J/ApJ/754/4 HST monitoring of flaring stars in the Galactic bulge (Osten+, 2012)
DRAFTS: a Deep, Rapid Archival Flare Transient Search in the Galactic bulge.
Osten R.A., Kowalski A., Sahu K., Hawley S.L.
<Astrophys. J., 754, 4 (2012)>
=2012ApJ...754....4O 2012ApJ...754....4O
ADC_Keywords: Stars, flare ; Photometry, HST ; Stars, variable
Keywords: binaries: close; stars: activity; stars: flare; stars: late-type
Abstract:
We utilize the Sagittarius Window Eclipsing Extrasolar Planet Search
Hubble Space Telescope/Advanced Camera for Surveys data set for a Deep
Rapid Archival Flare Transient Search (DRAFTS) to constrain the flare
rate toward the older stellar population in the Galactic bulge. During
seven days of monitoring 229293 stars brighter than V=29.5, we find
evidence for flaring activity in 105 stars between V=20 and V=28. We
divided the sample into non-variable stars and variable stars whose
light curves contain large-scale variability. The flare rate on
variable stars is ∼700 times that of non-variable stars, with a
significant correlation between the amount of underlying stellar
variability and peak flare amplitude. The flare energy loss rates are
generally higher than those of nearby well-studied single dMe flare
stars.
Description:
The data used in this paper originally came from the Sagittarius
Window Eclipsing Extrasolar Planet Search (SWEEPS) project, described
in Sahu et al. (2006Natur.443..534S 2006Natur.443..534S). The SWEEPS field (202"x202") was
imaged continuously for seven days in 2004 February. The observations
consist of 254 exposures in V (F606W) and 265 in I (F814W), each with
an exposure time of 339s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 57 105 Properties of DRAFTS flaring stars
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJS/207/15 : M dwarf flare spectra (Kowalski+, 2013)
J/AJ/141/50 : White-light flares on Kepler cool stars (Walkowicz+, 2011)
J/AJ/140/1402 : M dwarf flares from SDSS spectra (Hilton+, 2010)
J/other/A+ARV/17.251 : Stars observed with Doppler imaging (Strassmeier, 2009)
J/ApJ/685/463 : ChaMPlane X-ray sources in the Galactic bulge (Koenig+, 2008)
J/ApJS/173/673 : M dwarf UV flares in GALEX (Welsh+, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh [17] Hour of right ascension (J2000)
4- 5 I2 min RAm [58/59] Minute of right ascension (J2000)
7- 11 F5.2 s RAs Second of right ascension (J2000)
13 A1 --- DE- [-] Sign of declination (J2000)
14- 15 I2 deg DEd [29] Degree of declination (J2000)
17- 18 I2 arcmin DEm [10/13] Arcminute of declination (J2000)
20- 24 F5.2 arcsec DEs Arcsecond of declination (J2000)
26- 30 F5.2 mag Vmag [20/28] HST/ACS F606W magnitude
32- 36 F5.2 mag Imag [18/26] HST/ACS F814W magnitude
38- 46 A9 --- Var Variability type ("flat" or
"var/irreg", "var/reg")
48- 52 F5.2 d Per [0.06/11.8]? Period of any underlying
regular variability
54- 57 F4.2 mag DAmp [0.02/2.51] Range of the amplitude (1)
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Note (1): Range is defined as the difference in amplitude between the
values in the 95th and 5th percentile in the original light curve;
see Section 4.2 for details.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 25-Feb-2014