J/ApJ/781/22 Region I of La Silla QUEST RR Lyrae star survey (Zinn+, 2014)
La Silla QUEST RR Lyrae star survey: region I.
Zinn R., Horowitz B., Vivas A.K., Baltay C., Ellman N., Hadjiyska E.,
Rabinowitz D., Miller L.
<Astrophys. J., 781, 22 (2014)>
=2014ApJ...781...22Z 2014ApJ...781...22Z (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Stars, variable ; Stars, halo ; Photometry, UBV
Keywords: galaxies: individual: Sextans - Galaxy: halo -
stars: variables: RR Lyrae - surveys
Abstract:
A search for RR Lyrae stars (RRLSs) in ∼840deg2 of the sky in right
ascension 150°-210° and declination -10° to + 10°
yielded 1013 type ab and 359 type c RRLS. This sample is used to study
the density profile of the Galactic halo, halo substructures, and the
Oosterhoff type of the halo over distances (d☉) from ∼5 to
∼80kpc. The halo is flattened toward the Galactic plane, and its
density profile steepens in slope at galactocentric distances greater
than ∼25kpc. The RRLS in the stellar stream from the Sagittarius dwarf
spheroidal (dSph) galaxy match well the model of Law & Majewski for
the stars that were stripped 1.3-3.2Gyr ago, but not for the ones
stripped 3.2-5.0Gyr ago. Over densities are found at the locations of
the Virgo Overdensity and the Virgo Stellar Stream. Within 1° of
1220-1, which Jerjen et al. identify as a halo substructure at
d☉∼24kpc, there are four RRLS that are possibly members. Away
from substructures, the RRLS are a mixture of Oosterhoff types I and
II, but mostly OoI (∼73%). The accretion of galaxies resembling in
RRLS content the most massive Milky Way satellites (LMC, SMC, For,
Sgr) may explain this preponderance of OoI. Six new RRLS and three new
anomalous Cepheids were found in the Sextans dSph galaxy.
Description:
The RR Lyrae star (RRLS) survey reported here uses the data from the
La Silla-QUEST Southern Hemisphere Variability Survey (Hadjiyska et
al., 2012IAUS..285..324H 2012IAUS..285..324H), which is primarily a survey for supernovae
(Baltay et al., 2013PASP..125..683B 2013PASP..125..683B) and trans-Neptunian objects. The
survey employs the 10deg2 QUEST camera at the prime focus of the 1m
ESO Schmidt Telescope at the La Silla Observatory in Chile. The survey
commenced observations in September of 2009 and uses 90% of the
telescope time. The camera consists of 112 CCD detectors arranged in a
4*28 array (4 rows, labeled A, B, C, and D, with 28 CCDs each). A
search for RR Lyrae stars (RRLSs) in ∼840deg2 of the sky in right
ascension 150°-210° and declination -10° to +10°
yielded 1013 type ab and 359 type c RRLS (see Table1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 73 1372 RR Lyrae stars
table2.dat 64 6 Anomalous Cepheids in the Sextans dSph galaxy
table3.dat 30 103077 The observations
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See also:
J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013)
J/MNRAS/425/1459 : RR Lyrae in M32 (Sarajedini+, 2012)
J/ApJ/756/23 : V-band photometry of RR Lyrae from SEKBO (Akhter+, 2012)
J/ApJ/708/717 : Light curve templates of RR Lyrae stars (Sesar+, 2010)
J/AcA/60/165 : VI light curves of SMC RR Lyrae (Soszynski+, 2010)
J/AcA/59/1 : VI light curves of LMC RR Lyrae stars (Soszynski+, 2009)
J/ApJ/691/306 : RR Lyrae candidates photometry in Virgo stream (Prior+, 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/132/1361 : RR Lyrae variables in M33 (Sarajedini+, 2006)
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/130/1640 : Photometry of candidate RR Lyrae stars in the SDSS (Wu+, 2005)
J/AJ/127/1158 : QUEST RR Lyrae Survey first catalog (Vivas+, 2004)
J/AJ/115/193 : RR Lyrae V light curves (Layden, 1998)
J/AJ/110/2166 : Variables in Sextans dSph galaxy (Mateo+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star [1/1378] Running identification number of the
RR Lyrae star (RRLS) in order of increasing
RAdeg (1)
6- 13 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
15- 21 F7.4 deg DEdeg Declination in decimal degrees (J2000)
23- 25 I3 --- Nobs [11/311] Number of observations used in
template fit
27- 31 F5.2 mag <Vmag> [13.7/20.6] Intensity averaged mean magnitude
in the V band
33- 36 F4.2 mag Amp [0.1/1.5] Amplitude in the V band
38- 44 F7.5 d Per [0.2/0.9] Period
46- 56 F11.5 d HJDmax [55258.5/55347.6] Heliocentric Julian Date of
maximum brightness (HJD-2400000.0)
58- 59 A2 --- Type Type of RR Lyrae variable (ab, c)
61 I1 --- C [0/1] Photometric calibration (0=good, 1=poor) (2)
63- 70 A8 --- Mm RRLS that is suspected to be member of Sextans
dSph galaxy (Sex dSph)
72- 73 A2 --- OName Variable star number in Sextans (Mateo et al.
1995, cat. J/AJ/110/2166), if available
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Note (1): The missing numbers are stars that we believe are anomalous Cepheids
(ACs) in the Sextans dSph galaxy, which are listed in Table2.
Note (2): The filter that is used in the La Silla-QUEST (LSQ) survey is
physically two identical filters that butt together. We could not calibrate
well the observations obtained with the CCDs that lie behind the filter
joint, although we could measure the periods and the light curves of the
RRLS observed with them.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Star Identification number of the Cepheid in order
of increasing RAdeg
4- 11 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
13- 19 F7.4 deg DEdeg Declination in decimal degrees (J2000)
21- 22 I2 --- Nobs Number of observations used in template fit
24- 28 F5.2 mag <Vmag> Intensity averaged mean magnitude in the V band
30- 33 F4.2 mag Amp Amplitude in the V band
35- 41 F7.5 d Per Period
43- 53 F11.5 d HJDmax Heliocentric Julian Date of maximum brightness
(HJD-2400000.0)
55- 59 F5.2 --- VMag Absolute V-band magnitude
61 A1 --- r_OName Reference for OName (1)
62- 64 I3 --- OName ? Other identification number of the variable
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Note (1): Reference codes are defined as follows:
Q = Vivas et al. 2004 (cat. J/AJ/127/1158);
V = Mateo et al.1995 (cat. J/AJ/110/2166).
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Star number in Tables 1 or 2
6- 17 F12.6 d HJD Heliocentric Julian Date of observation
(HJD-2400000.0)
19- 24 F6.3 mag Vmag The observed V-band magnitude transformed to
the standard system
26- 30 F5.3 mag e_Vmag Standard deviation of Vmag (based on photon
statistics) (1)
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Note (1): While the uncertainty in the calibration to the standard system is
larger, in general, that these standard deviations, they provided a means
for weighting the observations when fitting the template light curves.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 25-Nov-2015