Search Publications
Swift J164449.3+573451 and Swift J2058.4+0516: Black hole mass estimates for tidal disruption event sources
Titarchuk, Lev; Seifina, Elena; Virgilli, Enrico
A tidal disruption event (TDE) is an astronomical phenomenon in which a previously dormant black hole (BH) destroys a star passing too close to its central part. We analyzed the flaring episode detected from the TDE sources, Swift J164449.3+573451 and Swift J2058.4+0516 (hereafter Swift J1644+57 and Swift J2058+05, respectively) using RXTE, Swift …
Discovery of Galactic O iv and O v X-ray absorption due to transition temperature gas in the PKS 2155-304 spectrum
Kaastra, J.; Bonamente, M.; Paerels, F. +4 more
Far-ultraviolet (FUV) observations have revealed transition temperature gas (TTG; log T(K) 5), located in the lower Galactic halo and in high-velocity clouds. However, the corresponding X-ray absorption has so far remained mostly undetected. In order to make an improvement in this respect in Galactic X-ray absorption studies, we accumulated very d…
Physical properties of seven binary and higher-order multiple OB systems
Mayer, Pavel; Harmanec, Petr; Chini, Rolf +7 more
Analyses of multi-epoch, high-resolution (R 50 000) optical spectra of seven early-type systems provided various important new insights with respect to their multiplicity. First determinations of orbital periods were made for HD 92206 C (2.^d022), HD 112244 (27.^d665), HD 164438 (10.^d25), HD 123056 A ( 1314 d) and HD 123056 B (<2 d); the orbit…
High signal-to-noise spectral characterization of the planetary-mass object HD 106906 b
Fortney, Jonathan J.; Meyer, Michael R.; Quanz, Sascha P. +4 more
Context. Directly imaged planets are ideal candidates for spectroscopic characterization of their atmospheres. The angular separations that are typically close to their host stars, however, reduce the achievable contrast and thus signal-to-noise ratios (S/N).
Aims: We spectroscopically characterize the atmosphere of HD 106906 b, which is a yo…
X-ray orbital modulation of a white dwarf accreting from an L dwarf. The system SDSS J121209.31+013627.7
de Martino, D.; Stelzer, B.; Wynn, G. A. +2 more
In an XMM-Newton observation of the binary SDSS J121209.31+013627.7, consisting of a white dwarf and an L dwarf, we detect X-ray orbital modulation as proof of accretion from the substellar companion onto the magnetic white dwarf. We constrain the system geometry (inclination as well as magnetic and pole-cap angle) through modelling of the X-ray l…
"TNOs are Cool": A survey of the trans-Neptunian region. XIII. Statistical analysis of multiple trans-Neptunian objects observed with Herschel Space Observatory
Lellouch, E.; Stansberry, J.; Doressoundiram, A. +3 more
Context. Gravitationally bound multiple systems provide an opportunity to estimate the mean bulk density of the objects, whereas this characteristic is not available for single objects. Being a primitive population of the outer solar system, binary and multiple trans-Neptunian objects (TNOs) provide unique information about bulk density and intern…
False outliers of the Ep,i - Eiso correlation?
Della Valle, M.; Götz, D.; Amati, L. +3 more
Context. In the context of an in-depth understanding of GRBs and their possible use in cosmology, some important correlations between the parameters that describe their emission have been discovered, among which the "Ep,i - Eiso" correlation is the most studied. Because of this, it is fundamental to shed light on the peculiar…
Miniature loops in the solar corona
Barczynski, K.; Peter, H.; Savage, S. L.
Context. Magnetic loops filled with hot plasma are the main building blocks of the solar corona. Usually they have lengths of the order of the barometric scale height in the corona that is 50 Mm.
Aims: Previously it has been suggested that miniature versions of hot loops exist. These would have lengths of only 1 Mm barely protruding from the …
The faint end of the red sequence galaxy luminosity function: unveiling surface brightness selection effects with the CLASH clusters
Rudnick, Gregory; Adami, Christophe; Durret, Florence +1 more
Characterizing the evolution of the faint end of the cluster red sequence (RS) galaxy luminosity function (GLF) with redshift is a milestone in understanding galaxy evolution. However, the community is still divided in that respect, hesitating between an enrichment of the RS due to efficient quenching of blue galaxies from z 1 to present-day or a …
Fifteen years in the high-energy life of the solar-type star HD 81809. XMM-Newton observations of a stellar activity cycle
Schmitt, J. H. M. M.; Orlando, S.; Micela, G. +5 more
Context. The modulation of the activity level of solar-like stars is commonly revealed by cyclic variations in their chromospheric indicators, such as the Ca II H&K S-index, similarly to what is observed in our Sun. However, while the variation of solar activity is also reflected in the cyclical modulation of its coronal X-ray emission, simila…