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J/ApJ/842/60    Variable stars in Logal Group galaxies. III.    (Monelli+, 2017)

Variable stars in Local Group galaxies. III. And VII, NGC 147, and NGC 185: insight into the building blocks of the M31 halo. Monelli M., Fiorentino G., Bernard E.J., Martinez-Vazquez C.E., Bono G., Gallart C., Dall'Ora M., Stetson P.B. <Astrophys. J., 842, 60 (2017)> =2017ApJ...842...60M
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry, HST Keywords: galaxies: evolution; galaxies: halos; galaxies: stellar content; Local Group; stars: variables: RR Lyrae Abstract: We present the discovery of 1568 RR Lyrae stars in three of the most luminous M31 satellites: And VII (573), NGC 147 (177), and NGC 185 (818). We use their properties to study the formation history of Local Group spiral haloes, and in particular, to infer about the nature of their possible building blocks by comparison with available data for RR Lyrae stars in the halo and in a sample of satellites of M31 and the Milky Way. We find that the brightest satellites and the halos of both galaxies host a number of High Amplitude Short Period (HASP) RR Lyrae variable stars, which are missing in the faintest satellites. HASP variable stars have been shown by Fiorentino+ (2015ApJ...798L..12F) to be tracers of a population of stars as metal-rich as [Fe/H]~-1.5 and older than ∼10Gyr. This suggests that the metal-rich M31 and MW halo component, which manifests through the HASP phenomenon, comes from massive dwarf galaxy building blocks, as the low-mass dwarfs did not chemically enrich fast enough to produce them. All detected variable stars are new discoveries; in particular, this work presents the first detections of RR Lyrae stars in And VII. Moreover, a number of candidate Anomalous Cepheids, and binary and long-period variable stars have been detected. We provide pulsation properties (period, amplitude, mean magnitude), light curves, and time series photometry for all of the variable stars in the three galaxies. Description: The data analyzed in this work consist of archival HST images from two different GO proposals: GO 10430 (And VII, PI Armandroff) and GO 11724 (NGC 185 and NGC 147, PI Geha). The central regions of And VII were observed using the ACS camera in 2006 June. The observations span 1.29 days, and 32 and 16 images were collected in the F435W and F555W filters, respectively. Two off-center fields in NGC 147 were observed with the ACS and the WFC3 cameras in the F606W and F814W filters. The observations of NGC147 were executed between 2009 November 21 and December 2. The observations with the ACS and the WFC3 cameras in the F606W and F814W filters of NGC 185 were executed between 2010 January 14 and February 5; the time baseline spans 22.2 days. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 59 3 Summary of the main properties of the three galaxies table3.dat 54 255 Log of the observations table4.dat 63 46426 Photometry of the variable stars table5.dat 89 1604 Mean properties of the variable stars
See also: B/hst : HST Archived Exposures Catalog (STScI, 2007) J/ApJ/562/303 : Old Stellar Populations of the SMC (Dolphin+ 2001) J/MNRAS/327/918 : CaII in extragalactic red giants (Tolstoy+, 2001) J/AJ/124/1464 : Variable stars in Andromeda VI (Pritzl+, 2002) J/A+A/402/113 : (RI)c photometry of variables in M31 (Joshi+, 2003) J/AJ/127/2738 : ACS VI photometry of M31 halo RR Lyrea (Brown+, 2004) J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004) J/AJ/127/1158 : QUEST RR Lyrae Survey first catalog (Vivas+, 2004) J/AJ/138/184 : RR Lyrae in 2 fields in M31 spheroid (Sarajedini+, 2009) J/AcA/59/1 : VI light curves of LMC RR Lyrae stars (Soszynski+, 2009) J/AcA/59/137 : ASAS Galactic fundamental mode RR Lyrae (Szczygiel+, 2009) J/ApJ/708/817 : RR Lyrae variables in M32 and M31 (Fiorentino+, 2010) J/AcA/60/165 : VI light curves of SMC RR Lyrae (Soszynski+, 2010) J/AJ/141/171 : RR Lyrae stars in 6 ultra-deep fields of M31 (Jeffery+, 2011) J/AcA/61/1 : VI light curves of Galactic Bulge RR Lyrae (Soszynski+, 