Publikace ÚTF

AT 2019abn: multi-wavelength observations over the first 200 days

Williams, S. C.; Jones, D.; Pessev, P.; Geier, S.; Corradi, R. L. M.; Hook, I. M.; Darnley, M. J.; Pejcha, O.; Núñez, A.; Meingast, S.; Moran, S.

Context. AT 2019abn was discovered in the nearby M51 galaxy by the Zwicky Transient Facility at more than two magnitudes and around three weeks prior to its optical peak.
Aims: We aim to conduct a detailed photometric and spectroscopic follow-up campaign for AT 2019abn, with early discovery allowing for significant pre-maximum observations of an intermediate luminosity red transient (ILRT) for the first time.
Methods: This work is based on the analysis of u'BVr'i'z'H photometry and low-resolution spectroscopy using the Liverpool Telescope, medium-resolution spectroscopy with the Gran Telescopio Canarias (GTC), and near-infrared imaging with the GTC and the Nordic Optical Telescope.
Results: We present the most detailed optical light curve of an ILRT to date, with multi-band photometry starting around three weeks before peak brightness. The transient peaked at an observed absolute magnitude of Mr' = -13.1, although it is subject to significant reddening from dust in M51, implying an intrinsic Mr' ~ -15.2. The initial light curve showed a linear, achromatic rise in magnitude before becoming bluer at peak. After peak brightness, the transient gradually cooled. This is reflected in our spectra, which at later times show absorption from such species as Fe I, Ni I and Li I. A spectrum taken around peak brightness shows narrow, low-velocity absorption lines, which we interpret as likely to originate from pre-existing circumstellar material.
Conclusions: We conclude that while there are some peculiarities, such as the radius evolution, AT 2019abn fits in well overall with the ILRT class of objects and is the most luminous member of the class seen to date.
type:article
journal:Astronomy & Astrophysics
volume:637
nr:0
pages:A20
year:2020
eprint:2001.08782
grants:Cat-In-hAT: Catastrophic Interactions of Binary Stars and the Associated Transients, Horizon 2020 ERC Starting Grant 803158; 2019-2023; hlavní řešitel: Ondřej Pejcha
Časová proměnnost v astronomii: účast v projektu All-Sky Automated Survey for Supernovae; 2019-2022; hlavní řešitel: Ondřej Pejcha
files:
williams_et_al_including_pejcha_aa37286-19.pdf (733.71 kB)

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