2005A&A...429..923R


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.28CET20:25:14

2005A&A...429..923R - Astronomy and Astrophysics, volume 429, 923-938 (2005/1-3)

ISO observations of the Galactic Center interstellar medium. Ionized gas.

RODRIGUEZ-FERNANDEZ N.J. and MARTIN-PINTADO J.

Abstract (from CDS):

We present fine structure and recombination line observations of the ionized gas toward a sample of 18 sources located within 300pc of the center of the Galaxy (hereafter Galactic center, GC). The sources were selected as molecular clouds located far from thermal continuum sources. The fine structure lines from [NII] and [SIII] were detected in 16 sources. In 10 sources we even detected the [OIII] 88µm line. Several techniques have been used to determine lower and upper limits to the extinction toward each source to correct the observed line fluxes. The derived electron densities of the ionized gas vary from ∼100 to ≤30cm–3. For some sources we were able to derive N, S and Ne abundances. We found that they are similar to those measured in the HII regions in the 5-kpc ring and in the nuclei of starburst galaxies. The fine structure lines ratios measured for all the sources can be explained by photo-ionization with an effective temperature of the ionizing radiation of 32000-37000K and an ionization parameter, U, of -1>logU>-3. The highest excitation is found in the Radio Arc region but it does not decrease smoothly with distance. There must be more ionizing sources distributed over the Galactic center than the known clusters of massive stars. Most of the clouds are located far (up to 45 pc for M-0.96+0.13) from the prominent continuum complexes (Sgr C, B ...). However, it is possible that the clouds are ionized by escaped photons from those complexes. The comparison of the effective temperatures of the ionizing radiation to the measured Lyman continuum photon emission rate implies that the clouds are indeed ionized by distant sources. The excitation ratios, effective temperature and ionization parameter measured in the GC are similar to those found in some low excitation starburst galaxies. The [NeIII]/[NeII] line ratios measured in the GC sources are consistent with the results of the Thornely et al. (2000ApJ...539..641T) model for a short burst of massive star formation less than 8Myr ago. We have also found that the [NeII] 13µm to far-infrared continuum ratio measured for the GC sources is similar to that of external galaxies, supporting the idea of Sturm et al. (2002A&A...393..821S) that the far-infrared continuum in Active Galaxies is dominated by dust heated by stellar radiation rather than by the AGN.

Abstract Copyright:

Journal keyword(s): ISM: abundances - ISM: clouds - infrared: ISM - Galaxy: center

CDS comments: Cloud 0.02-0.07 is a misprint for GCM -.02 -.07

Simbad objects: 46

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Number of rows : 46

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 55 GiG 00 14 53.602 -39 11 47.86 8.54 8.58 7.87 7.84   ~ 716 2
2 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 2998 2
3 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1404 1
4 NGC 1482 GiP 03 54 38.928 -20 30 08.82 13.15 13.14 12.15 11.29   ~ 260 2
5 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5422 6
6 NGC 3256 IG 10 27 51.284 -43 54 13.55   11.83 11.33 10.62 11.9 ~ 767 2
7 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1300 2
8 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4075 3
9 M 83 SBG 13 37 00.919 -29 51 56.74 8.85 8.11 7.52 7.21   ~ 2277 2
10 NGC 5253 AGN 13 39 55.990 -31 38 24.11 11.48 10.94 10.49 10.33   ~ 1281 4
11 NAME Sgr E Rad 17 42 38 -29 48.2           ~ 46 0
12 GCM -0.96 +0.13 MoC 17 42 48.3 -29 41 09           ~ 7 0
13 GCM -0.42 +0.13 MoC 17 44.1 -29 14           ~ 1 0
14 JCMTSF J174431.2-292538 MoC 17 44 31.3 -29 25 45           ~ 6 0
15 GCM -0.50 -0.03 MoC 17 44 32.5 -29 22 42           ~ 7 0
16 GCM -0.42 +0.01 MoC 17 44 35.2 -29 17 05           ~ 3 0
17 NAME Sgr C MoC 17 44 36.3 -29 28 13           ~ 318 0
18 NAME NTFs PoC 17 45.2 -29 03           ~ 37 2
19 NAME Sgr A Region reg 17 45 12 -28 48.3           ~ 920 0
20 GCM -0.15 -0.07 MoC 17 45 32.1 -29 06 02           ~ 7 0
21 GCM -0.32 -0.19 MoC 17 45 35.9 -29 18 30           ~ 8 0
22 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11996 0
23 GAL 000.095+00.012 HII 17 45 48 -28 50.9           ~ 11 0
24 GCM -0.02 -0.07 MoC 17 45 50.4 -28 59 06           ~ 147 0
25 NAME Arches Cluster Cl* 17 45 50.5 -28 49 28           ~ 649 0
26 GCM +0.24 +0.02 MoC 17 46 08.0 -28 43 22           ~ 8 0
27 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 462 0
28 NAME Sickle HII 17 46 15.2 -28 49 49           ~ 113 0
29 NAME Galactic Center Lobe X 17 46 16.9 -28 48 52           ~ 110 0
30 GCM +0.16 -0.10 MoC 17 46 24.9 -28 51 00           ~ 7 0
31 GCM +0.21 -0.12 MoC 17 46 34.9 -28 49 00           ~ 5 0
32 GCM +0.48 +0.03 MoC 17 46 39.9 -28 30 29           ~ 4 0
33 GCM +0.35 -0.06 MoC 17 46 40.0 -28 40 00           ~ 4 0
34 NAME Sgr B1 MoC 17 47 02.0 -28 31 57           ~ 131 0
35 NAME Sgr B MoC 17 47 02 -28 25.4           ~ 195 0
36 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1979 1
37 NAME Sgr B2 Main Rad 17 47 20.5 -28 23 06           ~ 346 1
38 GCM +0.58 -0.13 MoC 17 47 29.9 -28 30 30           ~ 4 0
39 GCM +0.76 -0.05 MoC 17 47 36.8 -28 18 31           ~ 7 0
40 GCM +0.83 -0.10 MoC 17 47 58.0 -28 16 49           ~ 6 0
41 NAME Sgr D HII HII 17 48 41.79 -28 01 41.3           ~ 63 1
42 GCM +0.94 -0.36 MoC 17 49 13.2 -28 19 13           ~ 7 0
43 GCM +1.56 -0.30 MoC 17 50 26.6 -27 45 30           ~ 5 0
44 GCM +3.06 +0.34 MoC 17 51 26.5 -26 08 29           ~ 6 0
45 GCM +2.99 -0.06 MoC 17 52 47.6 -26 24 25           ~ 6 0
46 [BC94] Clump 2 Rad ~ ~           ~ 2 0

    Equat.    Gal    SGal    Ecl

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2021.02.28-20:25:14

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