1 / 23

The Character of High Energy Emission From The Galactic Binary LS 1 +61 303

The Character of High Energy Emission From The Galactic Binary LS 1 +61 303. Andy Smith Smithsonian Astrophysical Observatory (for the VERITAS collaboration). LS 1 +61 303. -High Mass X-ray Binary -BH or NS? -26.496 day period -periodic outbursts in X-ray, radio, GeV ,

marysbrown
Download Presentation

The Character of High Energy Emission From The Galactic Binary LS 1 +61 303

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Character of High Energy Emission From The Galactic Binary LS 1 +61 303 Andy Smith Smithsonian Astrophysical Observatory (for the VERITAS collaboration)

  2. LS 1 +61 303 -High Mass X-ray Binary -BH or NS? -26.496 day period -periodic outbursts in X-ray, radio, GeV, and TeV gamma rays!

  3. LS 1 +61 303 Archival X-ray Outbursts (ROSAT,RXTE, XMM-Newton)

  4. LS 1 +61 303 TeV Emission (MAGIC)

  5. LS 1 +61 303 LS 1 +61 303 TeV Emission (MAGIC, VERITAS Radio Emission (VLA, GBI)

  6. Microquasar or Binary Pulsar?

  7. LS 1 +61 303 However, identification of system still an open issue- multiwavelength observations (with TeV) help to constrain rise time of high energy emission in different bands Pulsar Model given support by VLBA monitoring No X-ray or radio pulsations detected, but… Dhawan et al 2006

  8. VERITAS LS I +61 303 Observations: - New TeV Array in S. Arizona (see T.Weekes on Sat) -Sensitive in range 100 GeV->20 TeV -44h of data from September 2006-February 2007 -Observations covered phase bins 0.2-0.9 ->10 sigma detection in “active” phase bins (0.5-0.8)

  9. Phases 0.5->0.8

  10. TeV activity coincides with near-apastron passage

  11. Multiwavelength Monitoring • ToO observations approved for SWIFT and RXTE in late 2006 • RXTE: 2-10 keV monitoring in October • SWIFT 0.2-10 keV monitoring Sep->Dec (PSU data reduction: A.Falcone,D.Morris) • Flares observed by both instruments around phases 0.6->0.7

  12. Contemporaneous observations during Tev/X-ray flaring states

  13. Very high flux seen in both bands on same night- spectral analysis forthcoming

  14. Contemporaneous observations during X-ray flaring states

  15. TeV emission elevated, but not maximal Local TeV Peak Local X-ray Peak X-ray emission elevated, but not maximal

  16. Active TeV regions Active X-ray Regions

  17. Summary so far… • VERITAS observations confirm detection of LS 1 +61 303 as variable TeV source • One of 3 known “TeV” binaries- new class of sources • Multiwavelength observations show elevated TeV emission correlated with elevated X-ray behavior (not necessarily bijective....) • SWIFT observations show secondary X-ray peak near pre-periastron passage- no TeV observations yet for this region.

  18. Latest Observations…… TeV Emission X-ray Peaks

  19. Microquasar Scenario: X-ray Accretion Disk- ->Radio Loud Jets ->Upscatter stellar photons to TeV energies TeV Emission Accretion driven emission during and after density peaks. Supporting Evidence: -MERLIN Imaging -TeV emission agreeable with “Second Peak” Cons: No spectral evidence for accretion Where is primary peak?

  20. Or…….. Binary Pulsar Scenario: Shock acceleration at interface between pulsar and stellar wind drives X-ray/TeV emission- radio emission from cometary tail Cons: -No evidence for pulsations -Is stellar wind stronger than pulsar wind? -Difficult to say without greater understanding of orbital geometry Observational Evidence: -VLA imaging strongest evidence -Close rise time of X-ray/TeV emission

  21. Secondary X-ray Peak? TeV Emission X-ray Peaks

  22. Summary • Latest high energy observations of LS 1 +61 303 show evidence for correlation between X-ray and TeVbehavior • No clear indication of fundamental identification of system • Regardless of nature (MQ vs BP) , it is evident that “local“ compact systems are able to accelerate (most likely) electrons to TeV energies . • TeV binaries represents ideal laboratories for observations of high energy emission in the presence of strong gravity stellar environments.

  23. Watch this space....... • RXTE monitoring approved for bi-nightly observations from September 2007-->February 2008 • This, combined with TeV monitoring from VERITAS, will allow first multiwavelength observations taken between phases 0.9->0.2: more accurate measurement of full cycle behavior • If LS1 is a black hole, will add to study of BH dynamics. If it is a binary pulsar, will add to study of pulsar wind acceleration

More Related