J/A+A/341/98ivo://CDS.VizieR/J/A+A/341/98doi:10.26093/cds/vizier.33410098CDSSelman F.Melnick J.Bosch G.Terlevich R.2017-10-09T13:34:20Z2008-03-07T18:46:07ZCDS support team

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

cds-question@unistra.fropen-star-clustersvisible-astronomybroad-band-photometryUBV profile fitting photometry is presented for 1469 stars within 90arcsec of the center of the ionizing cluster of 30 Doradus (NGC 2070). A value of 0.82+/-0.03 is found for the extinction parameter S=E(U-B)/E(B-V), constant over almost the whole area covered by this research, with some evidence for local variations. Two reddening components can be identified: a smooth and moderate one that increases towards R136, and a clumpy one varying widely across the face of the cluster. The total-to-selective extinction parameter, R_V_= A_V_/E(B-V), is found to be in the range of 3.0 to 3.7, consistent with previous determinations. A new visualization tool, the colour-magnitude stereogram, is introduced and used to argue that: (1) the observations imply mass segregation in a dust filled cluster; (2) that there has been continuous dust formation near the cluster core up to the present; and (3) that an insidious systematic error has plagued previous determinations of IMF slopes. A method to obtain an unbiased estimate of the slope is discussed. Astrometric calibration (from B. Skiff): The source images were taken with the ESO NTT 3.6-meter telescope, with a CCD detector at an image scale of 0.13arcsec/pixel in about 0.8arcsec seeing. Positions were determined via a reference net of 26 relatively bright and isolated stars in the region appearing in either UCAC2 (Cat. I/289) or 2MASS (Cat. II/246). The x,y coordinates were transformed using a quadratic least-squares fit; the rms residuals using all the reference stars were 0.50 pixels in RA, and 0.55 pixels in Dec, i.e. 0.097arcsec total. A similar re-reduction of the survey by Parker (1993AJ....106..560P), which overlaps this one, shows that the Selman linkages with Parker stars (column 'P93') are incomplete and contain some errors. Some of these result from the relatively small image scale (0.49arcsec/pixel) and poor seeing (1.2-2.0arcsec) of Parker's data, such that a single Parker star is sometimes resolved into multiple components by Selman. Among bright stars (V <~ 15) that have been observed for spectral type there are few such errors in the match-up. But among Parker's fainter entries (V >~ 17) are numerous false detections (clumps in nebulosity) that are incorrectly linked by Selman with true stars a couple of arcseconds from Parker's non-stellar objects.1999A&A...341...98Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/341/98CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/187 : 30 Doradus OB Associations (Parker 1992)J/AJ/107/1054 : 30 Dor region UBV photometry (Malumuth+, 1994)J/ApJ/413/604 : 30 Dor UV and optical photometry (Hill+, 1993)J/A+A/443/851 : Effective temperature of 30 Dor population (Selman+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/341/98https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/341/98http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/341/98https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/341/98https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/341/98http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/341/98GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/341/98/table2 (UBV photometry of NGC 2070 star members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/341/98/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/341/98/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/341/98/table2?GETtext/xml+votable180.050000true84.67668333-69.100802780.0055555555555555566/33094https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/341/98?format=asciiOpticaldefaultJ/A+A/341/98/table2UBV photometry of NGC 2070 star membersSeqStar numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension J2000 (1)pos.eq.ra;meta.mainDEJ2000Declination J2000 (1)pos.eq.dec;meta.mainxposX coordinate (2)pixpos.cartesian.x;instr.detfloatyposY coordinate (2)pixpos.cartesian.y;instr.detfloatP93? Id in Parker's catalogue (3)meta.idintnullableVmagApparent V magnitudemagphot.mag;em.opt.Vfloate_VmagError in apparent V magnitudemagstat.error;phot.mag;em.opt.VfloatB-VSimbad column added by the CDSmagphot.color;em.opt.B;em.opt.VfloatnullableU-BSimbad column added by the CDSmagphot.color;em.opt.U;em.opt.BfloatnullableBmagApparent B magnitudemagphot.mag;em.opt.Bfloate_BmagError in apparent B magnitudemagstat.error;phot.mag;em.opt.BfloatUmagApparent U magnitudemagphot.mag;em.opt.Ufloate_UmagError in apparent U magnitudemagstat.error;phot.mag;em.opt.UfloatChi2Chi^2^ parameter from IRAF/DAOPHOT IIstat.fit.chi2float