Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67-002813.7

Adi Foord, Xin Liu, Kayhan Gültekin, Kevin Whitley, Fangzheng Shi, Yu Ching Chen

Research output: Contribution to journalArticlepeer-review


We present results of a multiwavelength analysis of SDSS J025214.67-002813.7, a system that has been previously classified as a binary active galactic nucleus (AGN) candidate based on periodic signals detected in the optical light curves. We use available radio-X-ray observations of the system to investigate the true accretion nature. Analyzing new observations from XMM-Newton and NuSTAR, we characterize the X-ray emission and search for evidence of circumbinary accretion. Although the 0.5-10 keV spectrum shows evidence of an additional soft emission component, possibly due to extended emission from hot nuclear gas, we find the spectral shape is consistent with that of a single AGN. Compiling a full multiwavelength spectral energy distribution (SED), we also search for signs of circumbinary accretion, such as a "notch"in the continuum due to the presence of minidisks. We find that the radio-optical emission agrees with the SED of a standard, radio-quiet, AGN; however, there is a large deficit in emission blueward of ∼1400 Å. Although this deficit in emission can plausibly be attributed to a binary AGN system, we find that the SED of SDSS J0252-0028 is better explained by emission from a reddened, single AGN. However, future studies of the expected hard X-ray emission associated with binary AGNs (especially in the unequal-mass regime) will allow for more rigorous analyses of the binary AGN hypothesis.

Original languageEnglish (US)
Article number3
JournalAstrophysical Journal
Issue number1
StatePublished - Mar 1 2022

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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