📝 SummarXiv

Abstract

We investigate the star formation activity and black hole scaling relations in a sample of 1451 AGN hosted by dwarf galaxies at redshift 0.5 to 0.9, drawn from the VIPERS survey. The sample comprises Seyferts and LINERs identified through emission-line diagnostics, as well as IR-selected AGN based on WISE colors. Using the parameter SFRnorm, defined as the ratio of the SFR of a galaxy hosting an AGN to the median SFR of star-forming galaxies of similar stellar mass and redshift, we compare AGN hosts to a control sample of non-AGN star-forming galaxies. We examine how SFRnorm varies with AGN power ([O III] luminosity), black hole mass, local environment, and stellar population age. We also analyze the MBH-Mstar relation and the evolution of the MBH/Mstar ratio, incorporating comparisons to X-ray AGN and high-redshift quasars (z > 4). Our key findings are: (i) all AGN populations show suppressed star formation at low AGN luminosities, with SFRnorm rising above unity at different luminosity thresholds depending on AGN type; (ii) LINERs show flat SFRnorm trends with MBH, remaining broadly consistent with unity; Seyferts display a mild increase with MBH, while IR AGN show a more pronounced positive trend; (iii) LINERs exhibit older stellar populations than Seyferts; (iv) at fixed stellar mass, Seyferts host more massive black holes than LINERs, with IR AGN falling in between; (v) the MBH/Mstar ratio is elevated relative to local scaling relations and remains approximately constant with redshift, in agreement with high-z AGN; (vi) the ratio decreases with stellar mass up to log(Mstar/Msun) approximately 11, beyond which it flattens toward values consistent with those of local, inactive galaxies, with this trend clearest for Seyferts and IR AGN. These results suggest that AGN in dwarf galaxies follow diverse evolutionary pathways shaped by gas availability, feedback, and selection effects.