J/A+A/693/L2 Properties of LRDs (Perger+, 2025)
Deep silence: Radio properties of little red dots.
Perger K., Fogasy J., Frey S., Gabanyi K.E.
<Astron. Astrophys. 693, L2 (2025)>
=2025A&A...693L...2P 2025A&A...693L...2P (SIMBAD/NED BibCode)
ADC_Keywords: Radio sources ; Active gal. nuclei ; Redshifts
Keywords: methods: data analysis galaxies: active - galaxies: high-redshift -
galaxies: star formation
Abstract:
To investigate the radio properties of the recently found
high-redshift population, we collected a sample of 919 little red dots
(LRDs) from the literature. By cross-matching their coordinates with
the radio catalogues based on the first- and second-epoch observations
of the Very Large Array Sky Survey (VLASS) and the Faint Images of the
Radio Sky at Twenty-centimeters (FIRST) survey, we found no radio
counterparts coinciding with any of the LRDs. To uncover possible
sub-mJy level weak radio emission, we performed mean and median image
stacking analyses of empty-field 'Quick Look' VLASS and FIRST image
cutouts centred on the LRD positions. We found no radio emission above
3 sigma noise levels (∼11 and ∼18uJy/beam for the VLASS and FIRST
maps, respectively) in either of the stacked images for the LRD
sample, while the noise levels of the single-epoch images are
comparable to those found earlier in the stacking of high-redshift
radio-quiet active galactic nuclei (AGNs). The non-detection of radio
emission in LRDs suggests these sources host weaker (or no) radio
AGNs.
Description:
The list of the selected LRDs from the literature at declinations
d>-40deg for the radio cross-match and stacking analyses.
The columns are: source identifier (ID) from the published papers
where they were presented, right ascension and declination coordinates
in decimal degrees, spectroscopic and/or photometric redshifts when
available, references to main discovery and analysis papers using
SAO/NASA Astrophysics Data System (https://ui.adsabs.harvard.edu/,
ADS) bibliographic identifiers. Additional information is provided in
the 'notes' column when either of the redshift values was collected
from an individual publication.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stacked.dat 109 919 List of the selected little red dots (LRDs)
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Byte-by-byte Description of file: stacked.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Source identifier from the discovery paper
18- 30 F13.9 deg RAdeg Right ascension (J2000)
32- 44 F13.9 deg DEdeg Declination (J2000)
46- 52 F7.5 --- zspec ? Spectroscopic redshift
54- 58 F5.2 --- zphot ? Photometric redshift
60- 78 A19 --- Ref Bibcode
80-109 A30 --- Notes Notes
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Acknowledgements:
Krisztina Perger, perger.krisztina(at)csfk.org
(End) Patricia Vannier [CDS] 05-Dec-2024