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Pulsar Science with Shanghai 65m Radio Telescope

Pulsar Science with Shanghai 65m Radio Telescope. Zhen Yan, Zhi-Qiang Shen, Xin-Ji Wu. On behalf of the Shanghai 65m Radio Telescope Team. Outline. Introduction to pulsar observation Introduction to SH-65m radio telescope Four low frequency Receivers of SH-65m

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Pulsar Science with Shanghai 65m Radio Telescope

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  1. Pulsar Science with Shanghai 65m Radio Telescope Zhen Yan, Zhi-Qiang Shen, Xin-Ji Wu On behalf of the Shanghai 65m Radio Telescope Team

  2. Outline • Introduction to pulsar observation • Introduction to SH-65m radio telescope • Four low frequency Receivers of SH-65m • The radio environment at SH-65m • Tentative pulsar observations with SH-65m • Prospects of pulsar observations with SH-65m • Conclusion

  3. yanzhen@shao.ac.cn

  4. The challenge of pulsar observation Observation sensitivity α dimensionlessloss factor, βthreshold signal-to-noise ratio, Tsys systemtemperature, Gtelescope gain, Npolnumber of polarizations, Bobservingbandwidth, tintegration time, δeffective dutycycle.

  5. Introduction to Shanghai 65m radio telescope • New built 65-m in diameter fully steerable radio telescope located in Song-Jiang district of Shanghai city • Phase of the SH-65m project • Funded in 2008; • Started manufacturing in 2009; • its 1st phase will be finished in July 2013, four low frequency receivers (L,S,C,X) have been installed. • Will expand to Q-band (43GHz) in 2015 using active surface system to make sure its efficiency

  6. The location of SH65

  7. The radio environment at SH-65m

  8. Comparison SH65m with other telescopes System Equivalent Flux Density (SEFD):

  9. Tentative Pulsar Observations with SH-65m • Backed: Pulsar Digital Filter Bank (PDFB4) from ATNF • Under the kind help of YNAO & NAOC • Incoherent de-dispersion • Maximum bandwidth 512MHz • S-band & X-band observations • S-band: band width ~150MHz used • X-band: band width ~350MHz used • Pulsars including normal pulsars and millisecond pulsars

  10. 38mJy@1.4G, Ob: S-band, tint~3min A Normal Pulsar –B2020+28

  11. 14mJy@1.4G, Ob: S-band, tint~15min Crab-A pulsar with frequent glitch

  12. A MSP-J2145-0450 8.9mJy@1.4G, Ob: S-band, tint~18min MSP

  13. A larger DM pulsar-J0248+6021 DM=370, Ob: S-band, tint~15min

  14. B0355+54@X-band 23mJy@1.4G, Ob: X-band, tint~5min

  15. DIBAS-The Digital BackendSystem for SH65m • Search mode • One beam, dual polarization • Up to 2 GHz bandwidth, depending on the analog bandwidth available at the telescope • 256, 512, 1024, 2048, 4096, and 8192 spectral channels • Full Stokes, summed polarizations, or Stokes I only modes • 8 bit output width • 800 MB/sec maximum output data rate to disks on a clustered file system • Online folding mode • Coherent-dedispersion & incoherent-dedispersion • Operate at 2 GHz bandwidth yanzhen@shao.ac.cn

  16. Block Diagram (GTX-580 GPU)

  17. The Advantage of C-band pulsar search • Low frequency is blocked by thick plasma around the Galactic center • lower galactic noise background, as the galactic noise is steeper power law • weaker dispersion effect, as the dispersion delay is in proportion with the square of observation frequency • weaker scattering, as the width of scattering broadening is in proportion of 4th power of observation frequency; • weaker scintillation Yellow：discovered by 1.4GHz survey Black：discovered by 430MHz survey

  18. A sample of pulsars discovered by Parkes-64m @6.5GHz the DM of these pulsars are very large (>900 pc cm−3) yanzhen@shao.ac.cn

  19. Unassociated γ-ray point sources GBTsearch 27bright γ-ray unassociated source，3 new pulsar discovered（all of them are binary）!

  20. Globular clusters • Globular clusters, which are found in the halo of a galaxy, contain considerably more stars and are much older than the less dense galactic, or open clusters, which are found in the disk. Globular clusters are fairly common; there are about 150to 158 currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered. • ~200 pulsars have been discovered in Globular clusters by now. • Most of these pulsars are recycled pulsars (P<50ms)

  21. Advantage of galactic center pulsar observation with sh-65m • By now, 5 pulsars have been discovered in the galactic center. (Johnston et al., 2006, Deneva1 et al.,2009) • Pfahl & Loeb（2004）predicted that there are at least 100-1000 pulsars circle Sgr A* . • Compared with Parkes 64m C-band pulsar search, the sensitivity of our search is with higher sensitivity. • Higher frequency is the good choice when we want to find some new pulsars in the galactic central area. This is approve by following research work: • A magnetar PSR J1745-2900 discovered only 3” from Sgr A* • This pulsar has detected with large telescope at 2.5GHz, 4.85 GHz, 7GHz, 8GHz, 14.6 GHz, 22GHz • But it can not be detected at 1GHz with GMRT and 1.5GHz with Lovell Telescope

