Upload
chloe-miller
View
247
Download
1
Embed Size (px)
Citation preview
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
No Band (GHz) Beams Pol. CryoTsys(K)
Science
1 0.07 – 0.14 1 RCP LCP
no1000
High-z HI(EoR),PSR, VLBI, Lines
2 0.14 – 0.28 1 RCP LCP
no400
High-z HI(EoR),PSR, VLBI, Lines
3 0.28 – 0.56 1 or multi RCP LCP
no150
High-z HI(EoR),PSR, VLBI, LinesSpace weather, Low frequency DSN
4 0.56 – 1.02 1 RCP LCP
yes60
High-z HI(EoR),PSR, VLBI, LinesExo-planet science
5 0.320 – 0.334 1 RCP LCP
no200
HI,PSR,VLBIEarly sciences
6 0.55 – 0.64 1 RCP LCP
yes60
HI,PSR,VLBIEarly Sciences
7 1.15 – 1.72 1 L wide RCP LCP
yes25
HI,PSR,VLBI,SETI,Lines
8 1.05 – 1.45 19 Lnarrow multibeam
RCP LCP
yes25
HI and PSR survey, Transients
9 2.00 – 3.00 1 RCP/LCP
yes25
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 ~400-560MHz
• 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, Tsys 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 Dill decrease as
frequency increase, Dill ~ 200m*(f/400MHz)^1/4 (very early stage)
– 300m diameter parabola• Two population– Normal pulsar– Millisecond pulsar
Drift survey simulation PSRPOP
PSRPOP website: http://psrpop.sourceforge.net/
Blue: ~100k pulsar generated Red: ~2300 detected by FAST
spherical surface
BW = 1/3 freqIntegration time ~60s *(400MHz/freq)Dill ~ 200m at 400MHz
Number of Normal pulsar detected
300m parabola
BW = 1/3 freqIntegration 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. 2009
Possible region?
16
17
GW detection limits adding new MSP from FAST drift scan survey36 from IPTA + 40 from FASTplot from K. J. Lee
RFI 2004 final freq and BWdepend 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 YouComments are welcome
Possible region?
Mean –1.6, deviation 0.35 used by Smits et al. 2009