Hyperluminous starburst gives up its secrets

Ivison, RJ; Page, MJ; Cirasuolo, M; Harrison, CM; Mainieri, V; Arumugam, V; Dudzevičiūtė, U

doi:10.1093/mnras/stz2180

Hyperluminous starburst gives up its secrets

Ivison, RJ; Page, MJ; Cirasuolo, M; Harrison, CM; Mainieri, V; Arumugam, V; Dudzevičiūtė, U

Authors

RJ Ivison

MJ Page

M Cirasuolo

CM Harrison

V Mainieri

V Arumugam

Ugne Dudzeviciute ugne.dudzeviciute2@durham.ac.uk
PGR Student Doctor of Philosophy

Abstract

HATLAS J084933.4+021443 was identified as a dusty starburst via its rest-frame far-infrared (far-IR) emission. Multi-frequency imaging and spectroscopy revealed a cluster of four dusty galaxies at z = 2.41, covering 80 kpc. Here, we use ALMA to confirm a more distant, fifth protocluster member, and present X-ray and rest-frame optical imaging spectroscopy of the brightest, an unlensed hyperluminous IR galaxy (HyLIRG). The data reveal broad Hα and bright [N II] lines, and bright X-ray emission, characteristics that betray a Type-1 active galactic nucleus (AGN), strengthening evidence that AGN are ubiquitous amongst HyLIRGs. The accreting black hole is super massive, Mbh ≈ 2 × 109 M⊙, with little intrinsic absorption, NH ≈ 5 × 1021 cm−2. The X-ray properties suggest the accretion luminosity rivals that of the starburst, yet it is not obvious where this emerges in its panchromatic spectral energy distribution (SED). We outline three scenarios that could give rise to the observed characteristics, and how we might distinguish between them. In the first, we see the AGN through the host galaxy because of the cavity it excavates. In the others, the AGN is not co-spatial with the starburst, having been ejected via asymmetric gravitational radiation, or having evolved towards the naked quasar phase in an unseen companion.

Citation

Ivison, R., Page, M., Cirasuolo, M., Harrison, C., Mainieri, V., Arumugam, V., & Dudzevičiūtė, U. (2019). Hyperluminous starburst gives up its secrets. Monthly Notices of the Royal Astronomical Society, 489(1), 427-436. https://doi.org/10.1093/mnras/stz2180

Journal Article Type	Article
Acceptance Date	Jul 26, 2019
Online Publication Date	Aug 8, 2019
Publication Date	Oct 31, 2019
Deposit Date	Aug 13, 2019
Publicly Available Date	Aug 13, 2019
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	489
Issue	1
Pages	427-436
DOI	https://doi.org/10.1093/mnras/stz2180

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Copyright Statement
This article has been accepted for publication in the Monthly notices of the Royal Astronomical Society ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.