J/ApJ/783/56ivo://CDS.VizieR/J/ApJ/783/56doi:10.26093/cds/vizier.17830056CDSKravtsov V.Alcaino G.Marconi G.Alvarado F.2017-01-23T22:00:00Z2016-04-14T15:54:00ZCDS support team

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

cds-question@unistra.frglobular-star-clustersinfrared-photometryvisible-astronomybroad-band-photometryccd-photometryThis paper is devoted to photometric study of the Galactic globular cluster (GGC) NGC 6752 in UBVI, focusing on the multiplicity of its stellar population. We emphasize that our U passband is (1) narrower than the standard one due to its smaller extension blueward and (2) redshifted by ~300{AA} relative to its counterparts, such as the HST F336W filter. Accordingly, both the spectral features encompassed by it and photometric effects of the multiplicity revealed in our study are somewhat different than in recent studies of NGC 6752. Main sequence stars bluer in U-B are less centrally concentrated, as red giants are. We find a statistically significant increasing luminosity of the red giant branch (RGB) bump of {Delta}U{approx}0.2mag toward the cluster outskirts with no so obvious effect in V. The photometric results are correlated with spectroscopic data: the bluer RGB stars in U-B have lower nitrogen abundances. We draw attention to a larger width of the RGB than the blue horizontal branch (BHB) in U-B. This seems to agree with the effects predicted to be caused by molecular bands produced by nitrogen-containing molecules. We find that brighter BHB stars, especially the brightest ones, are more centrally concentrated. This implies that red giants that are redder in U - B, i.e., more nitrogen enriched and centrally concentrated, are the main progenitors of the brighter BHB stars. However, such a progenitor-progeny relationship disagrees with theoretical predictions and with the results on the elemental abundances in horizontal branch stars. We isolated the asymptotic giant branch clump and estimated the parameter {Delta}V_ZAHB_^clump^=0.98+/-0.12.2014ApJ...783...56Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/783/56CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/A+A/573/A70 : UBVI photometry in 3 globular clusters (Nardiello+, 2015)J/A+A/567/A72 : Stellar parameters and abundances in NGC6752 (Gruyters+, 2014)J/A+A/557/A128 : Stellar [Fe/H] and [Na/H] in NGC6752 (Carretta, 2013)J/MNRAS/423/2901 : NGC 6752 multiwavelength survey (Thomson+, 2012)J/AcA/62/357 : Proper motions in 6 globular clusters (Zloczewski+, 2012)J/ApJ/750/L14 : Abundances of red giants in NGC 6752 (Carretta+, 2012)J/A+A/516/A23 : UBVI Photometry of NGC 1261 (Kravtsov+, 2010)J/A+A/469/529 : UBVI photometry of NGC 6864 (Kravtsov+, 2007)J/A+A/464/927 : Abundances of red giants in NGC 6752 (Carretta+, 2007)J/A+A/440/901 : Reddening and metallicity of NGC 6752 (Gratton, 2005)J/MNRAS/324/580 : Sources in NGC 4038-39 and 6752 direction (Daniels+, 2001)J/AJ/116/2415 : CCD UBVRI Photometry of M80 (Alcaino+ 1998)J/A+AS/121/95 : Giant stars abundances in 24 clusters (Carretta+ 1997)J/ApJS/99/637 : Equivalent widths for 54 red giants (Norris+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/783/56https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/783/56http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/783/56https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/783/56https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/783/56http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/783/56GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/783/56/table2 (Photometry of NGC 6752)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/783/56/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/783/56/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/783/56/table2?GETtext/xml+votable180.050000true287.7661719-60.10410530.0055555555555555566/47125 471683.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/783/56?format=asciiInfraredOpticaldefaultJ/ApJ/783/56/table2Photometry of NGC 6752sigV[0/0.92]? Standard deviation for V band magnitude {sigma}_V_magstat.stdevfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStar[1/18246] Star running sequence numbermeta.id;meta.mainintVmag[9.1/21.7] The V magnitudemagphot.mag;em.opt.VfloatU-B[-1.5/2.2]? The U-B color indexmagphot.color;em.opt.U;em.opt.BfloatnullableB-V[-0.6/1.8]? The B-V color indexmagphot.color;em.opt.B;em.opt.VfloatnullableV-I[-0.5/1.8]? The V-I color indexmagphot.color;em.opt.V;em.opt.IfloatnullablesigU[0/0.91]? Standard deviation for U band magnitude {sigma}_U_magstat.stdevfloatnullableNU[2/6]? Number of U band measurementsmeta.numberintnullablesigB[0/0.71]? Standard deviation for B band magnitude {sigma}_B_magstat.stdevfloatnullableNB[2/6]? Number of B band measurementsmeta.numberintnullableNV[2/6]? Number of V band measurementsmeta.numberintnullablesigI[0/1.3]? Standard deviation for I band magnitude {sigma}_I_magstat.stdevfloatnullableNI[2/6]? Number of I band measurementsmeta.numberintnullableXpos[0.1/2066] The X coordinate (1)pixpos.cartesian.x;instr.detfloatYpos[6.8/2059] The Y coordinate (1)pixpos.cartesian.y;instr.detfloat_RAPosition computed from a comparison with UCAC4 (I/322) ({sigma}=0.27'') (right ascension part)degpos.eq.ra;meta.main_DEPosition computed from a comparison with UCAC4 (I/322) ({sigma}=0.27'') (declination part)degpos.eq.dec;meta.main