XMM-Newton RGS and Chandra LETGS observations of the WHIM in 1ES 1028+511

Abstract

We report preliminary results on the detection of the Warm-Hot Intergalactic Medium (WHIM) along the line of sight toward the blazar 1ES 1028+511 (z = 0.361). 1ES 1028+511 was observed for 150 ks with the low energy transmission grating in combination with the high resolution camera onboard Chandra. An additional 300 ks observation was obtained using the reflection grating spectrometers (RGS) onboard XMM-Newton. We report the detection of three absorption lines which can be attributed to the WHIM, and compare the results with theoretical predictions.

2 pages, 1 figure, to appear in the proceedings of "The X-ray Universe 2005", San Lorenzo de El Escorial (Spain), 26-30 September 2005