Deep silence: radio properties of little red dots

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 ($\sim 11$ and $\sim 18\mu$Jy~beam${}^{-1}$ 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.

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

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• SHELLQs. Bridging the Gap: JWST Unveils Obscured Quasars in the Most Luminous Galaxies at z > 6
• Primordial Black-Hole-Based Pathways to Little Red Dots
• Possible environmental quenching in an interacting little red dot pair at $z\sim 7$
• A weak Ly$\alpha$ halo for an extremely bright Little Red Dot: Indications of enshrouded SMBH growth
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• Islands of Electromagnetic Tranquility in Our Galactic core and Little Red Dots that Shelter Molecules and Prebiotic Chemistry
• Mass and Spin Growth of Very Massive Stars in Star Clusters Potentially Associated with Little Red Dots
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