Quasar SDSS J142507.32+323137.4: dual AGNs?

Peng, Zhixin; Chen, Yanmei; Gu, Qiusheng; Hu, Chen

doi:10.1088/1674-4527/11/4/004

Cited by 11 publications

(27 citation statements)

References 45 publications

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“…The value is characteristic of optically thick synchrotron jet emission from the nucleus. This is consistent with a Type 1 AGN as the primary component in this pair (Peng et al ).…”

Section: The Two Radio Components Of J1425+3231supporting

confidence: 91%

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Two in one? A possible dual radio-emitting nucleus in the quasar SDSS J1425+3231

Frey¹,

Paragi

An³

et al. 2012

Monthly Notices of the Royal Astronomical Society

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The radio‐emitting quasar SDSS J1425+3231 (z = 0.478) was recently found to have double‐peaked narrow [O iii] optical emission lines. Based on the analysis of the optical spectrum, Peng et al. suggested that this object harbours a dual active galactic nucleus (AGN) system, with two supermassive black holes (SMBHs) separated on a kpc scale. SMBH pairs should be ubiquitous according to hierarchical galaxy formation scenarios in which the host galaxies and their central black holes grow together via interactions and eventual mergers. Yet the number of presently confirmed dual SMBHs on kpc or smaller scales remains small. A possible way to obtain direct observational evidence for duality is to conduct high‐resolution radio interferometric measurements, provided that both AGN are in an evolutionary phase when some activity is going on in the radio. We used the technique of very long baseline interferometry (VLBI) to image SDSS J1425+3231. Observations made with the European VLBI Network at 1.7‐ and 5‐GHz frequencies in 2011 revealed compact radio emission at sub‐mJy flux density levels from two components with a projected linear separation of ∼2.6 kpc. These two components support the possibility of a dual AGN system. The weaker component remained undetected at 5 GHz due to its steep radio spectrum. Further study will be necessary to securely rule out a jet–shock interpretation of the less dominant compact radio source. Assuming the dual AGN interpretation, we discuss black hole masses, luminosities and accretion rates of the two components using available X‐ray, optical and radio data. While high‐resolution radio interferometric imaging is not an efficient technique to search blindly for dual AGN, it is an invaluable tool to confirm the existence of selected candidates.

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“…The value is characteristic of optically thick synchrotron jet emission from the nucleus. This is consistent with a Type 1 AGN as the primary component in this pair (Peng et al ).…”

Section: The Two Radio Components Of J1425+3231supporting

confidence: 91%

“…The broad blueshifted wing arises in its intermediate‐line region. Peng et al () estimated ∼10 8 M ⊙ for the mass of the primary SMBH. The suggested secondary black hole is smaller (∼10 6 M ⊙ ) and could be a Type 2 AGN (i.e.…”

Section: Introductionmentioning

confidence: 99%

Two in one? A possible dual radio-emitting nucleus in the quasar SDSS J1425+3231

Frey¹,

Paragi

An³

et al. 2012

Monthly Notices of the Royal Astronomical Society

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“…In particular, one such signature is the few hundred km s −1 velocity splitting observed in AGN narrow emission lines (NELs; e.g., Sargent 1972;Heckman et al 1981) such as [O III] λλ4959,5007, which is seen in ∼ 1% of low-redshift AGNs (Liu et al 2010b;Smith et al 2010;Wang et al 2009;Ge et al 2012) as well as in quasars (Shen et al 2011b). The working hypothesis is that the velocity splitting signals the projected relative orbital motion of two narrow line regions (NLRs), each ionized by its own central AGN (e.g., Zhou et al 2004;Gerke et al 2007;Comerford et al 2009a;Xu & Komossa 2009;Peng et al 2011;Barrows et al 2012). By selection, only binaries with projected angular separations smaller than the spectroscopic aperture size will be included.…”

Section: Systematic Searches For Kpc-scale Binary Agnsmentioning

confidence: 99%

CHANDRAX-RAY ANDHUBBLE SPACE TELESCOPEIMAGING OF OPTICALLY SELECTED KILOPARSEC-SCALE BINARY ACTIVE GALACTIC NUCLEI. I. NATURE OF THE NUCLEAR IONIZING SOURCES

