Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): insights from the dark energy survey deep fields

ABSTRACT We present a sample of 706, z < 1.5 active galactic nuclei (AGNs) selected from optical photometric variability in three the Dark Energy Survey (DES) deep fields (E2, C3, and X3) over an area 4.64 deg2. construct light curves using difference imaging aperture photometry for resolved sources non-difference PSF unresolved sources, respectively, characterize significance. Our DES have mean cadence 7 d, 6-yr baseline, single-epoch depth up to g ? 24.5. Using spectral energy distribution (SED) fitting, we find 26 out total 706 variable galaxies are consistent with dwarf reliable stellar mass estimate ($M_{\ast }\lt 10^{9.5}\, {\rm M}_\odot$; median redshift 0.9). were able constrain rapid characteristic time-scales (? weeks) 15 AGN candidates (a subset our candidates) at 0.4. This is their low black hole (BH) masses. confirm low-mass nature one source high S/N spectrum. publish catalogue, curves, supplementary data, such as X-ray properties spectra, when available. measure fraction versus compare results forward model. work demonstrates feasibility identify AGNs lower BH masses fields, which may be more ‘pristine’ analogues supermassive seeds.