J/AJ/127/318 BV photometry of Andromeda II variables (Pritzl+, 2004) ================================================================================ The dwarf spheroidal companions to M31: variable stars in Andromeda II. Pritzl B.J., Armandroff T.E., Jacoby G.H., Da Costa G.S. =2004AJ....127..318P ================================================================================ ADC_Keywords: Stars, variable ; Photometry, UBV Keywords: Cepheids - galaxies: dwarf - galaxies: individual (Andromeda II) - Local Group - RR Lyrae variable - stars: variables: other Abstract: We present the results of a variable star search in Andromeda II, a dwarf spheroidal galaxy companion to M31, using Hubble Space Telescope Wide Field Planetary Camera 2 observations. Seventy-three variables were found, one of which is an anomalous Cepheid while the others are RR Lyrae stars. The anomalous Cepheid has properties consistent with those found in other dwarf spheroidal galaxies. For the RR Lyrae stars, the mean periods are 0.571 and 0.363 days for the fundamental mode and first-overtone mode stars, respectively. With this fundamental mode mean period and the mean metallicity determined from the red giant branch (<[Fe/H]>=-1.49), Andromeda II follows the period-metallicity relation defined by the Galactic globular clusters and other dwarf spheroidal galaxies. We also find that the properties of the RR Lyrae stars themselves indicate a mean abundance that is consistent with that determined from the red giants. Description: Observations of And II were taken by the HST Wide Field Planetary Camera 2 (WFPC2) as part of the GO program 6514 on 1997 August 29 and 1997 September 3, using the same orientation. Three 1200s integrations through the F555W filter and seven 1300s integrations through the F450W filter were taken during the first set of observations. Identical exposure times were used for the second set of observations, but there were four F555W and eight F450W integrations. The images were offset from the center of the dSph galaxy in order to avoid bright foreground stars. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 77 73 Light-Curve Properties table3.dat 956 15 Photometry of the Variable Stars (B-band) table4.dat 956 7 Photometry of the Variable Stars (V-band) table5.dat 81 10 Frequency of anomalous Cepheids (AC) in dwarf spheroidal galaxies refs.dat 61 18 References -------------------------------------------------------------------------------- See also: J/AJ/124/1464 : Variable stars in Andromeda VI (Pritzl+, 2002) J/AJ/127/2738 : HST photometry of Andromeda halo RR Lyrae (Brown+, 2004) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- ID Variable identification number (VNN) 5 I1 h RAh Hour of right ascension (J2000) 7- 8 I2 min RAm Minute of right ascension (J2000) 10- 14 F5.2 s RAs Second of right ascension (J2000) 15 A1 --- DE- Sign of declination (J2000) 16- 17 I2 deg DEd Degree of declination (J2000) 19- 20 I2 arcmin DEm Arcminute of declination (J2000) 22- 25 F4.1 arcsec DEs Arcsecond of declination (J2000) 27- 31 F5.3 d Period Period 33- 38 F6.3 mag Vmag Mean intensity-weighted V-band magnitude 40- 45 F6.3 mag Bmag Mean intensity-weighted B-band magnitude 47- 51 F5.3 mag B-V The magnitude weighted (B-V) color 53- 56 F4.2 mag AV The V-band amplitude 58- 61 F4.2 mag AB The B-band amplitude 63- 67 F5.2 --- DlogP ? Period shift {Delta}logP (1) 69- 73 F5.2 [Sun] [Fe/H] ? RR Lyrae [Fe/H] abundance (2) 75- 76 A2 --- Class Classification -------------------------------------------------------------------------------- Note (1): Where DlogP = -(0.129AB + 0.088 + log(Per)). Note (2): Where [Fe/H] = -8.85 (log P_ab_ + 0.15AV) - 2.60 and P_ab_ is the period of the RRab stars. