Timing studies and PSR J analysis Till Eifert, HU Berlin April, 2005

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 2 Outline ○Analysis of pulsar timing data Improvement of barycenter correction Implementation of binary correction ○PSR J Data analysis, first results ○Conclusion / Outlook

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 3 Analysis of pulsar timing data Given: GPS event time stamp from CentralTrigger intrinsic accuracy of GPS 10 μs ~ 30 μs from peak jitter of optical pulsar measurements Phase of a pulsar waveform depends on: ○Spin-down (→ ATNF PSR DB) ○Motion of Earth within the solar system (→ barycenter correction) ○Orbital motion of the pulsar (→ binary correction) Crosscheck with TEMPO: ○Standard tool from radio astronomers ○Evolving since 1972 ○Accuracy < μs range, proved by extensive tests with 6 years of data.

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 4 Barycenter correction t = toa in TDT (UTC + leap seconds) system t b units: Barycentric Dynamical Time (TDB) ∆t SSB correction to solar system barycenter (Roemer time delay) ∆t E  solar system “Einstein delay” (gravitational redshift & time dilation due to motions of the Earth = TDB correction) ∆t S  “Shapiro delay” (caused by propagation of the pulsar signal through curved spacetime) Taken from F. Schmidt

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 5 CRASH vs. TEMPO CRASH vs. TEMPO timing corrections: ○∆t E  (TDB) (< 25 μs) ○∆t S  + ∆t SSB (< 0.12 ms) ○proper motion, parallax not used for phase calculation in old Crash! Good enough? For young PSR: Yes! What about ms PSR? TDB (Crash – Tempo) SSB + Shapiro (Crash – Tempo)

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 6 CRASH vs. TEMPO PSR J0437 ephemeris (P ~ 5.7ms, proper motion ~ 100 mas/yr, parallax ~ 7 mas) ∆t b < 2 ms Thus, CRASH not applicable for analysis over long observation period of close ms PSR! ∆t bary (Crash – Tempo) ∆p (Crash – Tempo)

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 7 Improvements New in Crash module: ○New TDB algorithm ○New barycenter algorithm, taking into account: Shapiro delay Proper motion Parallax ○New routines to read in TEMPO and GRO parameter files ○Two binary models added ∆t bary (Crash – Tempo) ∆p (Crash – Tempo)

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 8 Improvements (zoomed) New in Crash module: ○New TDB algorithm ○New barycenter algorithm, taking into account: Shapiro delay Proper motion Parallax ○New routines to read in TEMPO and GRO parameter files ○Two binary models added ∆t bary (Crash – Tempo) ∆p (Crash – Tempo)

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 9 Binary models PSR in binary system → significant acceleration Blandford-Teukolsky (BT) model: ○Keplerian ellipse ○Newtonian dynamics ○ Einstein delay patched into model afterwards ○ additional effects are accommodated by nonzero time derivatives Damour-Deruelle (DD) model: ○more general ○Roemer time delay ○Orbital Einstein and Shapiro delay ○Aberration caused by rotation

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 10 Checking BT model correction against TEMPO ∆t binary < s

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 11 Checking DD model correction against TEMPO ∆t binary < s

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 12 Outline ○Analysis of pulsar timing data Improvement of barycenter correction Implementation of binary correction ○PSR J Data analysis, first results ○Conclusion / Outlook → New code: good agreement (<μs) with TEMPO Code will be merged with CVS head soon

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 13 PSR J ○Distance ~ 140 pc ○P ~ 5.75 ms, dP/dt ~ ○Low B ~ G ○Binary orbit ~ 5.74 days ○Low mass companion ~ 0.2 M  ○Not eclipsing ○No optical brightness variation ○Pulsed emission visible in radio, X-rays Harding, A.K., Usov, V. V., Muslimov, A. G., 2005, ApJ, 622, 531 Polar Cap model prediction

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 14 PSR J Radio observation at Parkes Two phase cycles! ROSAT High Resolution Imager (HRI) ROSAT Position Sensitive Proportional Counter (PSPC) Chandra High Resolution Camera (HRC)

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 15 Data analysis ○Data from October 2004 ○22 runs with 4 telescopes (passed quality check), ~ 9.1 h livetime ○Zenith angle range: 23.9 – 30 deg ○Energy threshold ~ 200 GeV ○Std. Hd Cuts: desert/phase1_0510_south ○Background model: SevenBackgroundMaker ○PSR analysis: ephemeris from ATNF ○Statistical tests: Z 2, H

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 16 DC analysis Std. Hd cuts 9.1 h livetime Significance: 0.4 σ … What about AC?

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 17 Timing analysis Question: just a fluctuation or possible hint for pulsed TeV emission? (note: fluctuation is on the right phase position!) On region Z 2 1 = 5.6 (Prob. 0.06) Z 2 2 = 5.7 (Prob. 0.23) H = 5.6 OFF region with highest H = 3.8 All energies, DC: 0.4 σ OFF regions (summed) ~ flat

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 18 Timing analysis, energy bins On region Z 2 1 = 6.4 (Prob. 0.04) Z 2 2 = 6.7 (Prob. 0.15) H = 6.4 All energies < 0.5 TeV, DC: 0.5 σ OFF regions flat All energies > 0.5 TeV, DC: -0.2 σ On region Z 2 1 = 0.2 (Prob. 0.92) Z 2 2 = 2.2 (Prob. 0.70) H = 0.2

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 19 Zenith angle DC Significance Energy < 0.5 TeV Maximize signal/noise ratio for low energy by using very small zenith angles only

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 20 Timing analysis All energies < 0.5 TeV, zenith angle < 25 deg On region DC: 2.0 σ 5.6 h livetime Z 2 1 = 9.4 (Prob ) Z 2 2 = 11.3 (Prob. 0.02) H = 9.4 OFF regions flat (max H = 2.2) with std. HD cuts !

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 21 Conclusion / Outlook ○We have developed and tested the tools to analyse ms PSR (sub μs agreement with TEMPO) ○It is difficult to ignore the fluctuation at the right phase position ○Optimizing cuts on MC with exp. cut-off spectra ○Cross-check with Mathieu’s model analysis ○We need more data with very low zenith angle

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 22 Leap seconds in UTC |UT1-UTC| < 0.9 seconds → leap seconds UT1: time scale based on the Earth’s rotation (irregular fluctuations, general slowing down) UTC: TAI (International Atomic Time) + leap seconds Taken from Earth Orientation Center

H.E.S.S. Collaboration Meeting, Palaiseau, 2005Till Eifert, HU Berlin p. 23 Data analysis On region Z 2 1 = 9.1 (Prob. 0.01) Z 2 2 = 9.3 (Prob. 0.05) H = 9.1 All energies: TeV, all zenith angle