The Hard X-ray Modulation Telescope Mission

The Hard X-ray Modulation Telescope Mission硬 X 射 线 调 制 望 远 镜Fangjun Lu 盧 方 軍on behalf of the HXMT group@Institute of High Energy PhysicsChinese Academy of SciencesHXMT @China-US bilateral workshop on astronomy 1

The Hard X-ray Modulation Telescope (HXMT)Chinese Academy of SciencesTsinghua UniversityChinese Academy of Space TechnologyHXMT @China-US bilateral workshop on astronomy 2

Payload CabinPlatform CabinHXMT @China-US bilateral workshop on astronomy 3

ME:Si-PIN,952 cm 2HE: NaI/CsI 5000 cm 2LE:SCD,384 cm 2Payloads onboard HXMTSize:1900×1600×1000 mmHXMT @China-US bilateral workshop on astronomy 4

Characteristics of the HXMT Mission• Main Detector NaI(Tl)/CsI(Na) Phoswich– Total Detect Area ~5000 cm 2– Energy Range 20~250 keV– Energy Resolution ~19% (@60keV)– Continuum Sensitivity ~3.0×10 -7 ph cm -2 s -1 keV -1 ,or 0.5 mCrab (3σ@100keV,10 5 s)– Field of View 5.7°x 5.7°(FWHM)– Source Location ≤1 arcmin(20σ)– Angular Resolution ≤5 arcmin(20σ)• Secondary Instruments ME (5-30 keV, Si-PIN, 952 cm 2 ),LE (1-15 keV, SCD, 384 cm 2 )• Mass 2700 kg (payload ~1000 kg)• Dimension 2.0×2.0×2.8 m 3 (L×W×H)• Nominal Mission lifetime 4 years• Orbit Altitude 550km,Inclination 43°• Attitude Three-axis stabilizedControl precision:±0.10°Stability: 0.005 °/sMeasurement accuracy:

The Configuration of the main detector assemblyActive ShieldCollimatorPhoswichdetectorStructuresPMTHXMT @China-US bilateral workshop on astronomy 7

Shielding RingCollimatorDetectorEach module has a field of view(FOV) of 5.7º×1.1º and the longaxes of two neighboring FOVsdiffer by 10º.HXMT @China-US bilateral workshop on astronomy 8

The Main Detector system of the HXMTHXMT @China-US bilateral workshop on astronomy 9

The medium energy Telescope (ME)Objectives: 5-30 keV sky survey and pointedobservationsDetector:Energy coverage:Detecting area:Sensitivity:Field of view: 1°×6°Energy resolution: < 3 keVTime resolution: 10 μsMass:60kgSi-PIN5-30 keV952 cm 2 (1944 pixels)0.25 mCrab2008-4-29HXMT @China-US bilateralworkshop on astronomy 10

MEUnit1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6Modu 1Modu 2 …… Modu 9Pixel 1 Pixel 2 …… Pixel 362008-4-29Architecture of HXMT/MEHXMT @China-US bilateralworkshop on astronomy 11

The low energy Telescope (LE)Objectives: low energy (1-15 keV) sky surveyand pointed observationsDetector:Energy coverage:Detecting area:Sensitivity:Field of view: 1°×6°& 1°×3°Energy resolution: < 450 keVTime resolution: 1 msMass:60 kgSCD (Swept Charge Device)1-15 keV,384 cm 2 (96 CCD236 chips)0.15 mCrab2008-4-29HXMT @China-US bilateralworkshop on astronomy 13

2×2CCD23616 cm 2HXMT @China-US bilateral workshop on astronomy 14

Charge flowReal & dummyoutputs in gapSCD read the events through the diagonal line. It reacheshigh time resolution (1ms) by sacrificing the positioninformation.HXMT @China-US bilateral workshop on astronomy 15

CCD236 55 Fe spectrum@-30.7°CE(keV)=0.00641*Ch-2.761FWHM=128eV@5.9keV; rms=6.9e -HXMT @China-US bilateral workshop on astronomy 16

Advantages of LE for X-ray timing/spectroscopyDetectorArea(cm 2 @ 6keV)Time resolution Energy resolution(@ 6 keV)EXOSAT/ME 1600 ~ms 1200 eVNoteGinga/LAC 4000 ~msASCA/GIS 250 0.06 msRXTE/PCA 5000 1μs1200 eV460 eV1125 eVChandra/ACIS200 3 ms 130 eV High pileup effect(CC mode)Chandra/HRC 40 16μsbadfor strong sourceXMM/MOS 768 1.5 ms 130 eV High pileup effect forstrong sourceHXMT/LE 240 1 ms 130 eV No pileup for 10Crab sourceHXMT @China-US bilateral workshop on astronomy 17

The imaging performance of the HXMT/HE20 sigma sourceSource Location

Simulated in-space background of HXMT/HEHXMT @China-US bilateral workshop on astronomy 19

Contributions of various components to the total backgroundHXMT @China-US bilateral workshop on astronomy 20

SensitivityHXMT/HEHXMT @China-US bilateral workshop on astronomy 21

Integral/IBIS HXMT/HE Swift/BATAngular Resolution 12’ < 5’ 14’Source Location (20σ) 1’ < 1’ 1’Pointed Sensitivity (mCrab@100 keV) 3.8 0.5 9Half Year Survey Sensitivity (mCrab) 2 0.5 1Observation CapabilityAll sky survey okgood yesSelected sky deep survey good good badNarrow field pointing observation badgood noHXMT @China-US bilateral workshop on astronomy 22

Observation modes• All-sky Survey mode• Deep imaging observation of selected skyregions• Pointed observationsHXMT @China-US bilateral workshop on astronomy 23

