Large Area X-ray Propor.onal Counter (LAXPC) instrument and ini.al science results (from payload verifica.on phase)

Transcription

1 Large Area X-ray Propor.onal Counter (LAXPC) instrument and ini.al science results (from payload verifica.on phase) J. S. Yadav Tata Ins.tute of Fundamental Research Mumbai, India 19-Jul-16 J S Yadav, TIFR 1

2 ACer comple.ng all electronic & detector tests and final calibra.on, all three flight units of LAXPC instrument in AIT lab for integra.on with satellite on 20 th October, Jul-16 J S Yadav, TIFR 2

3 LAXPC instrument`s capabili.es are similar or beser than that of NASA`s RXTE/PCA. 19-Jul-16 J S Yadav, TIFR 3

4 Payloads Instruments: ASTROSAT: Co-aligned multi-wave instruments Large Area X-Ray Proportional Counter (LAXPC) -TIFR SXT UVIT LAXPC Soft x-ray Telescope (SXT) - TIFR Cadmium Zinc Telluride Imager (CZTI) TIFR Ultra Violet Imaging Telescope (UVIT ) IIA Scanning Sky Monitor (SSM ) ISAC SSM CZTI J S Yadav, TIFR 19-Jul-16 4

5 LAXPC: Large Area X-ray Proportional Counters (~419 Kg) (became fully operational on 19 th Oct. 2015) A broad energy band (3-80 kev) with high detec.on efficiency of X-ray above 20 kev and high.ming resolu.on 10 μsec.. Three co-aligned iden.cal LAXPC detectors Each with a mul.-wire-mul.-layer configura.on filled with 90%Xe +10% Methane gas at 1520 torr. Energy resolu.on (12%@22 kev) A 50 micron thick aluminized Mylar window for X-ray entrance Mylar film support -- by a honeycomb window support collimator A narrow field of view of.8x.8 degs provided by mechanical collimators made of a sandwich of 50µ Sn + 25µ Cu + 100µ Al co-aligned with the window support collimator and siing above it. Blocking shield on sides and bosom : 1mm Sn mm Cu 19-Jul-16 J S Yadav, TIFR 5

6 LAXPC Flight Packages LAXPC DETECTOR 1 AS-LX-DT-10 LAXPC DETECTOR 2 AS-LX-DT-20 LAXPC DETECTOR 3 AS-LX-DT-30 PROCESSING ELECTRONICS 1 AS-LX-EL-10 PROCESSING ELECTRONICS 2 AS-LX-EL-20 PROCESSING ELECTRONICS 3 AS-LX-EL-30 PURIFIER ELECTRONICS (XPDE) AS-LX-EL-50 S. T. B. G. AS-LX-EL-40 Ø Ø Ø Ø LAXPC payload has 8 flight packages. Three Detectors, Corresponding Processing Electronics, Common STBG package, & XPDE package 19-Jul-16 J S Yadav, TIFR 6

7 Detector System Brief description LAXPC Instrument consists of 3 identical detectors. Each LAXPC has the following major components : Field of View Collimator (FOVC) Window Support Collimator (WSC) Collimator Housing Anode Frames Detector Housing Back Plate

8 Detector hardware 19/07/16 J S Yadav 8

9 Detector hardware 19/07/16 J S Yadav 9

10 Harness wiring of detector

11 Detector Front-End Electronics 19-Jul-16 J S Yadav, TIFR 11

12 LAXPC Detector on vibration table 19-Jul-16 J S Yadav, TIFR 12

13 Sor.ng out purifica.on cartridge issue in LAXPC30 at ISAC on 20 th August, /07/16 J S Yadav TIFR Mumbai 13

14 Calibration scan profile 19-Jul-16 J S Yadav, TIFR 14

15 Lx10 spectra of sources at different temperatures (10 c, 20 c & 30 c) LAXPC Calibration Meeting, Feb

16 Lab calibra.on: GEANT4 simula.on for LAXPC30 unit & results for Am source (all 5 layers) 19-Jul-16 J S Yadav, TIFR 16

17 Comparison of LAXPC with NASA s RXTE/PCA LAXPC instrument will have four.mes or more effec.ve area above 20 kev as compared to RXTE/PCA. It can detect 0.1 mcrab sources in few thousand second. 19-Jul-16 J S Yadav, TIFR 17

18 Detector performance: On-board Purifica.on & Detector energy resolu.on l On-Board Purification for Flight Detectors 19-Jul-16 J S Yadav, TIFR 18

19 Each of the LAXPC detectors has an onboard gas purifica.on system. This system will be operated as and when required to purify the gas filled in the detector by command. It is expected that energy resolu.on of LAXPC detector will degrade as impurity increases. 19-Jul-16 J S Yadav, TIFR 19

20 Energy resolu.on at 6.4 kev in orbit: We achieved around 20% Energy resolu.on as proposed. CAS A (supernova remnant) observa.on LAXPC30 (lec top) and RXTE/PCA ( lec bosom). GX observa.on in early May 2016 show similar Resolu.on ( Iron line is clearly visible ar 6.4 kev) RXTE/PCA CAS-A observa.on 19-Jul-16 J S Yadav, TIFR 20

