The Hard X-ray Modulation Telescope (HXMT)

Fangjun Lu (Institute of High Energy Physics, Chinese Academy of Sciences)

On behalf of the HXMT group

Low Energy X-ray Telescope (LE) (SCD, 1-15KeV,300 cm2)

Medium Energy X-ray Telescope (ME)(SiPIN, 5-30keV,1000 cm2)

Payloads of HXMT

High Energy X-ray Telescope (HE)

（ 18 modules, 20-250keV,5000 cm2）

• HE NaI(Tl)/CsI(Na) Phoswich– Total Detect Area ~5000 cm2

– Energy Range 20～ 250 keV– Energy Resolution ~16% (@60keV)– Continuum Sensitivity ~3.0×10-7 ph cm-2 s-1 keV-1 ,or 0.5 mCrab (3σ@100keV,105s)– Field of View 5.7°x 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 2.0×2.0×2.8 m3 (L×W×H)• Nominal Mission lifetime 3 years• Orbit Altitude 550km， Inclination 43° • Attitude Three-axis stabilized

Control precision： ±0.25° Stability: 0.005 °/s Measurement accuracy: <0.01°

Characteristics of the HXMT Mission

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.

Configuration of the high energy X-ray telescope

Active Shield

Collimator

Phoswich detector

PMTStructures

Each module has a field of view (FOV) of 5.7º×1.1º and the long axes of two neighboring FOVs differ by 10º.

Collimator

Shielding Ring

Detector

The Main Detector system of the HXMT

X-ray

photons

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

( )水平方向 度

()

垂直方向度

多 源 成像结果等高图

2mci

2mci 1mci

15.3m观测距离：放射源强度：已标注

( ) 20cm放射源间距 最小值 ：0.75对应角度为 度

0.1 成像位置精度： 度

The ground testing system

The imaging performance of the HXMT

Source Location < 1 arcmin

Angular resolution < 5 arcmin

20 sigma source

Sensitivity

Angular Resolution 12’ 5’ 14’

Source Location (20σ) 1’ 1’ 1’

Pointed Sensitivity (mCrab@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

Integral/IBIS HXMT/HE Swift/BAT

Low energy X-ray telescope(2 modules, 300 cm2)

Collimator ： fabricated with Electro-deposition or from plates.

FOV of 1°x 6°and 1°x 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@5.9keV

Working temperature ： -30 －0℃

Main Scientific Objectives：（ 1 ） Extending the energy coverage to low energy

（ 2 ） Multi-wavelength X-ray variability

（ 3 ） Absorption column density to AGNs

Medium Energy x-ray telescope (ME)(2 modules, 1000 cm2)

Collimator: similar to that of LE and defines FOV of 1°×6°.

Detector ： covers 5 －30keV, using SiPIN or thin CdZnTe

Main Scientific objectives：（ 1 ） Cosmic X-ray background; （ 2 ） Absorption materials surrounding AGNs; （ 3 ） Temporal variability in medium energy X-ray.

Continuum Sensitivity of ME

HXMT 3sigma in 10^5 s

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1 10 100 1000

Ex (keV)

Ph

oto

ns

cm-2

s-1 Crab

HXMT NaI

500u 10^3 cm^2

50u 10^3 cm^2

15u 10^3 cm^2

IBIS-ISGRI

0.1 mCrab@10 keV

A Possible Fourth Telescope

–ASI of Italy contributes a pair of X-ray focusing telescopes plus X-ray polarimeter (XRT+XPOL) for HXMT.

–People involved:

Enrico Costa, Fabio Muleri, Paolo Soffitta, Ronaldo Bellazzini Alessandro Brez, Gloria Spandre, Vincenzo Cotroneo, Giovanni Pareschi

From the modulation curve it is derived the polarization degree and angle of the X-ray source.

Bellazzini et al. 2006

Interface Electronics

Control Electr

Current design

Sensitive Area of the telescope

Minimum Detectable Polarization

Observation modes

• Survey

– All sky scan mode

– 3-axis stabilized anti-earth oriented:

• roll angle=0º , region span=-43º-43º, 66 days

• roll angle=30º , region span=-13º-73º, 66 days

• roll angle=-30º , region span=-73º-13º, 66 days

• Deep scanning observation of selected sky regions

• Pointed observations

HXMT Sky Survey Observations

The three-phase sky survey of HXMT. In phase (a) the roll angle is β=0°, and the scanned declination range is δ=-43° － 43°, in phase (b) β=30° and δ=-13° － 73°, and in phase (c) β=-30°, δ=-73° － 13°. (d) illustrates the total exposure after the three-phase scan survey.

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.

Background fluctuations, all within 3.15 σ Significance distribution of a 0.5 mCrab source, 60% are higher than 3.15σ

Monte-Carlo simulations of the sensitivity of HXMT (for point sources) in a half-year all-sky survey

Simulated HXMT capability on Galactic diffuse hard X-ray emission.

Model： Strong et al A&A 411, L447(2003), Fig.2

HXMT simulation

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 (l<45°, 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 l>45°(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.

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.

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-month’s 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.

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.

BeppoSAX Spectrum of Coma

Simulated HXMT specturm of Coma (105s)

BeppoSAX spectrum of Coma －－ 4.5σ detection of non-thermal X-ray emission.

Simulated HXMT spectrum of Coma－－ much better constraints on the non-thermal component.

Simulated HXMT spectrum of Cas A.

Current SNR X-ray specturm. Only up to 30 keV

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.

Main advantages and key science of HXMT

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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Ein

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HXMT

Orbit and Operation

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 station： Beijing Station only• Launch station: Xichang, Taiyuan, Jiuquan• Nominal Lifetime: 3 yrs (height > 500km)

Final orbit parameters

• Low Earth Orbit

• Height: 550km

• Inclination angle: 43~45°

• Period: ~96min.

HXMT schedule

2007

Con-X

XEUS

HXMT

See further (earlier)

and clearer

See inner

Evolution of the whole universe

Survey the local universe

Thanks!