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ASTROSAT: A Multi- Wavelength Satellite 1st Dedicated Indian Astronomical Mission. ISRO Satellite Centre (ISAC), Bangalore Tata Institute of Fundamental Research, Mumbai University of Leicester Indian Institute of Astrophysics (IIA), Bangalore
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ASTROSAT: A Multi-Wavelength Satellite 1st Dedicated Indian Astronomical Mission ISRO Satellite Centre (ISAC), Bangalore Tata Institute of Fundamental Research, Mumbai University of Leicester Indian Institute of Astrophysics (IIA), Bangalore Inter-University Centre for Astronomy & Astrophysics (IUCAA), Pune. Canadian Space Agency Raman Research Institute, Bangalore Vikram Sarabhai Space Centre, Trivandrum X-RAY UV/Opt G.C.Stewart Berlin
ASTROSAT(1.55 tons 600 kms, nearly equatorial orbit by PSLV, 3 gyros and 2 star trackers for attitude control by reaction wheel system with a Magnetic torquer ) 2 UV(+Opt ) Imaging Telescopes 3 Large Area Xenon Proportional Counters Soft X-ray Telescope Radiator Plates For SXT and CZT CZTI Scanning Sky Monitor (SSM) Folded Solar panels G.C.Stewart Berlin
UVIT: Two Telescopes • f/12 RC Optics • Focal Length: 4756mm • Diameter: 38 cm • Simultaneous Wide Angle ( ~ 28’) images in FUV (130-180 nm) in one and NUV (180-300 nm) & VIS (320-530 nm) in the other • MCP based intensified CMOS detectors • Spatial Resolution : 1.8” • Sensitivity in FUV: mag. 20 in 1000 s • Temporal Resolution ~ 30 ms, full frame ( < 5 ms, small window ) • Gratings for Slit-less spectroscopy in FUV & NUV • R ~ 100 G.C.Stewart Berlin
UVIT: filters G.C.Stewart Berlin
GALEX UVIT FoV (Circular dia) 1.24 degrees 27 arc-min No. of bands 2 (NUV, FUV) 2 channels (NUV, FUV) + Vis Filters in NUV NIL 5 filters Filters in FUV NIL 5 filters [multiple colour-colour diagrams] Spectroscopy Grism Grating Resolution R ~ 100-120 R ~ 100 No. of grism/grating 1 per band 2 per band Angular resolution 4.5-6.0 arcsec 1.8 arc-sec (FWHM) Saturation < 10 mag < 8.0 mag (neutral density filter) [can image fields with bright objects] Time resolution ~ 10 milli-sec ~ 5.0 milli-sec (window mode) ~ 30 milli-sec full field G.C.Stewart Berlin
Large Area Xenon Proportional Counter (LAXPC): Characteristics Energy Range : 3-80 keV (50 m Mylar window, 2 atm. of 90 % Xenon + 10 % Methane) Effective Area : 6000 cm² (@ 20 keV) Energy Resolution : ~10% FWHM at 22 keV Field of View : 1° x 1° FWHM (Collimator : 50µ Sn + 25µ Cu + 100µ Al ) Blocking shield on sides and bottom : 1mm Sn + 0.2 mm Cu Timing Accuracy : 10 μsec in time tagged mode (oven-controlled oscillator). Onboard purifier for the xenon gas G.C.Stewart Berlin
LAXPC: Effective Area G.C.Stewart Berlin
Large Area X-ray Proportional Counter (LAXPC) G.C.Stewart Berlin
LAXPC: Collimator G.C.Stewart Berlin
CZT Imager characteristics G.C.Stewart Berlin
CZT-Imager with a coded mask (Qualification Model) G.C.Stewart Berlin
CZT Detector 4 cm X 4 cm HV Connector Connectors CZT crystal Thermal conductor Thermal conductor ASIC G.C.Stewart Berlin
SXT Characteristics Telescope Length: 2465 mm (Telescope + camera + baffle + door) Top Envelope Diameter: 386 mm Focal Length: 2000 mm Epoxy Replicated Gold Mirrors on Al substrates in conical Approximation to Wolter I geometry. Radius of mirrors: 65 - 130 mm; Reflector Length: 100 mm Reflector thickness: 0.2 mm (Al) + Epoxy (~50 microns) + gold (1400 Angstroms) Minimum reflector spacing: 0.5 mm No. of reflectors: 320 (40 per quadrant) Detector (Swift Heritage): E2V CCD-22 600 x 600 Field of view : 41.3 x 41.3 arcmin PSF: 3 – 4 arcmins Sensitivity(expected): few x 10-14 cgs (1 cps/mCrab) G.C.Stewart Berlin
Soft X-ray Telescope G.C.Stewart Berlin
Four Fe-55 calibration (corner) sources • One Fe 55 calibration door source • Optical Blocking Filter • CCD Assy. including TEC • PCB with front-end electronics G.C.Stewart Berlin
