TY - JOUR
T1 - Millihertz oscillations near the innermost orbit of a supermassive black hole
AU - Masterson, Megan
AU - Kara, Erin
AU - Panagiotou, Christos
AU - Alston, William N.
AU - Chakraborty, Joheen
AU - Burdge, Kevin
AU - Ricci, Claudio
AU - Laha, Sibasish
AU - Arcavi, Iair
AU - Arcodia, Riccardo
AU - Cenko, S. Bradley
AU - Fabian, Andrew C.
AU - García, Javier A.
AU - Giustini, Margherita
AU - Ingram, Adam
AU - Kosec, Peter
AU - Loewenstein, Michael
AU - Meyer, Eileen T.
AU - Miniutti, Giovanni
AU - Pinto, Ciro
AU - Remillard, Ronald A.
AU - Sadaula, Dev R.
AU - Shuvo, Onic I.
AU - Trakhtenbrot, Benny
AU - Wang, Jingyi
N1 - © 2025, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2025/2/13
Y1 - 2025/2/13
N2 - Recent discoveries from time-domain surveys are defying our expectations for how matter accretes onto supermassive black holes (SMBHs). The increased rate of short-timescale, repetitive events around SMBHs, including the recently discovered quasi-periodic eruptions
1, 2, 3, 4–5, are garnering further interest in stellar-mass companions around SMBHs and the progenitors to millihertz-frequency gravitational-wave events. Here we report the discovery of a highly significant millihertz quasi-periodic oscillation (QPO) in an actively accreting SMBH, 1ES 1927+654, which underwent a major optical, ultraviolet and X-ray outburst beginning in 2018
6,7. The QPO was detected in 2022 with a roughly 18-minute period, corresponding to coherent motion on a scale of less than 10 gravitational radii, much closer to the SMBH than typical quasi-periodic eruptions. The period decreased to 7.1 minutes over 2 years with a decelerating period evolution (P¨ greater than zero). To our knowledge, this evolution has never been seen in SMBH QPOs or high-frequency QPOs in stellar-mass black holes. Models invoking orbital decay of a stellar-mass companion struggle to explain the period evolution without stable mass transfer to offset angular-momentum losses, and the lack of a direct analogue to stellar-mass black-hole QPOs means that many instability models cannot explain all of the observed properties of the QPO in 1ES 1927+654. Future X-ray monitoring will test these models, and if it is a stellar-mass orbiter, the Laser Interferometer Space Antenna (LISA) should detect its low-frequency gravitational-wave emission.
AB - Recent discoveries from time-domain surveys are defying our expectations for how matter accretes onto supermassive black holes (SMBHs). The increased rate of short-timescale, repetitive events around SMBHs, including the recently discovered quasi-periodic eruptions
1, 2, 3, 4–5, are garnering further interest in stellar-mass companions around SMBHs and the progenitors to millihertz-frequency gravitational-wave events. Here we report the discovery of a highly significant millihertz quasi-periodic oscillation (QPO) in an actively accreting SMBH, 1ES 1927+654, which underwent a major optical, ultraviolet and X-ray outburst beginning in 2018
6,7. The QPO was detected in 2022 with a roughly 18-minute period, corresponding to coherent motion on a scale of less than 10 gravitational radii, much closer to the SMBH than typical quasi-periodic eruptions. The period decreased to 7.1 minutes over 2 years with a decelerating period evolution (P¨ greater than zero). To our knowledge, this evolution has never been seen in SMBH QPOs or high-frequency QPOs in stellar-mass black holes. Models invoking orbital decay of a stellar-mass companion struggle to explain the period evolution without stable mass transfer to offset angular-momentum losses, and the lack of a direct analogue to stellar-mass black-hole QPOs means that many instability models cannot explain all of the observed properties of the QPO in 1ES 1927+654. Future X-ray monitoring will test these models, and if it is a stellar-mass orbiter, the Laser Interferometer Space Antenna (LISA) should detect its low-frequency gravitational-wave emission.
KW - astro-ph.HE
UR - http://www.scopus.com/inward/record.url?scp=85218004281&partnerID=8YFLogxK
U2 - 10.1038/s41586-024-08385-x
DO - 10.1038/s41586-024-08385-x
M3 - Article
SN - 1476-4687
VL - 638
SP - 370
EP - 375
JO - Nature
JF - Nature
ER -