Post on 06-Nov-2015
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This is a mosaic of the images covering the entire sky as observed by the Wide-field Infrared Survey Explorer (WISE), part of its All-Sky Data Release. Image credit: NASA/JPL-Caltech/UCLA Full image and caption Rectangular view
Over 11,000 years ago, a massive, supergiant star came to the end of its life. Image credit: NASA/JPL-Caltech/UCLA Full image and caption
PASADENA -- NASA unveiled a new atlas and catalog of the entire infrared sky today showing more than a half billion stars, galaxies and other objects captured by the Wide-field Infrared Survey Explorer (WISE) mission.
"Today, WISE delivers the fruit of 14 years of effort to the astronomical community," said Edward Wright, WISE principal investigator at UCLA, who first began working on the mission with other team members in 1998.
WISE launched Dec. 14, 2009, and mapped the entire sky in 2010 with vastly better sensitivity than its predecessors. It collected more than 2.7 million images taken at four infrared wavelengths of light, capturing everything from nearby asteroids to distant galaxies. Since then, the team has been processing more than 15 trillion bytes of returned data. A preliminary release of WISE data, covering the first half of the sky surveyed, was made last April.
The WISE catalog of the entire sky meets the mission's fundamental objective. The individual WISE exposures have been combined into an atlas of more than 18,000 images covering the sky and a catalog listing the infrared properties of more than 560 million individual objects found in the images. Most of the objects are stars and galaxies, with roughly equal numbers of each. Many of them have never been seen before.
WISE observations have led to numerous discoveries, including the elusive, coolest class of stars. Astronomers hunted for these failed stars, called "Y-dwarfs," for more than a decade. Because they have been cooling since their formation, they don't shine in visible light and could not be spotted until WISE mapped the sky with its infrared vision.
WISE also took a poll of near-Earth asteroids, finding there are significantly fewer mid-size objects than previously thought. It also determined NASA has found more than 90 percent of the largest near-Earth asteroids.
Other discoveries were unexpected. WISE found the first known "Trojan" asteroid to share the same orbital path around the sun as Earth. One of the images released today shows a surprising view of an "echo" of infrared light surrounding an exploded star. The echo was etched in the clouds of gas and dust when the flash of light from the supernova explosion heated surrounding clouds. At least 100 papers on the results from the WISE survey already have been published. More discoveries are expected now that astronomers have access to the whole sky as seen by the spacecraft.
"With the release of the all-sky catalog and atlas, WISE joins the pantheon of great sky surveys that have led to many remarkable discoveries about the universe," said Roc Cutri, who leads the WISE data processing and archiving effort at the Infrared and Processing Analysis Center at the California Institute of Technology in Pasadena. "It will be exciting and rewarding to see the innovative ways the science and educational communities will use WISE in their studies now that they have the data at their fingertips."
NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., manages and operates WISE for NASA's Science Mission Directorate in Washington. The mission was competitively selected under NASA's Explorers Program, which is managed by NASA's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah, and the spacecraft was built by Ball Aerospace and Technologies Corp., in Boulder, Colo. Science operations, data processing and archiving take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.
For a collection of WISE images released to date, visit: http://wise.ssl.berkeley.edu/gallery_images.html
An introduction and quick guide to accessing the WISE all-sky archive for astronomers is online at: http://wise2.ipac.caltech.edu/docs/release/allsky/
Instructions for technically minded individuals wanting to try their hand at using the archive are at: http://wise.ssl.berkeley.edu/wise_image_service.html
For more information about WISE, visit: http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise .
NASA releases infrared map of the entire universe
After fourteen years of preparation and three years of collecting data, we now have an atlas of the entire infrared sky. This image is just the capstone for a cosmic map that contains 18000 images and 560 million different objects.
This represents the culmination of years of work by NASA's WISE satellite and the astronomers behind it. By studying the universe in infrared wavelengths, we can see objects that are far too dim to be seen in visible light. Each of the 560 million objects represents either a star or entire galaxy, many of which were completely unknown until WISE began its survey three years ago.
Here's how all that data was transformed into the single 2D map of the universe you see up top, according to NASA:
The sky can be thought of as a sphere that surrounds us in three dimensions. To make a map of the sky, astronomers project it into two dimensions. Many different methods can be used to project a spherical surface into a 2-D map. The projection used in this image of the sky, called Aitoff, takes the 3-D sky sphere and slices open one hemisphere, and then flattens the whole thing out into an oval shape.
In the mosaic, the Milky Way Galaxy runs horizontally across this map. The Milky Way is shaped like a disk and our solar system is located in that disk about two-thirds of the way out from the center. So we see the Milky Way as a band running through the sky. As we look toward the center of the galaxy, we are looking through more of the disk than when we are looking at large angles away from the center, and you can see a noticeable increase in stars (colored blue-green) toward the center of the image.
WISE has been responsible for several key discoveries and has already produced over 100 scientific papers. For instance, WISE spotted the first clear evidence of Y-dwarfs, a special type of ultra-cool, ultra-faint failed star that could never be seen in anything other than infrared and even then required WISE's powerful cutting edge sensors to detect. Closer to home, the mission was essential in mapping all of Earth's nearby asteroids, and it helped us spot the first known Trojan asteroid sharing Earth's orbit.
