Among the virgul6000 new white dwarfs (WDs) spectroscopically confirmed by the SloanDigital Sky Survey (SDSS) are three cool DAs within 1. of super-soft ROSATAll-Sky Survey (RASS) sources. WDs at these relatively low temperatures (below23,000 K) are not expected to be X-ray emitters, but the SDSS photometric andspectroscopic data fail to identify any other obvious optical counterparts tothe RASS sources to the SDSS limits (gvirgul23 mag in photometry). We propose 6 ksecXMM-Newton observations of these three SDSS WDs to obtain pinpoint X-raypositions and improved flux measures for these objects. If XMM data confirm thatthe WDs are X-ray sources, they will be of great interest; in particular,theoretical work will be required to explain how such cool WDs can emit X rays.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2009-05-26T21:50:53Z/2009-06-14T15:02:35Z
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 Marcel Agueros, 2010, 'The Coolest X-ray Emitting White DwarfsquestionMark', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-s7hwycb
