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

ASTROSAT

IXAE

– EXOSAT-ME : – keV, 1800 sq cm –With LE Imaging Telescopes (CMA) – GINGA-LAC: –2-37 keV, 4000 sq cm –With All Sky Monitor – RXTE-PCA: ? –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

LAXPC Characteristics Area : 6, ,500 cm 2 Mass: 390 kg Time Resolution: 10 µs, dead time 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: % upto 20 keV, ~40% upto 80 keV Energy Resolution: 12-13% at keV Life Time: 3-10 Years, no Consumable

LAXPC: Effective Area

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

LAXPC: Energy resolution

Spectral Leakage in PCA and LAXPC PCA LAXPC

Spectral Leakage in PCA

LAXPC Schematic

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

ASTROSAT Ground Trace

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

CRSF with ASTROSAT LAXPCs

Hard X-ray QPOs

Long term intensity variations in Cen X-3

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

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

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

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

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

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

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

Survey with Slew Data

X-ray Polarimeter

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