For more, check out NASA's website and the WISE homepage.
March 14, 2012 - Mapping the Infrared Universe: The Entire WISE Sky
This is a mosaic of the images covering the entire sky as observed by the Wide-field Infrared Survey Explorer (WISE), part
of its All-Sky Data Release.
The sky can be thought of as a sphere that surrounds us in three dimensions. To make a map of the sky, astronomers
project it into two dimensions. Many different methods can be used to project a spherical surface into a 2-D map. The
projection used in this image of the sky is called Aitoff, named after the geographer who invented it. It takes the 3-D sky
sphere and slices open one hemisphere, and then flattens the whole thing out into an oval shape.
Any projection creates distortions, so people tend to use a particular projection type based on where in the resulting map
the distortions are minimal. This map is centered on the Milky Way Galaxy. The plane of the Galaxy runs along the equator,
and the center of the Galaxy is at the center of the map, where projection distortions are minimal. The distortions are most
pronounced at the edges of the map. The right and left edges of this oval shape are the same location in the sky. A second
projection of this image is also available, called equirectangular. This method projects the sky into a rectangular shape
with Cartesian coordinates, and is useful for planetariums that may wish to display the image on their domes.
In this mosaic, the Milky Way Galaxy runs horizontally across this map. The Milky Way is shaped like a disk and the Solar
System is located in that disk about two-thirds of the way out from the center. So we see the Milky Way as a band running
through the sky. As we look toward the center of the Galaxy we are looking through more of the disk than when we are
looking at large angles away from the center, and you can see a noticeable increase in stars (colored blue-green) toward
the center of the image.
There are some artifacts worth noting in the image. For the image atlas, moving objects such as asteroids and comets
were removed. However, some slower moving, bright objects did leave behind residuals. Residuals of the planets Saturn,
Mars, and Jupiter are visible in this image as bright red spots off the plane of the Galaxy at the 1:00, 2:00 and 7:00
positions, respectively. In addition, at several locations in the image there are small rectangular shaped features that
result from the difficulty in matching background levels of individual atlas frames.
With the exception of a few Solar System objects, all of the celestial bodies highlighted in previous featured images from
WISE are visible in this map. The annotated version of this map shows the locations of about half of the featured images
(the rest were omitted for clarity). Clicking on the name of the object in the annotated map above will open a new browser
window showing the featured image for that object.
Three of the four wavelengths surveyed by WISE were used to create this image. The colors used in this image represent
specific wavelengths of infrared light. Cyan (blue-green) represents light emitted predominantly from stars and galaxies at
a wavelength of 3.4 microns. Green and red represent light mostly emitted by dust at 12 and 22 microns, respectively.
Image Credit: NASA/JPL-Caltech/WISE Team
The Wide-field Infrared Survey
Explorer at IPAC
The Wide-field Infrared Survey Explorer
All-Sky Data Release
March 14, 2012
NASA's Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010) mapped the sky at 3.4,
4.6, 12, and 22 m (W1, W2, W3, W4) in 2010 with an angular resolution of 6.1", 6.4", 6.5", & 12.0" in the four bands. WISE achieved 5 point source sensitivities better than 0.08, 0.11, 1 and 6 mJy in unconfused regions on the ecliptic in the four bands. Sensitivity improves toward the
ecliptic poles due to denser coverage and lower zodiacal background.
The All-Sky Release includes all data taken during the WISE full cryogenic mission phase, 7
January 2010 to 6 August 2010, that were processed with improved calibrations and reduction
algorithms. Release data products include an Atlas of 18,240 match-filtered, calibrated and
coadded image sets, a Source Catalog containing positional and photometric information for over
563 million objects detected on the WISE images, and an Explanatory Supplement that is a guide
to the format, content, characteristics and cautionary notes for the WISE All-Sky Release
products. The WISE All-Sky Data Release products supersede those from the April 2011
Preliminary Data Release.
All-Sky Release ancillary products include a Reject Table containing 284 million detections that
were not selected for inclusion in the Source Catalog because they are low signal-to-noise ratio
or spurious detections of image artifacts, an archive of over 1.5 million Single-exposure Image
sets and a database of over 9.4 billion source extractions from those images, and moving object
tracklets identified as part of the NEOWISE program (Mainzer et al. 2011).
Access the Catalog and Image data via
IRSA Read the Explanatory Supplement
Top Ten List of things you should know
about the All-Sky Release Products
All-Sky Release sky coverage statistics
Image Atlas description
Source Catalog description
WISE Project website WISE mission description paper
Contact the WISE Help Desk
Frequently asked questions (FAQ)
Please include this acknowledgment in any published material that makes use of WISE data
products.
Research using WISE Release data is eligible for proposals to the NASA ROSES Astrophysics
Data Analysis Program.
