J/AJ/158/51 VR CCD photometry of variable stars in the GC NGC 4147 (Lata+, 2019)
VR CCD photometry of variable stars in the globular cluster NGC 4147.
Lata S., Pandey A.K., Pandey J.C., Yadav R.K.S., Pandey S.B., Gupta A.,
Bangia T., Chand H., Jaiswar M.K., Joshi Y.C., Joshi M., Kumar B.,
Kumar T.S., Medhi B.J., Misra K., Nanjappa N., Pant J., Purushottam,
Reddy B.K., Sahu S., Sharma S., Uddin W., Yadav S.
<Astron. J., 158, 51-51 (2019)>
=2019AJ....158...51L 2019AJ....158...51L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, VRI ;
Stars, distances ; Proper motions ; Abundances, [Fe/H] ;
Effective temperatures
Keywords: globular clusters: general - stars: variables: RR Lyrae
Abstract:
We present results of a search for variable stars in a region of the
globular cluster NGC 4147 based on photometric observations with a 4Kx4K
CCD imager mounted at the axial port of the recently installed 3.6 m
Devasthal optical telescope (DOT) at Aryabhatta Research Institute of
Observational Sciences (ARIES), Nainital, India. We performed time series
photometry of NGC 4147 in the V and R bands, and identified 42 periodic
variables in the region of NGC 4147, 28 of which have been detected for
the first time. Seventeen variable stars are located within the half-light
radius ~<0.48', of which 10 stars are newly identified variables. Two
of the 10 variables are located within the core radius ~<0.09'. Based
on their location in the V/(V-R) color-magnitude diagram and variability
characteristics, seven, eight, five, and one newly identified probable
member variables are classified as RRc, EA/E, EW, and SX Phe, respectively.
The metallicity of NGC 4147 estimated from the light curves of RRab and
RRc stars with the help of Fourier decomposition is found to be
characteristic of Oosterhoff II. The distance derived using the light
curves of RRab stars is consistent with that obtained from the observed
V/(V-R) color-magnitude diagram.
Description:
The CCD observations were carried using the 3.6 m DOT (f/9 Alt-azimuth
mounting) at ARIES, Devasthal (Nainital), India. The telescope is equipped
with a 4kx4k CCD imager, which is mounted on the main port of the
telescope. The CCD imager has a pixel size of 15 µm and a plate scale
of 0.095 arcsec per pixel, covering an approximately 6.23x6.23 arcmin2
field of view over the sky. The observations were taken in 4x4 binning
mode with 1000 kHz readout. We made observations in the V and R bands
on six nights between 2017 March 23 and April 9. In total, we collected
339 and 302 frames in the V and R bands, respectively. The exposure times
vary from 30 to 50 s. The FWHM of the observations varies between ∼0.7"
and 1.0". The sky brightness was found to be high due to the bright Moon
on two nights. Bias and twilight flats were also taken along with the
target field.
Objects:
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RA (ICRS) DE Designation(s)
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12 10 06.15 +18 32 31.8 NGC 4147 = GCl 18
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 89 42 The photometric data, period, amplitude, radial
distance, and classification of 42 variables
in the region of NGC 4147
table3.dat 65 42 Membership probabilities of variable stars
detected in the present work
table4.dat 111 44 The Fourier light-curve fitting parameters
of individual RRab, RRc, and other variables
table5.dat 28 23 The physical parameters of RRab and RRc
variables
fig5.dat 32 4860 The phased light curves of known variable stars
in V and R bands
fig6.dat 32 14173 The phased light curves of newly identified
variable stars in V and R bands
fig7.dat 32 1574 The phased light curves of V1, V6, V7 and V12
in V and R bands
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+AS/142/373 : Proper motions and BVRI photometry in NGC 4147
(Wang+, 2000)
J/other/RMxAA/40.209 : VR light curves of 15 RR Lyrae in NGC 4147
(Arellano+ 2004)
J/PASP/117/1325 : BVRI photometry in NGC4147 (Stetson+, 2005)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 A1 --- --- [V]
2- 3 I2 --- Num [1/47] Identification number of variable
(Cl* NGC 4147 SAW VNN for V1-V17,
LPP2019] VNN for V20-V47 in Simbad)
