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arXiv · 2307.01771

AT2023fhn (the Finch): a Luminous Fast Blue Optical Transient at a large offset from its host galaxy

A. A. Chrimes·P. G. Jonker·A. J. Levan·D. L. Coppejans·N. Gaspari·B. P. Gompertz·P. J. Groot·D. B. Malesani·A. Mummery·E. R. Stanway·K. Wiersema
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Abstract

Luminous Fast Blue Optical Transients (LFBOTs) - the prototypical example being AT2018cow - are a rare class of events whose origins are poorly understood. They are characterised by rapid evolution, featureless blue spectra at early times, and luminous X-ray and radio emission. LFBOTs thus far have been found exclusively at small projected offsets from star-forming host galaxies. We present Hubble Space Telescope, Gemini, Chandra and Very Large Array observations of a new LFBOT, AT2023fhn. The Hubble Space Telescope data reveal a large offset (greater than 3.5 half-light radii) from the two closest galaxies, both at a redshift of 0.24. The location of AT2023fhn is in stark contrast with previous events, and demonstrates that LFBOTs can occur in a range of galactic environments.

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A. A. Chrimes, P. G. Jonker, A. J. Levan, D. L. Coppejans, N. Gaspari, B. P. Gompertz, P. J. Groot, D. B. Malesani, A. Mummery, E. R. Stanway, K. Wiersema. 2023-07-04. AT2023fhn (the Finch): a Luminous Fast Blue Optical Transient at a large offset from its host galaxy. https://arxiv.org/abs/2307.01771

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