Search Publications
Multi-messenger astronomy with INTEGRAL
Mereghetti, Sandro; Götz, Diego; Kuulkers, Erik +19 more
At the time of defining the science objectives of the INTernational Gamma-Ray Astrophysics Laboratory (INTEGRAL), such a rapid and spectacular development of multi-messenger astronomy could not have been predicted, with new impulsive phenomena becoming accessible through different channels. Neutrino telescopes have routinely detected energetic neu…
Empirical tests of pre-main-sequence stellar evolution models with eclipsing binaries
Torres, Guillermo; Stassun, Keivan G.; Feiden, Gregory A.
We examine the performance of standard pre-main-sequence (PMS) stellar evolution models against the accurately measured properties of a benchmark sample of 26 PMS stars in 13 eclipsing binary (EB) systems having masses 0.04-4.0 M⊙ and nominal ages ≈1-20 Myr. We provide a definitive compilation of all fundamental properties for the EBs, …
Supersoft X-ray sources: Confronting the van den Heuvel paradigm
Charles, P. A.; Heathcote, B.; McGowan, K. E. +3 more
The origin of the extremely soft (low temperature) X-rays produced in the supersoft X-ray sources (or SSS) has been a subject of debate for much of the 25 years since their discovery. The currently accepted paradigm is that they are Eddington-limited accreting white dwarfs in which the accreted material is undergoing steady nuclear burning, thereb…
High velocity outflows in narrow absorption line quasars
Chartas, G.; Giustini, M.; Charlton, J. +6 more
The current paradigm for the AGN phenomenon is a central engine that consists of an inflow of material accreting in the form of a disk onto a supermassive black hole. Observations in the UV and optical find high velocity ionized material outflowing from the black hole. We present results from Suzaku and XMM-Newton observations of a sample of intri…
Cold and hot gas in the most HI deficient compact groups
Yun, Min S.; Verdes-Montenegro, Lourdes; Borthakur, Sanchayeeta +2 more
Dense groups of galaxies should be prime sites for galaxy interactions and mergers, and their evolution has been the subject of controversy for 25 years. In order to explain the HI deficiency found in compact groups of galaxies we previously proposed an evolutionary scenario in which the amount of HI decreases with the secular evolutionary state o…
Origin of the shrapnels around the Vela SNR
Katsuda, Satoru; Tsunemi, Hiroshi
There are several shrapnels around the Vela SNR that originated from the inner layer of the progenitor star. We present here the analysis of the X-ray spectrum of the Vela shrapnel A with XMM-Newton satellite. The Vela shrapnel A is one of several protrusions identified as bullets from Vela supernova explosion. We confirmed that there was a promin…
Elemental composition and distribution in SNRs: X-ray spectroscopy
Decourchelle, A.
I present a comparative review focusing on three young Supernova Remnants, Cas A, Tycho and Kepler, in the light of recent X-ray observations obtained with the XMM-Newton and Chandra satellites. Recently available, X-ray spectro-imagery of young Supernova Remnants is providing unique information on the interaction region between the ejected materi…
The downward X-ray spectrum of PKS 2155-304 in the inner jet description
Ciprini, Stefano
The compact radio source PKS 2155-304 ( z=0.116) is a gamma-ray blazar and one of the brightest in UV and X-ray bands, repeatedly monitored at X-ray frequencies in the past years, and observed recently by Chandra and XMM-Newton. Various intensity states and a continuously downward-curved trend with the energy is displayed clearly, summarizing some…
XMM-Newton observations of absorption features towards PKS 2155-304
Maraschi, L.; Tavecchio, F.; Treves, A. +2 more
We present XMM-Newton grating spectra of the bright BL Lac object PKS 2155-304 taken in November 2000. Various absorption features are detected in the range 5-38 Å. The results are compared with those recently obtained with Chandra gratings [ApJ 573 (2002) 157; Nature, 421 (2003) 719]. We discuss whether the absorption occurs at the source (in the…
Temporal variability of Mrk 421 from XMM-Newton observations
Haberl, F.; Papadakis, I.; Brinkmann, W. +1 more
Mrk 421 has been observed several times as a calibration target for the instruments on board XMM-Newton. We have studied in some detail the temporal and spectral variability of the source during eight pointings, mainly from the PN camera, which provides the by far highest S/N data available for that source.