J/A+A/402/113 (RI)c photometry of variables in M31 (Joshi+, 2003)
Identification of 13 Cepheids and 333 other Variables in M31.
Joshi Y.C., Pandey A.K., Narashimha D., Sagar R., Giraud-Heraud Y.
<Astron. Astrophys. 402, 113 (2003)>
=2003A&A...402..113J 2003A&A...402..113J
ADC_Keywords: Stars, variable ; Photometry, Cousins
Keywords: Cepheids - variable stars - M31 Galaxy - photometry
Abstract:
We present Cousins R and I band photometry of variable stars in a
∼13'x13' region in the disk of M31 galaxy, obtained during 141 nights.
Of the 26 Cepheid variables present in the region, two are newly
discovered, 11 are classified as Cepheids for the first time and 13
are confirmed as Cepheids. The extensive photometry of these Cepheids
enabled us to determine precise phase and amplitude of pulsation which
ranges from 0.11 to 0.48mag in R band. The period of variability
ranges from ∼7.5 to 56 days. The period-luminosity diagram is used to
derive a distance modulus of 24.49±0.11mag for M31 galaxy. We also
report variability in 333 other stars, of them, 115 stars appear to be
long period variables, 2 suspected eclipsing binaries and remaining
216 are irregular variables.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lc/* . 52 Cousins R and I light curves of the 26 Cepheids
table2.dat 41 141 Journal of the RI observations during the
period 1998-2002
table4.dat 101 26 List of 26 Cepheids observed in our study with
their characteristic parameters
table5.dat 64 333 The celestial coordinates of 333 variables
detected during our observations
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See also:
J/A+AS/126/401 : M 31 Cepheids periods (Magnier+ 1997)
J/AJ/115/1894 : M31A eclipsing binaries and Cepheids (Stanek+ 1998)
J/AJ/115/1016 : M31B eclipsing binaries and Cepheids (Kaluzny+ 1998)
J/AJ/117/2810 : M31C eclipsing binaries and Cepheids (Stanek+ 1999)
J/AJ/118/346 : M31D eclipsing binaries and Cepheids (Kaluzny+ 1999)
J/AJ/118/2211 : M31F eclipsing binaries and Cepheids (Mochejska+ 1999)
Byte-by-byte Description of file: lc/*
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Bytes Format Units Label Explanations
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2- 8 I7 d HJD Heliocentric Julian dat
14- 19 F6.3 mag mag Cousins R or I magnitude
26- 30 F5.3 mag e_mag rms uncertainty on mag
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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- 10 A10 "DD/MM/YYYY" Date Date of observation
14- 20 I7 --- HJD Heliocentric Julian date of observation
23- 24 I2 min ExpRc1 ? Total exposure time in Rc filter
25 A1 --- --- [x-]
26 I1 min ExpRc2 ? Total exposure time in Rc filter
29- 30 I2 min ExpIc1 ? Total exposure time in Ic filter
31 A1 --- --- [x-]
32 I1 min ExpIc2 ? Total exposure time in Ic filter
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Table 3: Internal photometric errors as a function of brightness
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Magnitude bin sigmaRc sigmaIc
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<14.0 0.01 0.01
14.0 - 15.0 0.01 0.01
15.0 - 16.0 0.01 0.01
16.0 - 17.0 0.01 0.02
17.0 - 18.0 0.02 0.04
18.0 - 19.0 0.04 0.06
19.0 - 20.0 0.07 0.13
20.0 - 21.0 0.15 0.33
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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- 3 A3 --- ID Identification of variable star in our sample
(V1 to V26)
4 A1 --- n_ID [*+] Note on ID (1)
6- 12 F7.4 deg RAdeg Right ascension in decimal degrees (J2000)
14- 21 F8.4 deg DEdeg Declination in decimal degrees (J2000)
23- 27 F5.2 mag Rcmag Mean magnitude of the star in Rc filter
29- 33 F5.2 mag Icmag Mean magnitude of the star in Ic filter
35- 38 F4.2 mag DeltaRc Change in magnitude of the star in Rc filter
40- 45 F6.3 d Per Period
47- 51 F5.3 d e_Per rms uncertainty on Per
53- 54 I2 Myr Age Age
56- 58 I3 --- o_Rcmag Number of observations on Rc filter
60- 66 A7 --- AName Other identification (2)
68- 73 F6.3 d OPer ? Period given in the catalogues
75- 77 F3.1 d e_OPer ? rms uncertainty on OPer
79- 89 A11 --- IcFile Name of the light curve file in Ic filter
91-101 A11 --- RcFile Name of the light curve file in Rc filter
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Note (1): The Cepheids discovered and classified by us are marked
as + and * respectively.
Note (2): Star identification:
K VNNNN = DIRECT VNNNN M31D,
Kaluzny et al., 1999, Cat. J/AJ/118/2211
TC NN = [TC96] NN, Tomaney & Crotts (1996AJ....112.2872T 1996AJ....112.2872T)
M NN = [MAP97] NN, Magnier et al., 1997, Cat. J/A+AS/126/401
B NNNN = [BHG88] DD NNNN,
Berkhuijsen et al. (1988, Cat. II/144 + II/145)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- ID Identificaiton of variable star in our sample
(VNNN, V27 to V359)
6- 12 F7.4 deg RAdeg Right ascension of the star (J2000)
15- 21 F7.4 deg DEdeg Declination of the star (J2000)
24- 28 F5.2 mag Rcmag Mean magnitude of the star in Rc filter
31- 35 F5.2 mag Icmag Mean magnitude of the star in Ic filter
38- 41 F4.2 mag DeltaRc Change in magnitude of the star in Rc filter
44- 50 A7 d Per Period, if it is a periodic variable
52- 57 A6 --- Type Nature of the star as given in SIMBAD catalogue
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Acknowledgements: Yogesh Chandra Joshi
(End) Patricia Bauer [CDS] 24-Mar-2003