1 / 24

Introduction to and methods of SPACE-based observational astronomy

Introduction to and methods of SPACE-based observational astronomy. 1 st MAGPOP School (Budapest, Aug 23-25 2006). Armando Gil de Paz (Universidad Complutense de Madrid). Current Space Observatories with GO/GI programs: (Guest Observer/Guest Investigator). Scheme.

clove
Download Presentation

Introduction to and methods of SPACE-based observational astronomy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to and methods of SPACE-based observational astronomy 1st MAGPOP School(Budapest, Aug 23-25 2006) Armando Gil de Paz (Universidad Complutense de Madrid)

  2. Current Space Observatories with GO/GI programs: (Guest Observer/Guest Investigator) Scheme 1st MAGPOP School(Budapest, Aug 23-25 2006) HST GALEX Spitzer MAGPOP’s favorites!

  3. Other current Space Observatories with GO/GI programs: Scheme Chandra Akari (Astro-F) FUSE 1st MAGPOP School(Budapest, Aug 23-25 2006) XMM-Newton Integral

  4. Past/Present/ Future Space Observatories: 1st MAGPOP School(Budapest, Aug 23-25 2006)

  5. Today’s lecture Scheme Covering the basics: • Why observing from Space? Image quality, low background, transparency VS. Costs & risks HST 1st MAGPOP School(Budapest, Aug 23-25 2006) • Description of the Observatory • Preparing a HST proposal: • Constraints, APT, etc. • Using Archival Data: MAST

  6. tomorrow Scheme GALEX • Description of the Observatory • Preparing a GALEX proposal • Bright-star and background limitations • Using Archival Data 1st MAGPOP School(Budapest, Aug 23-25 2006) Spitzer • Description of the Observatory • Preparing a Spitzer proposal: Using Spot • Observing constraints, pipeline, & latents • Using Archival Data: Using Leopard

  7. friday Scheme Past: • Using IUE, IRAS, ISO data Future: • James Webb Space Telescope (JWST) 1st MAGPOP School(Budapest, Aug 23-25 2006) Space-based Astronomy Tools and Science: • Use of Space-based data • Synergy with ground-based data (e.g. HST-Keck/VLT, JWST-ALMA)

  8. Ups Space Astronomy: Why? No atmosphere • Better image quality (no atmospheric seeing) FWHMseeing~-0.2 ; Diffraction limit = /D Mauna Kea (average) 1st MAGPOP School(Budapest, Aug 23-25 2006) Antarctica (average) Antarctica (best 25%) Diff.Lim 2m Diff.Lim 8m

  9. Antarctica Ups Space Astronomy: Why? No atmosphere • Better transparency & no cloudy nights 1st MAGPOP School(Budapest, Aug 23-25 2006)

  10. Antarctica Ups Space Astronomy: Why? No atmosphere • Less (scattered and thermal) background 1st MAGPOP School(Budapest, Aug 23-25 2006)

  11. In high orbits (Earth-trailing, L2) • Longer lasting (& fixed) CVZ • Lower thermal background from Earth • No South Atlantic Anomaly passages Ups Space Astronomy: Why? Existence of Continuous Viewing Zones (CVZ) 1st MAGPOP School(Budapest, Aug 23-25 2006) HST HDF observations in CVZ

  12. Downs Higher risks Space Astronomy: Why? • Not 100% launch and deploy successful rates (e.g. HETE, Abrixas, ASTRO-E, WIRE) • Telescope & instruments never tested under exact working conditions (e.g. HST). • Difficult to repair if something fails. Impossible for satellites in high orbits. 1st MAGPOP School(Budapest, Aug 23-25 2006) Limited lifetime • Instrument consumables (cooling: NICMOS, ISO, Spitzer) • Propellant (to compensate for atmospheric drag -Compton GRO- or angular momentum build up -JWST) • Gyros (despite redundant systems).

