APPROVED PROJECTS

Approved Key Projects

2022-03-17

Key Projects
Title PI name Abstract
The Commensal Radio Astronomy FAST Survey (CRAFTS) Di Li CRAFTS is a fully open, commensal, service survey, which aims to cover the full FAST sky in drift scan mode. With the 19 beam tilted to a certain angle, each drift scan covers about 21' in DEC. Combined with the proper shift and stacking, CRAFTS achieves super-Nyqvist (1.3' spacing in DEC) and even sampling of the sky, which produces unprecedented imaging quality and survey efficiency. Enabled by our novel and proprietary high-cadence CAL injection technique, CRAFTS can simultaneously take four independent data streams, namely, Galactic HI (10 MHz band), extra-galactic HI (400 MHz full band), pulsar search, and transient (FRB/SETI). One-pass coverage of the FAST sky will require about 5500 hours. In the next five years, the priority will be given to DEC -14 to +5.5. The survey team promises to deliver CRAFTS data with the basic calibration (i.e. Tsys applied to the data header) and high-cadence CAL signal processed. Any interested colleague can still join the survey and get access to raw and level 1 data immediately after data taking. The high-cadence CAL technique is not limited to drift-scan mode. We encourage anyone who wishes to reap the benefit of either effective sky coverage or commensality to try out the high-cadence mode. Upon request, the survey team will provide the pipeline or carry out the basic calibration for you, with no prerequisite authorship request. Our goal is to preserve the potential to combine all data taken in CRAFTS mode into a coherent set when they become public. For more detailed technical description, current coverage, survey membership, confirmed pulsar discoveries, etc., please refer to https://crafts.bao.ac.cn and Li et al. 2018 (https://ui.adsabs.harvard.edu/abs/2018IMMag..19..112L/abstract).
The Galactic Plane Pulsar Snapshot (GPPS) survey JinLin Han The Five-hundred-meter Aperture Spherical radio Telescope (FAST)with the L-band 19-beam receiver with a system temperature of about 20~K is the most sensitive radio telescope to discover pulsars. We designed the snapshot observation mode for a FAST key science project, the Galactic Plane Pulsar Snapshot (GPPS) survey, in which every four nearby pointings can observe a cover of a sky area of 0.1575 square degree through beam-switching of the L-band 19-beam receiver. The integration time for each pointing is 300 seconds so that the GPPS observations for a cover can be made in 21 minutes. The goal of the GPPS survey is to discover 1000 pulsars down to a sensitivity of a few microJy level in the Galactic disk (both inner and outer disk) within the Galactic latitude of ±10º from the Galactic plane, and the highest priority is given to the inner Galaxy within ±5º. The most important goal is to find exotic pulsars, especially pulsars with a very short spin period or a short orbit period or with a large mass or pulsars in neutron-star black-hole binary.
Pulsar timing: Chinese pulsar timing array Kejia Lee To detect gravitational wave radiating sources and study their extreme violent astrophysical processes on cosmological scale, we need to detect the gravitational waves (GWs) from the super massive black hole binaries (SMBHBs) in spiraling or merging states. The GW radiation of those massive objects fall in the nanoHertz band (nHz). Pulsar timing array (PTA) is the potential technique to detect nHz GWs. Thus, it is necessary to carry out PTA experiment in order to further develop the discipline of GW astronomy. It will provide the important missing piece on the current GW observation atlas, where the GW spectrum frequency atlas will be extended 11 order of magnitude down, i.e., from ~100 Hz to nHz. Due to the high sensitivity of FAST, systematically carrying out FAST PTA observation may lead to break through of nHz GW detection.
With the high precision FAST pulsar timing data, Chinese pulsar timing array (CPTA) will be able to join the International Pulsar Timing Array (IPTA) to collaborate and to compete for the scientific output. Furthermore, the long-term precision pulsar timing will also provide extremely valuable data for fundamental physics and metrological researches.
We proposed to start the CPTA project by observing 46 known millisecond pulsars in the IPTA list, with the aims of 1) achieving GW detection or best GW amplitude upper limits, 2) pulsar jitter noise, red noise, interstellar medium noise studies, and forming pulsar timescale with FAST observations, 3) studying the binary pulsar dynamics and constrain the equation of states for zero-temperature nuclear density matters, and 4) studying Solar system dynamics, planet orbital dynamics and solar system acceleration.
HI Mapping and pulsars searching toward M31 region Jie Wang We will blind map a region of 700 square degrees around the M31 and its dark matter halo in L band with about 700 FAST hours. In this survey, we will try to study the HVC mass function, HI satellite mass function in M31 halo, and cold CGM and ICM in the M31-M33 systems. Finally a HI galaxy sample up to z=0.35 in this region will be constructed and published. Also a very deep commensal survey on the M31 galaxy for a ultra-deep HI mapping and pulsar searching will be carried out. Combined with other multi-band information, we could investigate into the detailed physics on the star formation in this nearest neighbor galaxy. Finally several special populations of dwarf galaxies in the local Universe (blue compacted dwarf, spiral dwarf, and dwarf hosts of AGNS ) will be observed with FAST to understand their formation history.  
Fast radio burst searches and multi-wavelength observations Bing Zhang, Weiwei Zhu Fast radio bursts (FRBs) are a new type of mysterious astrophysical transients discovered in 2007. This key project aims at monitoring and observing known and potential FRB sources taking advantage of the high sensitivity of FAST. Simultaneous multi-wavelength observations will be coordinated. We plan to perform observations in the following four directions. 1. Regularly monitor known repeating FRB sources (such as FRB 121102 and 180301); 2. Monitor new repeating sources (such as the ones discovered by FAST and other telescopes such as CHIME); 3. Observe other one-off FRB sources that have not repeated yet, trying to search for possible repeated bursts; 4. Monitor some sources that could be potentially FRB emitters, including soft gamma-ray repeaters (SGRs), nearby star burst galaxies, and GRB/SLSN remnants. When feasible, multi-wavelength observations will be carried out during FAST observing windows. The goal of the key project is to collect essential information to understand the origin, bursting mechanism and radiation mechanism of FRBs.
Pulsar timing:  Physics and evolution of pulsars Na Wang  In this project, we will carry out follow-up observations on the new pulsars discovered by FAST. The primary objective is to perform timing observations on the pulsars for 1-3 years. This will make possible for precise measurements and cataloging of their spin and astrometric parameters in order to obtain the population properties of the FAST new pulsars and investigate their birth and evolution in large sample. We will focus on sources with distinctive characteristics, such as binary pulsars, intermittent pulsars and very young pulsars. The information is useful for distinguishing the timing noise between internal and external origins in the pulsars, which is crucial for exploring the connection between pulsar braking and activities in the magnetospheres. We seek to optimize the astronomical and technical methods to improve the timing precision in examining the evolution of binaries, testing relativistic effect and studying the physical properties of interstellar medium and circumstellar matter.