The Hard X-ray Modulation Telescope Mission LU Fangjun Particle Astrophysics Center

One-Three-Five Development Plan One Development Strategy To position IHEP to be one of world’s leading high energy physics research centers and a world-class, large, comprehensively multidisciplinary research base. Three Major Goals  Physics  Major Facilities – To complete the construction of nation’s major science facilities: CSNS, ADS, HXMT and to improve BEPCII luminosity ;  Application and Technology Transfer Five Top Priorities  Particle physics and astrophysics;  Research in accelerator physics and technology;  R&D in particle detection technology and associated electronics;  Study of radiation sources and application of nuclear technology;  Study of radiochemistry and related materials HXMT: Hard X-ray Modulation Telescope

Outline Scienctific objectives Introduction to the Payloads Project status and schedule The HXMT team Summary

Brief history of IHEP’s high energy astrophysics observations 1. Scientific objectives Brief history of IHEP’s high energy astrophysics observations IHEP’s High energy astrophysics observations began with balloon borne experiments in 1970s. Most of the data used in astrophysics research are from European or US satellites, such as COS-B, EXOSAT, ROSAT, RXTE etc. Balloon borne experiments

1. Scientific objectives (a) The input intensity distribution. (b) Convolution of the intensity distribution with the point spread function of a collimated telescope. (c) Restoration from a Monte-Carlo sample from (b). (d) is obtained by subtracting the background distribution from (c). The total number of photons from the point source is 120 and that from extended background is 1500. Li & Wu, 1993, Ap&SS, 206,91 In 1990’s IHEP scientists developed an image reconstruction method named “the direct demodulation method”, which solves the observation equations iteratively under physical constraints, and can obtain high sensitivity and resolution images from noisy data.

Map by Cross-correlation Map by D-D method Comparison of cross-correlation and direct demodulation imaging of the EXOSAT/ME Galactic plane scan observations. Lu et al., A&AS 115, 395 (1996) Map by Cross-correlation Map by D-D method The galactic center region from HEAO1-A4 all-sky survey (15-200 keV). Lu et al., Proc. CHEP’95, 848 (1995) Original Data Map by D-D method

1. Scientific objectives Based on the direct demodulation method and the experiences obtained in balloon borne hard X-ray experiments, IHEP proposed the Hard X-ray Modulation Telescope project in 1993. It contains 18 NaI/CsI phoswich scintillators with a total detection area of 5000cm2, aiming for a hard X-ray (20-250 keV) all-sky survey and pointed observations. The mission was officially approved in March 2011.

1. Scientific objectives < 2005 2005 2006 2010 Optimised for the working temperatures of the detectors Medium Energy X-ray Telescope added High energy X-ray telescopes only Low energy X-ray telescope added Evolution of the payloads onboard HXMT

1. Scientific objectives Satellite Facts: Weight: ~2800 kg Orbit: 550 km, 43° Attitude: 3-Axis Stabilized precision 0.1 ° Lifetime: 4 years Observation modes: Scan and pointing HXMT collaboration Institute of High Energy Physics (PI institute, payloads, scientific operation) Chinese Academy of Space Technology (satellite platform) National Space Science Center, CAS (space environment monitor, mission operation) Tsinghua University (participation in payloads and scientific operation) 9

1. Scientific objectives Sciences with HXMT Large sky-area scan Diffuse X-ray emission: cosmic X-ray background; X-ray emission from the Galactic ridge and the Galactic center region Detection of new (transient) sources and constrain their broad band (1-250 keV) properties Follow up observation of gravitational wave bursts Pointed observations X-ray binaries: multiwavelength temporal behaviors, broad band spectra and Fe emission line Equation of state in strong magnetic field: AXP, X-ray Bursts Monitoring of Blazars and bright AGNs 10

Diffuse X-ray background 1. Scientific objectives Diffuse X-ray background Blocked: only sensitive to local particle induced bkg Broad: source + diffuse X-ray bkg+ local bkg Narrow: source + diffuse X-ray bkg+ local bkg Advantages of HXMT’s FOV (Türler et al. 2010, A&A 512, 49) With the blocked, narrow, and broad FOVs, HXMT can subtract the charged particle induced background and can estimate the relative contributions of point source and diffuse background, and can thus give reliable measurements of the cosmic X-ray background in 1-250 keV. 11

Detection of transient sources 1. Scientific objectives Detection of transient sources HXMT will scan the Galactic Plane frequently, in which new transient sources could be discovered and the high state of a known X-ray binary could be detected. A quick look software will give the position and flux of the transient source every day. When an X-ray source is found in high state, the telescope will do pointed observations according to the decision of the PI. Transient source 12

