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J/PASJ/51/791  Molecular clouds in southern HII regions (Yamaguchi+ 1999)

Molecular clouds and star formation in the southern HII regions Yamaguchi R., Saito H., Mizuno N., Mine Y., Mizuno A., Ogawa H., Fukui Y. <Publ. Astron. Soc. Jap., 51, 791 (1999)> =1999PASJ...51..791Y
ADC_Keywords: H II regions ; Molecular clouds ; Infrared sources Keywords: ISM: H II regions - ISM: molecules - radio lines: ISM - stars: early-type - stars: formation Abstract: We have carried out extensive 13CO(J=1-0) observations toward 23 southern H II regions associated with bright-rimmed clouds. In total, 95 molecular clouds have been identified to be associated with the H II regions. Among the 95, 57 clouds are found to be associated with 204 IRAS point sources which are candidates for young stellar objects. There is a significant increase of star-formation efficiency on the side facing to the H II regions; the luminosity-to-mass ratio, defined as the ratio of the stellar luminosity to the molecular cloud mass, is higher by an order of magnitude on the near side of the H II regions than that on the. far side. This indicates that molecular gas facing to the H II regions is more actively forming massive stars whose luminosity is ~>103L. In addition, the number density of the IRAS point sources increases by a factor of 2 on the near side of the H II regions compared with on the far side. These results strongly suggest that the active formation of massive stars on the near side of the H II regions is due to the effects of the H II regions, such as the compression of molecular material by the ionization/shock fronts. For the whole Galaxy, we estimate that the present star-formation rate under such effects is at least 0.2-0.4M/yr, corresponding to a few 10% by mass. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 74 28 Observed H II regions refs.dat 72 24 References table2.dat 67 104 Observed properties of 13CO clouds table3.dat 53 104 Physical properties of 13CO clouds table4.dat 14 204 Associated IRAS point sources
See also: VII/20 : Catalogue of HII Regions (Sharpless 1959) J/A+A/284/233 : Association of HII regions & IRAS PSC sources (Codella+ 1994) J/A+AS/133/29 : Molecular line survey towards UC HII (Hatchell+ 1998) J/A+AS/131/319 : HII regions catalogue (Petit+ 1998) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 11 A11 --- HII HII region 13- 19 A7 arcmin Size Size (NN or NNNxNNN) in arcmin (1) 21- 31 A11 --- Star Exciting star 32 A1 --- n_Star [+] +: the earliest star probably contributing to ionization 34- 42 A9 --- SpType MK spectral type 44- 47 F4.2 kpc Dist ? Distance 49- 54 A6 --- r_Dist References for distance and exciting star (2), in refs.dat file 55- 74 A20 --- RelObj Related objects
Note (1): References for size: S = Sharpless (1959, Cat. VII/20) RCW = Rodgers et al. (1960, Cat. VII/216) Cum Nebula = Chanot and Sivan (1983A&A...121...19C) Others = Brand et al. (1986A&AS...65..537B)
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Ref Reference number 4- 22 A19 --- BibCOde BibCode 24- 43 A20 --- Aut Author's name 50- 72 A23 --- Com Comments
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 2 I2 --- [YSM99] [1-95] Sequential number 4- 13 A10 --- Cloud Cloud name 15- 20 F6.2 deg GLON Galactic longitude 22- 27 F6.2 deg GLAT Galactic latitude 29- 30 I2 h RAh Right ascension (1950) 32- 33 I2 min RAm Right ascension (1950) 35- 38 F4.1 s RAs Right ascension (1950) 40 A1 --- DE- Declination sign (1950) 41- 42 I2 deg DEd Declination (1950) 44- 45 I2 arcmin DEm Declination (1950) 47- 48 I2 arcsec DEs Declination (1950) 50- 52 F3.1 K TR* Peak antenna temperature (1) 54- 56 F3.1 km/s DV FWHM line width (1) 58- 62 F5.1 km/s Vlsr LSR velocity (1) 64- 67 F4.1 Int Velocity-integrated intensity (1)
Note (1): Observed properties at the peak position of molecular clouds. The typical rms noise fluctuations are 0.35K at a velocity resolution of 0.1km/s with 4-12s integration.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 2 I2 --- [YSM99] [1-95] Sequential number 4- 7 F4.2 --- tau ? Optical depth 9- 13 F5.2 10+21cm-2 N(H2) H2 column density 15- 17 F3.1 km/s DVc ? FWHM line width computed from gaussian fit 19- 22 F4.2 kpc Dist ? Distance to the molecular cloud 24- 27 F4.1 pc Rad ? Size of the molecular cloud 29- 34 I6 solMass Mass ? Molecular cloud mass 36- 50 A15 ---- HII Associated HII regions 52- 53 I2 --- IPS ? Number of cold IRAS points sources listed in table4
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 2 I2 --- [YSM99] [1-95] Sequential number 4- 13 A10 --- IRAS Associated IRAS point source 14 A1 --- m_IRAS [A] Multiplicity index on IRAS name
History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Vannier [CDS] 31-May-2005
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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