FAST Low Frequency Pulsar Survey Youling Yue ( 岳友岭 ) FAST Project, NAOC PKU Astrophysics Colloquium 2012

outline Current FAST receivers Receiver for early pulsar survey: Low frequency (~400MHz) 7-beam receiver Pulsar survey simulation using PSRPOP Gravitational wave detection limits RFI Single beam wideband receiver

NoBand (GHz)BeamsPol.Cryo Tsys(K) Science – 0.141RCP LCP no 1000 High-z HI(EoR),PSR, VLBI, Lines – 0.281RCP LCP no 400 High-z HI(EoR),PSR, VLBI, Lines – or multiRCP LCP no 150 High-z HI(EoR),PSR, VLBI, Lines Space weather, Low frequency DSN – 1.021RCP LCP yes 60 High-z HI(EoR),PSR, VLBI, Lines Exo-planet science – RCP LCP no 200 HI,PSR,VLBI Early sciences – 0.641RCP LCP yes 60 HI,PSR,VLBI Early Sciences – L wideRCP LCP yes 25 HI,PSR,VLBI,SETI,Lines – Lnarrow multibeam RCP LCP yes 25 HI and PSR survey, Transients – 3.001RCP/ LCP yes 25 PTA, DSN, VLBI, SETI FAST receivers From C. J. Jin

Need a receiver To work at low frequency (<1GHz) to meet early stage pointing accuracy To do a whole FAST sky pulsar survey (L-band 19-beam is not the best one)

7-beam receiver Propose to build a 7-beam receiver for early drift-scan pulsar survey, freq ~ MHz Similar design like current multibeam receivers, easy to build, ready in early 2016 Parkes Effelsberg Arecibo FAST

Pulsar science for 7-beam receiver Low frequency drift-scan pulsar survey – Detect ~2300 normal pulsar (~1700 new) – Detect ~300 MSP (~200 new), good for GW detection M31/M33 pulsar survey (tracking) Radio transient survey – Use same data set (piggyback) – good option for a whole FAST sky (2.3π) survey before PAF receiver is available

7-beam receiver details Optimized for pulsar (transients) survey at early science stage (Sept 2016 or earlier) Freq ~400MHz, BW ~150MHz (1/3 freq) Cooled, T sys without sky ~30K or less Light weight Horn, dipole, etc, not PAF Inexpensive (maybe <1 Million USD) Use 19-beam backends data ~2.4PB (one whole FAST sky scan)

Drift survey simulation with PSRPOP FAST sky drift-scan survey for pulsar Integration time ~40s at 400MHz Two working case – Spherical surface, illuminated aperture D ill decrease as frequency increase, D ill ~ 200m*(f/400MHz)^1/4 (very early stage) – 300m diameter parabola Two population – Normal pulsar – Millisecond pulsar

Drift survey simulation PSRPOP PSRPOP website: Blue: ~100k pulsar generated Red: ~2300 detected by FAST

spherical surface BW = 1/3 freq Integration time ~60s *(400MHz/freq) D ill ~ 200m at 400MHz Number of Normal pulsar detected

300m parabola BW = 1/3 freq Integration time ~40s *(400MHz/freq) 400MHz side is favored because of faster survey speed Number of Normal pulsar detected

For comparison, FAST L-band suvey will detect ~5000 pulsars (Smits et al. 2009)

MSP survey simulation Normal pulsar and MSP are of different population: different spectral index, spatial distribution, etc Change spectral index and spectral index deviation so that the simulation meets both Parkes multibeam survey and 70cm survey Search through the parameter space to find the best point

Sample (~100k pulsar) generated by matching PMB results (L-band) Constrain spectral index and its deviation by matching 70cm survey Green region meets the observed ~20 MSPs from 70cm survey

15 Mean –1.6, deviation 0.35 used by Smits et al Possible region?

16

17 GW detection limits adding new MSP from FAST drift scan survey 36 from IPTA + 40 from FAST plot from K. J. Lee

RFI 2004 final freq and BW depend on RFI

RFI 2005

Single beam wideband receiver for early pulsar timing Effelsberg, GBT, Parkes, Arecibo are developing or discussing wide band pulsar timing receivers ~500MHz-3GHz ~700MHz-4GHz For FAST pulsar timing – 500MHz-3GHz For FAST early science ~270MHz-1450MHz – Low end limited by RFI – High end covers HI Akgiray & Weinreb 2011

Thank You Comments are welcome

Possible region? Mean –1.6, deviation 0.35 used by Smits et al. 2009