J/AJ/158/31 Kepler K2 mission fields 3-5: radio continuum survey (Tingay+, 2019)
Multi-epoch low-radio-frequency surveys of the Kepler K2 mission campaign
fields 3, 4, and 5 with the Murchison Widefield Array.
Tingay S.J., Hancock P.J.
<Astron. J., 158, 31 (2019)>
=2019AJ....158...31T 2019AJ....158...31T (SIMBAD/NED BibCode)
ADC_Keywords: Radio continuum ; Radio sources
Keywords: catalogs - galaxies: active - instrumentation: interferometers -
radio continuum: general
Abstract:
We present Murchison Widefield Array (MWA) monitoring of the Kepler K2
mission fields 3, 4, and 5 at frequencies of 155 and 186 MHz, from
observations contemporaneous with the K2 observations. This work follows
from previous MWA and Giant Metrewave Radio Telescope (GMRT) surveys
of field 1, with the current work benefiting from a range of improvements
in the data processing and analysis. We continue to build a body of
systematic low-frequency blind surveys overlapping with transient/variable
survey fields at other wavelengths, providing multiwavelength data for
object classes such as flare stars. From the current work, we detect
no variable objects at a surface density above 2x10-4 per square degree,
at flux densities of ∼500 mJy, and an observation cadence of days to weeks,
representing almost an order of magnitude decrease in the measured upper
limits compared to previous results in this part of observational parameter
space. This continues to show that radio transients at meter and
centimeter wavelengths are rare.
Description:
The Kepler K2 mission commenced in 2014, designed to use the Kepler
spacecraft with a reduced number of reaction wheels, to observe a number
of fields near the ecliptic (Howell et al. 2014, Cat. IV/34). The
parameters of the Murchison Widefield Array (MWA) observations conducted
for K2 fields 3, 4, and 5 are given in Table 1 for the period 2014
November 7 to 2015 May 28. All observations were performed in a standard
imaging mode, as described in Tingay et al. (2016, J/AJ/152/82), at
the same center frequencies of 154.88 MHz and 185.60 MHz and with the
same processed bandwidth of 30.72 MHz (24x1.28 MHz coarse channels,
each comprised of 128x10 kHz fine channels).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 64 66 Murchison Widefield Array (MWA) observation log
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See also:
VIII/100 : GaLactic and Extragalactic All-sky MWA survey (Hurley-Walker+, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
J/ApJ/755/47 : Murchison Widefield Array 110-200MHz observations
(Williams+ 2012)
J/AJ/152/82 : Radio continuum survey of Kepler K2 mission Field 1
(Tingay+, 2016)
J/A+A/598/A78 : The GMRT 150MHz all-sky radio survey (Intema+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 I10 --- MWA MWA observation identifier
12- 30 A19 --- Obs.Date UT start time of observation
(YYYY-MMM-DDThh:mm:ss)
32- 34 I3 s Texp [112/296] Exposure time
36- 40 A5 --- Target Target identifier (1)
42- 48 F7.2 MHz Freq [154.88/1855.6] Center frequency
50- 56 F7.3 deg RAdeg Right Ascension in decimal degrees (J2000)
58- 64 F7.3 deg DEdeg Declination in decimal degrees (J2000)
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Note (1): Target identifier as follows:
F3 = Field 3;
F4 = Field 4;
F5 = Field 5;
HydA = Calibrator Hydra A;
3C444 = Calibrator 3C444.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 05-Sep-2019