The 28th Texas Symposium on Relativistic Astrophysics will be held in Geneva, Switzerland, from December 13 to 18, 2015. It is organized by the Astronomy Department and the Physics Section of the University of Geneva. The Symposium will include both invited and contributed talks and posters.
The Texas Symposia on Relativistic Astrophysics are an impressive series of events where major astrophysical discoveries have been announced and discussed in the field related to relativistic theory of gravitation and cosmology, such as black-holes, quasars, neutron stars, X-ray binaries, gamma-ray bursts, particle acceleration, the cosmic background, dark matter and dark energy.
We are excited to welcome hundreds of international astrophysicists and physicists in Geneva, the home town of the LHC, to review remarkable discoveries and prospects, one century after the publication of General Relativity by Albert Einstein, and to bridge astrophysics with particle physics.
The Symposium will include morning plenary sessions and afternoon parallel sessions which will function as mini-symposia in each sub-field. The plenary sessions will consist of 30-45 min review talks. The afternoon sessions will feature oral (about 20 min) and poster contributions.
IUPAP Young Astrophysicist Awards 2014/2015
The winners will receive their awards and present their scientific achievements at the 28th Texas Symposium on Relativistic Astrophysics.
Support astronomy in Nepal
The TEXAS symposium 2015 will use possibly remaining fund in its budget to help high-level education in physics and astronomy in Nepal. You have the possibility to contribute to that effort during the registration process.
|International Union of Pure and Applied Physics||University of Geneva|
|The Tomalla Foundation||Swiss National Science Foundation|
|INTEGRAL Science Data Center||Center for Astroparticle Physics|
|Swiss Institute of Particle Physics||Société Académique de Genève|
|Swiss Society for Astrophysics and Astronomy|
|République et Canton de Genève||Geneva Tourism & Conventions Foundation|
|International Conference Centre Geneva|
|Swiss International Air Lines|
The Texas Syposium 2015 will be conducted in accordance with IUPAP principles. In particular, no bona fide scientist will be excluded from participation on the grounds of national origin, nationality, or political considerations unrelated to science.
Compact objects in high mass X-ray binaries (HMXB), where the companion star underfills its Roche lobe, have been spotted as X-ray emitters, probably due to the presence of a surrounding disc, along with their low mass counterparts (LMXB). However, if the disc formation is well understood in LMXB where matter is poured through the first Lagrangian point, things get messier in HMXB, especially in Supergiant-HMXB whose number has almost tripled thanks to recent observations with Integral (Chaty 2011, Walter et al 2015). Indeed, the massive companion stars have dense and fast winds which can lead to a Bondi-Hoyle like accretion (a.k.a. wind accretion) onto the compact body. Given the variability of the instantaneous mass and angular momentum accretion rates in this configuration, the disc formation is way more uncertain. The observed photometric and spectral variabilities of the flux might reflect transient accretion phases due to orbital scale modulations like a clumpy wind or non-homogeneous streamlines.
So as to get a better feel of the properties of the subsequently formed disc, we designed a numerical setup able to grasp the huge spatial dynamics of the Bondi-Hoyle accretion onto a compact object for non-relativistic wind velocities (El Mellah and Casse, 2015). From the accretion radius of the black hole down to the vicinity of its event horizon, the flow spans up to 5 orders-of-magnitude. Taking the most of the highly parallelized code MPI-AMRVAC, we characterized the flow properties in the axysymmetric configuration, both in terms of observable-related quantities (e.g. mass accretion rates as a function of the Mach number of the unperturbed flow) and in terms of topology of the sonic surface, confirming the result derived in Foglizzo and Ruffert (1996). We then introduced non axysymmetric effects for specific sets of orbital parameters in full 3D simulations and monitored the formation and permanence of a disc-like structure.