Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
X-ray astronomy detector wikipedia , lookup
Allen Telescope Array wikipedia , lookup
James Webb Space Telescope wikipedia , lookup
CfA 1.2 m Millimeter-Wave Telescope wikipedia , lookup
Optical telescope wikipedia , lookup
Spitzer Space Telescope wikipedia , lookup
Reflecting telescope wikipedia , lookup
2001 Observational Techniques Workshop Gemini • Overview of the telescopes • Gemini’s core science goals • Gemini instrumentation • Applying for Gemini time Warrick Couch, UNSW Gemini North Overview of the telescopes (total capital cost = US$187M) Gemini South Primary mirror: • 8.1m diameter • 20cm thick • mass = 22.2 tonnes • coated for UV/IR performance Gem-N Gem-S Primary mirror supported by air pressure + 180 actuators which maintain shape to better than a micron. Secondary mirror (f/16): • 1.0m diameter • Mass 45kg • Fast tip-tilt at up to 200Hz Cassegrain Focus: Instrument Support Structure + A&G Core Science Goals • Circumstellar disks and planetary systems • Formation of the elements • Formation and evolution of galaxies • Star formation • Stellar interiors structure Circumstellar disks and possible planetary systems The nature of the particle disks discovered around stars like Pic detailed mapping to understand the process of planet formation. • Map at 10m and beyond, where Gemini should deliver a resolution of better than 0.3 arcsec, corresponding to 1-2AU for the nearest examples. • Gemini’s competitive edge: diffraction-limited imaging and low thermal emissivity. Formation of the elements Determination of the chemical enrichment history of the Galaxy and the Universe via high resolution spectroscopy of the oldest stars in the Milky Way and gas clouds illuminated by distant quasars. • High-resolution (R=50-150,000) spectroscopy of faint objects at uv-optical wavelengths This science program severely compromised with the cancellation of HROS, and its replacement with HRBS which, being fibre-fed, will be unable to observe at 3800Å. Formation and evolution of galaxies Determine the morphology, content, and composition of nascent and adolescent galaxies in the early universe. Do this at optical wavelengths, to reveal the properties of the youngest stars in such systems, through to the thermal infrared where dust re-radiates the emission at shorter wavelengths. • Imaging and multi-object spectroscopy at optical and infrared wavelengths, with high spatial resolution. Star formation Address the age-old question of how stars form and what conditions lead to protostellar collapse. In particular, study the role of outflows in the star formation process • Near infrared imaging and spectroscopy at the highest possible spatial resolution • Gemini advantage: diffraction-limited performance (or near to) in the near-infrared. Stellar structure Determination of the internal structure of stars through the study of the small and complex oscillations that take place at their visible surface. • Very high resolution optical spectroscopy and continual monitoring for many hours. Performance: it’s not just (aperture) size that counts! If sky- or detector-noise limited, then speed of observation (1/t) is proportional to: (D/)2 where D = aperture size and = image size. is usually dominated by seeing, with seeing-0.2 20% reduction V K. If can achieve diffraction-limited performance*, then dl1/D (Rayleigh) and speed proportional to: D4 [factor of 16 in going from 4m to 8m telescope!!] * For 8m, dl~0.02” in V, 0.07” in K, requiring wavefront correction using Adaptive Optics (only practical in IR) Seeing Constraints 2001B Instrument Availability Mauna Kea NIRI GMOS Hokupa’a/QUIRC Cerro Pachon FLAMINGOS-1 OSCIR Acquisition Camera 2002A Instrument Availability Mauna Kea NIRI GMOS MICHELLE Hokupa’a CIRPASS Cerro Pachon T-ReCS PHOENIX 2002B Instrument Availability Mauna Kea NIRI GMOS MICHELLE ALTAIR (NGS) CIRPASS Cerro Pachon T-ReCS GMOS FLAMINGOS-1 PHOENIX 2004B Instrument Availability Mauna Kea NIRI (NIR) GMOS (Opt) NIFS (NIR) OSCIR (MIR) ALTAIR+(LGS/AO) Cerro Pachon T-ReCS (MIR) GMOS (Opt) GNIRS (NIR) NICI (NIR) HRBS (Opt) FLAMINGOS-2 (NIR) MCAO (LGS/AO) Hokupa’a/QUIRC Hokupa’a 36 element curvature wavefront sensor and bimorph mirror which uses natural guide stars. QUIRC 1 – 2.5 m near-IR camera which is fed by Hokupa’a. 1024x1024 HgCdTe array; pixel size = 20 mas 20.2 arcsec FoV! Performance: near diffraction-limited (d-l) resolution in H & K; FWHM = 2x d-l in J. The rub: must have a bright point-source within 30arcsec of target! Very high Filters: extinction clouds •H •K’ •CO •CO cont. IRS8 (bow shock) 40” 4’ 5” Bow shock >10 stars per arcsec2 at K~18 >220 stars in 5”x5” UH-88”, Courtesy W.Brandner, 0.65” seeing IRS7 SgrA* Public