J/AJ/162/199 UV photometry of 548 variables stars in M31 (Leahy+, 2021)
Far-ultraviolet variables in M31: concentration in spiral arms and association
with young stars.
Leahy D.A., Buick M., Postma J.E.
<Astron. J., 162, 199-199 (2021)>
=2021AJ....162..199L 2021AJ....162..199L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable; Photometry, ultraviolet
Keywords: Andromeda galaxy; Ultraviolet astronomy; Ultraviolet surveys
Early-type variable stars
Abstract:
The Andromeda galaxy (M31) is an object of ongoing study with the
Ultraviolet Imaging Telescope (UVIT) on AstroSat. Field 2, which is
6.4kpc in diameter at the distance of M31, includes a substantial part
of the NE spiral arms of the galaxy. We have obtained a second
observation of Field 2 with the far-ultraviolet (FUV) F148W (148nm)
filter, separated from the first observation by 1465 days. Both
observations are analyzed to detect sources that are variable at a
>3σ confidence level. For sources with less than ∼2" separation,
we apply multi-Gaussian fits, to obtain reliable magnitudes in the
presence of source crowding. The variable sources are found to be
concentrated in the spiral arms, with fraction of variable to
nonvariable sources ∼2 times higher than for interarm regions,
indicating an association of FUV variables with young stellar
populations. UVIT FUV-NUV color-magnitude diagrams confirm the
association of FUV variables with young massive/hot stars. Using
existing catalogs, we obtain counterparts for 64 of the 82 most
variable sources (>5σ). The counterparts include 13 star
clusters, three ionized hydrogen (HII) regions, three novae, one S
Doradus star, eight eclipsing binaries, 20 foreground sources, two
regular variables, and 14 unspecified variables.
Description:
Ultraviolet Imaging Telescope (UVIT) observed M31 in FUV and NUV,
covering the galaxy in nineteen 28' diameter fields with a ∼1" spatial
resolution. UVIT Field 2 was observed in the F148W, F172M, N219M and
N279N filters near the beginning of the observing project, in F172M in
2019, and in F148W in 2020. We call these three time periods
Observation A, Observation B, and Observation C, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 78 548 Photometry for >3σ variable FUV sources
measured in UVIT Field 2
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
J/ApJ/759/11 : Wolf-Rayet content of M31 (Neugent+, 2012)
J/ApJS/199/37 : GALEX catalog of star clusters in M31 (Kang+, 2012)
J/ApJ/786/130 : Catalog of M31 SNR candidates (Lee+, 2014)
J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015)
J/ApJ/836/64 : Luminous variable stars in M31 & M33. IV. (Humphreys+, 2017)
J/AJ/156/241 : First catalog variable stars measured by ATLAS (Heinze+, 2018)
J/A+A/630/A92 : The Hubble Catalog of Variables (Bonanos+, 2019)
J/ApJS/247/47 : Ultraviolet survey of M31 with UVIT on AstroSat (Leahy+, 2020)
J/ApJS/250/23 : AstroSat/UVIT and Chandra X-ray sources in M31 (Leahy+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.5 deg RAdeg [10.7/11.4] Right Ascension (J2000)
10- 17 F8.5 deg DEdeg [41.3/41.9] Declination (J2000)
19- 23 F5.2 mag F148W-A [16.8/25.6]? Apparent A observation F148W AB mag
25- 28 F4.2 mag e_F148W-A [0.03/0.6]? Uncertainty in F148W-A
30- 34 F5.2 mag F148W-C [16.9/32.1]? Apparent C observation F148W AB mag
36- 39 F4.2 mag e_F148W-C [0.03/6]? Uncertainty in F148W-C
41- 45 F5.2 mag F148WSi [3.01/19.2]? Variability σ in F148W
47- 51 F5.2 mag N279N-A [15.4/25.1]? Apparent A observation N279N AB mag
53- 56 F4.2 mag e_N279N-A [0.03/1]? Uncertainty in N279N-A
58- 62 F5.2 mag N219M-A [16.7/25.7]? Apparent A observation N219M AB mag
64- 67 F4.2 mag e_N219M-A [0.04/1.1]? Uncertainty in N219N-A
69- 73 F5.2 mag F172M-A [17.8/26.4]? Apparent A observation F172W AB mag
75- 78 F4.2 mag e_F172M-A [0.05/1.8]? Uncertainty in F172M-A
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 11-Jan-2022