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Martin Elvis Smithsonian Astrophysical Observatory

Welcome to the 4 th Chandra – CIAO Workshop 20 – 22 May 2002. Martin Elvis Smithsonian Astrophysical Observatory. Chandra X-ray Observatory Overview. Martin Elvis Smithsonian Astrophysical Observatory CIAO Workshop 20 May 2001. NASA Great Observatories. CHANDRA. Focusing X-rays.

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Martin Elvis Smithsonian Astrophysical Observatory

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  1. Welcome to the 4th Chandra – CIAO Workshop 20 – 22 May 2002 Martin Elvis Smithsonian Astrophysical Observatory

  2. Chandra X-ray Observatory Overview Martin Elvis Smithsonian Astrophysical Observatory CIAO Workshop 20 May 2001

  3. NASA Great Observatories CHANDRA

  4. Focusing X-rays

  5. Chandra Mission Summary • Launch: July 23, 1999 • STS-93/ Inertial Upper Stage / Integral Propulsion System • 10,000 km x 140,000 km, 28.4o Inclined Orbit • Design Lifetime > 5 Years (in NASA plan for 10 year life) • 10-m Focal Length Wolter -1 Mirror: 4 nested Mirror Pairs • Energy Range: 0.1-10 keV • ¼ arcsecond resolution. Sub-0.5arcsec in practice • 2 Imaging Focal Plane Science Instruments • ACIS (Advanced CCD Imaging Spectrometer) • HRC (High Resolution Camera) • 2 Objective Transmission Gratings for Dispersive Spectroscopy • LETG(Low-Energy Transmission Grating) • HETG(High-Energy Transmission Grating)

  6. Mission and Observatory Description

  7. High Resolution Mirror Assembly • 4 pairs of concentric thin-walled zerodur, grazing incidence Wolter Type-I mirrors ->large area. ->800cm2 E<2keV Antennae galaxies • figured to 0.5” FWHM -> sensitivity, -> megapixel images • Focal length 10 m. -> response to 10keV Many independent pixels High sensitivity • polished to 3A -> low scattering high dynamic range Iridium edge PSR nebula PKS1127-145 95% High energy sources 100:1 AGN/jet contrast 1.6”

  8. Aspect Camera and Fiducial Transfer System Aspect Camera 4.25inch dia.15”pixels <0.25” r ms (typical)

  9. Chandra Science Instruments Z+ ACIS-I • Advanced CCD Imaging Spectrometer (ACIS) • CCD array with 16’x16’ field of view (ACIS-I) • grating readout array (ACIS-S) • High Resolution Camera (HRC) • microchannel plate imager with 31’x31’ field of view (HRC-I) • low energy grating readout array (HRC-S) • High time resolution • High Energy Transmission Grating Spectrometer (HETG) • transmission grating pairs for medium and high energy • Low Energy Transmission Grating Spectrometer (LETG) • transmission grating for low energy BI BI Y+ ACIS-S HRC-I HRC-S

  10. Advanced CCD Imaging Spectrometer (ACIS) • Ten 1024x1024 pixel CCDs (any 6 simultaneously) • Intrinsic energy resolution ~100eV -> imaging spectroscopy • ACIS-I: 2x2 array for imaging (16x16 arcmin) • ACIS-S: 1x6 array for imaging (8x8arcmin) or spectroscopy • 2 `back illuminated’ (BI) chips: good low E QE, higher throughput

  11. ACIS Issues CTI • Front Iluminated (FI) chips suffered proton damage just after launch. -> charge transfer inefficiency (CTI) -> much degraded energy resolution • CTI correction (Townsley, PSU) restores linearity, most dE/E Pileup • 3.2 s full frame readout time -> for sources >0.1ct/s suffer “pileup” I.e. 2 photons in same pixel/frame -> loss of energy information, and -> loss of PSF peak • Pileup correction (J.Davis, MIT) available in CIAO, Sherpa Low Energy Calibration • Non-linear gain • Changing QE • See H. Donnely talk

  12. Chandra Grating Spectrometers m=2 d Incoming Radiation m=1  m=0 m=-1 m = d sin m=-2

  13. Grating Spectrometers:HETG • HETG: High Energy Transmission Gratings • Designed for use with ACIS-S providing E/delta(E) to 1000 between 0.4 and 10.0 keV • Two sets of gratings • Medium Energy Gratings (MEG) use outer 2 mirrors • High Energy Gratings (HEG) use inner 2 mirrors • Mounted at different angles to form an “X” dispersed pattern Capella HETG spectrum

  14. Grating Spectrometers: LETG • LETG High Energy Transmission Gratings • Provides highest resolving power at low energies • Designed for use with HRC-S with 0.07 – 7.29 keV • E/delta(E) > 1000 for 0.07 < E < 0.15 keV • E/delta(E) < 1000 for E > 0.15 keV

  15. Chandra Operations • Mission science plan converted to command loads and uplinked to Chandra • X-ray events collected and stored on Solid-State Recorders (SSR) • Ground contact established every ~8 hours through Deep Space Network • SSR data downlinked • new command load uplinked (up to 72 hours of stored commands) • Data transferred to OCC through JPL for science processing sssssssssssssssssssssss CXO CXC OCC

  16. 6. Chandra X-ray Center Architecture uplink downlink

  17. Chandra Observing Cycle • High (66%) observing efficiency • TOOs, solar flares ->big hit on mission planning team • Annual Proposal Cycle: • Next Deadline: 15 March 2003 (anticipated) • + Archive, Theory grants • Funding expected to 2009

  18. enjoy the workshop!

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