Astronomers have studied a mysterious burst of activity in a distant galaxy

Astronomers from Ohio American University and other countries have made a series of observations in the X-ray range of a nuclear transition with an unexplained structure, called AT2019pev. The results of these studies, which provide new information about the nature of this unusual object, are published on the electronic preprint website. arXiv.orgThe article has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.

AT2019pev (other names ZTF19abvgxrq and Gaia19eby) is an astronomical object that has experienced some significant and dramatic changes, first recorded on September 1, 2019. We are talking about a type I Seyfert galaxy (a galaxy with an active core) with narrow spectral lines at a redshift of 0.096. Initial analysis of observations of the transient process showed that the event could be interpreted either as the tidal destruction of a star approaching the central supermassive black hole and being torn apart by gravity, or as other processes occurring in an active galactic core.

A team of astronomers led by You Zhefu of Ohio State University reanalyzed all X-ray observations to reveal the true nature of AT2019pev. To do this, they used information from NASA’s Swift and Chandra spacecraft, as well as the Neutron Star Interior Investigator, the NICER telescope installed on the International Space Station. Observations showed that AT2019pev’s X-ray luminosity increased by a factor of five, about five days after Swift’s first observation – the “Swift XRT era”, named after the X-ray telescope installed at Swift. The next 75 days and another hundred days experienced some fluctuations. Additionally, X-ray spectra showed a trend towards adding a harsher X-ray component of the radiation as events unfolded; this shows changes in the state of the accretion disk near the black hole, where the trapped material is slowly being absorbed. . Also, by analyzing data from the ESA Gaia satellite, it was possible to find that the optical light curve reached its maximum brightness 223 days after the start of observations in the visible range.

Combining observational data from X-ray and other ranges, the astronomers concluded that processes considered temporal are most likely related to some events occurring in the active galactic core, but not to explosions caused by tidal destruction.