Brief Overview of China’s Future Space X-ray Astronomy Program Shuang-Nan Zhang Center for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences

Outline Approved missions: launch within the next 5 years Hard X-ray Modulation Telescope (HXMT) Space Variable Object Monitor (SVOM): China-France collaboration (Barret’s Talk) Gamma-ray burst polarimeter (POLAR): China-Europe collaboration on China’s Spacelab In mission definition and technology development phase: launch within next ~10 years X-ray Timing and Polarization mission (XTP) Proposed onboard China’s Space Station: launch around 2021-2022 Optical/UV/X-ray All-Sky Monitor

HXMT is a collaboration between: Payload Cabin Platform Cabin HXMT is a collaboration between: Chinese Academy of Sciences, Tsinghua University Chinese Academy of Space Technology

HE: NaI/CsI 5000 cm2 LE:SCD,384 cm2 ME:Si-PIN,952 cm2 Payloads onboard HXMT Size：1900×1600×1000 mm3

LE The Sun A sunshading board will be set so that the LE and ME instruments can work at low temperatures

High Energy X-ray Instrument 1、其中NaI（Tl）作为主探测介质，而CsI（Na）在Na(Tl)的后面，屏蔽2π方向分本底 反符合屏蔽探测器是覆盖在主探测器顶部和周围的塑料闪烁体探测器，其目的是消除空间高能带电粒子在主探测器上形成的本底，提高探测灵敏度。 2、监测器系统，检测探测器接收的光子流强。当流强超过影响探测器性能的数值时，关闭探测器，使探测器停止工作，从而保护探测器；同时，通过分析粒子监视器记录的空间带电粒子流强信息，还可以与空间环境监测器SEM的数据结合，估计望远镜的本底水平。 3、实时跟踪并标定主探测器的工作情况，特别是测量稳定性情况，以便随后对主探测信号的校正或实现主探测器系统的自动增益校正。 bicrystal scintillation detector, and the effective area is 5000cm2. The whole telescope is divided into 18 modules with the same size of field of view 1.1◦×5.7◦ (FWHM). They are arranged to deflect successively from the normal direction of the collimator by an increment of 10◦. The pointing of every module is fixed by the upper, middle and lower pallets. The top and side surfaces are all attached with 6 pieces of charged-particle anticoincidence plates. Fig.13 shows the layout of the whole 18 modules of HE, and Fig.14 shows the overall structure of the effective payload of HE. HXMT/HE Components assembly The 18 main collimated phoswich detectors Charged-particle anticoincidence plates (6 pieces up side +12 lateral side) Particle Monitor detectors Calibration detectors (automatic gain control)

The Field of View configuration of HE 1 Blind Module 2 Modules of 5.7 °× 5.7 ° 15 Modules of 1.1 ° × 5.7 ° 高能X射线望远镜总体结构图（上）及主探测器示意图（下） 1、其中NaI（Tl）作为主探测介质，而CsI（Na）在Na(Tl)的后面，屏蔽2π方向分本底 反符合屏蔽探测器是覆盖在主探测器顶部和周围的塑料闪烁体探测器，其目的是消除空间高能带电粒子在主探测器上形成的本底，提高探测灵敏度。 2、监测器系统，检测探测器接收的光子流强。当流强超过影响探测器性能的数值时，关闭探测器，使探测器停止工作，从而保护探测器；同时，通过分析粒子监视器记录的空间带电粒子流强信息，还可以与空间环境监测器SEM的数据结合，估计望远镜的本底水平。 3、实时跟踪并标定主探测器的工作情况，特别是测量稳定性情况，以便随后对主探测信号的校正或实现主探测器系统的自动增益校正。 bicrystal scintillation detector, and the effective area is 5000cm2. The whole telescope is divided into 18 modules with the same size of field of view 1.1◦×5.7◦ (FWHM). They are arranged to deflect successively from the normal direction of the collimator by an increment of 10◦. The pointing of every module is fixed by the upper, middle and lower pallets. The top and side surfaces are all attached with 6 pieces of charged-particle anticoincidence plates. Fig.13 shows the layout of the whole 18 modules of HE, and Fig.14 shows the overall structure of the effective payload of HE.

(radiator) An ME detector box

Detector: Si-PIN Energy coverage: 5-30 keV Detecting area: ~950 cm2 (1728 pixels) Sensitivity: 0.5 mCrab Field of view: 1°×4°,4 °×4°, blind field Energy resolution: < 1.5 keV@17.8keV Work temperature: -20~-40℃ for Si-PIN Time resolution: 40 μs Mass: 105kg Power dissipation: 130 W 16 Si-PIN (0.56 cm2 each) pixels will be in one package and 2 packages read by a RENA-3 asic.

