Download with Simbol-X. - High Energy Astrophysics

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
A novel detector
design provides
energy response
with good energy
resolution from 0.580 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 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 highearth-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.
Multilayer coatings provide large effective
area out to 80 keV. The electroformed
nickel mirrors offer exceptional angular
resolution above 10 keV.
System Parameter
Value
Focal length
20 m
Number of nested
mirror shells
100
Effective Area
100 cm2 @ 0.5 keV
1000 cm2 @ 2 keV
600 cm2 @ 8 keV
300 cm2 @ 30 keV
100 cm2 @ 70 kev
Angular Resolution
(HEW)
< 20”, E < 30 keV
< 40”, E < 60 keV (goal)
Energy Resolution
E/E = 40-50 @ 6-10 keV
E/E = 50 @ 68 kev (goal)
Simbol-X Science
US Participation in Simbol-X
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.
SAO, with partners from NASA/MSFC and
NASA/GSFC, is proposing participation by
the US in the Simbol-X mission by
providing:
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.
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.
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.
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 inverseCompton emission components,
based on ROSAT, Chandra,
SAX, and RXTE observations.
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.
• Collaboration on multilayer coating
development
- SAO will use existing software to help
design and optimize coatings for highenergy 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.