Very-faint X-ray transients undergo accretion outbursts with a peak X-rayluminosity well below that of other black hole and neutron star low-mass X-raybinaries. These intriguing objects allow us to probe new parameter space forbinary evolution models, accretion flows, and neutron star physics. We proposeto study 2 very-faint X-ray transients in quiescence with XMM-Newton (100 ks intotal) and HST (3 orbits in total). The aim of these observations are to i)elucidate the nature of their compact primary, ii) test if the X-ray spectralevolution during outburst serves as a diagnostic to separate neutron stars fromblack holes and iii) provide the first detailed characterisation of thequiescent emission of very-faint X-ray transients.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2019-03-29T13:28:10Z/2019-04-09T14:28:27Z
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 nathalie degenaar, 2020, 'The nature of the compact accretor in exotic X-ray binaries', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-n8fzbqz
