2007A&A...472..471M


Query : 2007A&A...472..471M

2007A&A...472..471M - Astronomy and Astrophysics, volume 472, 471-482 (2007/9-3)

Integral-field spectroscopy of the Galactic cluster [DBS2003]8. Discovery of an ultra-compact HII region and its ionizing star in the bright rimmed cloud SFO49.

MESSINEO M., PETR-GOTZENS M.G., SCHULLER F., MENTEN K.M., HABING H.J., KISSLER-PATIG M., MODIGLIANI A. and REUNANEN J.

Abstract (from CDS):

We have started a program of infrared (IR) studies of the stellar clusters associated with HII regions in order to understand the structure of the spiral arms and their interaction with the central bar of the Galaxy better. This is accomplished by determining the distance to the OB stars embedded in the clusters. We want to use IR stellar spectro-photometric measurements to complement the kinematic distances from the radial velocity of the gas. SINFONI, the infrared integral-field spectrograph of the VLT, enabled us to image the clusters and to resolve them into individual stars, to get the spectra of the brightest stars, and to analyze the possible nebular emission. We performed pilot observations of [DBS2003]8, an embedded Galactic stellar cluster in the bright rimmed cloud SFO49, during the SINFONI science verification. The results are presented in this paper. The center of the cluster is resolved for the first time and four stars are detected, the brightest being a late O type or early B star. A spectro-photometric distance to the cluster of 2.65±0.4kpc is derived. We discovered that the O type star is located in the center of a nebula, which is quite circular in shape with an observed radius of ∼0.03-0.06pc, a value typical of an ultra-compact HII region. We measured the nebula's Brγ emission, which is generated by photo-ionization of the central star; and from the hydrogen molecular line ratio, we have proved that the ionized nebula is surrounded by a photo-dissociated region (PDR). We also detected [FeII] line emission at 1.664µm. The ratio of the iron flux to that of the Brγ line is found 15 times higher than in a classical HII region. This suggests that at least part of the [FeII] line emission emanates from shocked stellar wind material.

Abstract Copyright:

Journal keyword(s): stars: early-type - ISM: HII regions - Galaxy: structure - infrared: ISM - infrared: stars

Nomenclature: Fig.2, Table 1: [MPS2007] A (Nos A-D).

Simbad objects: 15

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Number of rows : 15
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 HD 1663 ** 00 20 54.59048 +10 58 36.8483 6.530 6.600 6.550     A0V 51 0
2 * 59 Ari PM* 03 19 55.7958132408 +27 04 16.068323604   6.774 5.918     G7IV 68 0
3 NAME Orion S reg 05 35 12.9 -05 24 10           ~ 139 0
4 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 841 0
5 IC 443 SNR 06 17 34.7 +22 28 03           ~ 1219 1
6 [DBS2003] 7 OpC 07 35 25 -18 40.6           ~ 15 1
7 SH 2-307 HII 07 35 33 -18 45.6           ~ 60 2
8 [MPS2007] D * 07 35 38.80 -18 48 48.9           ~ 1 0
9 [DBS2003] 8 Cl* 07 35 39 -18 48.8           ~ 7 0
10 [MPS2007] A * 07 35 39.08 -18 48 51.4           O9.5V 1 0
11 IRAS 07334-1842 MIR 07 35 39.09720 -18 48 50.5656           ~ 14 0
12 [MPS2007] B * 07 35 39.23 -18 48 53.4           F 1 0
13 [MPS2007] C * 07 35 39.24 -18 48 47.9           ~ 1 0
14 MSX6C G234.6358+00.8281 HII 07 35 40.9 -18 48 59           ~ 10 1
15 HD 63487 PM* 07 48 05.9776759056 -27 31 10.675343172   9.82 9.20     G2V 50 0

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2023.10.01-01:34:03

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