| Name | 050653 |
| Title | Understanding the on-off states in CAL 83 |
| URL | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0506530201 |
| DOI | https://doi.org/10.5270/esa-m024vk0 |
| Author | Dr Robert Schwarz |
| Description | CAL 83 is the canonical close-binary supersoft X-ray source and also among the two rare systems to show repeated on-off X-ray states. These systematic changes are anti-correlated with the optical brightness and closely connected to processes occuring at near Eddington accretion rates. We propose an optically triggered XMM monitoring of CAL 83 through one X-ray bright state following its evolution with many short pointings (5 ksec each). This will provide new insight into the yet unknown physical mechanism behind the X-ray on-off states by testing three alternatives: (a) Luminosity changes at constant temperature that indicate a cessation of the shell burning; (b) Temperature changes due to variations of the effective radius of the white dwarf; (c) Absorption, e.g. by a variable wind. |
| Publication | No observations found associated with the current proposal |
| Instrument | EMOS1, EMOS2, EPN, OM, RGS1, RGS2 |
| Temporal Coverage | 2008-03-20T00:33:22Z/2009-05-30T20:49:23Z |
| Version | 17.56_20190403_1200 |
| Mission Description | The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's 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 Earth's 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. |
| Creator Contact | https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk |
| Date Published | 2010-06-23T00:00:00Z |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, 2010-06-23T00:00:00Z, 050653, 17.56_20190403_1200. https://doi.org/10.5270/esa-m024vk0 |