English

Deep silence: radio properties of little red dots

Astrophysics of Galaxies 2024-12-25 v1

Abstract

To investigate the radio properties of the recently found high-redshift population, we collected a sample of 919919 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 3σ3\sigma noise levels (11\sim11 and 18 μ\sim18~\muJy~beam1^{-1} 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.

Keywords

Cite

@article{arxiv.2411.19518,
  title  = {Deep silence: radio properties of little red dots},
  author = {K. Perger and J. Fogasy and S. Frey and K. É. Gabányi},
  journal= {arXiv preprint arXiv:2411.19518},
  year   = {2024}
}

Comments

7 pages, 6 figures, 1 table. Accepted for publication in A&A Letters