Статья

A systematically selected sample of luminous, long-duration, ambiguous nuclear transients

P. WisemanSchool of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ ,R. WilliamsRoyal Observatory, University of Edinburgh , Edinburgh EH9 3HJ ,I ArcaviThe School of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978 ,L. GalbanyInstitut d’Estudis Espacials de Catalunya (IEEC) , E-08860 Castelldefels (Barcelona) ,M. J. GrahamCalifornia Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125 ,S. F. HönigSchool of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ ,Megan NewsomeDepartment of Physics, University of California , Santa Barbara, CA 93106-9530 ,Bhagya SubrayanDepartment of Physics and Astronomy, Purdue University , 525 Northwestern Avenue, West Lafayette, IN 47907 ,M. SullivanSchool of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ ,Yanan WangKey Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101 ,D. IlićDepartment of Astronomy, Faculty of Mathematics,University of Belgrade , Studentski trg 16, 11000 Belgrade ,M. NichollAstrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , Belfast BT7 1NN ,S. R. OatesPhysics Department, Lancaster University , Bailrigg, Lancaster LA1 4YB ,T. PetrushevskaCenter for Astrophysics and Cosmology, University of Nova Gorica , Vipavska 11c, SI-5270 Ajdovščina ,K. SmithAstrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , Belfast BT7 1NN ,

2025en

ABI

Аннотация

ABSTRACT We present a search for luminous long-duration ambiguous nuclear transients (ANTs) similar to the unprecedented discovery of the extreme ambiguous event AT2021lwx with a $\gt 150$ d rise time and luminosity $10^{45.7}$ erg s$^{-1}$. We use the Lasair transient broker to search Zwicky Transient Facility (ZTF) data for transients lasting more than one year and exhibiting smooth declines. Our search returns 59 events, 7 of which we classify as ANTs assumed to be driven by accretion onto supermassive black holes. We propose the remaining 52 are stochastic variability from regular supermassive black hole accretion rather than distinct transients. We supplement the seven ANTs with three nuclear transients in ZTF that fail the light curve selection but have clear single flares and spectra that do not resemble typical active galactic nucleus. All of these 11 ANTs have a mid-infrared flare from an assumed dust echo, implying the ubiquity of dust around the black holes giving rise to ANTs. No events are more luminous than AT2021lwx, but one (ZTF19aamrjar) has twice the duration and a higher integrated energy release. On the other extreme, ZTF20abodaps reaches a luminosity close to AT2021lwx with a rise time $\lt 20$ d and that fades smoothly in $\gt 600$ d. We define a portion of rise-time versus flare amplitude space that selects ANTs with $\sim 50$ per cent purity against variable AGNs. We calculate a volumetric rate of $\gtrsim 3\times 10^{-11}$ Mpc$^{-1}$ yr$^{-1}$, consistent with the events being caused by tidal disruptions of intermediate and high-mass stars.

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Идентификаторы

DOI: 10.1093/mnras/staf116

Цитирования и источники

Цитирований: 2Использованных источников: 0

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