N uSTAR Hard X-Ray Data and Gemini 3D Spectra Reveal Powerful AGN and Outflow Histories in Two Low-redshift Lyα Blobs
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 {L}2{--10{keV}}=(0.5{--}3)× {10}44 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 {N}{{H}}={5.1}-3.3+3.1× {10}23 cm-2 (J0113) and {N}{{H}}={6.0}-1.1+1.4× {10}22 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] log-luminosities 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2017
- DOI:
- 10.3847/1538-4357/aa8e46
- arXiv:
- arXiv:1709.07018
- Bibcode:
- 2017ApJ...848...42K
- Keywords:
-
- galaxies: active;
- galaxies: individual: SDSS J011341.11+010608.4;
- SDSS J115544.59–014739.9;
- X-rays: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 15 pages, 17 Figures, accepted for publication in ApJ