Long-term X-ray monitoring of the TeV binary LS i +61 303 with the Rossi X-ray Timing Explorer

A. Smith, P. Kaaret, J. Holder, A. Falcone, G. Maier, D. Pandel, M. Stroh

Research output: Contribution to journalArticle

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Abstract

We report on the results of a long-term X-ray monitoring campaign of the galactic binary LS I +61 303 performed by the Rossi X-ray Timing Explorer. This data set consists of 1 ks pointings taken every other day between 2007 August 28 and 2008 February 2. The observations covered six full cycles of the 26.496 day binary period and constitute the largest continuous X-ray monitoring data set on LS I +61 303 to date with this sensitivity. There is no statistically strong detection of modulation of the flux or the photon index with orbital phase; however, we do find a strong correlation between the flux and photon index, with the spectrum becoming harder at higher fluxes. The data set contains three large flaring episodes, the largest of these reaching a flux level of 7.2 +0.1 -0.2 × 10-11 erg cm-2 s-1 in the 3-10 keV band, which is a factor 3 times larger than the flux levels typically seen in the system. Analysis of these flares shows the X-ray emission from LS I +61 303 changing by up to a factor of 6 over timescales of several hundred seconds as well as doubling times as fast as 2 s. This is the fastest variability ever observed from LS I +61 303 at this wavelength and places constraints on the size of the X-ray emitting region.

Original languageEnglish (US)
Pages (from-to)1621-1627
Number of pages7
JournalAstrophysical Journal
Volume693
Issue number2
DOIs
StatePublished - Mar 10 2009

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X Ray Timing Explorer
monitoring
x rays
photons
erg
flares
wavelength
timescale
modulation
orbitals
cycles
sensitivity
wavelengths
index

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Smith, A. ; Kaaret, P. ; Holder, J. ; Falcone, A. ; Maier, G. ; Pandel, D. ; Stroh, M. / Long-term X-ray monitoring of the TeV binary LS i +61 303 with the Rossi X-ray Timing Explorer. In: Astrophysical Journal. 2009 ; Vol. 693, No. 2. pp. 1621-1627.
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Long-term X-ray monitoring of the TeV binary LS i +61 303 with the Rossi X-ray Timing Explorer. / Smith, A.; Kaaret, P.; Holder, J.; Falcone, A.; Maier, G.; Pandel, D.; Stroh, M.

In: Astrophysical Journal, Vol. 693, No. 2, 10.03.2009, p. 1621-1627.

Research output: Contribution to journalArticle

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