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

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

3. Chandra X-ray Center NASA Great Observatories CHANDRA

4. Chandra X-ray Center Focusing X-rays

5. Chandra X-ray Center u2 Imaging Focal Plane Science Instruments –ACIS (Advanced CCD Imaging Spectrometer) –HRC (High Resolution Camera) Chandra Mission Summary uLaunch: July 23, 1999 –STS-93/ Inertial Upper Stage / Integral Propulsion System –10,000 km x 140,000 km, 28.4 o Inclined Orbit u¼ arcsecond resolution. Sub-0.5arcsec in practice u10-m Focal Length Wolter -1 Mirror: 4 nested Mirror Pairs uEnergy Range: 0.1-10 keV uDesign Lifetime > 5 Years (in NASA plan for 10 year life) u2 Objective Transmission Gratings for Dispersive Spectroscopy –LETG (Low-Energy Transmission Grating) –HETG (High-Energy Transmission Grating)

6. Chandra X-ray Center Mission and Observatory Description

7. Chandra X-ray Center High Resolution Mirror Assembly upolished to 3A -> low scattering high dynamic range u4 pairs of concentric thin-walled zerodur, grazing incidence Wolter Type-I mirrors - >large area. ->800cm2 E<2keV u figured to 0.5” FWHM -> sensitivity, -> megapixel images uFocal length 10 m. -> response to 10keV 1.6” 95%

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

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

10. Chandra X-ray Center Advanced CCD Imaging Spectrometer (ACIS) uTen 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. Chandra X-ray Center ACIS Issues CTI u Front Iluminated (FI) chips suffered proton damage just after launch. -> charge transfer inefficiency (CTI) -> much degraded energy resolution Pileup u3.2 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 uPileup correction ( J.Davis, MIT ) available in Sherpa uCTI correction (Townsley, PSU) restores linearity, most dE/E Low Energy Calibration u Non-linear gain uChanging QE uSee L. David talk

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

13. Chandra X-ray Center Grating Spectrometers uHETG: 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 uLETG 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) 0.15 keV

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

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

16. Chandra X-ray Center Chandra Observing Cycle uHigh (66%) observing efficiency uTOOs, solar flares ->big hit on mission planning team uAnnual Proposal Cycle: uNext Deadline: 15 March 2003 (anticipated) u+ Archive, Theory grants uFunding expected to 2009

17. Chandra X-ray Center enjoy the workshop!