Open AccessChandra Observations of Spikey: A Possible Self-lensing Supermassive Black Hole Binary System
Author(s) -
Nicholas M. Sorabella,
Sayantan Bhattacharya,
S. Laycock,
Dimitris M. Christodoulou,
Alessandro Massarotti
Publication year - 2022
Publication title -
astrophysical journal/the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.3847/1538-4357/ac4a59
Subject(s) - physics , supermassive black hole , astrophysics , binary black hole , gravitational lens , doppler effect , astronomy , strong gravitational lensing , active galactic nucleus , wavelength , black hole (networking) , gravitational wave , galaxy , redshift , optics , computer network , routing protocol , routing (electronic design automation) , computer science , link state routing protocol
This work examines the recent X-ray observations of the active galactic nucleus KIC 11606854 (nicknamed “Spikey”) by the Chandra space telescope. Based on previous observations of a symmetric flare in the system’s light curve by the Kepler space telescope, Spikey has been proposed to be a self-lensing supermassive black hole binary system in which the more massive black hole gravitationally lenses the accretion flow of its smaller companion. The recent Chandra observations (2020 March–May) correspond to the time when the next pulse was expected to occur and were separated in enough time to observe the apparent relativistic Doppler boosting effect from the high orbital velocities of the black holes. We model the expected self-lensing plus Doppler boosting light curve using our wavelength-dependent extended source self-lensing model combined with our relativistic orbital motion code. This orbital motion code is capable of modeling the expected apsidal precession for Spikey, which can be used to predict future pulses. We show that the expected signal was undetectable in the Chandra data as the intrinsic X-ray variability associated with the system was large relative to the changes expected by self-lensing and Doppler boosting. Expected flux increases in more favorable wavelengths were also calculated using our wavelength-dependent self-lensing model, revealing a relationship between the observing wavelength and measured orbital inclination.