The low energy instrument (LE) 2×2 CCD236 16 cm2

The Hard X-ray Modulation Telescope @ EAMA-7 FOVs of an LE module The Hard X-ray Modulation Telescope @ EAMA-7

Schematic map of a CCD236 (e2v) Detector: SCD Energy coverage: 1-15 keV Detecting area: ~384 cm2 (96 chips) Sensitivity: 0.5 mCrab Field of view: 1.5°×6°,4 °×6°, blind field 60 °×3°(48cm2), Energy resolution: <150 eV@6keV Work temperature: -40~-80℃ for SCD Time resolution: 1 ms Mass: 105 kg Power dissipation: 130 W Schematic map of a CCD236 (e2v)

Characteristics of the HXMT Mission Detectors LE: SCD, 384 cm2;ME : Si-PIN, 952 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: 20μs;LE: 1ms Energy Resolution LE: 2.5% @ 6 keV ME: 8% @ 17.8 keV HE: 19% @ 60 keV Field of View of one module LE: 6°×1.5°; 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)

Sensitivity (3σ, in 105s) LE: 4.4×10-5 cts cm-2s-1 keV–1 (@6keV) ME: 2.6×10-5 cts cm-2s-1 keV–1 (@20keV) HE: 3×10-7 cts cm-2s-1 keV–1 (@100keV) 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, pointed observation

Scientific objectives of pointed observations X-ray Binaries Broadband X-ray variability, especially the QPO properties of BH binaries at energy higher than 20 keV; Broadband spectral characteristics and state transitions Cyclotron Resonance Features (CRF) close to the neutron star surface; Broadband spectrum of bright AGN: reflecting components and high energy cut off;

Observation modes Scanning Sky Survey mode Deep scanning observations of selected sky regions (such as the Galactic center region) Pointed observations The requirements of ADCS is based on HXMT mission objectives. In order to fulfill the objectives, the HXMT mission is divided into several mission phase. For every phase, a survey mode is defined. There are two main mission phases and two corresponding survey mode: The first is all sky scan phase .In this mode, the attitude of HXMT satellite is 3-axis stablized and earth oriented. The all-sky survey is carried through the motion of the satellite in its orbit and precession of the orbital plane. By rotating about the roll axis by thirty degrees and minus thirty degrees , HXMT is able to cover most sky region. This scan phase will take six months to complete. The second phase is pointing and deep scanning of selected sky region. The satellite will operate in inertial fixed attitude to stare the interested sky region. For each point in the sky region, the period of attitude stablization is thirty minutes.Then the satellite is maneuvered to observe next point. This phase will run through the rest of mission lifetime ,about eigthteen months.

Status of HXMT Full-funding decision: March 2011 Phase-B (pre-flight module): 2011.6-2012.12 Phase-C (flight module): 2013.1-2014.6 Launch: ~2015

Outline Approved missions: launch within the next 5 years Hard X-ray Modulation Telescope (HXMT) Space Variable Object Monitor (SVOM): China-France collaboration (Barret’s Talk) Gamma-ray burst polarimeter (POLAR): China-Europe collaboration on China’s Spacelab In mission definition and technology development phase: launch within next ~10 years X-ray Timing and Polarization mission (XTP) Proposed onboard China’s Space Station: launch around 2021-2022 Optical/UV/X-ray All-Sky Monitor

Gamma-ray burst polarization experiment onboard China’s Spacelab: POLAR GRB prompt emission polarization: a last observables of GRBs Different GRB models E-M Model: well defined, moderate Plin ~ 50% Fireball Model: high values excluded Plin ~ 10-20 % Cannon ball Model: full range possible Plin = 0 - 100% Probe quantum gravity (???): Amelino-Camelia G., 2000, Nature, 408, 661 Piran T, 2005, Lect. Notes Phys, 669, 351 Fan, Y-Z; Wei, D-M; Xu, D. 2007, MNRAS, 376, 1857 From M. Lyutikov, 2003 See papers discussing various GRB models: T. Piran, A. Dar, M. Lyutikov, D. Eichler, G. Ghisellini, D. Lazzatti, M. Medvedev, E. Rossi etc. 19

Plastic scintillator stacks Gamma-ray burst polarization experiment onboard China’s Spacelab: POLAR Onboard China’s spacelab TG-2: launch time 2012-13 A China-led international collaboration (Switzerland, France, Poland) FOV of POLAR: ~½ sky Tian-Gong 天宫 Palace in Heaven Plastic scintillator stacks Instrument concept proposed by N. Produit, et al., NIM (2005)

POLAR capability summary 10 GRBs per year down to 8%, or 60 GRBs per year down to 30%, or 100 GRBs per year down to 50% polarization,

