1. ASTROSAT Prospects for a Hard X-ray Survey  ASTROSAT Overview  LAXPC Details  Science Prospects  Hard X-ray Survey Prospects  Beyond ASTROSAT Biswajit Paul Raman Research Institute, Bangalore

2. ASTROSAT

4. IXAE

5. – EXOSAT-ME : 1983-1986 –1.5-15 keV, 1800 sq cm –With LE Imaging Telescopes (CMA) – GINGA-LAC: 1987-1991 –2-37 keV, 4000 sq cm –With All Sky Monitor – RXTE-PCA: 1996-201? –2-30 keV, 6000 sq cm –With All Sky Monitor and Hard X-ray Instrument – ASTROSAT-LAXPC: –2-80 keV, 6000 sq cm –With All Sky Monitor, Soft/Hard X-ray Instruments, UVIT Large Area X-ray Astronomical Observatories USA Exp,2000 sq cm IXAE, 1200 sq cm

6. LAXPC Characteristics Area : 6,000 - 7,500 cm 2 Mass: 390 kg Time Resolution: 10 µs, dead time 10-35 µs Absolute Timing Accuracy: 10 µs Front-end and Processing Electronics: separate electronics for each detector Data Storage: Onboard Memory 570 MB per Orbit Detection Efficiency: 90-100 % upto 20 keV, ~40% upto 80 keV Energy Resolution: 12-13% at 20-60 keV Life Time: 3-10 Years, no Consumable

8. LAXPC: Effective Area

9. LAXPC: Complex Energy Response Energy response generation: Monte Carlo simulation / Ground calibration

10. LAXPC: Energy resolution

11. Spectral Leakage in PCA and LAXPC PCA LAXPC

12. Spectral Leakage in PCA

13. LAXPC Schematic

14. LAXPC: Complex Energy Response PCA: Energy resolution of single events and escape events

15. ASTROSAT Ground Trace

16. LAXPC Advantages Large effective area in hard X-ray band Stable background Low Spectral leakage Wide energy band 2-80 keV with LAXPC 0.3-8 keV with SXT 10-150 keV with CZT Simultaneous, sensitive, multi-band UV/Optical observations Only timing instrument it this time frame

17. CRSF with ASTROSAT LAXPCs

18. Hard X-ray QPOs

19. Long term intensity variations in Cen X-3

20. Long term intensity variations and the orbital modulation Raichur & Paul 2008

21. Cen X-3: Precessing Warped Accretion Disk ?? Raichur & Paul 2008

22. Cen X-3: Precessing Warped Accretion Disk ?? Raichur & Paul 2008

23. Cen X-3: Intensity dependence of the pulsed fraction Raichur & Paul 2008

24. Long term intensity variations in Cen X-3 and the quasi-periodic oscillations Harhsa et al. 2008

25. Long term intensity variations in Cen X-3 and the quasi-periodic oscillations Raichur & Paul 2008

26. Hard X-ray Survey Explore the 10-60 keV band Period ic Scan Galactic plane + SMC region Extragalactic Survey 100 x 100 degree Survey with Slew Data Example: RXTE-PCA

27. Survey with Slew Data

29. X-ray Polarimeter

30. POLIX: Sensitivity GEMS MDP(n  ) =(n/  S)  (2(S+B)/T) 1/2