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Pulsar search and timing

Pulsar search and timing. Bhal Chandra Joshi . 22/10/2011 INDIGO discussions@IUCAA. Radio pulsar searches . Radio pulsars - highly magnetized rotating NS - compact - periodic pulses

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Pulsar search and timing

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  1. Pulsar search and timing Bhal Chandra Joshi 22/10/2011 INDIGO discussions@IUCAA

  2. Radio pulsar searches • Radio pulsars - highly magnetized rotating NS - compact • - periodic pulses • Motivation – 105 pulsars – exotic systems relevant to GR and GW • Searches - 5 dimensional – RA, Dec, DM, P, Pdot - blind and targetted • Analysis - Similarity with GW searches • - highly compute intensive - DM and resolution (k chan 10 ns) – HPC • - code involves ~ algorithm - harmonic analysis, matched filter, chirp • - interference rejection - RFI • - differences - DM search, resolution, integration time, templ match etc. • - GMRT searches code implemented on 72-node dual processor HPC(up) • Searches - PKSMB - 1000 pulsars - Parkes • - PHMB - 20 pulsars - Parkes - DPSR • - GMLPSR - 3 pulsars - GMRT • -GMGPPTS - 1 pulsar - GMRT • - other GMRT surveys • Goals - Normal pulsars, transient intermittant pulsars, high magnetic field PSR MSPs, binaries - NS-NS and NS-BH - relevance for GW community

  3. Pulsars for GR and GW • Double Pulsar - J0737-3039 – two radio pulsars 22 ms and 2.7 s (Burgay et al. 2003;Lyne et al. 2004) • - tight (2.5h) edge-on mildly elliptical orbit - eclipses of A and BP of B • -sharp pulses of MSP and Shapiro delay of A and B – best GR test • - evolution of light curves B and A - geodetic precession • - monitored at GMRT - no pulsar B now !! • Pulsar Timing Array for nH gravity waves - clock like stability - long time – nHz • Sources - SMBH, • cosmic strings, • inflation

  4. Pulsar Timing • - Most of our knowledge of radio pulsars is derived from pulsar timing studies - Pulsars are timed by associating a Time of Arrival (TOA) at the solar system barycenterto their integrated profiles - Comparison with model, .e.g. Constant period P • Timing Capability of GMRT has been recently established ~ 20 us residual • New pulsars discovered with GMRT are now being timed at GMRT • A project to measure DM variations of MSPs is ongoing • Search for new MSPs - better clocks than about 100 MSPs discovered so far • Aim of PTA to have an ensemble of 20 MSPs with residuals of 1 ns ( 2 100 ns) • Timing precision increases with time - Intensive timing campaign • involving 8 telescopes worldwide (2 USA, 4 Europe, 1 Australia, 1 India)

  5. Instrumentation development • High Time resolution timing - coherent dedispersion - smear in ISM • PSBR - software baseband pulsar backend • Upgrade of GMRT - wideband feeds & wideband backend • - improvement of sensitivity • - new feed design and digital hardware • GMRT Antenna control system upgrade • - improve the quality of GMRT images by better tracking • errors • - research in new control algorithms • - QFT feeback with FEM modeling of antenna structure • - collaborative effort with BARC – EIG, academic • Institutions in India and USA • Future - SKA - 2020 ?

  6. Thank you

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