The Transient Radio Sky as Viewed from the Allen Telescope Array

Steve Croft
LOFAR and the Transient Radio Sky, Amsterdam, December 2008

Transcript

1. THE TRANSIENT RADIO SKY As Viewed from the Allen Telescope Array Steve Croft UC Berkeley working with Geoff Bower Garrett Keating, Dave MacMahon, Peter Williams, Mel Wright and other collaborators at RAL and the SETI Institute ... and soon, Casey Law
2. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 ATA QUICK FACTS Joint effort between RAL and SETI Dedicated October 11, 2007 at Hat Creek, CA 42 Antennas (LNSD) Fast, for: Surveys Transients
3. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 FAST FOR SURVEYS
4. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 WIDE FIELD OF VIEW Small dishes give wide FOV High survey speed Beam FWHM 2´ x 4´ at 1.4 GHz VLA
5. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 WIDE FIELD OF VIEW Small dishes give wide FOV High survey speed Beam FWHM 2´ x 4´ at 1.4 GHz ATA VLA
6. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 WIDE FREQUENCY COVERAGE 0.5 - 11.2 GHz with 100 MHz bandwidth Multiple back ends allow multiple tunings
7. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 SCIENCE GOALS Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI
8. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI Adam Block & Tim Puckett Adam Block & Tim Puckett SCIENCE GOALS
9. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI Adam Block & Tim Puckett Adam Block & Tim Puckett SCIENCE GOALS
10. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI Adam Block & Tim Puckett Garrett Keating - single ATA pointing SCIENCE GOALS
11. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 SCIENCE GOALS Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI
12. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 SCIENCE GOALS Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI John Rowe - ATNF/CSIRO
13. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 SCIENCE GOALS Large surveys Transients Extragalactic hydrogen Spectroscopy Pulsar timing SETI
14. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CURRENT STATUS OF ATA Major upgrades this year From 8 FX8 to 4 FX64 correlators SETI beamformer, BAPP, Fly’s Eye Feed improvements, software upgrades, etc. Correlator and beamformer are taking data Some projects from external CFP being observed
15. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 FAST FOR SURVEYS
16. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CALIBRATION AND EDITING RAPID - automated RFI detection, intelligent CLEAN NVSS-based selfcal and flagging Solar interference
17. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CALIBRATION AND EDITING RAPID - automated RFI detection, intelligent CLEAN NVSS-based selfcal and flagging Solar interference
18. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CALIBRATION AND EDITING RAPID - automated RFI detection, intelligent CLEAN NVSS-based selfcal and flagging Solar interference
19. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CALIBRATION AND EDITING RAPID - automated RFI detection, intelligent CLEAN NVSS-based selfcal and flagging Solar interference
20. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 Figure 1: An 800-square-degree map made with the ATA in 10 hours of observing from 350 pointings at a frequency of 1.4 GHz. Several thousand sources are detected in the field. FiGSS will survey 10,000 square degrees an order of magnitude deeper. (8; 27) These unknown transient phenomena join the many known but incompletely characterized radio transient phenomena: radio supernovae and gamma-ray burst afterglows (55, including or- phan afterglows), active galactive nuclei, variability induced by interstellar propagation effects (41),
21. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17
22. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 ATATS VS. NVSS
23. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 SOFTWARE FOR TRANSIENT DETECTION SLOW Image mosaics, rejecting bad pointings Generate source lists at each epoch Keep only sources in good regions of all epochs Look for matches (optional NVSS match) Generate light curves and postage stamps
24. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17
25. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17
26. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17
27. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 GOALS FOR ATATS Demonstrate stability and reliability of ATA Find transient sources Build deep map and compare to NVSS Most sources should be stable Some will have changed
28. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 FIGSS 5 GHz Counterpart to Sloan Digital Sky Survey Overlap with NVSS, FIRST & SDSS 104 Square degrees at arcminute resolution High Frequency Deep, Large Radio Survey (0.6 mJy rms - factor ~10 more sensitive than GB6)
29. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 OTHER FUTURE GOALS Build out to 350 dishes SKA pathfinder Simultaneous campaigns
30. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 OTHER FUTURE GOALS Build out to 350 dishes SKA pathfinder Simultaneous campaigns
31. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 OTHER FUTURE GOALS Build out to 350 dishes SKA pathfinder Simultaneous campaigns
32. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 OTHER FUTURE GOALS Build out to 350 dishes SKA pathfinder Simultaneous campaigns
33. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 FLY’S EYE PULSE SEARCH Geoff Bower, Jim Cordes, Griffin Foster, Joeri van Leeuwen, William Mallard, Peter McMahon, Andrew Siemion, Mark Wagner, Dan Werthimer Current data will allow Fly’s Eye Team to place significant constraints on the rate and distribution of bright transients. First pass processing on about 500 hours of observation (50,000 CPU hours on 13 TB of data) is complete. VERY preliminary numbers: A search through 480 hours of processed results found about 50% suitable for automated analysis (low rfi). Approximately 80 events with dispersion measure > 50 pc/cm3 were found above 8.5 sigma. Many of these are obviously RFI, others are “interesting.”
34. Steve Croft, UC Berkeley - LOFAR and the Transient Radio Sky, 2008 Dec 17 CONCLUSIONS Plenty of transient parameter space to explore ATA is starting to do science Simultaneous multi-wavelength observations are important, as is follow-up Very likely we’ll find new classes of object