SXT Engineering and Flight Models G.C.Stewart Berlin
Astrosat SXT FM FPCA in Thermal Vacuum Chamber at Birmingham University G.C.Stewart Berlin
CCD Performance Nominal • Noise ~6 – 10 e- • Resolution at Mn ~157 eV (Lab Electronics) G.C.Stewart Berlin
SXT CCD (Eng.) Data with TIFR built Electronics Isolated pixels only 5.9 and 6.4 keV peaks Resolution ~140 eV Si escape peaks 3.70 and 4.15 keV G.C.Stewart Berlin
Door and Corner X-ray Calibration Sources Optical LED Image G.C.Stewart Berlin
SXT Effective Area vs. Energy (after subtraction of shadowing effects due to holding structure) G.C.Stewart Berlin
Scanning Sky Monitor (SSM) • Detector : 3 x Proportional counters with resistive anodes • Ratio of signals on either ends of anode gives position. • Energy Range : 2 - 10 keV • Position resolution : 1.5 mm • Field of View : 10o x 90o (FWHM) • Sensitivity : 30 mCrab (5 min integration) • Time resolution : 1 ms • Angular resolution : ~ 10 arc min G.C.Stewart Berlin
Status • Engineering Environmental Tests almost complete • Flight Model Construction Well Advanced (UVIT detectors and SXT CCD camera complete) • Spacecraft Assembly begun – most subsystems complete • Launcher Assigned • Launch Date G.C.Stewart Berlin
ASTROSAT – Key Strengths Simultaneous V/UV to hard X-ray measurements LEO+ 70 inclinclination Low , stable? Background Large area at high X-ray energies UV imaging capability Low pile-up in CCD Fast Slewing ?? G.C.Stewart Berlin
ASTROSAT – Key Projects AGN/Binaries: Simultaneous UV to hard X-ray timing/monitoring Galactic Novae: UV to X-ray Observations (TOO program) Magnetars: Multi-wave observations LMXBs: Persistent Pulsations and thermonuclear bursts Galactic Black Holes and micro / nano quasars Binary X-ray Pulsars: Cyclotron Resonance Scattering Features (X-ray Observations) Clusters of galaxies: X-ray & UV Observations G.C.Stewart Berlin
ASTROSAT – Key Projects Supernova Remnants: X-ray and UV Observations UVIT observations of Star Forming galaxies, Young stellar objects, Galactic Structure, Proto- and Planetary Nebulae UV Extinction in the Galaxy (Archival Data) Miscellaneous: Study nano quasars and Compton thick sources, Observations of Stellar Flares, GLAST/INTEGRAL/BAT Sources, Surveys - multi wave, deep fields G.C.Stewart Berlin
AGN (bright) • 4/5 decade SEDs - Resolving all the spectral components : UV and soft X-rays (thermal) from accretion disk, hard X-ray reflection component, intrinsic power-law component • Variability correlation and lags between UV, soft and hard X-rays • Variability correlation and lags between Fe-K line and Compton Reflection • Bright Compton thick G.C.Stewart Berlin
H LAXPC C SXT CZTI Spectral model from Rephaeli et al. (1999) SXT: Clusters of galaxies 34 G.C.Stewart Berlin
Binary X-ray Pulsars with Astrosat Simulated 10 ks observations of hard X-ray spectrum of Accreting Pulsar 4U 0115+63 The cyclotron lines are well resolved by ASTROSAT G.C.Stewart Berlin
Time Allocation G.C.Stewart Berlin
Coming Next Year ! G.C.Stewart Berlin
Simultaneous UV to hard X-ray spectral measurements with ASTROSAT: Blazars, HPQs, OVVs etc. • Science Drivers: Jet Physics, particle injection and acceleration • Synchrotron X-ray emission from the highest energy e- • Electron/proton injection. • Acceleration and cooling related variability patterns in Sync. components of FSRQs and LBLs. • UV and soft X-ray variability can pin down the transition between the emission from slow and fast cooling e- and thus obtain estimates of magnetic field and Doppler factors of the jets. • Shocks in jets. Geom: viewing angle, jet opening angle. • Underlying Accretion disk in Blazars ? Can be revealed during minima when the beamed component is suppressed. G.C.Stewart Berlin