21 Crab observa.on with LAXPC and RXTE/PCA(NASA) : RXTE/PCA took 3 years to fit 2-60 kev with reduced CHI square ~ 3 while we have fit LAXPC spectrum in 3-80 kev with reduced CHI square ~1.4. LAXPC detector Has higher efficiency at higher energy (RXTE/PCA has 1 c/s/kev at 30 kev while LAXPC has this flux value at 60 kev) RXTE/PCA 19-Jul-16 J S Yadav, TIFR 21

22

23 LAXPC instrument capabili.es: comparison with Nustar At present, NASA,s Nustar and LAXPC instrument are only two X-ray space instruments which cover 3-80 kev energy range. Here we show fit to simultaneous LAXPC and Nustar data of Crab (a X-ray pulsar) taken on 1 st April, It is a good fit with reduced chi square ~1.04. Nustar data shows large spread at high energy which suggests that its detec.on efficiency decreases fast at > 30 kev.

24 LAXPC instrument capabili.es: QPO (Quasi Periodic Oscilla.on) detec.on Rebinned power density spectra of GRS (a microquasar) in SPL state. It matches Well with the predicted Poisson noise level with dead.me 42.3 microseconds and a low Frequency power low component. The green line shows the expected peak power of a QPO With quality factor Q=4 and rms of 5%. LAXPC instrument would detect QPO of such a Strength easily.ll 3000 Hz. Observa.on 6 th March 2016

25 LAXPC first results : Crab ( a pulsar) : 19-Jul-16 J S Yadav, TIFR 25

26 First light results: 4U (a pulsar in outburst) Transient X-ray pulsar (3.6 seconds) 4U High Mass X-ray Binary with a neutron star (high magne.c field) companion that accretes mass 19-Jul-16 J S Yadav, TIFR 26

27 Radio jets observed simultaneously with GMRT Radio flares during X-ray theta class: 5-7 March Jul-16 J S Yadav, TIFR 27

28 6. Microquasar GRS in steep power law (SPL) state: Contribu.on of thermal and non-thermal process to total X-ray luminosity (lec panel) and varia.on of quasi-periodic Oscilla.on (QPOs) with X-ray luminosity (right panel) 19-Jul-16 J S Yadav, TIFR 28

29 During GRS observa.on during 5-7 th March, 2016 SPL (steep power law) X-ray state was observed for ~10 hrs. QPO frequency changes from 2.5 Hz to 6 Hz. 19-Jul-16 J S Yadav, TIFR 29

30 LACPC ini.al results; Cyg X-1 (persistent black hole X-ray binary) 19-Jul-16 J S Yadav, TIFR 30

31 Cyg X-1 Energy spectrum 19-Jul-16 J S Yadav, TIFR 31

32 19-Jul-16 J S Yadav, TIFR 32

33 LAXPC observa.on of Thermonuclear bursts and high frequency Quasi Periodic Oscilla.on (HF QPOs): LAXPC observed thermonuclear bursts in two neutron star X-ray binaries; 4U and 4U during instrument verifica.on phase. These are thermonuclear (atom bomb) explosions on accre.ng neutron star. Rise.me is ~ 1 sec ( X-ray flux rises by a factor of ~10) and decay.me sec. 4U Jul-16 J S Yadav, TIFR 33

34 Top panel shows dynamic power density Spectrum from LAXPC observa.on of 4U We observed burst oscilla.on for first Four sec at Hz (top panel). It suggests that this thermonuclear bursts happens at Equator and spreads in four sec and Become axisymmetric belt and QPO Disappears (bosom panel) 19-Jul-16 J S Yadav, TIFR 34

35 High Frequency Quasi-periodic Oscilla.ons (HF QPOs) : HF QPOs probe regions close to the compact objects (Neutron star and black hole Systems) which are characterized by very high gravity and magne.c field. Observed frequency is always < 1.2 KHz (for ~2 M sun ). The innermost stable circular orbit (ISCO) Is around km which corresponds to 1.2 KHz (right panel). LeC panel shows dynamic Power density spectrum from LAXPC observa.ons. As mass falls, qpo evolves (rises) and explores extreme condi.ons near neutron star. QPO frequency evolves from ~820 Hz to 850 Hz LeC panel shows dynamic power density Spectrum from LAXPC observa.on of 4U We observed 820 Hz HF QPOs showing dric to higher frequency. Orbit and frequency ISCO 12.5km 15 km 27km 19-Jul-16 J S Yadav, TIFR 35

36 NGC 4151 with LAXPC kev spectrum fit (5-50 kev range excluded) Which clearly shows presence of reflec.on component and iron line 19-Jul-16 J S Yadav, TIFR 36

37 LAXPC observed GRB in April, 2016: light curves and energy spectrum: This was not in LAXPC objec.ves, but we can study them. It will need some efforts to modify detector response. GRB A GRB A 19-Jul-16 J S Yadav, TIFR 37

38 Conclusion Exciting Science to come need more data of background (once every month) 19-Jul-16 J S Yadav, TIFR 38

39 LAXPC Instrument team Thanks! ISRO Satellite Centre (ISAC), Bangalore, Raman Research Ins.tute, Bangalore, Vikram Sarabhai Space Centre, Trivandrum, Space Applica.ons Centre, Ahmedabad IUCAA, Pune & Several colleagues at TIFR, Mumbai, PRL, Ahemdabad 19/07/16 J S Yadav TIFR Mumbai 39