2011) J/A+A/539/A138 : RR Lyr variable stars in M32 (Fiorentino+, 2012) J/ApJ/745/156 : M31 Cepheids with HST/WFC3 (Riess+, 2012) J/ApJ/779/7 : M31 dSph satellites. I. Variables in And XIX (Cusano+, 2013) J/ApJ/763/32 : Galactic halo RRab stars from CSS (Drake+, 2013) J/ApJ/790/73 : Abundances of RGBs in M31 satellites (Vargas+, 2014) J/ApJ/789/147 : Star formation histories of LG dwarf galaxies (Weisz+, 2014) J/ApJ/781/22 : Region I of La Silla QUEST RR Lyrae star survey (Zinn+, 2014) J/ApJ/798/77 : Metallicity of RGB stars in 6 M31 dwarf galaxies (Ho+, 2015) J/AcA/65/233 : OGLE Magellanic Clouds anomalous Cepheids (Soszynski+, 2015) J/MNRAS/451/724 : PHAT. XIII. M31 Cepheid P-L relation (Wagner-Kaiser+, 2015) J/ApJ/829/26 : Variable stars in the field of And XXV. III. (Cusano+, 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Gal Galaxy name 8- 9 I2 h RAh Hour of right ascension (J2000) 11- 12 I2 min RAm Minute of right ascension (J2000) 14- 17 F4.1 s RAs Second of right ascension (J2000) 19 A1 --- DE- Sign of declination (J2000) 20- 21 I2 deg DEd Degree of declination (J2000) 23- 24 I2 arcmin DEm Arcminute of declination (J2000) 26- 27 I2 arcsec DEs Arcsecond of declination (J2000) 29- 33 F5.2 mag (m-M)0 [23.9/24.5] Distance modulus 35- 38 F4.2 mag e_(m-M)0 [0.09/0.1] (m-M)0 uncertainty 40- 44 F5.1 mag VMag [-14.8/-12.6] V-band absolute magnitude 46- 50 F5.3 mag e_VMag [0.1/0.2] VMag uncertainty 52- 55 F4.1 [-] [Fe/H] [-1.4/-1.1] Metallicity 57- 59 F3.1 [-] e_[Fe/H] [0.1/0.3] [Fe/H] uncertainty
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Gal Satellite identifier 8- 11 A4 --- Inst HST instrument identifier (ACS or WFC3) 13- 21 A9 --- Image Image identifier 23- 27 A5 --- Filt Filter 29- 34 F6.1 s Exp [600/1463] Exposure time 36- 45 A10 "Y/M/D" UT date of observation start time 47- 54 A8 "h:m:s" Obs.time UT time of observation start time
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Gal Name of the satellite 7 A1 --- --- [-] 8- 11 A4 --- Var Object identifier within the galaxy 13- 22 F10.4 d HJD1 ? Modified Heliocentric Julian Date of 1st filter observation of mid-exposure; HJD-2400000 24- 30 F7.3 mag mag1 [22.3/100]? HST F606W apparent magnitude; F435W for And VII 32- 37 F6.3 mag e_mag1 [0.01/10]? Uncertainty in mag1 39- 48 F10.4 d HJD2 ? Modified Heliocentric Julian Date of 2nd filter observation of mid-exposure; HJD-2400000 50- 56 F7.3 mag mag2 [22.4/100]? HST F814W apparent magnitude; F555W for And VII 58- 63 F6.3 mag e_mag2 [0.01/10]? Uncertainty in mag2
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Gal Name of the satellite 7 A1 --- --- [-] 8- 11 A4 --- Var Object identifier within the galaxy 13- 14 I2 h RAh [0/23] Hour of Right Ascension (J2000) 16- 17 I2 min RAm [26/39] Minute of Right Ascension (J2000) 19- 24 F6.3 s RAs Second of Right Ascension (J2000) 26 A1 --- DE- [+] Sign of the Declination (J2000) 27- 28 I2 deg DEd [48/50] Degree of Declination (J2000) 30- 31 I2 arcmin DEm [16/43] Arcminute of Declination (J2000) 33- 37 F5.2 arcsec DEs Arcsecond of Declination (J2000) 39- 43 F5.3 d Per [0.1/2.2]?=9.999 Period 45- 50 F6.3 mag <mag1> [24/26.6]?=99.999 HST F606W mean magnitude; F435W for And VII 52- 56 F5.3 mag Amp1 [0.09/2]?=9.999 Amplitude in 1st filter 58- 63 F6.3 mag <mag2> [23.2/26.4]?=99.999 HST F814W mean magnitude; F555W for And VII 65- 69 F5.3 mag Amp2 [0/2.1]?=9.999 Amplitude in 2nd filter 71- 75 F5.3 mag <color> [0.004/1.1]?=9.999 Mean color; mag1-mag2 77- 89 A13 --- Type Variable type (1)
Note (1): Type as follows: RRab = RR Lyrae type ab star (1048 occurrences) RRc = RR Lyrae type c star (512 occurrences) RRd = RR Lyrae type d star (8 occurrences) AC = Anomalous Cepheid (7 occurrences) AC? = Anomalous Cepheid candidate (4 occurrences) BL Her = BL Her star (1 occurrence) Ecl. Bin. = Eclipsing binary (5 occurrences) LPV = Long Period Variable star (3 occurrences) Unclassified = 16 occurrences
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-Jan-2018
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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