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J/A+A/604/A120      omega Cen RR Lyrae and SX Phoenicis stars (Navarrete+, 2017)

Near-IR period-luminosity relations for pulsating stars in ω Centauri (NGC 5139). Navarrete C., Catelan M., Contreras Ramos R., Alonso-Garcia J., Gran F., Dekany I., Minniti D. <Astron. Astrophys., 604, A120 (2017)> =2017A&A...604A.120N (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, infrared Keywords: stars: variables: RR Lyrae - stars: variables: Cepheids - stars: variables: delta Scuti - infrared: stars - surveys - globular clusters: individual: NGC 5139 Abstract: The globular cluster ω Centauri (NGC 5139) hosts hundreds of pulsating variable stars of different types, thus representing a treasure trove for studies of their corresponding period-luminosity (PL) relations. Our goal in this study is to obtain the PL relations for RR Lyrae and SX Phoenicis stars in the field of the cluster, based on high-quality, well-sampled light curves in the near-infrared (IR). Observations were carried out using the VISTA InfraRed CAMera (VIRCAM) mounted on the Visible and Infrared Survey Telescope for Astronomy (VISTA). A total of 42 epochs in J and 100 epochs in KS were obtained, spanning 352 days. Point-spread function photometry was performed using DoPhot and DAOPHOT crowded-field photometry packages in the outer and inner regions of the cluster, respectively. Based on the comprehensive catalog of near-IR light curves thus secured, PL relations were obtained for the different types of pulsators in the cluster, both in the J and KS bands. This includes the first PL relations in the near-IR for fundamental-mode SX Phoenicis stars. The near-IR magnitudes and periods of Type II Cepheids and RR Lyrae stars were used to derive an updated true distance modulus to the cluster, with a resulting value of (m-M)0=13.708±0.035±0.10mag, where the error bars correspond to the adopted statistical and systematic errors, respectively. Adding the errors in quadrature, this is equivalent to a heliocentric distance of 5.52±0.27kpc. Description: The VIRCAM camera, mounted on the VISTA telescope, was used to monitor ω Cen, obtaining 42 and 100 epochs in the J and KS bands, respectively. The effective field of view (FoV) of VISTA (1.1x1.5deg2) is large enough to encompass all the pulsating stars known in the field of the cluster, except for four RRL located farther away than the cluster's tidal radius and which are thus likely non-members (Navarrete et al., 2015A&A...577A..99N). The characteristics of the observations and data reduction are the same as those already explained in Navarrete et al. (2013IBVS.6078....1N, 2015A&A...577A..99N), and will accordingly not be repeated here. Point-spread function (PSF) photometry was performed using the photometry packages DoPhot (Schechter et al., 1993PASP..105.1342S; Alonso-Garcia et al., 2012, Cat. J/AJ/143/70) for the outer regions, and DAOPHOT II/ALLFRAME (Stetson 1987PASP...99..191S, 1994PASP..106..250S) for the central part of the cluster (i.e., the innermost ∼10'). All the magnitudes are presented in the VISTA photometric system. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 92 149 Catalog of RR Lyrae stars in ω Cen field, used to derive the empirical PL relations tablea2.dat 71 45 Catalog of fundamental-mode candidate SX Phe stars in ω Cen, used to derive the empirical PL relations
See also: J/A+AS/105/145 : RR Lyr stars of ome Cen (Petersen 1994) J/A+AS/125/343 : OGLE RR Lyr stars in omega Cen (Kaluzny+ 1997) J/A+A/574/A15 : RR Lyrae in omega Cen (Fernandez-Trincado+, 2015) J/AJ/119/1824 : Caby photometry of Ω Centauri (Rey+, 2000) J/ApJ/640/L43 : Metallicities of RR Lyrae stars in Omega Cen (Sollima+, 2006) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 4 A4 --- VName Star identification (VNNN), Cl* NGC 5139 SAW VNNN in Simbad 5 A1 --- n_VName [abc] Note on VName (1) 7- 8 I2 h RAh Right ascension (J2000.0) 10- 11 I2 min RAm Right ascension (J2000.0) 13- 17 F5.2 s RAs Right ascension (J2000.0) 19 A1 --- DE- Declination sign (J2000.0) 20- 21 I2 deg DEd Declination (J2000.0) 23- 24 I2 arcmin DEm Declination (J2000.0) 26- 29 F4.1 arcsec DEs Declination (J2000.0) 31- 39 F9.7 d Per Period 41- 46 F6.3 mag Jmag VISTA J magnitude 48- 52 F5.3 mag e_Jmag rms uncertainty on Jmag 54- 59 F6.3 mag Ksmag VISTA Ks magnitude 61- 65 F5.3 mag e_Ksmag rms uncertainty on Ksmag 67- 70 A4 --- Type RR Lyrae type 72- 76 F5.2 [-] [Fe/H]R00 ?=- Metallicity from Rey et al. (2000, Cat. J/AJ/119/1824) 78- 81 F4.2 [-] e_[Fe/H]R00 ?=- rms uncertainty on [Fe/H]R00 83- 87 F5.2 [-] [Fe/H]S06 ? Metallicity from Sollima et al. (2006, Cat.J/ApJ/640/L43) 89- 92 F4.2 [-] e_[Fe/H]S06 ?=- rms uncertainty on [Fe/H]S06
Note (1): Notes as follows: a = Stars not considered to derive the PL-Z relations because their mean magnitudes are brighter than the mean locus of RRab or RRc stars (see Fig. 2). These "over-luminous" stars are due to unresolved companions and blending. b = The J and KS light curves have a considerable gap in the observations because of the one day period. This star was not considered to derive the PL-Z relations. c = Stars with metallicity measurements without error reported were not included to derive the PL-Z relations.
Byte-by-byte Description of file: tablea2.dat
Bytes Format Units Label Explanations
1- 4 A4 --- VName Star identification (VNNN), Cl* NGC 5139 SAW VNNN in Simbad 5 A1 --- --- [/] 6- 9 A4 --- OName Other name (WNNN), Cl* NGC 5139 WSB VNNN in Simbad 11- 12 I2 h RAh Right ascension (J2000.0) 14- 15 I2 min RAm Right ascension (J2000.0) 17- 21 F5.2 s RAs Right ascension (J2000.0) 23 A1 --- DE- Declination sign (J2000.0) 24- 25 I2 deg DEd Declination (J2000.0) 27- 28 I2 arcmin DEm Declination (J2000.0) 30- 33 F4.1 arcsec DEs Declination (J2000.0) 35- 43 F9.7 d Per Period 45- 50 F6.3 mag Jmag VISTA J magnitude 52- 56 F5.3 mag e_Jmag rms uncertainty on Jmag 58- 63 F6.3 mag Ksmag VISTA Ks magnitude 65- 69 F5.3 mag e_Ksmag rms uncertainty on Ksmag 71 I1 --- Rem [1/2] Remarks (1)
Note (1): Remarks as follows: 1 = variability recovered in our data 2 = variability not recovered in our data
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Oct-2017
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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