J/AJ/124/234 M31 outer halo UBVRI photometry and metallicity (Reitzel+, 2002)
Metallicity and kinematics of M31's outer stellar halo from a Keck spectroscopic survey. Reitzel D.B., Guhathakurta P. <Astron. J. 124, 234 (2002)> =2002AJ....124..234R
ADC_Keywords: Spectroscopy ; Stars, giant ; Photometry, UBVRI ; Abundances, [Fe/H] Keywords: galaxies: formation - galaxies: individual (M31) Abstract: We present first results from a spectroscopic survey designed to examine the metallicity and kinematics of individual red giant branch stars in the outer halo of the Andromeda spiral galaxy (M31). This study is based on multislit spectroscopy with the Keck II 10m telescope and Low Resolution Imaging Spectrograph of the Ca II near-infrared triplet in 99 M31 halo candidates in a field at R=19kpc on the southeast minor axis with brightnesses from 20<I<22. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 67 112 Astrometry and photometry for M31 spectroscopic targets and control sample table3.dat 62 112 Spectroscopic results for M31 targets and control sample
See also: J/AJ/96/1884 : BVRJHK photometry of M31 red supergiants (Humphreys+ 1988) J/AJ/109/2480 : VI photometry of late-type stars in M31. I. (Brewer+ 1995) J/ApJ/501/153 : VRB photometry of red supergiants (Massey 1998) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 A5 --- [RG2002] Object identification (G1) 7 A1 --- f_[RG2002] [*] Flag on [RG2002] (G2) 9- 10 I2 h RAh Hour of Right Ascension (J2000) 12- 13 I2 min RAm Minute of Right Ascension (J2000) 15- 19 F5.2 s RAs Second of Right Ascension (J2000) 21 A1 --- DE- Sign of Declination (J2000) 22- 23 I2 deg DEd Degree of Declination (J2000) 25- 26 I2 arcmin DEm Arcminute of Declination (J2000) 28- 31 F4.1 arcsec DEs Arcsecond of Declination (J2000) 33- 37 F5.2 mag Umag The U-band magnitude from Reitzel et al. (1998AJ....116..707R) study (3) 39- 43 F5.2 mag Bmag The B-band magnitude from Reitzel et al. (1998AJ....116..707R) study 45- 49 F5.2 mag Vmag The synthesized V-band magnitude (4) 51- 55 F5.2 mag Rmag The R-band magnitude from Reitzel et al. (1998AJ....116..707R) study 57- 61 F5.2 mag Imag The I-band magnitude from Reitzel et al. (1998AJ....116..707R) study 63- 66 F4.2 mag B-I The (B-I) color from Reitzel et al. (1998AJ....116..707R) study
Note (3): 26 objects in the main M31 spectroscopic target sample and 1 control sample object have U>Ulim, where Ulim=25.60 is the 3 σ limiting magnitude, and were treated as U upper limits in the UBRI-based selection process in the RGG study. Of the 29 objects comprising the secure M31 sample, 11 have U>Ulim and 2 of the 11 are red intermediate-velocity stars. Note (4): Synthesized from apparent B magnitude and B-I color of each object, using the relation between V-I and B-I colors for model stellar isochrones (Bergbusch & VandenBerg, 2001ApJ...556..322B).
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 5 A5 --- [RG2002] Object identification (G1) 7 A1 --- f_[RG2002] [*] Flag on [RG2002] (G2) 9- 12 I4 km/s VHel ? The heliocentric velocity 14- 18 F5.2 --- r-TD ? Cross-correlation peak significance from Tonry & Davis (1979AJ.....84.1511T) (3) 20- 25 F6.2 --- A-CCF ? Area under cross-correlation peak (4) 27- 31 F5.2 0.1nm S-Ca-CCF ? Effective weighted sum of equivalent widths of Ca II absorption-line triplet (5) 33- 37 F5.2 0.1nm W' ? Reduced Ca II line-strength index (6) 39- 44 F6.2 [Sun] Fe/H-ZW ? Spectroscopic metallicity estimate on Zinn & West (1984ApJS...55...45Z) scale (7) 46 A1 --- u_Fe/H-ZW [u] Uncertainty flag on Fe/H-ZW (8) 48- 52 F5.2 [Sun] Fe/H-CG97 ? Spectroscopic metallicity estimate on Carretta & Gratton (1997, Cat. J/A+AS/121/95) scale (7) 54 A1 --- u_Fe/H-CG97 [u] Uncertainty flag on Fe/H-CG97 (8) 56- 60 F5.2 [Sun] Fe/H-phot ? Photometric metallicity estimate (9) 62 A1 --- u_Fe/H-phot [u] Uncertainty flag on Fe/H-phot (8)
Note (3): rTD=h/(sqrt(2)*σCCF), where h is the height of the CCF peak and σCCF is the rms noise in the CCF. For 80 of the 99 objects comprising the main sample of M31 targets and all 13 control objects, there is an unambiguous peak in the CCF from which h is calculated; for the 19 targets for which there is no clear peak in the CCF, the highest point in the CCF is used to determine h, and they are excluded from further spectroscopic analysis. Note (4): Area under cross correlation peak, within ±225km/s of it, relative to a linear baseline fit; see section 4.2.2 for explanations. Note (5): Determined from empirical scaling of A-CCF (Section 4.2.2). Note (6): Corrected to a common value of log(g) and Teff for main M31 spectroscopic target sample only (section 4.2.2). Note (7): From Rutledge et al. (1997, Cat. J/PASP/109/883) for main sample only (section 4.2.2). Note (8): Represent extrapolations well beyond the calibrated range (by >0.5dex) and should be treated as highly uncertain. Note (9): Based on Bergbusch & VandenBerg (2001ApJ...556..322B) model isochrones and two high metallicity Padova (Girardi et al., 2000, Cat. J/A+AS/141/371) model isochrones (section 4.1.1).
Global notes: Note (G1): Object ID key is a single letter prefix (`t'/`c' for main sample of M31 targets/control sample), mask number (1-5), period, and slit number. Note (G2): *: Member of secure sample of M31 red giants: 25 stars with v←220km/s and 4 red (B-I>2) stars with -220<v←160km/s (section 3.2).
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 09-Sep-2002
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