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 journalArticlepeer-review

7 Citations (Scopus)


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
Issue number1
Publication statusPublished - 2017 Oct 10
Externally publishedYes


  • 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


Dive into the research topics of 'N uSTAR Hard X-Ray Data and Gemini 3D Spectra Reveal Powerful AGN and Outflow Histories in Two Low-redshift Lyα Blobs'. Together they form a unique fingerprint.

Cite this