J/ApJ/763/32 Galactic halo RRab stars from CSS (Drake+, 2013)
Probing the outer Galactic halo with RR Lyrae from the Catalina Surveys.
Drake A.J., Catelan M., Djorgovski S.G., Torrealba G., Graham M.J.,
Belokurov V., Koposov S.E., Mahabal A., Prieto J.L., Donalek C.,
Williams R., Larson S., Christensen E., Beshore E.
<Astrophys. J., 763, 32 (2013)>
=2013ApJ...763...32D 2013ApJ...763...32D
ADC_Keywords: Stars, variable ; Stars, distances ; Photometry, SDSS ; Surveys
Keywords: galaxies: stellar content; Galaxy: formation; Galaxy: stellar content;
Galaxy: structure; stars: variables: RR Lyrae
Abstract:
We present analysis of 12227 type-ab RR Lyraes (RRLs; ∼9400 are newly
discovered) found among the 200 million public light curves in
Catalina Surveys Data Release 1. These stars span the largest volume
of the Milky Way ever surveyed with RRLs, covering ∼20000deg2 of the
sky (0°<α<360°, -22°<δ<65°) to
heliocentric distances of up to 60kpc. Each of the RRLs is observed
between 60 and 419 times over a six-year period. Using period finding
and Fourier fitting techniques we determine periods and apparent
magnitudes for each source. We find that the periods are generally
accurate to σ=0.002% in comparison to 2842 previously known RRLs
and 100 RRLs observed in overlapping survey fields. We photometrically
calibrate the light curves using 445 Landolt standard stars and show
that the resulting magnitudes are accurate to ∼0.05mag using Sloan
Digital Sky Survey (SDSS) data for ∼1000 blue horizontal branch stars
and 7788 RRLs. By combining Catalina photometry with SDSS
spectroscopy, we analyze the radial velocity and metallicity
distributions for >1500 of the RRLs. Using the accurate distances
derived for the RRLs, we show the paths of the Sagittarius tidal
streams crossing the sky at heliocentric distances from 20 to 60kpc.
By selecting samples of Galactic halo RRLs, we compare their velocity,
metallicity, and distance with predictions from a recent detailed
N-body model of the Sagittarius system. We find that there are some
significant differences between the distances and structures predicted
and our observations.
Description:
The Catalina Sky Survey began in 2004 and uses three telescopes to
cover the sky between declination δ=-75° and +65° in
order to discover near-Earth objects (NEOs) and potential hazardous
asteroids (PHAs). Each of the survey telescopes is run as separate
sub-surveys. These consist of the Catalina Schmidt Survey (CSS) and
the Mount Lemmon Survey (MLS) in Tucson Arizona, and the Siding Spring
Survey (SSS) in Siding Spring, Australia.
In this paper, we concentrate on the data taken by the CSS 0.7m
telescope between 2005 April and 2011 June. These data cover
20155deg2 in the region 0°<α<360° and
-22°<δ<65°. All these archival observations analyzed in
this work were taken during spans of 21 nights per lunation in sets of
four images separated by 10 minutes. The exposure times are typically
30s and reach objects to V=20mag, depending on seeing and sky brightness.
