W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology WISE - the Wide-field Infrared Survey Explorer Ned Wright (UCLA) ELW - 1 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Two decades ago IRAS gave us what is still our best view of the mid − infrared sky. ELW - 2 6 Dec 07
WISE will map the entire sky with resolution comparable to the few square degrees shown here, achieving 500 times better sensitivity than IRAS.
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Project Overview Jet Propulsion Laboratory California Institute of Technology Wide Field Infrared Survey Explorer Science • Sensitive all sky survey with 8X redundancy – Find the most luminous galaxies in the universe – Find the closest stars to the sun – Provide an important catalog for JWST – Provide lasting research legacy Salient Features • 4 imaging channels covering 3 - 25 microns wavelength • 40 cm telescope operating at <17K • Two stage solid hydrogen cryostat • Delta launch from WTR in November, 2009 • Sun-synchronous 6am/6pm 500km orbit • Scan mirror provides efficient mapping • Operational life: 7 months (124% margin) • 4 TDRSS tracks per day ELW - 4 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE Will Fill “the Gap” Administration Jet Propulsion Laboratory California Institute of Technology GAL 2MA Pla GAL GAL 2MA 2MA Pla Pla IRIS IRIS IRIS DPOSS DPOSS DPOSS EX SS nck EX EX SS SS nck nck • WISE will fill the gap in wavelengths covered by sensitive all sky surveys • Many pointed JWST observations will be in this wavelength gap ELW - 5 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Why Infrared? Jet Propulsion Laboratory California Institute of Technology Visible NGC2024 1- 2 µ m z =1.3 Galaxy Cluster The Dusty Universe The Distant Universe The Cold Universe 12 µ m HR 4796 23 µ m ELW - 6 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Why Space? Jet Propulsion Laboratory California Institute of Technology “Ground-based infrared astronomy is like observing stars in broad daylight with a telescope made out of fluorescent lights’’ — George Rieke. 40 cm WISE telescope in space equals six thousand 8-meter telescopes on the ground! ELW - 7 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Why All Sky? Administration Jet Propulsion Laboratory California Institute of Technology • For superlative and/or unique objects, such as the nearest stars or the most luminous galaxies, only an all-sky survey will do. • For uniformly distributed objects, a fast shallow survey finds more sources per unit time than a deep narrow survey. • An all-sky survey finds the brightest objects in a class, which are the easiest to follow up in detail with large telescopes like the JWST. ELW - 8 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE Survey Strategy Provides Minimum of 8 Exposures Per Position Administration Jet Propulsion Laboratory California Institute of Technology • Single observing mode • Scan mirror enables efficient surveying • Minimum 8, median 14 – 8.8-s exposure/11-s duty cycle exposures/position after losses to • 10% frame to frame overlap Moon and SAA • 90% orbit to orbit overlap • Sky covered in 6 months observing 47 ′ One One Two Many orbits frame orbit orbits 1 Orbit 2 Consecutive Orbits 2 Orbits 20 Days Apart ELW - 9 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE and Asteroids Administration Jet Propulsion Laboratory California Institute of Technology Gaspra • Asteroids are much brighter in the IR than in the optical: 100 to 400 times more photons. • They move in the hours between WISE frames. • For asteroids with known orbits, WISE sensitivity will be slightly better than for fixed celestial objects: –Asteroids generally move in the same direction that WISE scans and thus get more repeated observations than stars. –Asteroids’ movement across the sky greatly reduces the confusion noise from unresolved celestial sources. Asteroids move ELW - 10 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE Will See Many Asteroids Administration Jet Propulsion Laboratory California Institute of Technology • Most of the bright objects are asteroids! • Spitzer 24 µ m data in Taurus • Flux limit 0.7 mJy • Size 0.7 o ≈ WISE FOV • Thermal IR provides diameters, needed for hazard assessment ELW - 11 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Value of IR Asteroid Data Jet Propulsion Laboratory California Institute of Technology • The total flux of an asteroid, integrated over frequency and angle, gives the power intercepted from the Sun and thus the diameter. • The range in optical albedo (Stuart & Binzel, 2004) corresponds to more than a factor of 5 in diameter, for the same (reflected) optical flux. 2.3% albedo, 2.6 km diameter 63% albedo, 0.5 km diameter • The range in IR emission due to absorbed and reradiated sunlight for a given diameter asteroid is much smaller (Walker 2003). • With both IR & optical data the diameter and albedo are well determined. – Albedo also provides an estimate of asteroid composition and density, hence mass. – Asteroid mass is essential for hazard assessment. ELW - 12 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE Simulations Administration Jet Propulsion Laboratory California Institute of Technology • Launch on 2 Nov 2009 • Cover off on 16 Nov 2009 • Hypothetical IOC test using many repeated scans over the same strip of ecliptic longitude – This is not the normal data taking survey plan – But it makes visualizing the asteroids easier • Noise and source density semi-realistic. • Cosmetically perfect detectors for easy visualization • Everything from Bowell’s astorb.dat of 21 May 2007 plotted • FOV is 47 arc-minutes on a side ELW - 13 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Simulated 12 µ m data Administration Jet Propulsion Laboratory California Institute of Technology • 20 Nov 2009 • Ecliptic coords 332.65,-14.49 • Unusually large number of objects for this far off the ecliptic. ELW - 14 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Simulated 12 µ m data Administration Jet Propulsion Laboratory California Institute of Technology • 20 Nov 2009 • Ecliptic coords 332.65,-14.49 • Unusually large number of objects for this far off the ecliptic. ELW - 15 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Large Area Shallow Surveys Find the Most Interesting Objects for Targeted Followup Observations Spitzer/IRAC Shallow Survey 4.5 µ m image 8.5 sq degrees 3 x 30 sec/position Eisenhardt et al 2004 ApJSupp 154, 54 ELW - 16 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Administration The First Field Brown Dwarf Discovered by Spitzer Jet Propulsion Laboratory California Institute of Technology • The brown dwarf found in the 8 square degree Spitzer/IRAC Shallow Survey would be a 6 σ detection with WISE. • WISE will survey 5000 times more sky. • WISE should discover several hundred brown dwarfs cooler than any currently known, and double or triple the density of known star systems in the solar neighborhood. Field T4.5 BD Stern et al 2006 ApJ submitted ELW - 17 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space WISE and Brown Dwarfs/Superplanets Administration Jet Propulsion Laboratory California Institute of Technology GL 229B Jupiter at 5 µ m • Brown Dwarfs (BDs): stars with too little mass to fuse H into He. • WISE 3.3 & 4.7 µ m filters tuned to methane dominated BD spectra. • WISE could identify Gliese 229B (10 -5 L ) to 150 light years, a free floating planet (FFP) like Jupiter (10 -9 L ) to 1 light year, BDs with T > 200 K (10 -8 L ) if closer than α Centauri. ELW - 18 6 Dec 07
W ide-field I nfrared S urvey E xplorer (WISE) National Aeronautics and Space Theoretical BD Spectra Administration Jet Propulsion Laboratory California Institute of Technology • Very strong spectral features • Ground-based 0.95 & 1.25 µ m in warmer BDs • 4.7 µ m very strong in cooler BDs ELW - 19 6 Dec 07
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