J/MNRAS/429/385 Short-period variables near Galactic Centre (Matsunaga+, 2013)
Cepheids and other short-period variables near the Galactic Centre.
Matsunaga N., Feast M.W., Kawadu T., Nishiyama S., Nagayama T., Nagata T.,
Tamura M., Bono G., Kobayashi N.
<Mon. Not. R. Astron. Soc., 429, 385-397 (2013)>
=2013MNRAS.429..385M 2013MNRAS.429..385M
ADC_Keywords: Stars, variable ; Photometry ; Stars, population II
Keywords: binaries: eclipsing - stars: variables: Cepheids - Galaxy: bulge -
Galaxy: centre - infrared: stars
Abstract:
We report the result of our near-infrared survey of short-period
variable stars (P<60d) in a field of view of 20'x30' towards
the Galactic Centre (GC). Forty-five variables are discovered and we
classify the variables based on their light-curve shapes and other
evidence. In addition to 3 classical Cepheids reported previously, we
find 16 type II Cepheids, 24 eclipsing binaries, 1 pulsating star with
P=0.265d (RR Lyr or δ Sct) and 1 Cepheid-like variable
whose nature is uncertain. Eclipsing binaries are separated into the
foreground objects and those significantly obscured by interstellar
extinction. One of the reddened binaries contains an O-type supergiant
and its light curve indicates an eccentric orbit. We discuss the
nature and distribution of type II Cepheids as well as the distance to
the GC based on these Cepheids and other distance indicators. The
estimates of R0(GC) we obtained based on photometric data agree
with previous results obtained with kinematics of objects around the
GC. Furthermore, our result gives support to the reddening law
obtained by Nishiyama and collaborators, AKs/E(H-Ks)=1.44, because a
different reddening law would result in a rather different distance
estimate.
Description:
Observations were conducted using the IRSF 1.4m telescope and the
SIRIUS camera which collects images in the J(1.25um), H(1.63um) and
Ks(2.14um) bands, simultaneously. Observations at about 90 epochs were
made between 2001 and 2008 of which the majority were obtained in 2005
and 2006.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 90 45 The catalogue of short-period variables detected
towards the GC
table3.dat 31 3707 Light variations for the catalogued variables
table7.dat 86 263 2MASS counterparts for the OGLE-III type-II Cepheids
(T2Cs) in the bulge
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AcA/61/285 : VI light curves of Galactic Bulge Cepheids (Soszynski+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [1/45] Sequential number
3 A1 --- n_Seq [*] Individual note (1)
5- 20 A16 --- 2MASS 2MASS ID (HHMMSSss+DDMMSSs)
22- 28 F7.4 deg GLON [-1/1] Galactic longitude
30- 36 F7.4 deg GLAT Galactic latitude
38- 42 F5.2 mag Jmag ?=- Mean J magnitude
44- 48 F5.2 mag Hmag ?=- Mean H magnitude
50- 54 F5.2 mag Ksmag ?=- Mean Ks magnitude
56- 59 F4.2 mag DJ ?=- Peak-to-valley amplitude in J band
61- 64 F4.2 mag DH ?=- Peak-to-valley amplitude in H band
66- 69 F4.2 mag DKs ?=- Peak-to-valley amplitude in Ks band
71- 73 I3 --- Mfl [0/777] M flag (uncertainty) (2)
75- 82 F8.5 d Per Period (3)
84- 90 A7 --- Type Variable type (4)
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Note (1): Individual notes as follows:
3 = may be either an RR Lyr or a δ Sct star
34 = seems to be a kind of Cepheid, possibly an anomalous Cepheid, but it is
unclear to which group it belongs.
Note (2): M flag shows the reasons of non-detection or the qualities of
the listed magnitudes, as follows:
0 = mean magnitude was obtained properly
3 = some measurements were affected by the detection limit leading to an
uncertain mean magnitude
7 = photometry of the object is affected by the crowding
Note (3): For eclipsing binaries except for No. 30, half the orbital periods
are listed.
Note (4): The classifications are as follows:
Cep(I) = CCEP, Type I Cepheid
Cep(II) = T2C, Type II Cepheid
Cep(?) = Cepheid ?
Ecl = eclipsing binary
RR/DS = RR Lyrae or δ Scuti star
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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- 2 I2 --- Seq [1/45] Sequential number
4- 13 F10.4 d MJD [52079.9/54545] Modified Julian date
15- 19 F5.2 mag Jmag ?=99.99 J magnitude
21- 25 F5.2 mag Hmag ?=99.99 H magnitude
27- 31 F5.2 mag Ksmag ?=99.99 Ks magnitude
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- --- [OGLE-BLG-T2CEP-]
16- 18 I03 --- OGLE OGLE BLG-T2CEP number from Soszynski et al.,
2011, Cat. J/AcA/61/285,
in Simbad
20- 29 F10.7 d Per Period
31- 46 A16 --- 2MASS 2MASS ID (HHMMSSss-DDMMSSs)
48- 53 F6.3 mag Jmag ?=99.999 2MASS J magnitude
55- 60 F6.3 mag Hmag ?=99.999 2MASS H magnitude
62- 67 F6.3 mag Ksmag ?=99.999 2MASS Ks magnitude
69- 71 A3 --- Qfl 2MASS photometric quality flags
73- 75 I3 --- Bfl 2MASS blend flags
77- 79 A3 --- Cfl 2MASS confusion flags
81- 86 F6.3 mag Dphi ?=99.999 Phase corrections Δφ to
convert 2MASS magnitudes into mean magnitudes
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-Mar-2014