The objects in this catalog generally have average absolute V
magnitudes with uncertainties <0.1mag and periods accurate to better
than 0.01%.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 118 12379 Parameters of RRab stars
table2.dat 63 7760 SDSS data for CSS RRab stars
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)
J/AJ/144/114 : Radial velocities of 6 field RR Lyrae (Sesar+, 2012)
J/AJ/144/39 : Galactic RRab from the GEOS RR Lyr Survey (Le Borgne+, 2012)
J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)
J/AJ/142/187 : HST observations of 7 Pop.II variable stars (Benedict+, 2011)
J/AJ/139/2014 : BV light curves of 11 RR Lyrae (Kinman+, 2010)
J/ApJ/708/717 : Light curve templates of RR Lyrae stars (Sesar+, 2010)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/AcA/59/137 : ASAS Galactic fundamental mode RRL stars (Szczygiel+, 2009)
J/AcA/59/1 : VI light curves of LMC RR Lyrae stars (Soszynski+, 2009)
J/ApJ/678/865 : LONEOS-I RR Lyrae stars (Miceli+, 2008)
J/ApJ/678/851 : RR Lyrae survey in the Galactic Halo (Keller+, 2008)
J/AJ/136/1645 : Spectroscopy of bright QUEST RR Lyrae stars (Vivas+, 2008)
J/A+A/476/307 : Period variations in galactic RRab stars (Le Borgne+, 2007)
J/AJ/132/1202 : RR Lyrae in Northern Sky Variability Survey (Kinemuchi+, 2006)
J/AJ/132/714 : QUEST RR Lyrae survey. II. Halo overdensities (Vivas+, 2006)
J/AJ/129/267 : RR Lyrae variables in NGC 5272 (Cacciari+, 2005)
J/ApJ/598/597 : Frequency analysis of fundamental-mode RR Lyrae (Alcock+, 2003)
J/A+A/375/909 : RR Lyrae stars in the Sgr dwarf (Cseresnjes 2001)
J/ApJ/542/257 : MACHO LMC first-overtone RR Lyrae (Alcock+, 2000)
J/A+A/322/817 : Theoretical RRab light curves properties (Feuchtinger+ 1997)
J/A+A/312/111 : [Fe/H] from RR Lyrae light curves (Jurcsik+, 1996)
J/AJ/108/1016 : Kinematics of local RR lyrae stars. I. (Layden, 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [CSS_]
5- 20 A16 --- ID CSS identifier;
<[DCD2013] CSS JHHMMSS.s+DDMMSS> in Simbad
22- 30 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
32- 40 F9.5 deg DEdeg Declination in decimal degrees (J2000)
42- 46 F5.2 mag <Vmag> [11.1/20] Average V band magnitude (1)
48- 56 F9.7 d Per [0.43/0.95] Period
58- 61 F4.2 mag Amp [0.1/1.8] Amplitude of variation
63- 65 I3 --- Num [60/416] Number of photometric observations
67- 71 F5.2 kpc Dist [0.1/72.1] Heliocentric distance
73- 77 F5.3 mag Av [0.006/6.6] V band extinction (2)
79- 89 F11.5 d T0 Ephemeris MJD (η)
91-118 A28 --- AID Alternative stellar identifier (for sources
that were perviously known)
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Note (1): From the Fourier fit to the light curve.
Note (2): Based on the Schlegel, Finkbeiner & Davis (1998ApJ...500..525S 1998ApJ...500..525S)
reddening map.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [CSS_]
5- 20 A16 --- ID CSS identifier;
<[DCD2013] CSS JHHMMSS.s+DDMMSS> in Simbad
22- 26 F5.2 mag u0mag [10.1/25] Extinction corrected SDSS u band
magnitude
28- 32 F5.2 mag g0mag [10.3/25.1] Extinction corrected SDSS g band
magnitude
34- 38 F5.2 mag r0mag [11/24.7] Extinction corrected SDSS r band
magnitude
40- 44 F5.2 mag i0mag [11/24.4] Extinction corrected SDSS i band
magnitude
46- 50 F5.2 mag z0mag [11.5/22.8] Extinction corrected SDSS z band
magnitude
52- 57 F6.1 km/s Vgsr [-359/308]? Galactic standard of rest velocity (1)
59- 63 F5.2 [Sun] [Fe/H] [-3/-0.7]? Metallicity (1)
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Note (1): Based on SDSS spectra. The galactic standard of rest assumes the
solar peculiar motion of (U,V,W) = (9, 12+220, 7)km/s
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History:
From electronic version of the journal
Reference:
Drake et al. Paper II. 2013ApJ...765..154D 2013ApJ...765..154D Cat. J/ApJ/765/154
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 09-Oct-2014