Topic A: Performance of the ASTRO-H micro-calorimeter (by Tsujimoto) 10 min Introduction (by Takahashi) 5min Topic B: X-ray Observations to study the EOS (by Dotani) 10 min Approaches to study the EOS for neutron star matter from X-ray astronomy satellites (Report from Group C01) Tadayuki Takahashi, Tadayasu Dotani, Masahiro Tsujimoto Institute of Space and Astronautical Science (ISAS)/JAXA Toru Tamagawa RIKEN Yasunobu Uchiyama Rikkyo Univ. ( Collaborators: Hirokazu Odaka, Teruaki Enoto, Dmitry Khangulyan, Atsushi Harayama, Hirokazu Ikeda, Masachika Iwai, Chris Done, Hiroki Yoneda) Program for Specific topics (talks) Kazuo Maxima (RIKEN), Teruaki Enoto (Kyoto U.)
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Topics covered in the C-01 research project 1) Neutron star observations with X-ray missions such as ASTRO-H. (1) Prepare for high-resolution observations by using the micro-calorimeter (SXS) onboard ASTRO-H. (e.g. high counting rate Pulse Shape SXS Dewar Processor (PSP)) (2) Prepare for wide-band observations from 0.3 keV to 600 keV by using SXI (X-ray CCD), HXI (CdTe DSD) and SGD (Si/CdTe Compton Camera) onboard ASTRO-H (e.g. ground calibration) (3) Find good targets to be observed by ASTRO-H based on studies by using archival data from Chandra, XMM, HXI Test Model Suzaku.
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Topics covered in the C-01 research project 2) Study new X-ray missions, to open up a new field for studying neutron star matter (1) Participate in international mission proposals 1. NICER (Enoto’s talk) 2. PRAXyS 3. LOFT (2) Develop new detectors for future X-ray missions (Si and CdTe Imaging detectors wth high counting & high resolution capability) 3) MonteCarlo calculation code to simulate the emission from neutron star surface (under strong magnetic field) 4) Use GeV Gamma-ray observatory (Fermi Satellite) to find another approach to study the neutron star. X-ray Path in the MC Simulation of Accretion Column
T,Takahashi, “Recent Development of CdTe Imagers", Arizona, 25 Aug. 2016 ASTRO-H (Hitomi) Chandra (Marshall et al. 2001) 2.7 ton/14 m
T,Takahashi, “Recent Development of CdTe Imagers", Arizona, 25 Aug. 2016 ASTRO-H (Hitomi) But lost its function on March 26, 2016 All mission instruments showed good performance as expected. Chandra (Marshall et al. 2001) Part A of this presentation (Tsujimoto)
preflight X-ray polarimeter X-ray polarimetry can address the questions of: precise modeling of emission mechanism and environment of NSs. Although these observations do not answer NS EOS directly, they contribute to the pulsars (Viironen & Poutanen, 2004) T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 New Missions (PRAXyS, NICER, LOFT) PRAXyS (Polarimeter for Astrophysical X-ray Sources) Project deployable optical boom X-ray polarimeters X-ray mirror f = 4 . 5 m 7 . 0 m 2014/12: Proposed to NASA's Small Explorer program 2015/07: Selected for Phase A study (three projects selected) 2016/07: Submitted Conceptual Study Report to NASA HQ 2017/02: Down selection (only one project will be selected.) 2020/08: Launch 1. X-ray emission point and mechanism of neutron stars (Meszaros+1998) 2. Vacuum birefringence in strong magnetic field of magnetars (Lai & Ho, 2003) 3. Inclination and magnetic inclination configuration of accreting millisecond
Abdo et al. (2013) . T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 GeV/TeV Gamma-ray Observations of Pulsars/Pulsar Wind Nebulae Some Radio-quiet pulsars show large Gamma- ray luminosity close to its Spin-down power: Gamma-ray observations can constrain NS’s “moment of inertia, I”. Fermi Satellite Spin-down power: E = − I Ω ˙ ˙ Ω = 4 π 2 I ˙ PP − 3 L γ =E for I 0 pulse measurement gamma-ray luminosity of (radio/gamma) pulsar/pulsar wind nebula Then, moment of inertia, I, can constrain EOS. I = kMR 2 Number of gamma-ray pulsars detected with Fermi-LAT is 205! (as of 2016 Feb), ˙ Figure 6.9: including PSRJ0537-6910 in LMC (Large Magellanic Cloud).
