J/MNRAS/495/4071 Lockman Hole region 325MHz source catalogue (Mazumder+, 2020)
Characterizing EoR foregrounds: a study of the Lockman Hole region at 325 MHz.
Mazumder A., Chakraborty A., Datta A., Choudhuri S., Roy N., Wadadekar Y.,
Ishwara-Chandra C.H.
<Mon. Not. R. Astron. Soc. 495, 4071-4084 (2020)>
=2020MNRAS.495.4071M 2020MNRAS.495.4071M (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Radio sources ; Morphology
Keywords: techniques: interferometric - surveys - galaxies: general -
diffuse radiation
Abstract:
One of the key science goals for the most sensitive telescopes, both
current and upcoming, is the detection of the redshifted 21-cm signal
from the Cosmic Dawn and Epoch of Reionization. The success of
detection relies on accurate foreground modelling for their removal
from data sets. This paper presents the characterization of
astrophysical sources in the Lockman Hole region. Using 325-MHz data
obtained from the Giant Metrewave Radio Telescope, a 6°x6°
mosaiced map is produced with an rms reaching 50uJy per beam. A source
catalogue containing 6186 sources is created, and the Euclidean
normalized differential source counts have been derived from it,
consistent with previous observations as well as simulations. A
detailed comparison of the source catalogue is also made with previous
findings - at both lower and higher frequencies. The angular power
spectrum (APS) of the diffuse Galactic synchrotron emission is
determined for three different Galactic latitudes using the tapered
gridded estimator. The values of the APS lie between ∼1 and ∼100mK2.
Fitting a power law of the form Al-β gives values of A and
β varying across the latitudes considered. This paper
demonstrates, for the first time, the variation of the power-law index
for diffuse emission at very high Galactic locations. It follows the
same trend that is seen at locations near the Galactic plane, thus
emphasizing the need for low-frequency observations for developing
better models of the diffuse emission.
Description:
Catalogue of sources detected at 325MHz in the Lockman Hole region
using the legacy GMRT archival data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 108 6186 The 325MHz source catalogue of Lockman Hole region
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- SourceId [0/6185] Sequential number
6- 15 F10.6 deg RAdeg Right Ascension of source (J2000)
17- 24 F8.6 arcsec e_RAdeg Error in Right Ascension
26- 34 F9.6 deg DEdeg Declination of sources (J2000)
36- 43 F8.6 arcsec e_DEdeg Error in Declination
45- 55 F11.6 mJy FluxTot Total source flux at 325MHz
57- 67 F11.6 mJy/beam FluxPeak Peak source flux at 325MHz
69- 76 F8.6 mJy/beam rms Island RMS
78- 87 F10.6 arcmin Maj Major axis
89- 97 F9.6 arcmin Min Minor axis
99-108 F10.6 deg PA Parallactic angle
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Acknowledgements:
Aishrila Mazumder, aishri0208(at)gmail.com
(End) Patricia Vannier [CDS] 15-Jul-2020