Yao, Y, Chornock, R, Ward, C, Hammerstein, E, Sfaradi, I, Margutti, R, Kelley, LZ, Lu, W, Liu, C, Wise, J, Sollerman, J, Alexander, KD, Bellm, EC, Drake, AJ, Fremling, C, Gilfanov, M, Graham, MJ, Groom, SL, Hinds, KR, Kulkarni, SR et al (2025) A Massive Black Hole 0.8 kpc from the Host Nucleus Revealed by the Offset Tidal Disruption Event AT2024tvd. The Astrophysical Journal Letters, 985 (2). ISSN 2041-8205
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A Massive Black Hole 0.8 kpc from the Host Nucleus Revealed by the Offset Tidal Disruption Event AT2024tvd.pdf - Published Version Available under License Creative Commons Attribution. Download (2MB) | Preview |
Abstract
Tidal disruption events (TDEs) that are spatially offset from the nuclei of their host galaxies offer a new probe of massive black hole (MBH) wanderers, binaries, triples, and recoiling MBHs. Here we present AT2024tvd, the first off-nuclear TDE identified through optical sky surveys. High-resolution imaging with the Hubble Space Telescope shows that AT2024tvd is 0"914 ± 0"010 offset from the apparent center of its host galaxy, corresponding to a projected distance of 0.808 ± 0.009 kpc at z = 0.045. Chandra and Very Large Array observations support the same conclusion for the TDE's X-ray and radio emission. AT2024tvd exhibits typical properties of nuclear TDEs, including a persistent hot UV/optical component that peaks at Lbb ∼ 6 × 1043 erg s−1, broad hydrogen lines in its optical spectra, and delayed brightening of luminous (LX,peak ∼ 3 × 1043 erg s−1), highly variable soft X-ray emission. The MBH mass of AT2024tvd is 106±1 M⊙, at least 10 times lower than its host galaxy's central black hole mass (≳108 M⊙). The MBH in AT2024tvd has two possible origins: a wandering MBH from the lower-mass galaxy in a minor merger during the dynamical friction phase or a recoiling MBH ejected by triple interactions. Combining AT2024tvd with two previously known off-nuclear TDEs discovered in X-rays (3XMM J2150 and EP240222a), which likely involve intermediate-mass black holes in satellite galaxies, we find that the parent galaxies of all three events are very massive (∼1010.9 M⊙). This result aligns with expectations from cosmological simulations that the number of offset MBHs scales linearly with the host halo mass.
Item Type: | Article |
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Uncontrolled Keywords: | 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5109 Space sciences |
Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
Divisions: | Astrophysics Research Institute |
Publisher: | American Astronomical Society |
Date of acceptance: | 25 April 2025 |
Date of first compliant Open Access: | 3 June 2025 |
Date Deposited: | 03 Jun 2025 15:57 |
Last Modified: | 03 Jun 2025 16:00 |
DOI or ID number: | 10.3847/2041-8213/add7de |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/26514 |
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