N uSTAR Hard X-Ray Data and Gemini 3D Spectra Reveal Powerful AGN and Outflow Histories in Two Low-redshift Lyα Blobs

Taiki Kawamuro, Mischa Schirmer, James E.H. Turner, Rebecca L. Davies, Kohei Ichikawa

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We have shown that Lyα blobs (LABs) may still exist even at z ∼ 0.3, about seven billion years later than most other LABs known (Shirmer et al.). Their luminous Lyα and [O III] emitters at z ∼ 0.3 offer new insights into the ionization mechanism. This paper focuses on the two X-ray brightest LABs at z ∼ 0.3, SDSS J0113+0106 (J0113) and SDSS J1155-0147 (J1155), comparable in size and luminosity to "B1, " one of the best-studied LABs at z ≳ 2. Our NuSTAR hard X-ray (3-30 keV) observations reveal powerful active galactic nuclei (AGN) with L2-10 keV =(0.5-3) × 1044 erg s-1. J0113 also faded by a factor of ∼5 between 2014 and 2016, emphasizing that variable AGN may cause apparent ionization deficits in LABs. Joint spectral analyses including Chandra data constrain column densities of NH 5.1+3.13.3 ×1023 (J0113) and NH 6.0+1.41.1 × 1022 cm-2 (J1155). J0113 is likely buried in a torus with a narrow ionization cone, but ionizing radiation is also leaking in other directions, as revealed by our Gemini/GMOS 3D spectroscopy. The latter shows a bipolar outflow over 10 kpc, with a peculiar velocity profile that is best explained by AGN flickering. X-ray analysis of J1155 reveals a weakly absorbed AGN that may ionize over a wide solid angle, consistent with our 3D spectra. Extinction-corrected [O III] logluminosities are high, ∼43.6. The velocity dispersions are low, ∼100-150 km s-1, even at the AGN positions. We argue that this is a combination of high extinction hiding the turbulent gas and previous outflows that have cleared the escape paths for their successors.

Original languageEnglish
Article number42
JournalAstrophysical Journal
Volume848
Issue number1
DOIs
Publication statusPublished - 2017 Oct 10

Keywords

  • X-rays: galaxies
  • galaxies: active
  • galaxies: individual (SDSS J011341.11+010608.4, SDSS J115544.59-014739.9)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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