pulsar timing at parkes

Pulsar Timing at Parkes

George HobbsCSIRO Australia Telescope National [email protected]

Purpose of talk

• Highlight some recent results relating to pulsar timing and the Parkes Observatory

• Time constraints => will mainly concentrate on work that I’ve been involved in

CSIRO. Gravitational wave detection

Large number of collaborators including: CASS pulsar group, PPTA team, Chinese pulsar community ….


TOA (measured using the observatory clock) Residual

Pulsar timing

Fold Fold

Model

Slide from D. Champion


A few simulations

• With one pulsar you cannot (normally) tell what unmodelled physical effect is causing the residuals

GW background Spin-down irregularities Clock noise

Simulated data


Spin-down irregularities

No angular signature


Terrestrial time standard irregularities

Monopolar signature


Errors in the planetary ephemerides - e.g. error in the mass of Jupiter

Dipolar signature


What if gravitational waves exist?

Quadrapolar signature

Studying individual pulsars using Parkes data

• M. Yu et al. (in preparation) – detection of 105 glitches in 36 pulsars observed at Parkes

• X. You et al. (in preparation) – analysis of the Solar Wind magnetic field and electron density using PPTA observations of J1022+1001

• Manchester et al. (2010) – relativistic spin precession in PSR J1141-6545

• Weltevrede et al. (2010) – Pulsar timing for the Fermi mission• Verbiest et al. (2008) - Limits on the variation of the

gravitational “constant” • You et al. (2007) - Studies of the interstellar medium• ….

• - concentrate in this talk on looking for correlations between timing residuals ….


Developing a pulsar-based time standardParkes data + Arecibo


Pulsar time standard w.r.t TT(TAI)

Best time standard w.r.t. TT(TAI)

Measuring planetary masses

• Use International Pulsar Timing Array data from Parkes, Effelsberg, Nancay and Arecibo.

• Champion et al. 2010, ApJ.• A planetary mass error will lead to incorrect

determination of the Solar System barycentre => correlated pulsar timing residuals

• Can fit to multiple pulsars simultaneously to search for such a signal



Measuring planetary mass

• Champion, Hobbs, Manchester et al. (2010), ApJ, 720, 201• Use data from Parkes, Arecibo, Effelsberg and NancayMSun Best Published This workMercury 1.66013(7)x10-7 1.660(2)x10-7

Venus 2.4478686(4)x10-6 2.44782(10)x10-6

Mars 3.227151(9)x10-7 3.2277(8)x10-7

Jupiter* 9.547919(8)x10-4 9.547916(4)x10-4

Saturn 2.85885670(8)x10-4 2.858858(14)x10-4

9.54791915(11)x10-4

Published limits on gravitational wave background (95% confidence)


All use the same Kaspi et al. (1994) data set

Tentative new bound

Poor choice of pulsar?

Incorrect algorithm?

Use same data set

Pulsar navigation: assume that you are on the Earth’s surface

• PULSE@Parkes observations



• Parkes observations



• Parkes observations … correct to within a few kilometres


Pulsar navigation: in 3D


Conclusion

• Can distinguish between many phenomena by looking for correlated timing residuals between pulsars

• Have improved understanding of individual pulsars• Have developed a pulsar-based time standard• Have the most precise, published, mass estimate for the Jovian

system• Have not detected gravitational waves, but getting closer• Can reverse the timing procedure to determine our position.


pulsar timing at parkes

Documents

gravitational wave background

pulsar timing pulsar

gravitational waves

gravitational constant

cass pulsar group

chinese pulsar community

use data

parkes datam