02 00.00           ~ 454 3
2 NAME Sgr E Rad 17 42 38 -29 48.2           ~ 42 0
3 GCM -0.96 +0.13 MoC 17 42 48.3 -29 41 09           ~ 7 0
4 JCMTSF J174431.2-292538 MoC 17 44 31.3 -29 25 45           ~ 6 0
5 GCM -0.50 -0.03 MoC 17 44 32.5 -29 22 42           ~ 7 0
6 GCM -0.42 +0.01 MoC 17 44 35.2 -29 17 05           ~ 3 0
7 NAME Sgr A Region reg 17 45 12 -28 48.3           ~ 916 0
8 GCM -0.15 -0.07 MoC 17 45 32.1 -29 06 02           ~ 7 0
9 GCM -0.32 -0.19 MoC 17 45 35.9 -29 18 30           ~ 8 0
10 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11613 0
11 GCM +0.24 +0.02 MoC 17 46 08.0 -28 43 22           ~ 8 0
12 GCM +0.16 -0.10 MoC 17 46 24.9 -28 51 00           ~ 7 0
13 GCM +0.21 -0.12 MoC 17 46 34.9 -28 49 00           ~ 5 0
14 GCM +0.48 +0.03 MoC 17 46 39.9 -28 30 29           ~ 4 0
15 GCM +0.35 -0.06 MoC 17 46 40.0 -28 40 00           ~ 4 0
16 NAME Sgr B MoC 17 47 02 -28 25.4           ~ 189 0
17 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1920 1
18 GCM +0.58 -0.13 MoC 17 47 29.9 -28 30 30           ~ 4 0
19 GCM +0.76 -0.05 MoC 17 47 36.8 -28 18 31           ~ 6 0
20 GCM +0.83 -0.10 MoC 17 47 58.0 -28 16 49           ~ 6 0
21 NAME Sgr D MoC 17 48 41.75 -28 01 45.0           ~ 118 1
22 GCM +0.94 -0.36 MoC 17 49 13.2 -28 19 13           ~ 7 0
23 GCM +2.99 -0.06 MoC 17 52 47.6 -26 24 25           ~ 6 0
24 NGC 7023 RNe 21 01 36.9 +68 09 48           ~ 631 0
25 SH 2-140 OpC 22 19 07.8 +63 17 07           ~ 634 2
26 IRAS 22176+6303 Y*O 22 19 17.978 +63 18 52.92           ~ 590 0

    Equat.    Gal    SGal    Ecl

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2020.08.09-05:29:10

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