Obscured AGN at z < 1.5: X-ray to Far-Infrared SEDs and Host Galaxy Morphologies in the GOODS Fields

William W. H. Jarvis, Connor Auge, David Sanders, Xuheng Ding, Jeana Kim-Bolt, C. Megan Urry, Eric Hooper, Alessandro Peca, Aritra Ghosh, Chuan Tian, Tonima T. Ananna, Md Mahmudunnobe

First listed 2026-01-29 | Last updated 2026-01-29

Abstract

We present an analysis of spectral energy distributions (SEDs), galaxy light profiles, and visual morphological classifications for 194 X-ray luminous AGN (intrinsic absorption-corrected log10 LX(0.5 to 7 keV) less than 42.5, with a maximum of 45.2 ergs per second) at redshift z less than 1.5 in the GOODS fields. We generate X-ray to far-infrared SEDs normalized at 1 micron for all AGN and sort them according to their emission slopes in the ultraviolet and infrared. We visually classify their host galaxy morphologies and compute their bulge-to-total light ratios using the software Galaxy Shapes of Light (galight). Most (94 percent) GOODS AGN exhibit obscured SEDs, defined by diminished ultraviolet and/or mid-infrared emission, while only 6 percent show unobscured, quasar-like SEDs. Secular processes appear to play a large role in stimulating AGN emission, as only around one-third of galaxies are undergoing interactions. We also describe the morphological identification of a population of suspected post-merger spheroid galaxies with obscured ultraviolet and infrared SEDs, and distinguish them from the host galaxies of AGN with less obscuration in the ultraviolet or infrared.

Short digest

SEDs from X-ray to far-IR are assembled for 194 GOODS-N/S AGN at z < 1.5, normalized at 1 μm, and paired with visual morphologies and bulge-to-total ratios from galight. The headline result is that 94% show obscured SEDs (diminished UV and/or MIR), with only 6% quasar-like, and only around one-third of hosts display interactions, pointing to predominantly secular fueling. The authors also flag a population of suspected post-merger spheroids with obscured UV/IR SEDs, separating them from less-obscured hosts. A four-shape SED taxonomy finds nearly half in Shape 3 and differing FIR detection rates across shapes, linking obscuration patterns to dust heating and host structure.

Key figures to inspect

• Figure 1 — Intrinsic 0.5–7 keV LX histogram: verify the luminosity range probed by GOODS and how far into the low-LX regime the sample extends compared to wide fields; confirms the sample is AGN-dominated.
• Figure 2 — SED atlas (normalized at 1 μm): scan UV and MIR deficits object-by-object versus LX color-coding; note the wavelength gap with no data and how it affects perceived obscuration.
• Figure 3 — Median SED ‘shapes’: check the dominance of Shape 3 and the FIR detection fractions (≈51% vs 45% vs 12% for Shapes 3/4/5) to see how dust/ISM conditions vary with SED slope.
• Figure 4 — galight fitting flow: examine PSF testing and point-source subtraction criteria to judge B/T robustness and how nuclear light contamination was controlled.