Liu

Civano

Shen

et al. 2012

ApJ

114

165

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Kiloparsec-scale binary active galactic nuclei (AGNs) signal active supermassive black hole (SMBH) pairs in merging galaxies. Despite their significance, unambiguously confirmed cases remain scarce and most have been discovered serendipitously. In a previous systematic search, we optically identified four kpc-scale binary AGNs from candidates selected with double-peaked narrow emission lines at z = 0.1-0.2. Here we present Chandra and Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging of these four systems. We critically examine and confirm the binary-AGN scenario for two of the four targets, by combining high angular resolution X-ray imaging spectroscopy with Chandra ACIS-S, better nuclear position constraints from WFC3 F105W imaging, and direct starburst estimates from WFC3 F336W imaging; for the other two targets, the existing data are still consistent with the binary-AGN scenario, but we cannot rule out the possibility of only one AGN ionizing gas in both merging galaxies. We find tentative evidence for a systematically smaller X-rayto-[O III] luminosity ratio and/or higher Compton-thick fraction in optically selected kpc-scale binary AGNs than in single AGNs, possibly caused by a higher nuclear gas column due to mergers and/or a viewing angle bias related to the double-peak narrow line selection. While our result lends some further support to the general approach of optically identifying kpc-scale binary AGNs, it also highlights the challenge and ambiguity of Xray confirmation.

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“…Specifically, objects have been identified as dual AGN candidates because they show strongly double-peaked [O iii]5007 lines (Zhou et al 2004;Gerke et al 2007;Peng et al 2011), or double peaks in all of the narrow lines, both permitted and forbidden, e.g., SDSS 092712.65+294344.0 (J0927+2943, Komossa et al 2008b;Bogdanović et al 2009b;Dotti et al 2009). These double peaks indicate two sets of narrow emission line regions (NLRs) and are suggestive of dual AGNs with separations up to several kpc.…”

Section: Introductionmentioning

confidence: 99%

A CANDIDATE DUAL ACTIVE GALACTIC NUCLEUS ATz= 1.175

Barrows

Stern

Madsen

et al. 2011

ApJ

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The X-ray source CXOXBJ142607.6+353351 (CXOJ1426+35), which was identified in a 172 ks Chandra image in the Boötes field, shows double-peaked rest-frame optical/UV emission lines, separated by 0. 69 (5.5 kpc) in the spatial dimension and by 690 km s −1 in the velocity dimension. The high excitation lines and emission line ratios indicate both systems are ionized by an active galactic nucleus (AGN) continuum, and the double-peaked profile resembles that of candidate dual AGNs. At a redshift of z = 1.175, this source is the highest redshift candidate dual AGN yet identified. However, many sources have similar emission line profiles for which other interpretations are favored. We have analyzed the substantial archival data available in this field as well as acquired near-infrared (NIR) adaptive optics (AO) imaging and NIR slit spectroscopy. The X-ray spectrum is hard, implying a column density of several 10 23 cm −2 . Though heavily obscured, the source is also one of the brightest in the field, with an absorption-corrected 2-10 keV luminosity of ∼10 45 erg s −1 . Outflows driven by an accretion disk may produce the double-peaked lines if the central engine accretes near the Eddington limit. However, we may be seeing the narrow line regions of two AGNs following a galactic merger. While the AO image reveals only a single source, a second AGN would easily be obscured by the significant extinction inferred from the X-ray data. Understanding the physical processes producing the complex emission line profiles seen in CXOJ1426+35 and related sources is important for interpreting the growing population of dual AGN candidates.

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Quasar SDSS J142507.32+323137.4: dual AGNs?

Cited by 11 publications

References 45 publications

Two in one? A possible dual radio-emitting nucleus in the quasar SDSS J1425+3231

Two in one? A possible dual radio-emitting nucleus in the quasar SDSS J1425+3231

CHANDRAX-RAY ANDHUBBLE SPACE TELESCOPEIMAGING OF OPTICALLY SELECTED KILOPARSEC-SCALE BINARY ACTIVE GALACTIC NUCLEI. I. NATURE OF THE NUCLEAR IONIZING SOURCES

A CANDIDATE DUAL ACTIVE GALACTIC NUCLEUS ATz= 1.175

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