  22. Multi-frequency observation • The multi-frequency integration profile and flux density are important information for studying the pulsar radiation process • The high frequency (>4GHz) integration profile and flux density of almost all the pulsars have not been measured. • A project that measures the high frequency integration profile and flux density of a large sample (~60) of pulsars with SH65m will be carried out. • C-band (central frequency ~5GHz), for some strong pulsars, will expand to X-band

  23. The pulsar Catalog ---------------------------------------------------------------------------- # NAME P0 DM W10 S1400 (s) (cm^-3 pc) (ms) (mJy) ---------------------------------------------------------------------------- 1 B0329+54 0.714520 26.83 31.400 203.00 2 B0950+08 0.253065 2.96 20.600 84.00 3 B1933+16 0.358738 158.52 17.700 42.00 4 B2020+28 0.343402 24.64 15.800 38.00 5 B1929+10 0.226518 3.18 14.000 36.00   6 B1133+16 1.187913 4.86 41.800 32.00 7 B2016+28 0.557953 14.17 22.200 30.00 8 B2021+51 0.529197 22.65 29.400 27.00 9 B0355+54 0.156382 57.14 10.800 23.00 ……. 56 J1852-0635 0.524151 171.00 * 5.90 57 B1900+01 0.729304 245.17 23.000 5.50 58 B2106+44 0.414871 139.83 102.000 5.40 59 B0450-18 0.548939 39.90 36.800 5.30 ----------------------------------------------------------------------------

  24. Single pulse observation • Pulsars with giant pulse • —————————————————— • PSR P (ms) S1400 (mJy) • —————————————————— • B0531+21 33 14.00 • B1937+21 1.5 10 • B0031-07 942 11.00 • B0656+14 385 3.70 • ____________________________________ • In order to study their radiation process (coherent curvature radiation, plasma ) • Carried out at L / C band • 30min/pulsar, twice a month; or monitoring one pulsar for several hours

  25. RRAT (rotating radio transient) • Discovered recent years (2006) ———————————————————————————————— RRAT P (s) DM (cm-3 pc) S1400 (mJy) 备注 ———————————————————————————————— J1819-1458 4.263 196 3600 新疆25米1.5GHz已观测 J1826-17 0.77 159 600 尝试65米能否观测到 J1913+1333 0.92 175 650 尝试65米能否观测到 ————————————————————————————————

  26. Pulsars with nulling phenomenon • Candidates --------------------------------------------------------------------------- • NameP(s) NF (percent) S1400 (mJy) -------------------------------------------------------------------------- J1115+5030 1.656 60 3 J1717–4054 0.887 >95 54 J1727–2739 1.293 52 (3) 1.6 J1933+2421 0.814 80 25.9（400MHz） J1944+1755 1.997 60 40（400MHz） J1946+1805 0.441 55 10 J1853+0505 0.905 73 1.5 ---------------------------------------------------------------------------- • Observe at L&C band • 2 hours/pulsar, twice a month Wang et al., 2007

  27. Pulsars with mode change • L&C band • 30min/pulsar, twice a month --------------------------------------------- # NAME P0 DM S1400 (s) (cm^-3 pc) (mJy)----------------------------------------------------------------1 B0329+54 0.714520 26.83 203.002 B0355+54 0.156382 57.14 23.003 B1937+21 0.001558 71.04 13.204 B1822-09 0.769006 19.38 12.005 B2319+60 2.256488 94.59 12.006 B0031-07 0.942951 11.38 11.007 B0809+74 1.292241 6.12 10.008 B0823+26 0.530661 19.45 10.009 B1237+25 1.382449 9.24 10.0010 B0818-13 1.238130 40.94 7.00-----------------------------------------------------------------

  28. Regular pulsar timing yanzhen@shao.ac.cn

  29. Pulsar in the Galactic center • (C-band, ~1hour/pulsar) • MSPs selected from NanoGrav, EPTA& PPTA source list • (L-band,~30min/pulsar) • Pulsar with glitch phenomenon, such as Crab et al • (C-band, >30min/pulsar). • twice a month • Long term monitoring. The longer the better.

  30. Pulsar scintillation at C-band GBT have detected the scintillation of PSR B0329+54 at 15GHz (private discussion) Lorimer & Kramer 2005 Wang et al., 2005

  31. Pulsar Astrometry with VLBA plus SH-65m For pulsars located at high declination (DEC>45 deg), the resolution in right ascension (RA) will be affected because of the limited length of projected baseline along East-West direction of VLBA . The partition of some Chinese antennas will lengthen the baseline twice times in East-West direction and make the UV-coverage of observation of source much better. . Yan et al.,2013

  32. Conclusions • Pulsar will be one of important scientific targets of SH-65m • Some tentative pulsar observations with SH-65m have been done. And good results have been obtained. • SH-65m can play an important role in the fields of pulsar research, such as pulsar searching, nulling, giant pulse, RRAT, pulsar timing, astrometry plus VLBA et al. We are looking for cooperators who are interested with about fields. Welcome to use our telescope!

  33. Thank you!

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