5- 15 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000)
17- 26 F10.7 deg DEdeg Declination in decimal degrees (J2000)
28- 33 F6.3 mag Vmag [13.436/19.419]?=- V band magnitude
35- 40 F6.4 mag e_Vmag [0.0054/0.0805]?=- Uncertainty in Vmag
42- 46 F5.3 mag V-R [0.044/1.026]?=- The (V-R) color index
48- 53 F6.4 mag e_V-R [0.0086/0.122]?=- Uncertainty in V-R
55- 59 F5.3 arcmin r [0.047/3.209] Radial distance
61- 65 F5.3 mag AmpV [0.063/1.17]?=- Amplitude in V band
67- 71 F5.3 mag AmpR [0.062/1.319]?=- Amplitude in R band
73- 80 F8.6 d Per [0.104889/0.609663] Period
82- 87 A6 --- Class Classification of variable
89 I1 --- Fig [5/7] fig.dat file number containing V and R
light curves (column added by the CDS)
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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 A1 --- --- [V]
2- 3 I2 --- Num [1/47] Identification number of variable
5- 10 F6.2 mas/yr pmRAW [-29.43/12.4]?=- Proper motion along RA from
Wang et al. (2000, J/A+AS/142/373) (pmRA*cosDE)
12- 17 F6.2 mas/yr pmDEW [-25.17/25.38]?=- Proper motion along DE from
Wang et al. (2000, J/A+AS/142/373)
19- 22 F4.2 --- Prob1 [0/0.98]?=- Membership probability
24- 30 F7.3 mas/yr pmRAG [-17.932/1.334]?=- Proper motion along RA from
Gaia astrometric mission (pmRA*cosDE)
32- 37 F6.4 mas/yr e_pmRAG [0.078/2.635]?=- Uncertainty in pmRAG
39- 44 F6.3 mas/yr pmDEG [-4.062/2.378]?=- Proper motion along DE from
Gaia astrometric mission
46- 50 F5.3 mas/yr e_pmDEG [0.071/2.101]?=- Uncertainty in pmDEG
52- 55 F4.2 --- Prob2 [0/0.98]?=- Membership probability
57- 61 F5.3 --- Pgeom [0.167/1] Geometric membership probability (1)
63- 65 A3 --- Memb Member star (=1) or nonmember (=0)
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Note (1): The geometric membership probabilities of stars were calculated using
the relation Pgeom=1-πr2/S given by Rozyczka et al.
(2017AcA....67..203R 2017AcA....67..203R), where r is the radial distance from the cluster center
in arcseconds and S is the size of the field of view in arcsec2. The value
of S is taken as 139726.644 arcsec2.
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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- 6 A6 --- Class Type of variable (RRab, RRc or Others)
8 A1 --- --- [V]
9- 10 I2 --- Num [1/47] Identification number of variable
12 I1 --- m_Num [1/2]? Component of Num
14 A1 --- Band [VR] Band
16- 21 F6.3 --- A0 [13.445/19.35] Fundamental Fourier coefficient
A0
23- 27 F5.3 --- e_A0 [0.001/0.026] Uncertainty in A0
29- 33 F5.3 --- A1 [0.015/0.407] First order Fourier coefficient A1
35- 39 F5.3 --- e_A1 [0.001/0.042] Uncertainty in A1
41- 45 F5.3 --- R21 [0.031/0.611] R21=A2/A1 Fourier coefficient
47- 51 F5.3 --- e_R21 [0.007/0.161] Uncertainty in R21
53- 57 F5.3 --- R31 [0.024/0.605] R31=A3/A1 Fourier coefficient
59- 63 F5.3 --- e_R31 [0.006/0.123] Uncertainty in R31
65- 69 F5.3 --- R41 [0.012/0.28] R41=A4/A1 Fourier coefficient
71- 75 F5.3 --- e_R41 [0.007/0.126] Uncertainty in R41
77- 81 F5.3 --- psi21 [1.002/5.722] ψ21 Fourier coefficient
83- 87 F5.3 --- e_psi21 [0.024/1.439] Uncertainty in psi21
89- 93 F5.3 --- psi31 [1.042/5.249] ψ31 Fourier coefficient
95- 99 F5.3 --- e_psi31 [0.031/1.748] Uncertainty in psi31
101-105 F5.3 --- psi41 [1.051/5.244] ψ41 Fourier coefficient
107-111 F5.3 --- e_psi41 [0.04/1.62] Uncertainty in psi41
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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 --- Class Type of variable (RRab or RRc)
6 A1 --- --- [V]
7- 8 I2 --- Num [1/42] Identification number of variable
10 I1 --- m_Num [1/2]? Component of Num
12- 17 F6.3 [-] [Fe/H] [-2.15/-0.737] Metallicity
19- 22 F4.2 mag VMag [0.74/0.85]?=- Absolute V band magnitude
24- 28 F5.3 [K] logTeff [3.776/3.793]?=- Log effective temperature
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Byte-by-byte Description of file: fig5.dat fig6.dat fig7.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Num [1/47] Variable identifier
4 A1 --- Filt [VR] Filter
6- 19 F14.6 d HJD Heliocentric Julian Date
21- 26 F6.3 mag mag [13.27/19.757] Apparent magnitude in Filt
28- 32 F5.3 mag e_mag [0.002/0.217]?=9.999 Uncertainty in mag
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 13-Sep-2019