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arXiv · astro-ph/9907383

Simultaneous X-ray and infrared variability in the quasar 3C273

Ian McHardy·Anthony Lawson·Andrew Newsam·Alan Marscher·Ian Robson·Jason Stevens
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Abstract

From a combination of high quality X-ray observations from the NASA Rossi X-ray Timing Explorer (RXTE), and infrared observations from the UK Infrared Telescope (UKIRT) we show that the medium energy X-ray (3-20 keV) and near infrared fluxes in the quasar 3C273 are highly correlated. It is widely believed that the X-ray emission in quasars like 3C273 arises from Compton scattering of low energy seed photons and our observations provide the first reliable detection of correlated variations in 3C273 between the X-ray band and any lower energy band. For a realistic electron distribution we demonstrate that it is probable that each decade of the seed photon distribution from the mm to IR waveband contributes roughly equally to the medium energy X-ray flux. However the expected mm variations are too small to be detected above the noise, probably explaining the lack of success of previous searches for a correlation between X-ray and mm variations. In addition we show that the infrared leads the X-rays by 0.75+/-0.25 days. These observations rule out the `External Compton' emission process for the production of the X-rays.

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Ian McHardy, Anthony Lawson, Andrew Newsam, Alan Marscher, Ian Robson, Jason Stevens. 1999-07-27. Simultaneous X-ray and infrared variability in the quasar 3C273. https://doi.org/10.1046/j.1365-8711.1999.02959.x

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