J/AJ/124/1464 Variable stars in Andromeda VI (Pritzl+, 2002)
The dwarf spheroidal companions to M31: variable stars in Andromeda VI.
Pritzl B.J., Armandroff T.E., Jacoby G.H., da Costa G.S.
<Astron. J. 124, 1464 (2002)>
=2002AJ....124.1464P 2002AJ....124.1464P
ADC_Keywords: Stars, variable ; Photometry, UBV
Keywords: galaxies: dwarf - galaxies: individual (Andromeda VI = Pegasus dSph) -
Local Group - RR Lyrae variable - stars: variables: general
Abstract:
We have surveyed Andromeda VI, a dwarf spheroidal galaxy companion to
M31, for variable stars by using F450W and F555W observations obtained
with the Hubble Space Telescope on 1999 October 25 and 1999 October 27
(WFPC2 instrument). A total of 118 variables were found, including 111
RR Lyrae stars, six anomalous Cepheids, and one variable that we were
unable to classify.
We find that the Andromeda VI anomalous Cepheids have properties
consistent with those of anomalous Cepheids in other dwarf spheroidal
galaxies. We revise the existing period-luminosity relations for these
variables. Further, using these and other available data, we show that
there is no clear difference between fundamental and first-overtone
anomalous Cepheids in a period-amplitude diagram at shorter periods,
unlike the RR Lyrae stars. For the Andromeda VI RR Lyrae stars, we
find that they lie close to the Oosterhoff type I Galactic globular
clusters in the period-amplitude diagram, although the mean period of
the RRab stars, <Pab≥0.588days, is slightly longer than that of the
typical Oosterhoff type I cluster. The mean V magnitude of the RR
Lyrae stars in Andromeda VI is 25.29±0.03, resulting in a distance
815±25kpc on the Lee, Demarque, & Zinn (1990ApJ...350..155L 1990ApJ...350..155L)
distance scale. This is consistent with the distance derived from the
I magnitude of the tip of the red giant branch. Similarly, the
properties of the RR Lyrae stars indicate a mean abundance for
Andromeda VI that is consistent with that derived from the mean red
giant branch color.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 118 Light-curve properties
table2.dat 30 1872 Photometry of the Variable Stars (B)
table3.dat 30 936 Photometry of the Variable Stars (V)
table4.dat 82 69 Properties of anomalous Cepheids
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- [PAJ2002] Variable name
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 15 F4.1 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 33 F5.3 d Per Period
35- 40 F6.3 mag <Vmag> ? Intensity-weighted mean F555W (V) magnitude
42- 47 F6.3 mag <Bmag> ? Intensity-weighted mean F450W (B) magnitude
49- 53 F5.3 mag - ? Magnitude-weighted B-V colour index
55- 58 F4.2 mag AV ? V amplitude
60- 63 F4.2 mag AB ? B amplitude
65- 69 F5.2 --- DlogP ? Period amplitude [ = -(0.129AB+0.088+logP) ]
71- 75 F5.2 [Sun] [Fe/H] ? Resulting metallicity
77- 91 A15 --- Class Classification
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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- 11 F11.3 d HJD Heliocentric Julian Date of observation
13- 16 A4 --- [PAJ2002] Variable identification
18- 23 F6.3 mag Bmag ?=0.0 The F450W (B band) magnitude
25- 29 F5.3 mag e_Bmag The photometric error in Bmag
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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- 11 F11.3 d HJD Heliocentric Julian Date of observation
13- 16 A4 --- [PAJ2002] Variable identification
18- 23 F6.3 mag Vmag ?=0.0 The F555W (V) band magnitude
25- 29 F5.3 mag e_Vmag The photometric error in Vmag
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- GName Galaxy name
12- 16 F5.2 mag MOD Distance modulus of the system
18- 21 F4.2 mag E(B-V) Reddening of the system (1)
23- 26 I4 --- Seq Sequential number of the star in the system (1)
27 A1 --- n_Seq [*]
29- 30 A2 --- Mode Pulsation mode (2)
32- 36 F5.3 d Per Period
38- 43 F6.3 mag <Vmag> ? Intensity-weighted mean F555W (V) magnitude
45- 50 F6.3 mag <Bmag> ? Intensity-weighted mean F450W (B) magnitude
52- 56 F5.2 mag VMAG ? Absolute V magnitude
58- 62 F5.2 mag BMAG ? Absolute B magnitude
64- 67 F4.2 mag AV ? V amplitude
69- 72 F4.2 mag AB ? B amplitude
74- 88 A15 --- Ref References (3)
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Note (1): Identification of the variables:
And VI : Seq NNN = [PAJ2002] NNN
Carina : Seq NNN = [SMS86] NNN
Draco : Numbers as in Kinemuchi et al., in ASP Conf. Ser. 259, 130
Fornax : Seq 1 = Fornax 2 V1 = [BCF85] Cluster 2 76 (in Simbad)
Other numbers: last three digits of the full IDs given in
Bersier & Wood (2002, Cat. J/AJ/123/840)
Leo I : Seq NN = [HW78] VNN, Hodge & Wright, 1978AJ.....83..228H 1978AJ.....83..228H
Leo II : Seq NNN = [SM2000] VNNN
NGC 5466: Seq 19 = Cl* NGC 5466 BBC V19,
Sculptor: Seq NNN = OGLE Scl NNNN
Sextans : Seq NN = [MFK95] VNN
Ursa Minor: Seq NNN = [NWM88] VNNN
Note (2): Pulsation mode:
F: fundamental mode
H: first-overtone mode
Note (3): References:
AJD99: Armandroff, Jacoby, & Davies, 1999AJ....118.1220A 1999AJ....118.1220A
BW02 : Bersier & Wood, 2002, Cat. J/AJ/123/840
CCN99: Corwin, Carney, & Nifong, 1999AJ....118.2875C 1999AJ....118.2875C
HW78 : Hodge & Wright, 1978AJ.....83..228H 1978AJ.....83..228H
K95 : Kaluzny et al., 1995A&AS..112..407K 1995A&AS..112..407K
K02 : Kinemuchi et al., in ASP Conf. Ser. 259, 130
LAZ86: Light, Armandroff, & Zinn, 1986AJ.....92...43L 1986AJ.....92...43L
MFK95: Mateo et al., 1995, Cat. J/AJ/110/2166
NWM88: Nemec et al., 1988AJ.....96..528N 1988AJ.....96..528N
SM00 : Siegel & Majewski, 2000, Cat. J/AJ/120/284
SMS86: Saha, Monet, & Seitzer, 1986AJ.....92..302S 1986AJ.....92..302S
ZS76 : Zinn & Searle, 1976AJ.....81..527Z 1976AJ.....81..527Z
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 08-Nov-2002