Topic A: Performance of the ASTRO-H micro-calorimeter (Masahiro Tsujimoto) Topic B: X-ray Observations to study the EOS (Tadayasu Dotani) T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016
Array (5mm 2 ) Topic A: Performance of the ASTRO-H micro-calorimeter (SXS) 約 熱 T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 • X-ray micro-calorimeter array. • 6x6 pixels : 10.6 μ m HgTe absorber + Si thermometer at 50 mK. 8 0 m • Measure T increase (about 1 mK) by s 浴 energy deposit of individual X-ray Ts ( 約 photons (about 1 fJ). 50 m K) • Multi-stage cooling using (a) 3 ADRs, (b) 4 Stirling coolers, (c) 1 Joule- Thomson cooler, (d) 30 litter liquid He. • Thermal relaxation time scale : about 5 ms = 200 Hz/pixel
• • • Sample ADU(t) at 4 Hz/pixel T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Onboard Digital Electronics Waveform : ADU(t) is cross-correlated with a template to derive energy by optimum filtering. Onboard digital electronics is the bottleneck in total throughput. 150 Hz/ array (about 1/10 of Crab flux) required. Efforts for high CR performance made in development phase.
Perseus cluster of galaxies (Hitomi collab. 2016, Nature) Hitomi SXS Suzaku XIS Cr XXIII Mn XXIV Fe XXV Fe XXVI Ni XXVII Fe XXV T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 In-orbit Performance • Energy resolution : 4.9 eV (FWHM) at 5.9 keV. • Energy range : 2-20 keV.
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 High CR observation • Crab nebula observed. • About 200 Hz events processed. • Most illuminated pixels have >25% live time. • Superb spectroscopic performance verified for a high CR observation.
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Spectroscopy of high CR • Most stringent upper limit for X-ray line emission from Crab, a super-nova remnant. • Constraint on the origin of this super nova SN1054.
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Summary (Topic A) • SXS worked successfully in the orbit. No major problems. The first satellite-borne X-ray micro-calorimeter to observe X-ray sources. • Superb spectroscopic performance achieved. Tremendous advantages beyond all other X-ray spectrometers for various topics, including NS. • Efforts to make high CR observations paid off. Verified with Crab.
X-ray emission T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Topic B: X-ray Observations of Neutron Stars to Study the EOS Importance of X-ray observations In order to get information on the radius, we need to observe radiation from the neutron star surface. Thermal emission from the mass-accreting neutron stars 1/4 − 1/2 1/4 ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ M R L T = 1.8 ⎜ ⎟ keV ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ M ⊙ 10km L Edd X-ray observations are essential to get information on radius of the neutron stars.
T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Observational Methods to probe the neutron star radius (1)Mass-Radius Ratio Gravitational redshift of the atomic features in the X-ray spectrum from the NS surface. X-ray bursts (2) Radius (and Mass) Light bending and Doppler boosting Pulse profile of the millisecond pulsars with thermal emission NICER: Talk by T. Enoto
X-ray bursts Properties of the NS in LMXBs Run-away nuclear reaction of He (H) on the NS surface T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Low-mass X-ray binaries and X-ray Bursts Accretion disk • B s <10 9 -10 10 G • Spin ~ 200-600 Hz • T < 0.1 ~ 2 keV Neutron star • persistent / Transient Low-mass star Duration : ~ 10-100 sec Interval : hours ~ days Luminosity : ≤Eddington limit ~ 10 38 erg/s Burst oscillation is used to infer the spin frequency.
slow spin. We need burst sources with T,Takahashi, T. Dotani, M. Tsujimoto, T. Tamagawa, Y. Uchiyama, NSMAT 2016, Nov. 21-24, 2016 Why X-ray bursts? Mean composition of the envelope (1) Enrichment of heavy elements in the atmosphere Heavy elements up to Z~50 are produced in X-ray bursts. Metal poor Solar Atomic features in the spectra. Parikh et al. 2013, Prog. Part. Nucl. Phys. 69, 225 Mass number A (2) Temperature structure of the atmosphere Photons created at the bottom of the atmosphere will go through the relatively cool layer, where absorption lines/edges are formed. Caveat: Rapid spin of the neutron star X-ray bursters: typical spin 200-600 Hz Spectral features may be smeared out.
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