J/ApJ/559/864 Extragalactic ultracompact H II regions (Johnson+, 2001)
A sample of clusters of extragalactic ultracompact H II regions.
Johnson K.E., Kobulnicky H.A., Massey P., Conti P.S.
<Astrophys. J. 559, 864 (2001)>
=2001ApJ...559..864J 2001ApJ...559..864J
ADC_Keywords: H II regions ; Radio continuum
Keywords: galaxies: individual (M33, NGC 253, NGC 6946) - galaxies: ISM -
galaxies: star clusters - H II regions - radio continuum: galaxies -
stars: formation
Abstract:
We report on the detection of optically thick free-free radio sources
in the galaxies M33, NGC 253, and NGC 6946 using data in the
literature. We interpret these sources as being young embedded star
birth regions that are likely to be clusters of ultracompact H II
regions. All 35 of the sources presented in this article have positive
radio spectral indices (α>0 for Sν)∝να),
suggesting an optically thick thermal bremsstrahlung origin from the
H II region surrounding the hot stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 16 Ultra-dense (UD) H II Candidates in NGC 6946
table2.dat 67 14 Ultra-dense (UD) H II Candidates in M33
table3.dat 80 5 Ultra-dense (UD) H II Candidates in NGC 253
table4.dat 52 16 Comparison with Optical Images of NGC 6946
table5.dat 59 14 Comparison with Optical Images of M33
table6.dat 57 5 Comparison with Optical Images of NGC 253
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See also:
J/A+A/336/339 : VLA observations of ultracompact HII regions (Molinari+ 1998)
J/A+AS/120/283 : Water maser features in UC HII regions (Hofner+ 1996)
J/A+AS/133/29 : Molecular line survey towards UC HII (Hatchell+ 1998)
J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)
J/MNRAS/291/261 : Ultracompact HII regions studies. I. (Walsh+ 1997)
J/MNRAS/301/640 : Ultracompact HII regions studies. II. (Walsh+, 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [NGC 6946]
10- 11 I2 --- [JKM2001] Source identification (NGC 6946 NN)
13- 14 I2 h RAh Right ascension (J2000) (1)
16- 17 I2 min RAm Right ascension (J2000) (1)
19- 23 F5.2 s RAs Right ascension (J2000) (1)
25 A1 --- DE- Declination sign (J2000) (1)
26- 27 I2 deg DEd Declination (J2000) (1)
29- 30 I2 arcmin DEm Declination (J2000) (1)
32- 36 F5.2 arcsec DEs Declination (J2000) (1)
38- 41 F4.1 10+17W/Hz L6cm 6cm luminosity
43- 45 F3.1 10+17W/Hz e_L6cm rms uncertainty on L6cm
46 A1 --- n_L6cm [*] Note on L6cm (2)
47- 51 F5.2 10+17W/Hz L20cm 20cm luminosity
53- 55 F3.1 10+17W/Hz e_L20cm rms uncertainty on L20cm
56 A1 --- n_L20cm [*] Note on L20cm (2)
57- 62 F6.2 10+49s-1 QLyc Production rate of Lyman continuum photon
64- 67 F4.1 10+49s-1 e_QLyc rms uncertainty on QLyc
69- 72 F4.2 --- SI Spectral index 20cm to 6cm
74- 77 F4.2 --- e_SI rms uncertainty on SI
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Note (1): These coordinates are accurate to approximately the half
beamwidth of ∼1".
Note (2): *: Luminosities are less than a 4σ detection.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [M 33]
6- 7 I2 --- [JKM2001] Source identification (M33 NN)
9- 10 I2 h RAh Right ascension (J2000)
12- 13 I2 min RAm Right ascension (J2000)
15- 18 F4.1 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs Declination (J2000)
32- 35 F4.1 10+16W/Hz L6cm 6cm luminosity
37- 39 F3.1 10+16W/Hz e_L6cm rms uncertainty on L6cm
41- 44 F4.1 10+16W/Hz L20cm 20cm luminosity
46- 48 F3.1 10+16W/Hz e_L20cm rms uncertainty on L20cm
50- 53 F4.1 10+49s-1 QLyc Production rate of Lyman continuum photon
55- 57 F3.1 10+49s-1 e_QLyc rms uncertainty on QLyc
59- 62 F4.2 --- SI Spectral index 20cm to 6cm
64- 67 F4.2 --- e_SI rms uncertainty on SI
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- --- [NGC 253]
9 I1 --- [JKM2001] Source identification (NGC 253 N)
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 21 F5.2 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 34 F5.2 arcsec DEs Declination (J2000)
36- 39 F4.1 10+17W/Hz L1.3cm 1.3cm luminosity
41- 44 F4.1 10+17W/Hz e_L1.3cm rms uncertainty on L1.3cm
46- 49 F4.1 10+17W/Hz L2cm ? 2cm luminosity
51- 53 F3.1 10+17W/Hz e_L2cm ? rms uncertainty on L2cm
55- 58 F4.1 10+17W/Hz L3.6cm 3.6cm luminosity
60- 62 F3.1 10+17W/Hz e_L3.6cm rms uncertainty on L3.6cm
64- 66 I3 10+49s-1 QLyc Production rate of Lyman continuum photon
68- 70 I3 10+49s-1 e_QLyc rms uncertainty on QLyc
72- 75 F4.2 --- SI Spectral index 3.6cm to 1.3cm
77- 80 F4.2 --- e_SI rms uncertainty on SI
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [NGC 6946]
10- 11 I2 --- [JKM2001] Source identification (NGC 6946 NN)
13- 28 A16 --- R R-band counterpart ?
31- 46 A16 --- Halpha Hα counterpart ?
50- 52 I3 --- [LDG97] Lacey et al. (1997ApJS..109..417) number
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [M 33]
6- 7 I2 --- [JKM2001] Source identification (M33 NN)
9- 37 A29 --- B B-band counterpart ?
41- 54 A14 --- HII HII counterpart ? (1)
57- 59 I3 --- [GDK99] Gordon et al. (1999, Cat. J/ApJS/120/247
number
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Note (1): HII counterpart designations:
HBW = Hodge et al., 1999, Cat. J/PASP/111/685 catalog
BCLMP = Boulesteix et al. (1974A&A....37...33B 1974A&A....37...33B) catalog
Z = Courtes et al. (1987A&A...174...28C 1987A&A...174...28C) catalog
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- --- [NGC 253]
9 I1 --- [JKM2001] Source identification (NGC 253 N)
11- 27 A17 --- I I-band counterpart ?
29- 45 A17 --- Halpha Hα counterpart ?
49- 57 A9 --- [AU88] Ulvestad & Antonucci (1997ApJ...488..621U 1997ApJ...488..621U)
number
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 24-Apr-2002