Search Publications
Multiwavelength campaign on Mrk 509. XII. Broad band spectral analysis
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +12 more
The origin of the different spectral components present in the high-energy (UV to X-rays/gamma-rays) spectra of Seyfert galaxies is still being debated a lot. One of the major limitations, in this respect, is the lack of really simultaneous broad-band observations that allow us to disentangle the behavior of each component and to better constrain …
X-ray follow-ups of XSS J12270-4859: a low-mass X-ray binary with gamma-ray Fermi-LAT association
Mukai, K.; Belloni, T.; de Martino, D. +10 more
Context. XSS J1227.0-4859 is a peculiar, hard X-ray source recently positionally associated to the Fermi-LAT source 1FGL J1227.9-4852/2FGL J1227.7-4853. Multi-wavelength observations have added information on this source, indicating a low-luminosity low-mass X-ray binary (LMXB), but its nature is still unclear.
Aims: To progress in our unders…
No anticorrelation between cyclotron line energy and X-ray flux in 4U 0115+634
Klochkov, D.; Wolff, M. T.; Wilms, J. +18 more
We report on an outburst of the high mass X-ray binary 4U 0115+634 with a pulse period of 3.6 s in 2008 March/April as observed with RXTE and INTEGRAL. During the outburst the neutron star's luminosity varied by a factor of 10 in the 3-50 keV band. In agreement with earlier work we find evidence of five cyclotron resonance scattering features at ~…
Kinematics of massive star ejecta in the Milky Way as traced by 26Al
Wang, Wei; Gerhard, Ortwin; Diehl, Roland +5 more
Context. Massive stars form in groups and their winds and supernova explosions create superbubbles up to kpc in size. The fate of their ejecta is of vital importance for the dynamics of the interstellar medium, for chemical evolution models, and the chemical enrichment of galactic halos and the intergalactic medium. However, ejecta kinematics and …
Infrared identification of high-mass X-ray binaries discovered by INTEGRAL
Chaty, S.; Rahoui, F.; Tomsick, J. A. +2 more
Context. Since it started observing the sky, the INTEGRAL satellite has discovered new categories of high mass X-ray binaries (HMXB) in our Galaxy. These observations raise important questions on the formation and evolution of these rare and short-lived objects.
Aims: We present here new infrared observations from which to reveal or constrain…
Unveiling the nature of INTEGRAL objects through optical spectroscopy. X. A new multi-year, multi-observatory campaign
Palazzi, E.; Minniti, D.; Masetti, N. +18 more
Within the framework of our program (running since 2004) of identification of hard X-ray INTEGRAL sources through optical spectroscopy, we present the results concerning the nature of 33 high-energy objects. The data were acquired with the use of six telescopes of different sizes and from one on-line archive. The results indicate that the majority…
Tidal disruption of a super-Jupiter by a massive black hole
Walter, R.; Nikołajuk, M.
Aims: A strong, hard X-ray flare was discovered (IGR J12580+0134) by INTEGRAL in 2011, and is associated to NGC 4845, a Seyfert 2 galaxy never detected at high-energy previously. To understand what happened we observed this event in the X-ray band on several occasions.
Methods: Follow-up observations with XMM-Newton, Swift, and MAXI are …
RX J0440.9 + 4431: a persistent Be/X-ray binary in outburst
Klochkov, D.; Ferrigno, C.; Bozzo, E. +3 more
The persistent Be/X-ray binary
Variable pulse profiles of Hercules X-1 repeating with the same irregular 35 d clock as the turn-ons
Klochkov, D.; Wilms, J.; Staubert, R. +4 more
The accreting X-ray pulsar Her X-1 shows two types of long-term variations, both with periods of ~35 days: 1) turn-on cycles, a modulation of the flux, with a ten-day long main-on and a five-day long short-on, separated by two off-states, and 2) a systematic variation in the shape of the 1.24 s pulse profile. While there is general consensus that …
The simultaneous low state spectral energy distribution of 1ES 2344+514 from radio to very high energies
Maraschi, L.; Covino, S.; Antonelli, L. A. +193 more
Context. BL Lacertae objects are variable at all energy bands on time scales down to minutes. To construct and interpret their spectral energy distribution (SED), simultaneous broad-band observations are mandatory. Up to now, the number of objects studied during such campaigns is very limited and biased towards high flux states.
Aims: We pres…