Multi-wavelength observations have been the key to identifying the manyunassociated gamma-ray sources detected by the Fermi-LAT telescope. In two ofthe top ten brightest Fermi sources that remain unassociated, opticalobservations of their error ellipses have revealed variable stars eachcoincident with an X-ray source detected by Swift. In both cases, a putativebinary orbital period of has been identified from the optical variability,indicating that these are candidate millisecond pulsars (MSPs) that may be thecounterparts to the bright gamma-ray sources. However, unlike all previousgamma-ray MSPs detected by Fermi, there is no indication of radio emission fromeither source.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2014-06-14T19:11:12Z/2014-06-15T15:37:52Z
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 Fabio Acero, 2015, 'Two candidates radio-quiet millisecond pulsars in Fermi unassociated sources', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-4ismfq9
