Gamma ray burst studies with THESEUS     

Ghirlanda  G.  Salvaterra  R.  Toffano  M.  Ronchini  S.  Guidorzi  C.  Oganesyan  G.  Ascenzi  S.  Bernardini  M. G.  Camisasca  A. E.  Mereghetti  S.  Nava  L.  Ravasio  M. E.  Branchesi  M.  Castro-Tirado  A.  Amati  L.  Blain  A.  Bozzo  E.  O’Brien  P.  Götz  D.  Le Floch  E.  Osborne  J. P.  Rosati  P.  Stratta  G.  Tanvir  N.  Bogomazov  A. I.  D’Avanzo  P.  Hafizi  M.  Mandhai  S.  Melandri  A.  Peer  A.  Topinka  M.  Vergani  S. D.  Zane  S. 《Experimental Astronomy》2021,52(3):277-308

Gamma-ray Bursts (GRBs) are the most powerful transients in the Universe, over–shining for a few seconds all other γ-ray sky sources. Their emission is produced within narrowly collimated relativistic jets launched after the core–collapse of massive stars or the merger of compact binaries. THESEUS will open a new window for the use of GRBs as cosmological tools by securing a statistically significant sample of high-z GRBs, as well as by providing a large number of GRBs at low–intermediate redshifts extending the current samples to low luminosities. The wide energy band and unprecedented sensitivity of the Soft X-ray Imager (SXI) and X-Gamma rays Imaging Spectrometer (XGIS) instruments provide us a new route to unveil the nature of the prompt emission. For the first time, a full characterisation of the prompt emission spectrum from 0.3 keV to 10 MeV with unprecedented large count statistics will be possible revealing the signatures of synchrotron emission. SXI spectra, extending down to 0.3 keV, will constrain the local metal absorption and, for the brightest events, the progenitors’ ejecta composition. Investigation of the nature of the internal energy dissipation mechanisms will be obtained through the systematic study with XGIS of the sub-second variability unexplored so far over such a wide energy range. THESEUS will follow the spectral evolution of the prompt emission down to the soft X–ray band during the early steep decay and through the plateau phase with the unique ability of extending above 10 keV the spectral study of these early afterglow emission phases.

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Analytical structure of steady radiative shocks in magnetic cataclysmic variables     

E. Falize  C. Michaut  C. Cavet  S. Bouquet  M. Koenig  B. Loupias  A. Ravasio  C. G. Gregory 《Astrophysics and Space Science》2009,322(1-4):71-75

In this paper we study specific classes of radiating shocks which are widely spread in astrophysical environments. We present new analytical solutions available for any exponents of typical power-law cooling function which generalize the five special cases (corresponding to specific values of these exponents) of radiating shocks structure and proceed to the analytical determination of physical quantities. Then an application of the results for the accretion shock in polar is realized. A discussion of the reproducibility of cooling layer in laboratory is proposed using scaling laws.  相似文献   

The scalability of the accretion column in magnetic cataclysmic variables: the POLAR project     

��. Falize  B. Loupias  A. Ravasio  C. D. Gregory  A. Dizi��re  M. Koenig  C. Michaut  C. Cavet  P. Barroso  J.-P. Leidinger  X. Ribeyre  J. Breil  H. Takabe  Y. Sakawa  Y. Kuramitsu  T. Morita  N. C. Woolsey  W. Nazarov  S. Pikuz 《Astrophysics and Space Science》2011,336(1):81-85

In this paper, theoretical and experimental laboratory astrophysics results are presented from the POLAR project, the main focus of which is to design and diagnose an exact scaled accretion column using powerful lasers. These measurements allow the testing of the astrophysical models of accretion processes present in magnetic cataclysmic variables.  相似文献   

Experimental results to study astrophysical plasma jets using Intense Lasers     

B. Loupias  C. D. Gregory  E. Falize  J. Waugh  D. Seiichi  S. Pikuz  Y. Kuramitsu  A. Ravasio  S. Bouquet  C. Michaut  P. Barroso  M. Rabec le Gloahec  W. Nazarov  H. Takabe  Y. Sakawa  N. Woolsey  M. Koenig 《Astrophysics and Space Science》2009,322(1-4):25-29

We present experimental results of plasma jet, interacted with an ambient medium, using intense lasers to investigate the complex features of astrophysical jets. This experiment was performed in France at the LULI facility, Ecole Polytechnique, using one long pulse laser to generate the jet and a short pulse laser to probe it by proton radiography. A foam filled cone target was used to generate high velocity plasma jet, and a gas jet nozzle produced the well known ambient medium. Using visible pyrometry and interferometry, we were able to measure the jet velocity and electronic density. We get a panel of measurements at various gas density and time delay. From these measurements, we could underline the growth of a perturbed shape of the jet interaction with the ambient medium. The reason of this last observation is still in debate and will be presented in the article.  相似文献   

Highly radiative shock experiments driven by GEKKO XII     

A. Dizi��re  C. Michaut  M. Koenig  C. D. Gregory  A. Ravasio  Y. Sakawa  Y. Kuramitsu  T. Morita  T. Ide  H. Tanji  H. Takabe  P. Barroso  J.-M. Boudenne 《Astrophysics and Space Science》2011,336(1):213-218

In this paper, recent results obtained on highly radiative shocks generated in a xenon filled gas cell using the GEKKO XII laser facility are presented. Data show extremely high shock velocity (??150 km/s) never achieved before in gas. Preliminary analyses based on theoretical dimensionless numbers and numerical simulations suggest that these radiative shocks reach a new radiative regime where the radiative pressure plays a role in the dynamics and structure of the shock. A major effect observed is a strong anisotropic emission in the downstream gas. This unexpected feature is discussed and compared to available 2D radiation hydrodynamic simulations.  相似文献   

Density Measurements of Shock Compressed Matter Using Short Pulse Laser Diagnostics     

M. Koenig  A. Ravasio  A. Benuzzi-Mounaix  B. Loupias  N. Ozaki  M. Borghesi  C. Cecchetti  D. Batani  R. Dezulian  S. Lepape  P. Patel  H. S. Park  D. Hicks  A. Mckinnon  T. Boehly  A. Schiavi  E. Henry  M. Notley  R. Clark  S. Bandyopadhyay 《Astrophysics and Space Science》2007,307(1-3):257-261

In this paper, experimental results on X-ray and proton radiography of shock compressed matter are presented. It has been performed at the Rutherford Appleton Laboratory (RAL) using three long pulse beams to generate a shock wave in a multi-layer foil and a short pulse beam to create either an X-ray or protons source for a transverse radiography. Depending on the probe material (aluminium or carbon foam) a Molybdenum Kα source or a proton beam are used. Density data of the shocked aluminium, in the multimagabar regime are presented.  相似文献