SV Data: M32 Used core of this nearby elliptical galaxy as WFS reference K’ 480s 0.13” FWHM 0.5 arcsec Public SV Data: M15 20 arcsec Measured PSF variation over field and H/Q stability and repeatibility on this globular cluster 2 datasets released K’ 18 x 30s 0.12” FWHM Example QS Data (GN-2000QS-Q-9) FWHM 65 milli-arcsec Elliptical galaxy at 150Mpc IR surface brightness fluctuations Example QS Data: Galaxies in Abell 665 Colour composite of Abell 665 (z=0.18) K’ (28min) J (20 min) HST-I (80 min) 0.2 arcsec FWHM (GN-2000QS-Q-29) NIRI – Near Infrared Imager Detector: 1024x1024 Aladdin InSb array Imaging: ‘wide-field’ (2’x2’) f/6 mode ( J – L bands) ‘low-bg’ (0.9’x0.9’) f/14 mode ( J, H, K ) ‘high-bg’ (0.9’x0.9’) f/14 mode ( L & M ) Spectroscopy: Long-slit + grism ( 1 – 5.5 microns) [ R of up to ~1700 (in H) with 0.23” slit ] Wavefront correction: Active optics (aO) only, with IR on-instrument wavefront sensor available except in f/6 mode f/32 camera will be fed by ALTAIR (laser g/s) NIRI Filters available for 2001B J H K, Kshort, K´ L´ M´ Order sorting filters: [Fe II] H-continuum H2 1-0 S(1) Br Gamma K-continuum (2) PK50 long-wave blocker J, H, K, L, M Integration Time Calculator (ITC) available GMOS – Gemini Multi-Object Spectrograph Optical spectrograph/imager with a 5.5’ field of view [duplicated for both telescopes] Spectroscopic modes: standard ‘long-slit’ ‘multi-object’ using aperture mask with multiple slits [ up to several hundred in 5.5’ FoV] Integral Field Unit (IFU) covering 50 arcsec2 with 0.2” sampling Spectral resolution: R = 670 – 4400 (0.5” slit) ITC available FLAMINGOS-1 World’s first fully cryogenic multi-object near-IR ( J, H, K ) spectrograph/imager. Field of view = 2.7 arcmin (f/16 + 2048x2048 Rockwell HgCdTe array). ‘Long-slit’ and ‘multi-slit’ modes Spectral resolution: R = 300 (low!) [grisms giving R~2400 planned]. OSCIR Mid-infrared (8-25m) imager and low/medium resolution (R=100-1000) spectrograph. Uses a 128x128 SiAs detector. Field of view = 11 arcsec! Range of broad/narrow filters available centred on: 7.9, 8.8, 9.8, 10.3, 11.7, 12.5, 18, 20.8 m + N-band (10.8 m) Uses chopping secondary capability of Gemini telescopes. Acquisition Camera Optical CCD camera, which can provide U,B,V,R,I imaging over a 2’x2’ field. Offered in 2001B to develop `quick response’ mode of operation (e.g. for SN and gamma-ray burst follow-up). ITC available Applying for time on Gemini – it’s the PITs! • Proposals to use Australia’s share of time on Gemini are considered by ATAC; semester deadlines are: March 31st (for ‘B’ semester, Aug-Jan) Sep 30th (for ‘A’ semester, Feb-July) • If you collaborate with people from other partner countries, then time can be sought from their TACs as well. Applying for time on Gemini – it’s the PITs! • Gemini proposals are assembled and submitted using the Phase-I Tool (PIT), a supposedly user-friendly ‘GUI’-styled program* which solicits: all the usual info: title, abstract, instrument/mode required, nights (D,G,B), list of targets, guide stars, etc PLUS attached 3-page postscript file containing scientific justification (and figures) for ATAC • Once complete, hit the “SUBMIT” button in PIT; it then verifies your proposal and (if OK) sends it to the AAO for official submission. *that should be generally available at your institute; ask your system manager! Applying for time on Gemini – extra requirements • Guide stars: these need to be selected and listed along with each target object: at a minimum, 1 is required for the peripheral wave front sensor (PWFS), with additional guide stars required if instrument has an On-Instrument Wave Front Sensor (OIWFS), and/or observations involve AO. The PIT makes the selection process simple through internet links to a guide-star catalog (USNO) and digital sky survey. Applying for time on Gemini – extra requirements • “Classical” or “Queue” time (where there’s a choice)? Classical time is the traditional type of allocation where your nights are scheduled and you travel to the telescope (minimum allocation = 0.5 nights). Queue scheduled time is where your observations are executed by Gemini Observatory staff at a time when the conditions best suit your program. In this case you have to be much more specific about the observing conditions: seeing, cloud cover, water vapour content, sky and telescope background, air mass. Key web addresses www.gemini.anu.edu.au (Australian mirror of the main Gemini web site – with all the information on the telescopes/instruments) www.ausgo.unsw.edu.au (Australian Gemini Office web site – with all the information relevant to Australian users) www.aao.gov.au/local/www/sll/applicati ons/ATAC-applications.html (information on applying for time through ATAC)