The Hard X-ray Modulation Telescope (HXMT)

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The Hard X-ray Modulation Telescope (HXMT)
Fangjun Lu (Institute of High Energy Physics,
Chinese Academy of Sciences) On behalf of the
HXMT group
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Low Energy X-ray Telescope (LE) (SCD,
1-15KeV,300 cm2)
Payloads of HXMT
High Energy X-ray Telescope (HE) (18 modules,
20-250keV,5000 cm2)
Medium Energy X-ray Telescope (ME) (SiPIN,
5-30keV,1000 cm2)
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Characteristics of the HXMT Mission

• HE NaI(Tl)/CsI(Na) Phoswich
• Total Detect Area 5000 cm2
• Energy Range 20250 keV
• Energy Resolution 16 (_at_60keV)
• Continuum Sensitivity 3.010-7 ph cm-2 s-1 keV-1
  ,or 0.5 mCrab (3s_at_100keV,105s)
• Field of View 5.7x 5.7
• Source Location 1 arcmin (20?)
• Angular Resolution 5 arcmin (20?)
• ME
  5-30 keV, SiPIN, 1000 cm2
• (we are optimizing the design of
  HXMT and may will double the detecting area of
  ME)
• LE
  1-15 keV, SCD, 300 cm2
• Mass
  2700 kg (payload 1100 kg)
• Dimension
  2.02.02.8 m3 (LWH)
• Nominal Mission lifetime 3 years
• Orbit
  Altitude 550km,Inclination 43
• Attitude
  Three-axis stabilized
• Control precision0.25
• Stability 0.005 /s
• Measurement accuracy lt0.01

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Current Status of the HXMT Mission

• Proposed in 1993
• 973 Major State Basic Research Project in China
  since April 2000 (Pre-Phase A study)
• Total about 5M
• All the key technical problems for the HE
  telescope solved.
• Main participating institutions
• Chinese Academy of Sciences
• Tsinghua University
• Chinese Academy of Space Technology
• PI and Co-PI Ti-Pei Li and Shuang-Nan Zhang
• Selected last year as the first Chinese space
  astronomy mission for launch around 2010
• Full mission cost about 80M
• We just passed a technical review on this
  Wednesday, and HXMT is scheduled to enter
  pre-flight phase (Phase B) next October.

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Configuration of the high energy X-ray telescope
Active Shield
Phoswich detector
Collimator
PMT
Structures
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Shielding Ring
Collimator
Detector
Each module has a field of view (FOV) of
5.7º1.1º and the long axes of two neighboring
FOVs differ by 10º.
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The Main Detector system of the HXMT
X-ray photons
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The ground testing system
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The imaging performance of the HXMT
20 sigma source
Source Location lt 1 arcmin Angular resolution lt 5
arcmin
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Sensitivity
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Integral/IBIS HXMT/HE Swift/BAT
Angular
Resolution
12 5
14 Source Location
(20s) 1
1
1 Pointed Sensitivity (mCrab_at_100
keV, 105s) 3.8
0.5 9 ½
Year Survey Sensitivity (mCrab,20-250keV)
2 0.5
1 Observation Capability
All sky survey
ok
good
yes Selected sky deep survey
good
good bad Narrow field
pointing observation bad
good
no
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Low energy X-ray telescope (2 modules, 300 cm2)
Main Scientific Objectives (1)Extending the
energy coverage to low energy (2)Multi-wavelength
X-ray variability (3)Absorption column density to
AGNs
Collimatorfabricated with Electro-deposition or
from plates. FOV of 1x 6and 1x 3,
Thickness 5cm. Material can be Gold-plated
copper. Detector SCD(Swept Charge
Device)developed by e2v. Energy range 1-15
keV, Time resolution 1ms, Spectral
resolution 450eV_at_5.9keV Working
temperature-30-0?
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Medium Energy x-ray telescope (ME) (2 modules,
1000 cm2)
Main Scientific objectives (1)Cosmic X-ray
background(2)Absorption materials surrounding
AGNs(3)Temporal variability in medium energy
X-ray.
Detectorcovers 5-30keV, using SiPIN or thin
CdZnTe
Collimator similar to that of LE and defines
FOV of 16.
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Continuum Sensitivity of ME
0.1 mCrab_at_10 keV
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A Possible Fourth Telescope

• ASI of Italy contributes a pair of X-ray
  focusing telescopes plus X-ray polarimeter
  (XRTXPOL) for HXMT.
• People involved
• Enrico Costa, Fabio Muleri, Paolo Soffitta,
  Ronaldo Bellazzini Alessandro Brez, Gloria
  Spandre, Vincenzo Cotroneo, Giovanni Pareschi

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From the modulation curve it is derived the
polarization degree and angle of the X-ray
source.
Bellazzini et al. 2006
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Interface Electronics
Control Electr
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Current design
Sensitive Area of the telescope
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Minimum Detectable Polarization
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Observation modes

