LU Fangjun (on behalf of the HXMT team) Institute of High Energy Physics, Chinese Academy of Science Current Status of the Hard X-ray Modulation Telescope Project

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

The Hard X-ray Modulation Telescope project was proposed in In the first proposal, HXMT contains 18 NaI/CsI phoswich scintillators with a total detection area of 5000cm 2, aiming for a hard X-ray ( keV) all-sky survey and pointed observations. The mission was officially approved in March Scientific objectives

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

Satellite Facts: Weight: ~2800 kg Orbit: 550 km, 43° Attitude: 3-Axis Stabilized precision 0.1 ° Lifetime: 4 years Observation modes: Scan and pointing 1. Scientific objectives 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)

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 ( 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 Sciences with HXMT 1. Scientific objectives

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 measure the diffuse X-ray emission in keV. The quality of the measurement is highly related to the in-orbit particle background determination. Diffuse X-ray background (Türler et al. 2010, A&A 512, 49) 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 1. Scientific objectives

Detection of transient sources Transient source 1. Scientific objectives

HXMT will do time resolved broadband spectroscopy for the brightest X-ray binaires. Illustration of a black hole X-ray binary Broad Fe-Kα line of XTE J by XMM-Newton pn (Credit: ESA/XMM-Newton ) MissionSpectral resolution 6keV) Timing resolution (ms) Energy coverage (keV) Detection Area (cm Strongest sources without pileup (Crab) HXMT No limit XMM-Newton (pn, timing mode) Chandra (ACIS, cc mode) RXTE No limit 1. Scientific objectives

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

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 High Energy X-ray Telescope (HE) 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 cm 2. The in-orbit working temperature of ME is -40 to -20 ℃ 2. Introduction to the payloads

2×2 CCD cm 2 The low Energy X-ray Telescope (LE) 2. Introduction to the payloads 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 keV). The total detection area is 384 cm 2. The in-orbit working temperature is between -80 to -40 ℃.

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

15 2. Introduction to the payloads HXMTRXTEINTEGRAL/IBISSWIFTNuSTAR Energy Band (keV) LE: ME: 5-30 HE: PCA: 2-60 HEXTE: XRT: BAT: Detection Area (cm 2 ) LE: 384 ME: 950 HE: 5000 PCA: 6000 HEXTE: XRT: 110 BAT: keV 78 keV Energy Resolution (eV) 6 keV 20 keV keV keV keV 60 keV 60 keV Time Resolution (ms) LE: 1 ME: 0.18 HE: PCA: HEXTE: XRT: 0.14, 2.2,2500 BAT: Sensitivity 3σ ， 10 5 s, mCrab) 20 keV Comparison between HXMT and other major hard X-ray telescopes

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

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 Project status and schedule The electric model of HXMT’s payloads in assembling and testing ( ).

Vacuum thermal balance tests of the satellite were carried out in Dec, 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. The payloads after thermal control coating Some of the components jointed the vacuum tests 3. Project Status and schedule

October 22 ， Project status and schedule All the space qualification models and the environmental tests were finished in 2013 and 2014.

The electric fitting of the flight models of the payloads is almost finished. Environment tests started. Calibration procedures fully tested for HE and LE, and partly for ME. The payloads will be delivered before the end of November, and the expected launch date will be around September next year. October 22 ， Project status and schedule

The ground calibration facilities Finished in May The energy coverage of the monochromatic beam is 15~150 keV HE calibration facility Finished in the end of The energy coverage of the monochromatic beam is keV. ME 、 LE calibration facility

Comparison of the different sampling methods for calibration The calibration results are consistent with each other. The 27 points sampling mode will be used. 27 points 192 points 22 annuli

The energy linearity and resolution of the HE main detector How to deal with the “deviations” at the energy of the Iodide absorption line?

The detection efficiency of the HE main detector The measured data and the simulation are not consistent especially in the low energy band. More factors such as the air absorption, moving of the beam position with energy need to be considered.

Preliminary calibration of LE

LE 正样探测器 C 机箱能量分辨率随温度变化的初步标定结果

Signal amplitude as a function of temperature for LE flight model

The calibration procedure of ME has also been tested.

The electric fitting of the flight models of the payloads is almost finished. Environment tests started. Calibration procedures fully tested for HE and LE, and partly for ME. The payloads will be delivered before the end of November, and the expected launch date will be around September next year. October 22 ， Summary Thank you for your attention!

Backup materials

DetectorsLE: SCD, 384 cm 2 ;ME : Si-PIN, 952 cm 2 HE : NaI/CsI, 5000 cm 2 Energy RangeLE: 1-15 keV;ME: 5-30 keV;HE: keV Time ResolutionHE: 25μs; ME: 180μs;LE: 1ms Working Temperature HE: 18±1 ℃ ; ME: -50~-20 ℃ ; LE: ℃ Energy ResolutionLE: 6 keV ME: 17.8 keV HE: 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) Characteristics of the HXMT Mission

OrbitAltitude: ~550 km ; Inclination: ~43° AttitudeThree-axis stabilized Control precision: ±0.1° Measurement accuracy: ±0.01° Data RateLE: 3 Mbps; ME: 3 Mbps; HE: 300 kbps Payload Mass~1000 kg Nominal Lifetime4 years Working ModeScan survey, small region scan, pointed observation

Total background of HE varying with time Different background components of HE 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 cm 2 ), 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 cm 2, 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)

Test the performance of the automatic gain control by changing the angle between the main detector and the geomagnetic field. With out the gain control ， the amplitude variation of the same energy incident photons can reach 10.6% ， and it decreased to 0.243% using the AGC, the effect on the energy resolution is as small as 1.31% 。 Automatic Gain Control