1. Gravitational Wave Observations with Pulsar Timing Arrays Andrea Lommen Franklin and Marshall College Lancaster, PA

2. Pulsar Timing Array: the GW detector handed to us by the universe Gravitational wave detectors and the wave periods to which they are tuned. CMB polarization experiments – Hubble times PTA (pulsar timing array) - years LISA – hours/seconds? LIGO/TAMA/GEO/VIRGO – seconds/milliseconds?

3. Collaborators Don Backer, UC Berkeley David Nice, Princeton University Andrew Jaffe, Imperial College, London Ingrid Stairs, University of British Columbia Rick Jenet, JPL/Cal Tech

4. The pulsar standard model

5. Millisecond Pulsars make the best clocks

6. The Arecibo Observatory

7. PSR B1855+09 over 17 years Kaspi et al 1994 Residual = TOA - Model

8. What effect would a gravitational wave have on our pulsar timing? From LISA web page: lisa.jpl.nasa.gov Earth Pulsar

9. PSR B1855+09 with a simulated gravitational wave

10. PSR B1855+09 over 17 years

11. Periodogram of B1855+09 residuals

12. Limit on Energy Density of Gravitational Waves

13. Consider a single GW….

14. Jaffe and Backer 2002 Ingredients of new estimate of GW background –Observed population of MBH’s by Merritt and Ferrarese (2001) –Assume the population is constant with redshift –Use Merger rate estimated by Patton et al. (2002) –Look at two different possibilities for the evolution of the merger rate with red shift

15. Characteristic strain spectrum for two models Need plot from Don here.

16. The spectrum of gravitational radiation Figure courtesy of Don Backer

17. PSR B1937+21 over 17 years

18. PSR B1937+21 with a planet included

20. Orbital Motion in the Radio Galaxy 3C 66B: Evidence for a Supermassive Black Hole Binary Hiroshi Sudou, 1* Satoru Iguchi, 2 Yasuhiro Murata, 3 Yoshiaki Taniguchi 1 Supermassive black hole binaries may exist in the centers of active galactic nuclei such as quasars and radio galaxies, and mergers between galaxies may result in the formation of supermassive binaries during the course of galactic evolution. Using the very-long-baseline interferometer, we imaged the radio galaxy 3C 66B at radio frequencies and found that the unresolved radio core of 3C 66B shows well-defined elliptical motions with a period of 1.05 ± 0.03 years, which provides a direct detection of a supermassive black hole binary. Volume 300, Number 5623, Issue of 23 May 2003, pp. 1263-1265. Copyright © 2003 by The American Association for the Advancement of Science. All rights reserved.

22. From Jenet, Lommen, Larson, & Wen, submitted to ApJ Letters Sept 2001

25. Summary Pulsars make a gravitational wave detector that complements LISA, LIGO/TAMA/GEO, and CMB polarization experimentPulsars make a gravitational wave detector that complements LISA, LIGO/TAMA/GEO, and CMB polarization experiment Our new limit on the energy density in gravitational radiation begins to put constraints on the merger rate of galaxiesOur new limit on the energy density in gravitational radiation begins to put constraints on the merger rate of galaxies There are cute things you can do with individual sources tooThere are cute things you can do with individual sources too