• Survey
• All sky scan mode
• 3-axis stabilized anti-earth oriented
• roll angle0º , region span-43º-43º, 66 days
• roll angle30º , region span-13º-73º, 66 days
• roll angle-30º , region span-73º-13º, 66 days
• Deep scanning observation of selected sky regions
• Pointed observations

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HXMT Sky Survey Observations
The three-phase sky survey of HXMT. In phase (a)
the roll angle is ß0, and the scanned
declination range is d-43-43, in phase (b)
ß30 and d-13-73, and in phase (c) ß-30,
d-73-13. (d) illustrates the total exposure
after the three-phase scan survey.
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Monte-Carlo simulations of the sensitivity of
HXMT (for point sources) in a half-year all-sky
survey
Background fluctuations, all within 3.15 s
Significance distribution of a 0.5 mCrab
source, 60 are higher than 3.15s

• HXMT is capable of conducting a deep full sky
  survey in half a year with a sensitivity of 0.5
  mCrab (20-250 keV), and more than 1,000 hard
  X-ray sources will be detected. The sensitivity
  around 10 keV is about 0.1 mCrab with ME.

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Simulated HXMT capability on Galactic diffuse
hard X-ray emission.
ModelStrong et al AA 411, L447(2003), Fig.2
HXMT simulation
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On going hard X-ray survey projects

• The US satellite SWIFT can do hard X-ray all-sky
  survey. Its survey sensitivity is dominated by
  systematic errors. For regions in the Galactic
  Plane (llt45, 2/3 of the whole sky ) where there
  are several strong sources always in the BAT FOV,
  the limiting sensitivity will be 2 mCrab. For
  lgt45(1/3 sky), the limiting sensitivity will be
  0.6 mCrab. The final SWIFT hard X-ray catalogue
  may will contain 200 extragalactic hard X-ray
  sources (Barthelmy et al. astroph/0507410) .
• Two years of INTEGRAL/IBIS observation has
  reached 1 mCrab for regions with the deepest
  exposures and 209 sources (in which 50 are
  active galactic nuclei) have been catalogued.

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The real survey program may will be changed
according to how deep the final SWIFT/BAT and
INTEGRAL/IBIS survey will be. If they reach a
sensitivity of 0.5 mCrab for most of the sky, we
may will carry out for example an one-year
survey for half sky to improve the sensitivity.
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Small region scan

• Deep scan of interesting regions to reach high
  sensitivity (such as the lockmann hole region
  and the Galactic Center region. Theoretically, an
  one-months observation of a region with a radius
  of 10º can reach a sensitivity limit of 0.1mCrab.
• Periodically scan of the Galactic bulge to study
  the variations of the Galactic hard X-ray
  sources.

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Pointed Observations

• Study the X-ray variability at multi-wavelength
  (1-250 keV) of the X-ray binary systems QPOs,
  relations between the hard and soft X-ray
  components.
• Study the broad band X-ray spectrum of bright
  AGNs, X-ray binaries, bright SNRs, pulsars, and
  bright clusters of galaxies.

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Simulated HXMT specturm of Coma (105s)
BeppoSAX Spectrum of Coma
BeppoSAX spectrum of Coma--4.5s detection of
non-thermal X-ray emission.
Simulated HXMT spectrum of Coma--much better
constraints on the non-thermal component.
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Current SNR X-ray specturm. Only up to 30 keV
Simulated HXMT spectrum of Cas A.
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Main advantages and key science of HXMT

• Hard X-ray sky survey with highest sensitivity
• High precision multi-wavelength X-ray full sky
  map diffuse background and cosmic variance
• Discover highly obscured supermassive BHs and
  study the obscuring materials galaxy formation
  and evolution
• Discover new types of high energy objects
  usual surprises of new surveys
• Diffuse hard X-ray emission in the Galaxy.

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Main advantages and key science of HXMT (II)

• High precision pointed observations of high
  energy objects
• Space-time in strong gravitational field
  dynamics and radiation near BH horizons of
  stellar mass and supermassive BHs
• Equation of state in strong magnetic field
  neutron star and its surface properties
• High energy particle acceleration AGN, SNR,
  shock and relativistic jets
• Large scale structure through hard X-ray
  detection of galaxy clusters

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Beyond Einstein Program
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Orbit and Operation
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Constraints on Orbit Design

• Operation mode survey mode requires inclination
  angle not less than 25 (sky coverage) and
  precession speed of the orbital plane not exceeds
  0.3 /orbit ( 1/3 of FOV 1.1 )
• Low background level lower inclination angle
• Reduce the passage of SAA belt and other
  radiation belt
• Ground stationBeijing Station only
• Launch station Xichang, Taiyuan, Jiuquan
• Nominal Lifetime 3 yrs (height gt 500km)

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Final orbit parameters

• Low Earth Orbit
• Height 550km
• Inclination angle 4345
• Period 96min.

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HXMT schedule
2007
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See further (earlier) and clearer
Evolution of the whole universe
XEUS
Con-X
Survey the local universe
See inner
HXMT
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Thanks!