A Late-Time Radio Flare following a Possible Transition in Accretion State in the Tida l Disruption Event AT 2019azh
View / Open Files
Authors
Sfaradi, Itai
Horesh, Assaf
Fender, Rob
Williams, DRA
Bright, Joe
Schulze, Steve
Journal Title
The Astrophysical Journal: an international review of astronomy and astronomical physics
ISSN
0004-637X
Publisher
American Astronomical Society
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Sfaradi, I., Horesh, A., Fender, R., Green, D., Williams, D., Bright, J., & Schulze, S. A Late-Time Radio Flare following a Possible Transition in Accretion State in the Tida l Disruption Event AT 2019azh. The Astrophysical Journal: an international review of astronomy and astronomical physics https://doi.org/10.17863/CAM.85058
Abstract
We report here radio follow-up observations of the optical Tidal Disruption Event (TDE) AT 2019azh. Previously reported X-ray observations of this TDE showed variability at early times and a dramatic increase in luminosity, by a factor of ~10, about 8 months after optical discovery. The X-ray emission is mainly dominated by intermediate hard--soft X-rays and is exceptionally soft around the X-ray peak, which is L_X ~10^43 erg/s. The high cadence 15.5 GHz observations reported here show an early rise in radio emission followed by an approximately constant light curve, and a late-time flare. This flare starts roughly at the time of the observed X-ray peak luminosity and reaches its peak about 110 days after the peak in the X-ray, and a year after optical discovery. The radio flare peaks at nu L_nu ~ 10^38 erg/s, a factor of two higher than the emission preceding the flare. In light of the late-time radio and X-ray flares, and the X-ray spectral evolution, we speculate a possible transition in the accretion state of this TDE, similar to the observed behavior in black hole X-ray binaries. We compare the radio properties of AT 2019azh to other known TDEs, and focus on the similarities to the late time radio flare of the TDE ASASSN-15oi.
Embargo Lift Date
2100-01-01
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.85058
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337652
Rights
Publisher's own licence
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.