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NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-α blobs

Kawamuro, Taiki and Schirmer, Mischa and Turner, James E. H. and Davies, Rebecca L. and Ichikawa, Kohei (2017) NuSTAR hard X-ray data and Gemini 3D spectra reveal powerful AGN and outflow histories in two low-redshift Lyman-α blobs. Astrophysical Journal, 848 (1). Art. No. 42. ISSN 1538-4357.

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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) x 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^(+3.1)_(-3.3) x 10^(23) cm^(−2) (J0113) and N_H = 6.0^(+1.4)_(-1.1) x 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.

Item Type:Article
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URLURL TypeDescription Paper
Kawamuro, Taiki0000-0002-6808-2052
Schirmer, Mischa0000-0003-2568-9994
Davies, Rebecca L.0000-0002-3324-4824
Ichikawa, Kohei0000-0002-4377-903X
Additional Information:© 2017 The American Astronomical Society. Received 2017 July 4; revised 2017 September 7; accepted 2017 September 19; published 2017 October 10. This work was financially supported by the Grant-in-Aid for JSPS fellows for young researchers (T.K.) and also for Scientific Research 40756293 (K.I.). Further financial support was provided by the Gemini Observatory (T.K.). M.S. acknowledges support by the National Aeronautics and Space Administration through Chandra Award Number GO4-15110X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Author contributions: T.K. reduced the NuSTAR and Chandra X-ray data and performed the joint spectral analysis; T.K. and M.S. wrote the manuscript; M.S. performed the analysis of the 3D spectra and led the NuSTAR, Chandra, and Gemini proposals; J.T. reduced the Gemini 3D spectra and obtained the [O iii]luminosities; and R.D. obtained the velocity, velocity dispersion, and line flux maps. M.S. thanks Claudio Ricci, Daniel Asmus, and Ai-Lei Sun for sharing their expertise on the subject. This work is based on data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by NASA. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center and the California Institute of Technology. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. Based on observations made by the Chandra X-ray Observatory, and on data obtained from the Chandra Data Archive. We also made use of the software provided by the Chandra X-ray Center (CXC) in the application packages CIAO. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).
Subject Keywords:galaxies: active – galaxies: individual (SDSS J011341.11+010608.4, SDSS J115544.59–014739.9) – X-rays: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20170924-173321511
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Official Citation:Taiki Kawamuro et al 2017 ApJ 848 42
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:81789
Deposited By: Joy Painter
Deposited On:25 Sep 2017 00:37
Last Modified:03 Oct 2019 18:47

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