A Massive Gas Outflow Outside the Line-of-Sight: Imaging Polarimetry of the Blue Excess Hot Dust Obscured Galaxy W0204-0506

Abstract

(Aims) Hot Dust Obscured Galaxies (Hot DOGs) are a population of hyper-luminous, heavily obscured quasars. Although nuclear obscurations close to Compton-thick are typical, a fraction show blue UV spectral energy distributions consistent with unobscured quasar activity, albeit two orders of magnitude fainter than expected from their mid-IR luminosity. The origin of the UV emission in these Blue excess Hot DOGs (BHDs) has been linked to scattered light from the central engine. Here we study the properties of the UV emission in the BHD WISE J020446.13-050640.8 (W0204-0506). (Methods) We use imaging polarization observations in the $R_{\mathrm{Special}}$ band obtained with the FORS2 instrument at VLT. We compare these data with radiative transfer simulations to constrain the characteristics of the scattering material. (Results) We find a spatially integrated polarization fraction of $24.7\pm 0.7$%, confirming the scattered-light nature of the UV emission of W0204-0506. The source is spatially resolved in the observations and we find a gradient in polarization fraction and angle that is aligned with the extended morphology of the source found in HST/WFC3 imaging. A dusty, conical polar outflow starting at the AGN sublimation radius with a half-opening angle $\lesssim 50\mathrm{deg}$ viewed at an inclination $\gtrsim 45\mathrm{deg}$ can reproduce the observed polarization fraction if the dust is graphite-rich. We find that the gas mass and outflow velocity are consistent with the range of values found for [OIII] outflows through spectroscopy in other Hot DOGs, though it is unclear whether the outflow is energetic enough to affect the long-term evolution of the host galaxy. Our study highlights the unique potential for polarization imaging to study dusty quasar outflows, providing complementary constraints to those obtained through traditional spectroscopic studies.

arXiv comment8 pages, 4 figures, 1 table. Submitted to A&A

References in corpus (38)

• Energy input from quasars regulates the growth and activity of black holes and their host galaxies
• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• Composite Quasar Spectra From the Sloan Digital Sky Survey
• Cosmic-Ray Rejection by Laplacian Edge Detection
• Infrared Emission from Interstellar Dust. II. The Diffuse Interstellar Medium
• Scattering by Interstellar Dust Grains: Optical and Ultraviolet
• Quasar Feedback: More Bang for Your Buck
• The dust covering factor in active galactic nuclei
• Dust in active nuclei. I. Evidence for "anomalous" properties
• Clearing Out a Galaxy
• The CatWISE2020 Catalog
• Low Resolution Spectral Templates For AGNs and Galaxies From 0.03 -- 30 microns
• An ALMA [CII] survey of 27 quasars at z>5.94
• SKIRT: an Advanced Dust Radiative Transfer Code with a User-Friendly Architecture
• Discovery of extreme [OIII]5007A outflows in high-redshift red quasars
• The First Hyper-Luminous Infrared Galaxy Discovered by WISE
• The WISSH Quasars Project I. Powerful ionised outflows in hyper-luminous quasars
• Half of the Most Luminous Quasars May Be Obscured: Investigating the Nature of WISE-Selected Hot, Dust-Obscured Galaxies
• The Nuclear Reddening Curve for Active Galactic Nuclei and the Shape of the Infra-Red to X-Ray Spectral Energy Distribution
• The Most Luminous Galaxies Discovered by WISE
• Submillimeter Follow-up of WISE-Selected Hyperluminous Galaxies
• The KMOS AGN Survey at High redshift (KASHz): the prevalence and drivers of ionised outflows in the host galaxies of X-ray AGN
• Redefining the torus: A unifying view of AGN in the infrared and sub-mm
• Dissecting the active galactic nucleus in Circinus -- I. Peculiar mid-IR morphology explained by a dusty hollow cone
• The Strikingly Uniform, Highly Turbulent Interstellar Medium of the Most Luminous Galaxy in the Universe
• Hot Dust Obscured Galaxies with Excess Blue Light: Dual AGN or Single AGN Under Extreme Conditions?
• Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions
• New High-Redshift Radio Galaxies from the MIT-Green Bank Catalog
• [OIII] Emission Line Properties in a New Sample of Heavily Reddened Quasars at $z>2$
• Hot Dust-Obscured Galaxies with Excess Blue Light
• Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Luminous Infrared Galaxy Candidates
• Spectropolarimetry of High Redshift Obscured and Red Quasars
• Fast Outflows in Hot Dust-Obscured Galaxies with Keck/NIRES
• Spectral Classification and Ionized Gas Outflows in $z\sim 2$ WISE-Selected Hot Dust-Obscured Galaxies
• Imaging Polarization of the Blue-Excess Hot Dust-Obscured Galaxy WISE J011601.41-050504.0
• Tips and Tricks in linear imaging polarimetry of extended sources with FORS2 at the VLT
• A Big Red Dot: Scattered light, host galaxy signatures and multi-phase gas flows in a luminous, heavily reddened quasar at cosmic noon
• Dissecting the active galactic nucleus in Circinus -- III. VLT/FORS2 polarimetry confirms dusty cone illuminated by a tilted accretion disc