J/AJ/111/1128ivo://CDS.VizieR/J/AJ/111/1128doi:10.26093/cds/vizier.51111128CDSMalumuth E.M.Waller W.H.Parker J.Wn.2023-04-06T16:50:20Z1997-12-09T20:33:53ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frh-ii-regionsvisible-astronomybroad-band-photometryultraviolet-photometryAs 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_{sun}_. 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_{sun}_ yields a total mass of 7350M_{sun}_, while integration down to 0.1_{Msun}_ yields a total mass of 18000M_{sun}_. 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.1996AJ....111.1128Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/111/1128CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/111/1128https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/111/1128http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/111/1128https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/111/1128https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/111/1128http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/111/1128GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/111/1128/table1 (NGC 595 photometry)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/111/1128/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/111/1128/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/111/1128/table1?GETtext/xml+votable180.050000true23.392708330.68722220.0055555555555555566/2155https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/111/1128?format=asciiUVdefaultJ/AJ/111/1128/table1NGC 595 photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification numbermeta.id;meta.mainintDMS[]? Star number from table 1 of Drissen et al. (1993AJ....105.1400D)meta.idintRAJ2000Right ascension, J2000pos.eq.ra;meta.mainDEJ2000Declination signpos.eq.dec;meta.mainnullableUVmag[]? Ultraviolet magnitude (F170W HST filter)magphot.mag;em.UV.100-200nmfloatUmag[]? U magnitudemagphot.mag;em.opt.UfloatBmag[]? B magnitudemagphot.mag;em.opt.BfloatVmag[]? V magnitudemagphot.mag;em.opt.Vfloat