We propose deep X-ray observations of ASASSN-15lh at t>500 days to unveil itsnature, as part of our multi-wavelength follow-up. ASASSN-15lh has been inter-preted as either (i) the most luminous stellar explosion, or (ii) a stellartidal disruption by the most massive, spinning black hole to date. In eithercase the observed properties of ASASSN-15lh are unprecedented, with profoundimplications to our understanding of stellar explosions (case i) or stronggravity regimes around supermassive spinning BHs (case ii). The two scenarioshave markedly different predictions of the associated X-ray emission and itsevolution at late times. Continued monitoring of the X-ray source that weuncovered at its location thus holds the keys to unveiling the true nature of this unique transient.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2018-04-12T10:58:36Z/2018-04-13T13:48:36Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
European Space Agency, Dr Raffaella Margutti, 2019, 'Unveiling the true nature of the remarkable transient ASASSN-15lh', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-nhjjoju