1. Scientific objectives HXMT will do time resolved broadband spectroscopy for the brightest X-ray binaires. Broad Fe-Kα line of XTE J165-500 by XMM-Newton pn (Credit: ESA/XMM-Newton) Illustration of a black hole X-ray binary Mission Spectral resolution (eV, @ 6keV) Timing resolution (ms) Energy coverage (keV) Detection Area (cm2, @6keV) Strongest sources without pileup (Crab) HXMT 150 1 0.7-250 240 No limit XMM-Newton (pn, timing mode) 0.03 0.5-10 800 0.085 Chandra (ACIS, cc mode) 2.7 0.5-8 300 0.02 RXTE 1200 0.006 2-250 6000

2. Introduction to the payloads Star tracker ME:Si-PIN,5-30 keV, 952 cm2 LE:SCD,1-15 keV, 384 cm2 Size：1900×1650×1000 mm HE: NaI/CsI, 20-250 keV, 5000 cm2

The High Energy X-ray Telescope (HE) 2. Introduction to the payloads The High Energy X-ray Telescope (HE) HXMT/HE Components assembly 18 main collimated phoswich detectors 18 calibration detectors (automatic gain control) 18 charged-particle anticoincidence plates (6 top +12 lateral side) 3 particle monitors

The Medium Energy X-ray Telescope (ME) 2. Introduction to the payloads The Medium Energy X-ray Telescope (ME) ME uses 1728 Si-PIN detectors read out by 54 ASIC (application specified integrated circuit). The energy coverage of ME is 5-30 keV, and the total detection area is 952 cm2. The in-orbit working temperature of ME is -40 to -20 ℃

2. Introduction to the payloads The low Energy X-ray Telescope (LE) 2×2 CCD236 16 cm2 LE consists of 3 detector boxes, and each boxes contains 32 CCD 236 chips, which have a time resolution of 1ms and energy resolution of <140 eV (@6 keV) . The total detection area is 384 cm2. The in-orbit working temperature is between -80 to -40 ℃.

2. Introduction to the payloads HXMT/LE INTEGRAL/IBIS HXMT/ME RXTE/HEXTE HXMT/HE NuSTAR The sensitivities of the three telescopes of HXMT. The sensitivities of NuSTAR, INTEGRAL/IBIS and RXTE/HEXTE were reprinted from Koglin et al. (2005)3.

2. Introduction to the payloads Comparison between HXMT and other major hard X-ray telescopes HXMT RXTE INTEGRAL/IBIS SWIFT NuSTAR Energy Band (keV) LE: 0.8-15 ME: 5-30 HE: 15-250 PCA: 2-60 HEXTE: 15-250 15-10000 XRT: 0.5-10 BAT: 10-150 3-79 Detection Area (cm2) LE: 384 ME: 950 HE: 5000 PCA: 6000 HEXTE: 1600 2600 XRT: 110 BAT: 5200 847 @ 9 keV 60 @ 78 keV Energy Resolution (eV) 150@ 6 keV 2500@ 20 keV 10000@60 keV 1200@6keV 8000@ 100 keV 150 @ 6 keV 3300 @ 60 keV 900 @ 60 keV Time Resolution (ms) LE: 1 ME: 0.18 HE: 0.012 PCA: 0.001 HEXTE: 0.006 0.06 XRT: 0.14, 2.2,2500 BAT: 0.1 0.1 Sensitivity (@100keV, 3σ，105s, mCrab) 0.5 1.5 3.8 9 0.03 @ 20 keV

3. Project status and schedule Measureing the weight center and rotation inertia of the telescope (2012.11) The Mechanical Model of the satellite was finished in 2012. The payloads and platform both passed the dynamical environment tests. The mechanical model of the satellite in dynamical environment tests (2012.11)

3. Project status and schedule The electric model of HXMT’s payloads in assembling and testing (2012.12). The tests of the electric performance of the payloads were finished in Dec. 2012, and those of the whole satellite were finished in early March of 2013.

3. Project Status and schedule The payloads after thermal control coating Some of the components jointed the vacuum tests Vacuum thermal balance tests of the satellite were carried out in Dec, 2012. The quasi-qualification models of all the detectors joined the tests. Those of HE and LE worked well during the tests, but that of ME had some problems with the FPGA, which were fixed and tested early this year.

3. Project status and schedule The electric fitting of the qualification models are onging, and most of them (except the ME detector box) will be finished in this month. The space environment tests will be done in November and December.

3. Project status and schedule X-ray machine 13-70 keV band: Monoenergy fraction >90% Monochromaticity <1% Background shielding box for the calibrated detector Double crystal monochromator We have successfully constructed a double crystal monochromator X-ray calibration facility for HE, and the other one for LE and ME will be finished before March 2014.

prototype for observation program draw up 3. Project status and schedule prototype for observation program draw up Observation visibility study HXMT mission movement trajectory Observation Schedule Monitoring of payload working status The detailed design of the scientific ground segments and the software requirements have been finished. We are writing the codes of the softwares, which will be finished in the first season of the next year.

