CLEAR: Spatially Resolved Emission Lines and Active Galactic Nuclei at $0.6<z<1.3$

Abstract

We investigate spatially-resolved emission-line ratios in a sample of 219 galaxies ($0.6<z<1.3$) detected using the G102 grism on the \emph{Hubble Space Telescope} Wide Field Camera 3, taken as part of the CANDELS Ly$\alpha$ Emission at Reionization (CLEAR) survey, to measure ionization profiles and search for low-luminosity active galactic nuclei (AGN). We analyze \OIII\ and \Hb\ emission-line maps, enabling us to spatially resolve the \OIIIHb\ emission-line ratio across the galaxies in the sample. We compare the \OIIIHb\ ratio in galaxy centers and outer annular regions to measure ionization gradients and investigate the potential of sources with nuclear ionization to host AGN. We investigate some of the individual galaxies that are candidates to host strong nuclear ionization and find that they often have low stellar mass and are undetected in X-rays, as expected for low-luminosity AGN in low-mass galaxies. We do not find evidence for a significant population of off-nuclear AGN or other clumps of off-nuclear ionization. We model the observed distribution of \OIIIHb\ gradients and find that most galaxies are consistent with small or zero gradients, but 6-16\% of galaxies in the sample are likely to host nuclear \OIIIHb\ that is $\sim$0.5~dex higher than in their outer regions. This study is limited by large uncertainties in most of the measured \OIIIHb\ spatial profiles, therefore deeper data, e.g, from deeper \textit{HST}/WFC3 programs or from \textit{JWST}/NIRISS, are needed to more reliably measure the spatially resolved emission-line conditions of individual high-redshift galaxies.

16 pages, 13 figures, 2 tables

References in corpus (23)

• The NumPy array: a structure for efficient numerical computation
• Cosmic Star Formation History
• EAZY: A Fast, Public Photometric Redshift Code
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Strong Nebular Line Ratios in the Spectra of z~2-3 Star-forming Galaxies: First Results from KBSS-MOSFIRE
• The Chandra Deep Field-South Survey: 7 Ms Source Catalogs
• Understanding Galaxy Evolution through Emission Lines
• Obscuration-dependent evolution of Active Galactic Nuclei
• AGN Emission Line Diagnostics and the Mass-Metallicity Relation up to Redshift z~2: the Impact of Selection Effects and Evolution
• The MOSDEF Survey: Optical AGN Diagnostics at z~2.3
• Nebular spectroscopy: A guide on H II regions and planetary nebulae
• Wandering Black Holes in Bright Disk Galaxy Halos
• The Limitations of Optical Spectroscopic Diagnostics in Identifying AGNs in the Low Mass Regime
• CLEAR II: Evidence for Early Formation of the Most Compact Quiescent Galaxies at High Redshift
• CLEAR: Emission Line Ratios at Cosmic High Noon
• FIGS -- Faint Infrared Grism Survey: Description and Data Reduction
• Millimetre-wave Emission from an Intermediate-Mass Black Hole Candidate in the Milky Way
• The evolution of the size-mass relation at $z$=1-3 derived from the complete Hubble Frontier Fields data set
• AGN Selection Methods Have Profound Impacts on the Distributions of Host Galaxy Properties
• CLEAR: The Evolution of Spatially Resolved Star Formation in Galaxies between $0.5\lesssim z\lesssim 1.7$ using H$\alpha$ Emission Line Maps
• CLEAR: Boosted Ly$\alpha$ Transmission of the Intergalactic Medium in UV bright Galaxies
• Detectability of Wandering Intermediate-Mass Black Holes in the Milky Way Galaxy from Radio to X-rays

Cited by in corpus (4)

• New AGN diagnostic diagrams based on the [OIII]$\lambda 4363$ auroral line
• CLEAR: High-Ionization [Ne V] $\lambda$3426 Emission-line Galaxies at $1.4<z<2.3$
• CLEAR: Survey Overview, Data Analysis and Products
• The MUSE Ultra Deep Field (MUDF). III. Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging