|Title||The Coolest X-ray Emitting White Dwarfs?|
|Author||Dr Marcel Agueros|
|Description||Among the virgul6000 new white dwarfs (WDs) spectroscopically confirmed by the Sloan Digital Sky Survey (SDSS) are three cool DAs and two cool DBs within 1. of super-soft ROSAT All Sky Survey (RASS) sources. WDs at these relatively low temperatures (<23,000K) are not expected to be X-ray emitters, but the SDSS photometric and spectroscopic data fail to identify any other obvious optical counterparts to the RASS sources to the SDSS limits (gvirgul23 mag in photometry). We propose 5 ksec XMM-Newton observations of these five SDSS WDs to obtain pinpoint X-ray positions and improved flux measures for these objects. If XMM data confirm that the five 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.|
|Publication||No observations found associated with the current proposal|
|Instrument||EMOS1, EMOS2, EPN, OM, RGS1, RGS2|
|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.
|Publisher And Registrant||European Space Agency|
|Credit Guidelines||European Space Agency, 2009-04-15T00:00:00Z, 050355, 17.56_20190403_1200. https://doi.org/10.5270/esa-g4lnep8|