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 F7.3 d HJD-2450000 Heliocentric Julian Date minus 2450000.0 9- 14 F6.3 mag V01 ?=0 Variable V01 V or B-band photometry 16- 20 F5.3 mag e_V01 The photometric error in V01 22- 27 F6.3 mag V02 ?=0 Variable V02 V or B-band photometry 29- 33 F5.3 mag e_V02 The photometric error in V02 35- 40 F6.3 mag V03 ?=0 Variable V03 V or B-band photometry 42- 46 F5.3 mag e_V03 The photometric error in V03 48- 53 F6.3 mag V04 ?=0 Variable V04 V or B-band photometry 55- 59 F5.3 mag e_V04 The photometric error in V04 61- 66 F6.3 mag V05 ?=0 Variable V05 V or B-band photometry 68- 72 F5.3 mag e_V05 The photometric error in V05 74- 79 F6.3 mag V06 ?=0 Variable V06 V or B-band photometry 81- 85 F5.3 mag e_V06 The photometric error in V06 87- 92 F6.3 mag V07 ?=0 Variable V07 V or B-band photometry 94- 98 F5.3 mag e_V07 The photometric error in V07 100-105 F6.3 mag V08 ?=0 Variable V08 V or B-band photometry 107-111 F5.3 mag e_V08 The photometric error in V08 113-118 F6.3 mag V09 ?=0 Variable V09 V or B-band photometry 120-124 F5.3 mag e_V09 The photometric error in V09 126-131 F6.3 mag V10 ?=0 Variable V10 V or B-band photometry 133-137 F5.3 mag e_V10 The photometric error in V10 139-144 F6.3 mag V11 ?=0 Variable V11 V or B-band photometry 146-150 F5.3 mag e_V11 The photometric error in V11 152-157 F6.3 mag V12 ?=0 Variable V12 V or B-band photometry 159-163 F5.3 mag e_V12 The photometric error in V12 165-170 F6.3 mag V13 ?=0 Variable V13 V or B-band photometry 172-176 F5.3 mag e_V13 The photometric error in V13 178-183 F6.3 mag V14 ?=0 Variable V14 V or B-band photometry 185-189 F5.3 mag e_V14 The photometric error in V14 191-196 F6.3 mag V15 ?=0 Variable V15 V or B-band photometry 198-202 F5.3 mag e_V15 The photometric error in V15 204-209 F6.3 mag V16 ?=0 Variable V16 V or B-band photometry 211-215 F5.3 mag e_V16 The photometric error in V16 217-222 F6.3 mag V17 ?=0 Variable V17 V or B-band photometry 224-228 F5.3 mag e_V17 The photometric error in V17 230-235 F6.3 mag V18 ?=0 Variable V18 V or B-band photometry 237-241 F5.3 mag e_V18 The photometric error in V18 243-248 F6.3 mag V19 ?=0 Variable V19 V or B-band photometry 250-254 F5.3 mag e_V19 The photometric error in V19 256-261 F6.3 mag V20 ?=0 Variable V20 V or B-band photometry 263-267 F5.3 mag e_V20 The photometric error in V20 269-274 F6.3 mag V21 ?=0 Variable V21 V or B-band photometry 276-280 F5.3 mag e_V21 The photometric error in V21 282-287 F6.3 mag V22 ?=0 Variable V22 V or B-band photometry 289-293 F5.3 mag e_V22 The photometric error in V22 295-300 F6.3 mag V23 ?=0 Variable V23 V or B-band photometry 302-306 F5.3 mag e_V23 The photometric error in V23 308-313 F6.3 mag V24 ?=0 Variable V24 V or B-band photometry 315-319 F5.3 mag e_V24 The photometric error in V24 321-326 F6.3 mag V25 ?=0 Variable V25 V or B-band photometry 328-332 F5.3 mag e_V25 The photometric error in V25 334-339 F6.3 mag V26 ?=0 Variable V26 V or B-band photometry 341-345 F5.3 mag e_V26 The photometric error in V26 347-352 F6.3 mag V27 ?