Outline Approved missions: launch within the next 5 years Hard X-ray Modulation Telescope (HXMT) Space Variable Object Monitor (SVOM): China-France collaboration (Barret’s Talk) Gamma-ray burst polarimeter (POLAR): China-Europe collaboration on China’s Spacelab In mission definition and technology development phase: launch within next ~10 years X-ray Timing and Polarization mission (XTP) Proposed onboard China’s Space Station: launch around 2021-2022 Optical/UV/X-ray All-Sky Monitor

X-ray Timing and Polarization (XTP) mission Key Science: Matter under extreme conditions Precise Light curve: Neutron Star equation of state, BH basic parameters, formation and growth … Polarization of X-ray: Radiation mechanism… Diffuse X-ray emission, hot gas distribution in Galaxy … Main Requirement: large effective area & high counting rate The most accurate light curve and polarization observation at 1-30 keV

HERO concept: High Energy Replicated Optics – Small Aperture, Short Focal Length and Shallow Grazing Incidence Using small mirror array to achieve large collection area at hard X-ray (>10 keV): technically more feasible than single large mirror. Ramsey et al, SPIE 2000

Bepicolombo soft X-ray (<10 keV) MPO telescope: short focal length & lightweight 2009-11-19 25

XTP Mission Concept

XTP (Possible) Instruments SDD/CZT High-energy Collimated Array (1-100 keV) SDD/CZT High-energy Focused Array (1-100 keV) CZT All Sky Monitor (5-300 keV) GEM Polarization Observation Telescope (2-10 keV) CCD Low-energy Focused (0.5-10 keV) SCD Low-energy Collimated Array (0.5-15 keV) 4 m focal length

有效载荷初步方案 LFA: Low energy X-ray Focusing telescope Array 0.5-10 keV Micro-pore Optics (MPO) mirrors, mDEPFET detectors

High energy X-ray Focusing telescope Array (HFA): 1-100 keV Double conical nested mirrors SDD+CZT composite detector

Low energy x-ray Collimated detector Array (LCA): 0.5-15 keV SCD: e2V LIGA made collimator: 30μm thickness each layer 一个LCA模块示意图

HCA composite detector HCA: High energy X-ray Collimated detector Array 1-100 keV HCA composite detector

POT: Polarization Observation Telescopes 2-10 keV GEM-TPC: 0.25-30 keV 掠射望远镜可通过国际合作由意大利INAF研制，图示为意大利原为HXMT设计的多层掠射镜的装配图。

ASM: All-Sky Monitor FOV~2Sr, 4-300 keV, 1000cm2, 6400 × 4mm×4mm CdZnTe

XTP Basic Parameters Total satellite mass: 3210 kg Energy Range, Weight, FOV & Angular Resolution HFA：1-100 keV, 480 kg, 1°×1°, 1’ LFA：0.5-10 keV, 170 kg, 1°×1°, 1’ HCA：1-100 keV, 500 kg, 2°×2° LCA：0.5-15 keV, 400 kg, 2°×2° ASM：4-300 keV, 100 kg, 2 Sr POT：2-10 keV, 110 kg, 22’ ×22’ Total satellite mass: 3210 kg Geometrical Area HFA: 5000 cm2 (1-6 keV), 2800 cm2@30 keV LFA：7400 cm2@1 keV HCA: 15000 cm2 (6-30 keV) LCA: 15000 cm2 (1-6 keV) Energy Resolution 150 eV@5.9 keV 4 keV@30 keV Timing Resolution 10 μs May choose near-earth orbit or L2 orbit, depending on available launcher (money)

Outline Approved missions: launch within the next 5 years Hard X-ray Modulation Telescope (HXMT) Space Variable Object Monitor (SVOM): China-France collaboration (Barret’s Talk) Gamma-ray burst polarimeter (POLAR): China-Europe collaboration on China’s Spacelab In mission definition and technology development phase: launch within next ~10 years X-ray Timing and Polarization mission (XTP) Proposed onboard China’s Space Station: launch around 2021-2022 Optical/UV/X-ray All-Sky Monitor

OUVX-ASM Mission Concept zenith One X-ray ASM Module Motion of spacecraft FOV of OUV-ASM FOV of X-ASM

Summary on China’s Future Space X-ray Astronomy Program Approved missions Hard X-ray Modulation Telescope (HXMT): 2014-2015 Space Variable Object Monitor (SVOM): China-France collaboration (Barret’s Talk) ~2015 Gamma-ray burst polarimeter (POLAR): China-Europe collaboration on China’s Spacelab 2012-2013 In mission definition and technology development phase X-ray Timing and Polarization mission (XTP) ~2020 Proposed onboard China’s Space Station Optical/UV/X-ray All-Sky Monitor ~2021-2022