HXMT in all-sky surveyHXMT @China-US bilateral workshop on astronomy 24

HXMT Sky Survey ObservationsExposuredistribution ofthe one year’sall-sky surveyHXMT @China-US bilateral workshop on astronomy 25

Cosmic X-ray Background and the resolvedfraction as a function of energyWe can see:1)The hard X-ray background was studied only by HEAO-1 A42) The hard X-ray background has not been well resolved.3)The CXB peaks around 20-30 keV.4)A more sensitive all-sky hard X-ray survey is demanding.HXMT @China-US bilateral workshop on astronomy 26

Simulation of a 0.5mCrab source in halfyear’s all-sky surveyLeft: Distribution of the background fluctuation; Right: Distribution of the source significanceThe highest background fluctuation is 3.15σ, and in 60% of thesimulations the source has a significance higher than 3.15 σ. Soa half-year all-sky survey can reach a sensitivity of 0.5 mCrab.HXMT @China-US bilateral workshop on astronomy 27

One-year sky survey sensitivity distribution (mCrab)HXMT @China-US bilateral workshop on astronomy 28

AGN Luminosity function0.42mCrab0.5mCrabAbout 1000 AGNs will be discovered in the HXMT all-sky surveyHXMT @China-US bilateral workshop on astronomy 29

The main objective of HXMT sky survey is todetect about 1000 AGNs in the hard X-ray band 。≥2010 Hard X-ray SkyHXMTHXMT @China-US bilateral workshop on astronomy 30

Simulated HXMT AGN luminosity functionINTEGRAL AGNluminosity functionHXMT @China-US bilateral workshop on astronomy 31

Pointed observationsHXMT @China-US bilateral workshop on astronomy 32

Scientific objectives of the pointed observations• X-ray Binary: multi-wavelength X-ray variability;especially the QPO properties of BH binaries atenergy higher than 20 keV;• Cyclotron Resonance Features (CRF) close tothe neutron star surface;• Broad band (1-250 keV) AGN spectrum,reflecting components and high energy cut off;• Hard X-ray emission from clusters of galaxies;• Non-thermal X-ray emission of SNRs andcosmic-ray acceleration。HXMT @China-US bilateral workshop on astronomy 33

Previous hard X-ray telescopes are of too small collectingarea (

Cyclotron Resonance Features in neutron star binariesTruemper et al. 1978, ApJ 215, L109HXMT @China-US bilateral workshop on astronomy 35

Simulated HXMT/HE spectrum of Her X-1Left: The absorption line is as strong as in Truemper et al.(1978). Right: If the absorption feature is 10 times weaker, itcan also be detected at 10σ confidence level.HXMT @China-US bilateral workshop on astronomy 36

Broad band X-ray spectrum of AGN(Pounds et al. 2003, MNRAS, 341, 953)X-ray spectrum of MCG 6-30-15 by SuzakuOne of HXMT’sscientific objectives isjust to measure thebroad band X-ray Xspectrum of AGNs.HXMT @China-US bilateral workshop on astronomy 37

Simulated HXMT spectrum of AGNThe reflecting component notincluded in the modelThe reflecting componentincluded in the modelHXMT @China-US bilateral workshop on astronomy 38

Hard X-ray from clusters of galaxiesFusco-Femiano et al. , 1999, ApJ 513, L21;Evidence for hard X-ray emission in the Coma clusterHXMT @China-US bilateral workshop on astronomy 39

Debate on the hard X-ray emission of the Comacluster1. Hard X-Ray Radiation in the Coma Cluster Spectrum,Fusco-Femiano et al. , 1999, ApJ 513, L21;2. Is there a hard tail in the Coma Cluster X-ray spectrum?,Rossetti & Molendi, 2004, A&A 414, L41;3. Confirmation of Nonthermal Hard X-Ray Excess in the ComaCluster from Two Epoch Observations, Fusco-Femiano et al.,2004, ApJ 602, L73;4. Nonthermal Hard X-Ray Excess in the Coma Cluster:Resolving the Discrepancy between the Results of DifferentPDS Data Analyses, Fusco-Femiano et al., 2007, ApJ 654, L9;5. The Coma Cluster hard X-ray spectrum revisited: still noevidence for a hard tail, Rossetti & Molendi, 2007, astroph/0702417;6. Hard X-Ray Excess in the Coma Cluster: a Reply to Rossetti &Molendi (astro-ph/0702417) , Fusco-Femiano et al. 2007, astroph/0702576.HXMT @China-US bilateral workshop on astronomy 40

Simulated hard X-ray spectrum of Coma byHXMT/HEHXMT will make sure whether there is hard X-ray emissionin the coma cluster and further quantify its hard X-ray flux.HXMT @China-US bilateral workshop on astronomy 41

Main advantages and key sciences of HXMTHard X-ray sky survey with highest sensitivity• High precision hard X-ray full sky map: diffuse background and cosmic variance• Discover highly obscured supermassive BHs: galaxy formation and evolution• Discover new types of high energy objects: usual surprises of new surveysHigh precision pointed observations of high energy objects• Space-time in strong gravitational field: dynamics and radiation near BHhorizons 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 clustersHXMT @China-US bilateral workshop on astronomy 42

Schedule of HXMT• Satellite Ready: end of 2010• Year I: All-sky survey (No AO time)• Year II: Pointed Observations and small region imaging.( 3 months for AO)• Year III: Pointed Observations (6 months for AO)• Year IV: Pointed Observations and imaging ( 3 months for AO)• >Year V: (7 months for AO per year)HXMT @China-US bilateral workshop on astronomy 43

Thanks!HXMT @China-US bilateral workshop on astronomy 45