3. Project status and schedule 12/2012 We are here . 2015 12/2013

PI: Li, Tipei; Co-PI: Zhang, Shuangnan 4. The HXMT team HXMT PI: Li, Tipei; Co-PI: Zhang, Shuangnan Payloads Director: Wang, Huanyu Chief Designer: LU, Fangjun Scientific Ground Segements Director: Wang, Huanyu Chief Designer: Song, Liming Science working group Director: Zhang, Shuangnan Coordinator: Feng, Hua (Tsinghua University) General Technology group 15 people >70 astrophysicists from all the major astronomy instituations in China Calibration group HE group ME Group LE Group 46 people

Scientific and Technical Leaders Chief Desginer of Payloads, 2002-- Professor of IHEP 2001-2002, Research Associate at Univ. of Mass. 1998-1999, visiting scholar at MPE, 1996, PhD at IHEP. PI of HXMT, Professor of IHEP and Tsinghua University. Academician of CAS. LI Tipei LU Fangjun Co-PI of HXMT, 2009-- Professor of IHEP 2002-2009 Professor of Tsinghua University. 1992-2002, Research Scientist at NASA/MSFC, Assistant Professor of UAH 1989-1992, Postdoc at Univ. of Penn. 1989, PhD at Univ. of Southampton Chief Desginer of SGS, 2000-- Professor of IHEP 1998-1999 , Visiting Scientist at Riken 1996, PhD at Nanjing University. ZHANG Shuangnan SONG Liming

4. The HXMT team HXMT general techonology group and the project office (11 people)

The high energy telescope group (8 people @IHEP; 8 @Tsinghua Univ.) 4. The HXMT team Group Leader: Dr. LIU Congzhan The high energy telescope group (8 people @IHEP; 8 @Tsinghua Univ.)

The medium energy telescope group (14 people) 4. The HXMT team Group Leader: Dr. CAO Xuelei The medium energy telescope group (14 people)

The low energy telescope group (13 people). 4. The HXMT team Group leader: Prof. CHEN Yong The low energy telescope group (13 people).

The HXMT Scientific Ground Segements group (13 people) 4. The HXMT team Group Leader: Prof. SONG Liming The HXMT Scientific Ground Segements group (13 people)

5. Summary Thank you for your attention! IHEP proposed the HXMT satelite, which has unique capabilities for X-ray binary studies and the measurements the diffuse X-ray background. IHEP is in charge of the constructions of the payloads, calibration facilities, and the science ground segments, in which many young people become experts. These are important for the future of China’s X-ray astronomy. The satellite will be launched in 2015. The observational data will be opened to astrophysicists in China and world wide. Challenges: to keep the project schedule and to have the instruments well calibrated. Thank you for your attention!

Supplementary materials

Characteristics of the HXMT Mission Detectors LE: SCD, 384 cm2;ME : Si-PIN, 950 cm2 HE : NaI/CsI, 5000 cm2 Energy Range LE: 1-15 keV;ME: 5-30 keV;HE: 20-250 keV Time Resolution HE: 25μs; ME: 180μs;LE: 1ms Working Temperature HE: 18±1℃; ME: -50~-20℃; LE: -80-45℃ Energy Resolution LE: 2.5% @ 6 keV ME: 14% @ 17.8 keV HE: 19% @ 60 keV Field of View of one module LE: 6°×1.6°; 6°×4°; 60°×3°; blind; ME: 4°×1°; 4°×4°; blind; HE: 5.7°×1.1°; 5.7°×5.7°；blind Source Location <1' (20σ source)

Orbit Altitude: ~550 km ; Inclination: ~43° Attitude Three-axis stabilized Control precision: ±0.1° Measurement accuracy: ±0.01° Data Rate LE: 3 Mbps; ME: 3 Mbps; HE: 300 kbps Payload Mass ~1000 kg Nominal Lifetime 4 years Working Mode Scan survey, small region scan, pointed observation

Simulation of the in-orbit background of HXMT Different background components of HE Total background of HE varying with time Background components of ME Background components of LE Simulation of the in-orbit background of HXMT

Short timescale varibility of black hole X-ray binaries up to 250 keV. The hard X-ray detectors RXTE/HEXTE、Suzaku/HXD and BeppoSAX/PDS are too small (<1000 cm2) , and INTEGRAL/ibis and SWIFT/BAT are of too high background to study the short timescale hard X-ray varibilities of black hole X-ray binaries. HXMT, with the large detecting area (5000 cm2, 20-250 keV) and the relatively small field of view (low background) , will provide unique opportunity for studies in this field. Variability amplitude as a function of energy for several black hole binaries. (Kaaret 2004)