Commensal Radio Astronomy FAST Survey (CRAFTS)
CRAFTS Pulsar list
Having achieved 'first-light' right before the opening ceremony on September 25, 2016, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is now kept busy with commissions. Its innovative design requires ~1,000 points to be measured and driven instead of just the two axes of motion, e.g. Azimuth and Elevation for most of the conventional antennae, to realize pointing and tracking. We have devised a survey plan to utilized the full sensitivity of FAST, while minimizing the complexities in operation the system. The 19-beam L band focal plan array will be rotated to specific angles and taking continuous data streams while the surface shape and the focal cabin stay fixed. Such a survey will cover the northern sky in about 220 full days. Our aim is to obtain data for pulsar search, HI (neutral hydrogen) galaxies, HI imaging, and radio transients, simultaneously, through multiple backends. These data sets could be a significant contribution to all related fields in radio astronomy and remain relevant for decades.
FAST in Space: Considerations for a Multibeam, Multipurpose Survey Using China's 500-m Aperture Spherical Radio Telescope (FAST)
Di Li; Pei Wang; Lei Qian; Marko Krco; Alex Dunning; Peng Jiang; Youling Yue; Chenjin Jin; Yan Zhu; Zhichen Pan; and Rendong Nan;
IEEE Microwave Magazine, Volume 19, Issue 3, pp.112-119 ADS Link
FAST's First Discovery of a Millisecond Pulsar (MSP)
On 27 Feb. 2018, the Five-hundred-meter Aperture Spherical radio Telescope (FAST), operated by the National Astronomical Observatories, Chinese Academy of Sciences, discovered a radio millisecond pulsar (MSP) coincident with the unassociated gamma-ray source 3FGL J0318.1+0252 in the Fermi Large Area Telescope (LAT) point-source list. It was confirmed by the Fermi-LAT team in reprocessing of Fermi data on April 18th. This is another milestone of FAST.
Radio follow-up of Fermi-LAT unassociated sources is one of the effective ways for finding new pulsars. Previous radio observations, including three epochs with Arecibo in June 2013, failed to detect the MSP. In an one-hour tracking observation with the FAST ultra-wide band receiver, the radio pulses toward 3FGL J0318.1+0252 were detected with a spin period of 5.19 milliseconds, an estimated distance of about 4 thousand light-years, and as potentially one of the faintest radio MSPs. The newly discovered pulsar, now named PSR J0318+0253, is confirmed to be isolated through timing of gamma-ray pulsations. This discovery is the first result from the FAST-Fermi LAT collaboration outlined in a MoU signed between the FAST team and Fermi-LAT team.
Millisecond pulsars is a special kind of neutron stars that rotate hundreds of times per second. It is not only expected to play an important role in understanding the evolution of neutron stars and the equation of state of condense matter, but also can be used to detect low-frequency gravitational waves. The pulsar timing array (PTA) attempts to detect low-frequency gravitational waves from merging supermassive black holes using the long-term timing of a set of stable millisecond pulsars. Pulsar search is the basis of gravitational wave detection. The planned Commensal Radio Astronomy FAST Survey (CRAFTS, arxiv:1802.03709; http://localhost/) is expected to discover many millisecond pulsars and thus will make significant contribution to the PTA experiment.
Kejia Lee, a staff scientist at the Kavli Institute of Astronomy and Astrophysics, Peking University, said that “This discovery demonstrated the great potential of FAST in pulsar searching, highlighting the vitality of the large aperture radio telescope in the new era. It is a great achievement fo FAST, still under commissioning. (He) looks forward to its full operation soon.”
Renxin Xu, a professor of astronomy at Peking University, said that “Besides their scientific significance, millisecond pulsars also have potential value in other applications. MSP discoveries from FAST will provide better opportunities for scientists and engineers around the world.”
George Hobbs, a staff scientist of the Commonwealth Scientific and Industrial Research Organisat (CSIRO)of Australia and a member of the Gravitational Wave International Committee (GWIC), said “The international radio-astronomy community is excited about the amazing FAST telescope. The Australian Parkes Telescope helped confirm FAST’s first pulsar discovery and now Fermi Space Observatory is instrumental in FAST’s first millisecond pulsar. FAST will soon discover a large number of millisecond pulsars and I am looking forward to seeing FAST’s contribution to gravitational wave detection.”
FAST will be under commissioning until it reaches the designed specifications and becomes a Chinese national facility.
Fig1. The Gamma-ray sky map and integrated pulse profiles of the new MSP:
Upper panel shows the region of the gamma-ray sky where the new MSP is located.
Lower panel a) shows the observed radio pulses in a one-hour tracking observation of FAST.
Lower panel b) shows the folded pulses from more than 9 years of Fermi-LAT gamma-ray data.