The MeerKAT Absorption Line Survey Data Release 2: Wideband continuum catalogues and a measurement of the cosmic radio dipole
Journal article, 2024
We present the second data release of the MeerKAT Absorption Line Survey (MALS), consisting of wideband continuum catalogues of 391 pointings observed at L band. The full wideband catalogue covers 4344 deg2 of sky, reaches a depth of 10 μJy beam-1, and contains 971 980 sources. With its balance between survey depth and sky coverage, MALS DR2 covers five orders of magnitude of flux density, presenting a robust view of the extragalactic radio source population down to 200 μJy. Using this catalogue, we perform a measurement of the cosmic radio dipole, an anisotropy in the number counts of radio sources with respect to the cosmic background, analogous to the dipole found in the cosmic microwave background (CMB). For this measurement, we present the characterisation of completeness and noise properties of the catalogue, and show that a declination-dependent systematic affects the number density of faint sources. In the dipole measurement on the MALS catalogue, we recover reasonable dipole measurements once we model the declination systematic with a linear fit between the size of the major axis of the restoring beam and the amount of sources of each pointing. The final results are consistent with the CMB dipole in terms of direction and amplitude, unlike many recent measurements of the cosmic radio dipole made with other centimetre wavelength catalogues, which generally show a significantly larger amplitude. This result demonstrates the value of dipole measurements with deeper and more sparse radio surveys, as the population of faint sources probed may have had a significant impact on the measured dipole.
Large-scale structure of Universe
Radio continuum: galaxies
Galaxies: statistics
Surveys
Author
Jonah D. Wagenveld
Max Planck Society
H. R. Klockner
Max Planck Society
N. Gupta
Inter-University Centre for Astronomy and Astrophysics
S. Sekhar
National Radio Astronomy Observatory Socorro
P. Jagannathan
National Radio Astronomy Observatory Socorro
Partha P. Deka
Inter-University Centre for Astronomy and Astrophysics
J. Jose
ThoughtWorks Technologies India
S. Balashev
Russian Academy of Sciences
D. Borgaonkar
Inter-University Centre for Astronomy and Astrophysics
A. Chatterjee
ThoughtWorks Technologies India
F. Combes
Paris Observatory
K.L. Emig
National Radio Astronomy Observatory Socorro
Paris Observatory
Collège de France
A. N. Gaunekar
ThoughtWorks Technologies India
M. Hilton
University of Witwatersrand
University of KwaZulu-Natal
G. I.G. Józsa
Rhodes University
Max Planck Society
D. Klutse
University of KwaZulu-Natal
K. Knowles
Rhodes University
J. K. Krogager
University of Chile (UCH)
Université de Lyon
E. Momjian
National Radio Astronomy Observatory Socorro
Sebastien Muller
Chalmers, Space, Earth and Environment, Onsala Space Observatory
S. Sikhosana
University of KwaZulu-Natal
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 690 A163Subject Categories
Subatomic Physics
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202450291
Related datasets
URI: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ A+A/690/A163