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J/AJ/111/1128       UV-UBV photometry in NGC 595 (Malumuth+ 1996)

The stellar initial mass function in the giant H II region NGC 595 Malumuth E.M., Waller W.H., Parker J.Wn. <Astron. J. 111, 1128 (1996)> =1996AJ....111.1128M
ADC_Keywords: H II regions ; Photometry, UBV ; Photometry, ultraviolet Abstract: As part of a larger effort to study the resolved and composite properties of the giant H II regions in Messier 33, we have analyzed multiband HST/WFPC-2 images of NGC 595 in terms of the ionizing cluster's resolved stellar population. Photometric reductions of the PC images yield 100 stars in the UV image, 272 stars on the U image, 345 stars on the B image, and 561 stars on the V image. A total of 267 stars are common to the U, B, and V images while 86 stars are detected on all 4 images. Although some clustering is evident, the degree of central concentration is less than that seen in 30 Doradus. The resulting U-B vs B-V diagram of the resolved stars is used to determine the reddening of each star. The average reddening derived from this diagram is E(B-V)=0.36±0.28mag. The dereddened color-M_V diagram is best fit by a model cluster having an age of 4.5±1.0Myr, and hence initial masses no greater than 51M. A total of 13 supergiant stars and 10 candidate WR stars [Drissen et al. (1993AJ....105.1400D), and references therein] are identified with M_V=-5 to -8mag. The remainder are main-sequence O-type (98) and early B-type (>145) stars with M_V=-1 to -6mag. The ratio of WR to O stars is WR/O=0.11±0.01, roughly the same as found in the core of 30 Doradus. The resulting luminosity function has a slope of alpha=-0.71. The derived IMF has a slope of Gamma=-1.32±0.02 before subtracting a background component, and Gamma=-1.00±0.05 after subtracting a background based on photometry of the surrounding WF images. Integration of the derived IMF down to a lower mass limit of 4M yields a total mass of 7350M, while integration down to 0.1{Msun} yields a total mass of 18000M. The total estimated ionizing luminosity is 5.0x10^50photon/s, roughly half that which is inferred from the Halpha luminosity in this region. This shortfall of ionizing photons can be reconciled by allowing for a spread in the stellar ages, and/or increasing the modeled EUV luminosity of the stars at the inferred cluster age. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 62 573 NGC 595 photometry
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- ID Identification number 5- 8 I4 --- DMS []? Star number from table 1 of Drissen et al. (1993AJ....105.1400D) 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 24 A1 --- DE- Declination sign 25- 26 I2 deg DEd Declination, J2000 28- 29 I2 arcmin DEm Declination, J2000 31- 34 F4.1 arcsec DEs Declination, J2000 36- 41 F6.2 mag UVmag []? Ultraviolet magnitude (F170W HST filter) 43- 48 F6.2 mag Umag []? U magnitude 50- 55 F6.2 mag Bmag []? B magnitude 57- 62 F6.2 mag Vmag []? V magnitude
Origin: AAS CD-ROM series, Volume 6, 1996 Lee Brotzman [ADS] 02-May-1996
(End) [CDS] 05-Sep-1996
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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