J/AJ/161/120 gri photometry for 73 stars in NGC419 (Martinez-Vazquez+, 2021) ================================================================================ Short-period variability in the globular cluster NGC419 and the SMC field. Martinez-Vazquez C.E., Salinas R., Vivas A.K. =2021AJ....161..120M ================================================================================ ADC_Keywords: Clusters, globular; Stars, variable; Photometry, VRI Keywords: Globular star clusters ; Delta Scuti variable stars ; Small Magellanic Cloud ; Variable stars Abstract: Delta Scuti ({delta}Sct) stars have been extensively studied in our Galaxy but far less in extragalactic systems. Here we study the population of {delta}Sct variables in NGC419, an intermediate-age globular cluster of the Small Magellanic Cloud (SMC), using g, r, and i Gemini-S/Gemini Multi-Object Spectrograph (GMOS) time-series observations. Our goal is to study the role of such variables in the cluster extended main-sequence turnoff (MSTO). We report the discovery of 54 {delta}Sct stars and three eclipsing binaries in the NGC419 field. We find only a handful of the {delta}Sct stars at the MSTO of NGC419, while the majority are fainter, indicating that the cluster is younger (<~1.2Gyr) than previously thought. Considering their radial distribution, we identify only six {delta}Sct stars as probable members of NGC419, while the 48 remaining are likely {delta}Sct stars of the SMC field. Cluster {delta}Sct stars appear close to the red edge of the MSTO, supporting the idea that the extended MSTO has its origin in an age spread. The 48 field {delta}Sct stars represent the largest detection of {delta}Sct stars made in the SMC. The period distribution of these newly detected {delta}Sct stars (0.04day<~P<~0.15day) is similar to that detected in other systems. The amplitude distribution (0.05mag<~{Delta}r<~0.60mag) is likely biased because of the lack of low-amplitude stars. We finally use the {delta}Sct stars to calculate distances using different period-luminosity relations. The average distance moduli obtained are 18.76{+/-}0.14mag for NGC419 and 18.86{+/-}0.11mag for the SMC field, which agree with previous measurements. Description: Time-series imaging of NGC419 was obtained with the Gemini Multi-Object Spectrograph (GMOS) mounted at the Gemini-S telescope at Cerro Pachon, Chile. Observations were carried out on the nights of 2017 September 14, 22, and 27 as part of the Fast Turnaround program GS-2017B-FT-2. Observations were obtained with 2x2 binning, resulting in a pixel scale of 0.16pixel/arcsec. Images were obtained in Sloan Digital Sky Survey (SDSS) g, r, and i, with 11, 112, and 7 frames in total and exposure times of 120, 90, and 80s, respectively, reaching a signal-to-noise ratio (S/N) ~50 at the level of the main-sequence turnoff (MSTO). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table3.dat 126 73 Position and mean pulsation properties of the variables stars detected and discovered in NGC419 table4.dat 81 8050 Photometry of the variable stars in NGC 419 -------------------------------------------------------------------------------- See also: J/A+AS/122/131 : Delta Scuti rotational velocities and Teff (Solano+ 1997) J/AJ/115/193 : RR Lyrae V light curves (Layden, 1998) J/A+AS/144/469 : Delta Scuti stars (Rodriguez+, 2000) J/AJ/132/1630 : CaII spectro. in Magellanic Cloud clusters (Grocholski+, 2006) J/AJ/131/895 : Stars in the Carina dwarf spheroidal galaxy (Koch+, 2006) J/MNRAS/389/678 : Catalogue of extended objects Magellanic Clouds (Bica+, 2008) J/AJ/136/1039 : CaII index of SMC red giant branch stars (Carrera+, 2008) J/AJ/135/836 : Calcium triplet index in LMC stars (Carrera+, 2008) J/AJ/136/1703 : Ridgelines of six intermediate-age SMC clusters (Glatt+, 2008) J/ApJ/685/947 : SX Phe stars in Fornax. II. (Poretti+, 2008) J/AJ/140/328 : LMC High-amplitude delta Scuti stars (Garg+, 2010) J/AcA/60/1 : VI light curves of LMC delta Scuti stars (Poleski+, 2010) J/MNRAS/419/342 : SX Phe stars in globular clusters (Cohen+, 2012) J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013) J/AJ/145/160 : Variables LMC globular clusters. III. Reticulum (Kuehn+, 2013) J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013) J/AJ/146/141 : BV photometry of dwarf Cepheids in Carina (Vivas+, 2013) J/ApJ/780/59 : Araucaria project: eclipsing binaries in SMC (Graczyk+, 2014) J/ApJ/814/71 : Carina project IX: UBVI data Carina variables (Coppola+, 2015) J/AcA/65/233 : OGLE Magellanic Clouds anomalous Cepheids (Soszynski+, 2015) J/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015) J/MNRAS/462/4349 : Variable stars in Sculptor dSph (Martinez-Vazquez+, 2016) J/AcA/66/421 : Eclipsing binaries in the Magellanic System (Pawlak+, 2016) J/AcA/66/131 : VI light curves of SMC and LMC RR Lyrae (Soszynski+, 2016) J/MNRAS/473/3131 : VMC survey. XXVI. SMC RR Lyrae stars (Muraveva+, 2018) J/AJ/155/183 : Properties of variables in the NGC 1846 field (Salinas+, 2018) J/AJ/157/35 : Population pulsating variable stars in Sextans (Vivas+, 2019) Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- ID Variable identifier 4 A1 --- f_ID [*] Flag means A{delta} Scuti star within 2r_h_ of NGC 419 (6 occurrences) 7- 15 F9.6 deg RAdeg [16.92/17.23] Right Ascension (J2000) 17- 26 F10.6 deg DEdeg [-72.93/-72.83] Declination (J2000) 28- 32 F5.2 mag rmag [16.07/22.37] Weighted intensity-average r band magnitude (1) 34- 38 F5.2 mag gmag [16.39/22.63] Weighted intensity-average g band magnitude (1) 40- 44 F5.2 mag imag [16.07/22.43] Weighted intensity-average i band magnitude (1) 46- 49 F4.1 --- RoMS [1.6/84.6] The robust median statistic value 51- 55 F5.1 --- J [2.2/122.1] Welch-Stetson variability index 57 A1 --- Type Variable type (2) 59- 67 F9.5 d Per [0.03/251] Period 68 A1 --- u_Per [:] Uncertainty flag on Period 70- 74 F5.2 mag rint [18.8/22.5]? Intensity-averaged r band magnitude (3) 75 A1 --- u_rint [:] Uncertainty flag on rint 77 A1 --- l_Delr Limit flag on Delr 78- 81 F4.2 mag Delr [0.05/0.76]? r band amplitude 82 A1 --- u_Delr [:] Uncertainty flag on Delr 84- 88 F5.2 mag gint [18.65/22.7]? Intensity-averaged g band magnitude (3) 89 A1 --- u_gint [:] Uncertainty flag on gint 91- 94 F4.2 mag Delg [0.01/1.45]? g band amplitude 95 A1 --- u_Delg [:] Uncertainty flag on Delg 97-101 F5.2 mag iint [19.06/22.52]? Intensity-averaged i band magnitude (3) 102 A1 --- u_iint [:] Uncertainty flag on iint 104-107 F4.2 mag Deli [0/0.8]? i band amplitude 108 A1 --- u_Deli [:] Uncertainty flag on Deli 110-126 A17 --- OGLE Previous name; OGLE identifier -------------------------------------------------------------------------------- Note (1): Calculated from the individual measurements. Note (2): Types as follows: C = Cepheid (10 occurrences) D = {delta}Scuti (54 occurrences) E = Eclipsing binary (9 occurrences) Note (3): Obtained by fitting the light curves with the Layden+, 1998, J/AJ/115/193 templates. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- ID Variable identifier 5- 14 F10.4 d MJDr [58010/58024] Modified Julian Date of r band observation at mid-exposure 16- 22 F7.3 mag rmag [16.03/22.97] Apparent r band magnitude 24- 29 F6.3 mag e_rmag [0.001/0.6] Uncertainty in rmag 31- 40 F10.4 d MJDg [58010/58024]? Modified Julian Date of g band observation at mid-exposure 42- 48 F7.3 mag gmag [16.33/23.14]? Apparent g band magnitude 50- 55 F6.3 mag e_gmag [0.001/0.2]? Uncertainty in gmag 57- 66 F10.4 d MJDi [58010/58024]? Modified Julian Date of i band observation at mid-exposure 68- 74 F7.3 mag imag [15.91/23.19]? Apparent i band magnitude 76- 81 F6.3 mag e_imag [0/0.26]? Uncertainty in imag -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Coralie Fix [CDS], 26-Apr-2021