=0 Variable V27 V or B-band photometry 354-358 F5.3 mag e_V27 The photometric error in V27 360-365 F6.3 mag V28 ?=0 Variable V28 V or B-band photometry 367-371 F5.3 mag e_V28 The photometric error in V28 373-378 F6.3 mag V29 ?=0 Variable V29 V or B-band photometry 380-384 F5.3 mag e_V29 The photometric error in V29 386-391 F6.3 mag V30 ?=0 Variable V30 V or B-band photometry 393-397 F5.3 mag e_V30 The photometric error in V01 399-404 F6.3 mag V31 ?=0 Variable V31 V or B-band photometry 406-410 F5.3 mag e_V31 The photometric error in V31 412-417 F6.3 mag V32 ?=0 Variable V32 V or B-band photometry 419-423 F5.3 mag e_V32 The photometric error in V32 425-430 F6.3 mag V33 ?=0 Variable V33 V or B-band photometry 432-436 F5.3 mag e_V33 The photometric error in V33 438-443 F6.3 mag V34 ?=0 Variable V34 V or B-band photometry 445-449 F5.3 mag e_V34 The photometric error in V34 451-456 F6.3 mag V35 ?=0 Variable V35 V or B-band photometry 458-462 F5.3 mag e_V35 The photometric error in V35 464-469 F6.3 mag V36 ?=0 Variable V36 V or B-band photometry 471-475 F5.3 mag e_V36 The photometric error in V36 477-482 F6.3 mag V37 ?=0 Variable V37 V or B-band photometry 484-488 F5.3 mag e_V37 The photometric error in V37 490-495 F6.3 mag V38 ?=0 Variable V38 V or B-band photometry 497-501 F5.3 mag e_V38 The photometric error in V38 503-508 F6.3 mag V39 ?=0 Variable V39 V or B-band photometry 510-514 F5.3 mag e_V39 The photometric error in V39 516-521 F6.3 mag V40 ?=0 Variable V40 V or B-band photometry 523-527 F5.3 mag e_V40 The photometric error in V40 529-534 F6.3 mag V41 ?=0 Variable V41 V or B-band photometry 536-540 F5.3 mag e_V41 The photometric error in V41 542-547 F6.3 mag V42 ?=0 Variable V42 V or B-band photometry 549-553 F5.3 mag e_V42 The photometric error in V42 555-560 F6.3 mag V43 ?=0 Variable V43 V or B-band photometry 562-566 F5.3 mag e_V43 The photometric error in V43 568-573 F6.3 mag V44 ?=0 Variable V44 V or B-band photometry 575-579 F5.3 mag e_V44 The photometric error in V44 581-586 F6.3 mag V45 ?=0 Variable V45 V or B-band photometry 588-592 F5.3 mag e_V45 The photometric error in V45 594-599 F6.3 mag V46 ?=0 Variable V46 V or B-band photometry 601-605 F5.3 mag e_V46 The photometric error in V46 607-612 F6.3 mag V47 ?=0 Variable V47 V or B-band photometry 614-618 F5.3 mag e_V47 The photometric error in V47 620-625 F6.3 mag V48 ?=0 Variable V48 V or B-band photometry 627-631 F5.3 mag e_V48 The photometric error in V48 633-638 F6.3 mag V49 ?=0 Variable V49 V or B-band photometry 640-644 F5.3 mag e_V49 The photometric error in V49 646-651 F6.3 mag V50 ?=0 Variable V50 V or B-band photometry 653-657 F5.3 mag e_V50 The photometric error in V50 659-664 F6.3 mag V51 ?=0 Variable V51 V or B-band photometry 666-670 F5.3 mag e_V51 The photometric error in V51 672-677 F6.3 mag V52 ?=0 Variable V52 V or B-band photometry 679-683 F5.3 mag e_V52 The photometric error in V52 685-690 F6.3 mag V53 ?=0 Variable V53 V or B-band photometry 692-696 F5.3 mag e_V53 The photometric error in V53 698-703 F6.3 mag V54 ?=0 Variable V54 V or B-band photometry 705-709 F5.3 mag e_V54 The photometric error in V54 711-716 F6.3 mag V55 ?=0 Variable V55 V or B-band photometry 718-722 F5.3 mag e_V55 The photometric error in V55 724-729 F6.3 mag V56 ?=0 Variable V56 V or B-band photometry 731-735 F5.3 mag e_V56 The photometric error in V56 737-742 F6.3 mag V57 ?