| Proposal ID | 050653 |
| Title | Understanding the on-off states in CAL 83 |
| Download Data Associated to the proposal | https://nxsa.esac.esa.int/nxsa-sl/servlet/data-action-aio?obsno=0506530201 |
| DOI | https://doi.org/10.5270/esa-m024vk0 |
| Principal Investigator, PI | Dr Robert Schwarz |
| Abstract | CAL 83 is the canonical close-binary supersoft X-ray source and also among thetwo rare systems to show repeated on/off X-ray states. These systematic changesare anti-correlated with the optical brightness and closely connected toprocesses occuring at near Eddington accretion rates. We propose an opticallytriggered XMM monitoring of CAL 83 through one X-ray bright state following itsevolution with many short pointings (5 ksec each). This will provide new insightinto the yet unknown physical mechanism behind the X-ray on/off states bytesting three alternatives: (a) Luminosity changes at constant temperature thatindicate a cessation of the shell burning; (b) Temperature changes due tovariations of the effective radius of the white dwarf; (c) Absorption, e.g. by a variable wind. |
| Publications |
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| 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 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. |
| Creator Contact | https://www.cosmos.esa.int/web/xmm-newton/xmm-newton-helpdesk |
| Date Published | 2010-06-23T00:00:00Z |
| Keywords | "short pointings", "processes occuring", "eddington accretion rates", "physical mechanism", "constant temperature", "XMM", "cal 83", "effective radius", "closely connected", "optical brightness", "anti correlated", "white dwarf", "shell burning", "variable wind", "testing alternatives", "xray bright", "optically triggered xmm", "rare systems" |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, Dr Robert Schwarz, 2010, 'Understanding the on-off states in CAL 83', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-m024vk0 |