Simbol X: A New Generation Soft/Hard X-ray Telescope

1. Simbol X: A New Generation Soft/Hard X-ray Telescope P. Slane, S. Romaine, S.S. Murray, R. Brissenden, M. Elvis, P.Gorenstein, E. Mattison, S. Steel (SAO), S. O’Dell, J. Kolodziejczak, B. Ramsey (NASA/MSFC), L. Angelini (NASA/GSFC), O. Citterio, G. Pareschi (Brera Observatory) • Mission Summary • Simbol-X is a broad-band focusing hard-X-ray telescope that operates from 0.5 to 80 keV. The mission is sponsored jointly by CNES (French Space Agency) and ASI (Italian Space Agency). Its single optics module contains a set of nested nickel shells coated with special multilayers to boost high-energy response and field of view. Its focal plane detectors are a novel hybrid configuration, with thick-depletion silicon providing the low energy range and Cadmium Telluride the high. To achieve a long focal length, for large collecting area at high energies, the optics and detectors are on separate high-earth-orbit formation-flying spacecrafts, 20 m apart. Simbol-X will be three orders of magnitude more sensitive than current non-focusing hard-X-ray missions. Key features of the mission include: • Soft and hard X-ray response from novel detectors and multilayer coatings. • Good angular resolution with nickel electroform replication mirrors like those on XMM-Newton and Swift XRT. • Formation-flying to provide the long focal length necessary for good high-energy response. • High-earth-orbit to provide high-efficiency viewing and long, uninterrupted observing. A novel detector design provides energy response with good energy resolution from 0.5-80 keV. Multilayer coatings provide large effective area out to 80 keV. The electroformed nickel mirrors offer exceptional angular resolution above 10 keV. Formation-flying provides the long focal length needed for good high-energy efficiency. Simbol-X will use a highly elliptical orbit for increased viewing efficiency. Simbol-X Science The wide Simbol-X discovery space is particularly significant for advancing the critical areas of high energy astrophysics and cosmology: black hole accretion, shock physics, and particle acceleration. These broad topics define the core scientific objectives of Simbol-X and drive the mission requirements. Here we describe several Simbol-X key projects. • US Participation in Simbol-X • SAO, with partners from NASA/MSFC and NASA/GSFC, is proposing participation by the US in the Simbol-X mission by providing: • Collaboration on multilayer coating development • - SAO will use existing software to help • design and optimize coatings for high- • energy response. Test coatings will • be fabricated/tested at SAO and OAB • Thermal filter development • - SAO will oversee fabrication of the • thermal and optical blocking filter used • in the Simbol-X mirror system. • Flight system end-to-end calibration • - X-ray testing and calibration of the • Simbol-X flight mirror and focal-plane • detector will be carried out at the • NASA/MSFC X-ray Calibration Facility • Flight data analysis and archiving • - NASA/GSFC HEASARC will contribute • to the definition and development FITS • format standards, software tools, and • configuration of Simbol-X data archive • DSN Operations Support • - Goldstone coverage will support need • for accurate station-keeping for the • formation-flying configuration. Black Hole Physics and Census The cosmic X-ray background (CXB) is dominated by the integrated output of all the accretion onto supermassive black holes (SMBHs) that has taken place over all of cosmic history. These SMBHs, which we observe as quasars and AGNs, appear to play a key role in galaxy formation. However, the CXB spectral density peaks at ~30 keV, well above the ~10 keV predicted from AGN currently observed to make up the soft CXB. A population of Compton-thick AGNs twice as large as the unobscured population appears to be exist. Deep surveys with Simbol-X will reveal this long-sought population, providing crucial constraints on accretion efficiency and feedback effects on galaxy formation and evolution. The good image quality and relatively large field-of-view for Simbol-X are crucial for this census of SMBHs. Energetic Particles in Galaxy Clusters The main baryonic mass component in clusters is hot (kT ~ 5-10 keV) intergalactic gas emitting in thermal X-rays. However, radio observations reveal a significant component of synchrotron-emitting relativistic electrons (E ~ 1-10 GeV) in some clusters. The radio-emitting clusters show evidence of recent mergers, suggesting that these events provide the energy source of the energetic electrons. However, the process by which the particles are accelerated is unclear. Simbol-X will map the inverse-Compton emission produced by these same energetic electrons, decoupling the degenerate contributions of particle density and magnetic field strength that determine the radio intensity, thereby constraining the origin of the electrons. Simulated Simbol-X observation of 5x5 arcmin region of A2256 illustrating thermal and inverse-Compton emission components, based on ROSAT, Chandra, SAX, and RXTE observations. Simulated 1 Msec deep survey of the Chandra Deep Field South (blue) with Simbol-X. (red). Red circles are Spitzer-discovered Compton-thick AGN candidates Black Hole Binaries Accreting BHs are observed to have three distinct spectral states thought to correspond to different flow configurations and accretion rates. Thermal emission from the disk is observed, as is a power law component whose origin is controversial. It may arise from Comptonization of the disk photons or from relativistic electrons produced in jets. Simultaneous determination of the soft and hard spectra with Simbol-X will constrain the nature of the hard emission, providing crucial information on the geometry and dynamics of accretion flows onto BHs. Acceleration Mechanisma in Supernova Remnants Supernova remnants are prime sources for particle acceleration to energies approaching the knee of the cosmic-ray spectrum. A cut-off energy is expected in the X-ray synchrotron spectrum that depends on the maximum electron energy and the magnetic field strength. High-sensitivity measurements with Simbol-X will probe this cut-off region and help differentiate between inverse-Compton and pion-decay models for the energetic gamma-ray emission. The combined soft and hard X-ray response will allow the separation of thermal and nonthermal emission, each of which constrain the above emission mechanisms. The large field-of-view will permit mapping of the emission over extended SNRs. Cyg X-1 spectra. The peak flux shifts from soft to hard in different states. Simbol-X will measure both soft and hard emission components simultaneously.