=0 Variable V57 V or B-band photometry 744-748 F5.3 mag e_V57 The photometric error in V57 750-755 F6.3 mag V58 ?=0 Variable V58 V or B-band photometry 757-761 F5.3 mag e_V58 The photometric error in V58 763-768 F6.3 mag V59 ?=0 Variable V59 V or B-band photometry 770-774 F5.3 mag e_V59 The photometric error in V59 776-781 F6.3 mag V60 ?=0 Variable V60 V or B-band photometry 783-787 F5.3 mag e_V60 The photometric error in V60 789-794 F6.3 mag V61 ?=0 Variable V61 V or B-band photometry 796-800 F5.3 mag e_V61 The photometric error in V61 802-807 F6.3 mag V62 ?=0 Variable V62 V or B-band photometry 809-813 F5.3 mag e_V62 The photometric error in V62 815-820 F6.3 mag V63 ?=0 Variable V63 V or B-band photometry 822-826 F5.3 mag e_V63 The photometric error in V63 828-833 F6.3 mag V64 ?=0 Variable V64 V or B-band photometry 835-839 F5.3 mag e_V64 The photometric error in V64 841-846 F6.3 mag V65 ?=0 Variable V65 V or B-band photometry 848-852 F5.3 mag e_V65 The photometric error in V65 854-859 F6.3 mag V66 ?=0 Variable V66 V or B-band photometry 861-865 F5.3 mag e_V66 The photometric error in V66 867-872 F6.3 mag V67 ?=0 Variable V67 V or B-band photometry 874-878 F5.3 mag e_V67 The photometric error in V67 880-885 F6.3 mag V68 ?=0 Variable V68 V or B-band photometry 887-891 F5.3 mag e_V68 The photometric error in V68 893-898 F6.3 mag V69 ?=0 Variable V69 V or B-band photometry 900-904 F5.3 mag e_V69 The photometric error in V69 906-911 F6.3 mag V70 ?=0 Variable V70 V or B-band photometry 913-917 F5.3 mag e_V70 The photometric error in V70 919-924 F6.3 mag V71 ?=0 Variable V71 V or B-band photometry 926-930 F5.3 mag e_V71 The photometric error in V71 932-937 F6.3 mag V72 ?=0 Variable V72 V or B-band photometry 939-943 F5.3 mag e_V72 The photometric error in V72 945-950 F6.3 mag V73 ?=0 Variable V73 V or B-band photometry 952-956 F5.3 mag e_V73 The photometric error in V73 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 A10 --- Galaxy Galaxy name 13- 16 F4.1 [Sun] [Fe/H] Metallicity 18- 22 F5.1 mag VMAG Absolute V magnitude 24- 26 I3 deg PA Position angle (north to east) 28- 31 F4.2 --- ell Ellipticity (1-b/a) 33- 36 F4.1 arcmin rexp Exponential scale length 38- 40 I3 % Sur Percentage of the dSph luminosity surveyed 42- 43 I2 --- NAC Number of anomalous Cepheids (ACs) found 45- 48 F4.2 --- S Specific frequency of the AC (1) 50- 54 F5.2 --- logS Log of the specific frequency (1) 56- 59 F4.2 --- E_logS Error on logS (upper limit) (2) 61- 64 F4.2 --- e_logS ? Error on logS (lower limit) (2) 65 A1 --- f_logS [i] i for infinity 66- 81 A16 --- r_Sur References, for Sur and S, in refs.dat file -------------------------------------------------------------------------------- Note (1): S is defined as the number of ACs per 10^5^L_V{sun}_ and was calculated for only the fraction of the dSph's luminosity that was surveyed for variable stars. Note (2): The uncertainties in the logS values were determined by assuming that the number of observed ACs is subject to Poisson statistics. -------------------------------------------------------------------------------- Byte-by-byte Description of file: refs.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- Ref Reference number 4- 22 A19 --- BibCode BibCode 24- 41 A18 --- Aut Author's name 42- 61 A20 --- Com Comments -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Patricia Vannier [CDS] 16-Mar-2004