  13. Downs Space Astronomy: Why? Higher costs • For both telescope & instruments plus launch cost. • Example: All four VLTs cost ~1/7 HST. 1st MAGPOP School(Budapest, Aug 23-25 2006) Source: Federation of American Scientists

  14. Downs Space Astronomy: Why? Higher rates of high-energy particles: • Cosmic-rays events in HST detectors are several times higher than in the ground (1.5-3% ACS/WFC pixels affected in 1000s). • This situation is worse in high orbits (5%-10% pixels expected to be affected in a JWST 1000s exposure) where there is no protection by the Van Allen belts. 1st MAGPOP School(Budapest, Aug 23-25 2006) Single 600s-long HST ACS/WFC raw image

  15. Space Astronomy: Specifics These Ups and downs determine the specifics of the analysis methods used in Space Astronomy: • High-spatial res. & Diff.Lim. images: PSF phot. (HST, Spitzer) • Low background: Highly Poissonian statistics (HST & GALEX) • High cosmic-rays rates: (HST CR-SPLIT) 1st MAGPOP School(Budapest, Aug 23-25 2006) Specifics of the instrumentation used in Space Observatories exploring new windows (UV, FIR): • Count-rate, color, and position-dependent PSF (GALEX & MIPS) • Multiple time constant response (MIPS 70 & 160um) • Confusion limits (GALEX & MIPS)

  16. 2.5-m telescope in a low orbit (600 km) deployed in 1990. • Current functioning instruments: ACS, NICMOS, WFPC2 • Replaced or non-functioning (“legacy”) instruments: FOC, FOS, GHRS, HST, WF/PC, STIS • New service mission (SM4) has not yet been decided. Hubble Space Telescope 1st MAGPOP School(Budapest, Aug 23-25 2006)

  17. Imaging: HST Instruments 1st MAGPOP School(Budapest, Aug 23-25 2006)

  18. Choosing the right imaging instrument: HST Instruments 1st MAGPOP School(Budapest, Aug 23-25 2006)

  19. Slitless spectroscopy: (no long-slit spectroscopy since STIS failure in 2004) HST Instruments 1st MAGPOP School(Budapest, Aug 23-25 2006)

  20. Feasibility: Proposing for HST • Reasonable number of orbits (compared with the expected scientific return and number of people involved). Use ETC. • The assumptions for determining the number of orbits are well justified and the overheads are properly accounted for. • Also address: 2-gyros mode impact, parallel observations. 1st MAGPOP School(Budapest, Aug 23-25 2006) Need for HST: • HST (and only HST) can address this particular science topic. • Available in the MAST archive? If so, justify additional time. Flexibility: • Long & frequent visibility windows and no unnecessary timing or orientation constraints.

  21. Orbit: 96 min long. Most objects partially occulted by the Earth (up to 44 min/orbit). CVZ within 24o the orbital poles. • (Note: CVZ should not be requested for background-limited broad-band imaging or observations with timing constraints, special orientation requirements, or ToO) • SAA: Although precession cycle is 56 days (so objects can be in the CVZ for many days in a row), the SAA limits the longest continuous observation to 5-6 orbits. • Pointing constraints: Within 60o of the Sun, 20o of the Earth and 9.5o of the Moon. Additional constraints for the ACS/SBC MAMA detector apply. • Other constraints: Since Aug 2005, HST is observing in two-gyros mode. Proposing for HST: Constraints 1st MAGPOP School(Budapest, Aug 23-25 2006)

  22. HST Phase I: APT First steps: • Documentation: Call for Proposals, HST Primer, and relevant instrument (ACS, NICMOS, WFPC2) handbook. • Get Scientific Justification LaTeX/Word/PDF template • Software: Proposer Tool (APT) & Visualizer (VTT, Aladin) • (See APT training materials!) 1st MAGPOP School(Budapest, Aug 23-25 2006)

  23. HST Phase I: APT 1st MAGPOP School(Budapest, Aug 23-25 2006)

  24. Images can be retrieved using starview and visualized using VTT (included in APT) or directly from MAST. • Data formats (see the instruments data handbooks): Multiextension FITS: Science, data quality and error arrays • Extensions:RAW, FIT, CRJ, DRZ (ACS & STIS), _raw, _ima, _cal, _mos (NICMOS), _d0f, _c0f (WFPC2) • WFPC2 associations: 15000 combined WFPC2 images created from associations of 50000 individual WFPC2 frames. • Images are VO complaint. HST archive: MAST 1st MAGPOP School(Budapest, Aug 23-25 2006)

More Related