English

Lyman Continuum Emission from AGN at 2.3$\lesssim$z$\lesssim$3.7 in the UVCANDELS Fields

Astrophysics of Galaxies 2024-01-09 v1

Abstract

We present the results of our search for Lyman continuum (LyC) emitting AGN at redshifts 2.3\lesssimz\lesssim4.9 from HST WFC3 F275W observations in the UVCANDELS fields. We also include LyC emission from AGN using HST WFC3 F225W, F275W, and F336W found in the ERS and HDUV data. We performed exhaustive queries of the Vizier database to locate AGN with high quality spectroscopic redshifts. In total, we found 51 AGN that met our criteria within the UVCANDELS and ERS footprints. Of these 51, we find 12 AGN had \geq4σ\sigma detected LyC flux in the WFC3/UVIS images. Using space- and ground-based data from X-ray to radio, we fit the multi-wavelength photometric data of each AGN to a CIGALE SED and correlate various SED parameters to the LyC flux. KS-tests of the SED parameter distributions for the LyC-detected and non-detected AGN showed they are likely not distinct samples. However, we find that X-ray luminosity, star-formation onset age, and disk luminosity show strong correlations relative to their emitted LyC flux. We also find strong correlation of the LyC flux to several dust parameters, i.e., polar and toroidal dust emission, 6 μm\mu m luminosity, and anti-correlation with metallicity and AFUVA_{FUV}. We simulate the LyC escape fraction (fescf_{esc}) using the CIGALE and IGM transmission models for the LyC-detected AGN and find an average fescf_{esc}\simeq18%, weighted by uncertainties. We stack the LyC flux of subsamples of AGN according to the wavelength continuum region in which they are detected and find no significant distinctions in their LyC emission, although our submm detectedsub-mm\ detected F336W sample shows the brightest stacked LyC flux. These findings indicate that LyC-production and -escape in AGN is more complicated than the simple assumption of thermal emission and a 100% escape fraction. Further testing of AGN models with larger samples than presented here is needed.

Keywords

Cite

@article{arxiv.2401.03094,
  title  = {Lyman Continuum Emission from AGN at 2.3$\lesssim$z$\lesssim$3.7 in the UVCANDELS Fields},
  author = {Brent M. Smith and Rogier A. Windhorst and Harry Teplitz and Matthew Hayes and Marc Rafelski and Mark Dickinson and Vihang Mehta and Nimish P. Hathi and John MacKenty and L. Y. Aaron Yung and Anton M. Koekemoer and Emmaris Soto and Christopher J. Conselice and Ray A. Lucas and Xin Wang and Keunho J. Kim and Anahita Alavi and Norman A. Grogin and Ben Sunnquist and Laura Prichard and Rolf A. Jansen and the UVCANDELS team},
  journal= {arXiv preprint arXiv:2401.03094},
  year   = {2024}
}

Comments

21 pages, 6 figures, 3 tables. Accepted for publication in The Astrophysical Journal