---
res:
  bibo_abstract:
  - We present analysis of Chandra X-ray observations of seven quasars that were identified
    as candidate subparsec binary supermassive black hole (SMBH) systems in the Catalina
    Real-Time Transient Survey based on the apparent periodicity in their optical
    light curves. Simulations predict that close-separation accreting SMBH binaries
    will have different X-ray spectra than single accreting SMBHs, including harder
    or softer X-ray spectra, ripple-like profiles in the Fe K-α line, and distinct
    peaks in the spectrum due to the separation of the accretion disk into a circumbinary
    disk and mini disks around each SMBH. We obtained Chandra observations to test
    these models and assess whether these quasars could contain binary SMBHs. We instead
    find that the quasar spectra are all well fit by simple absorbed power-law models,
    with the rest-frame 2–10 keV photon indices, Γ, and the X-ray-to-optical power
    slopes, αOX, indistinguishable from those of the larger quasar population. This
    may indicate that these seven quasars are not truly subparsec binary SMBH systems,
    or it may simply reflect that our sample size was too small to robustly detect
    any differences. Alternatively, the X-ray spectral changes might only be evident
    at energies higher than probed by Chandra. Given the available models and current
    data, no firm conclusions are drawn. These observations will help motivate and
    direct further work on theoretical models of binary SMBH systems, such as modeling
    systems with thinner accretion disks and larger binary separations.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: M. Lynne
      foaf_name: Saade, M. Lynne
      foaf_surname: Saade
  - foaf_Person:
      foaf_givenName: Daniel
      foaf_name: Stern, Daniel
      foaf_surname: Stern
  - foaf_Person:
      foaf_givenName: Murray
      foaf_name: Brightman, Murray
      foaf_surname: Brightman
  - foaf_Person:
      foaf_givenName: Zoltán
      foaf_name: Haiman, Zoltán
      foaf_surname: Haiman
      foaf_workInfoHomepage: http://www.librecat.org/personId=7c006e8c-cc0d-11ee-8322-cb904ef76f36
  - foaf_Person:
      foaf_givenName: S. G.
      foaf_name: Djorgovski, S. G.
      foaf_surname: Djorgovski
  - foaf_Person:
      foaf_givenName: Daniel
      foaf_name: D’Orazio, Daniel
      foaf_surname: D’Orazio
  - foaf_Person:
      foaf_givenName: K. E. S.
      foaf_name: Ford, K. E. S.
      foaf_surname: Ford
  - foaf_Person:
      foaf_givenName: Matthew J.
      foaf_name: Graham, Matthew J.
      foaf_surname: Graham
  - foaf_Person:
      foaf_givenName: Hyunsung D.
      foaf_name: Jun, Hyunsung D.
      foaf_surname: Jun
  - foaf_Person:
      foaf_givenName: Ralph P.
      foaf_name: Kraft, Ralph P.
      foaf_surname: Kraft
  - foaf_Person:
      foaf_givenName: Barry
      foaf_name: McKernan, Barry
      foaf_surname: McKernan
  - foaf_Person:
      foaf_givenName: Alexei
      foaf_name: Vikhlinin, Alexei
      foaf_surname: Vikhlinin
  - foaf_Person:
      foaf_givenName: Dominic J.
      foaf_name: Walton, Dominic J.
      foaf_surname: Walton
  bibo_doi: 10.3847/1538-4357/abad31
  bibo_issue: '2'
  bibo_volume: 900
  dct_date: 2020^xs_gYear
  dct_isPartOf:
  - http://id.crossref.org/issn/0004-637X
  - http://id.crossref.org/issn/1538-4357
  dct_language: eng
  dct_publisher: American Astronomical Society@
  dct_title: Chandra observations of candidate subparsec binary supermassive black
    holes@
...