General information about the WISE All-Sky Data Release
Sky Coverage Statistics
Figure 1 - Equatorial Aitoff projection sky map showing
the average number of individual 7.7 sec (W1 and W2)
and 8.8 sec (W3 and W4) exposure frames within 14
14 spatial bins going into the WISE All-Sky Release
Atlas and Catalog. Colors encode different frame
depths-of-coverage, and the legend on the left gives
the cumulative area in square degrees as a function of
coverage depth.
Figure 2 - Differential area as a function of
average W1 frame depth-of-coverage in the All-
Sky Release Atlas and Catalog, computed in 14
14 spatial bins.
WISE imaged the entire sky with multiple, independent exposures during its full cryogenic
survey. All four bands were imaged simultaneously during each exposure, and the exposure
times were 7.7 sec in W1 and W2 and 8.8 sec in W3 and W4. As illustrated in Figure 1, the
survey scanning strategy resulted in 12 to 13 exposures of each point on the ecliptic plane.
Coverage increases to over 3000 exposures at the ecliptic poles. WISE completed its first
complete sky coverage on 17 July 2010 and surveyed approximately 20% of the sky a second
time before the end of the full cryogenic mission phase.
All of the individual exposures that met minimum requirements for image quality and noise
levels were combined to form the All-Sky Release Image Atlas and Source Catalog. The
localized decreases in coverage in small areas seen in Figure 1 are the result of exclusion of
lower quality exposures. Additionally, coverage depth was artificially capped at approximately
160 exposures near the ecliptic poles for processing runtime and memory usage requirements.
A plot of the approximate differential area as a function of the average W1 exposure depth-of-
coverage realized in the All-Sky Release Atlas and Source Catalog is shown in Figure 2. The
peak near 12 coverages corresponds the ecliptic plane in the nominal survey, and the secondary
peak at 24 coverages is the ecliptic plane in the two-epoch coverage part of the sky. The peak
near 160 coverages and maximum depth near 250 result from the artificial attenuation of the
coverage near the ecliptic poles. Pixel-level frame effective coverage information is provided in
the WISE Image Atlas depth-of-coverage maps.
Image Atlas
Figure 3 - (left,
top row) 3.4, 4.6,
12, 22 m
intensity images,
(left, center row)
depth-of-
coverage maps,
and (left, bottom
row) uncertainty
maps for the Atlas
Tile
1253m425_ab41
that contains the
Puppis A
supernova
remnant. The
color scale on the
bottom of the grid
refers to the
depth-of-
coverage maps.
(above) 4.6, 12,
22 m 3-color
composite
intensity map of
Tile
1253m425_ab41.
The WISE Image Atlas is comprised of 18,240 4095x4095 pixel @1.375"/pix FITS format
image sets. One image set is produced for each Atlas Tile. The 1.564x1.564 Atlas Tiles are
built on an equatorial projection and are distributed in 119 iso-declination bands with 238 Tiles
on the celestial equator and six Tiles in the ||=89.35 declination band. Tiles overlap by 180" in RA and Dec on the equator, and the RA overlap increases towards the equatorial poles.
Each Atlas Image set consists of:
Intensity images - Four spatially registered images, one in each of the WISE bands, produced by match-filtering and coadding multiple 7.7 sec (W1 and W2) and 8.8 sec (W3 and W4) Single-exposure images covering the Tile area. Because of the matched filtering, the SNR in the Image Atlas is optimized but the angular resolution is degraded by a factor of sqrt(2). Pixel outlier rejection used during coaddition suppresses transient events such as cosmic rays, hot pixels and satellite trails when there are five or more Single-exposure images available.
Depth-of-coverage maps - Four maps, one in each WISE band, that provide the realized frame coverage for each pixel in the corresponding coadded intensity images following outlier rejection.
Uncertainty maps - Four images that give the propagated 1 uncertainty for each pixel in the corresponding coadded intensity images. The uncertainty maps should be used for error estimation when making photometric measurements on the intensity images.
The headers of each Atlas Image provide WCS information to convert pixel to equatorial
coordinates and photometric zero points for calibration of relative photometry.
See section II.3 of the WISE All-Sky Release Explanatory Supplement for more information
about the content, format, and properties of the Image Atlas.
Source Catalog
The WISE Source Catalog contains the attributes for 563,921,584 point-like and resolved objects
detected on the Atlas Intensity images. Catalog sources are required to have a measured SNR>5
in at least one band, and to meet other criteria to insure a high degree of reliability. Attributes
included for each entry in the Source Catalog include:
J2000 positions and uncertainties reconstructed using the 2MASS Point Source Catalog as astrometric reference. Astrometric accuracy is approximately ~200 mas RMS on each axis with respect to the 2MASS reference frame for sources brighter than SNR=40.
Photometry and uncertainties in the four WISE bands. Photometry is performed using point source profile-fitting and multi-aperture photometry. WISE 5 photometric sensitivity is estimated to be 0.068, 0.098, 0.86 and 5.4 mJy (16.6, 15.6, 11.3, 8.0 Vega mag) at 3.4, 4.6, 12 and 22 m in unconfused regions on the ecliptic plane. Sensitivity is better at higher ecliptic latitudes where coverage is deeper and the zodiacal background is lower, and poorer when limited by confusion in high source density or complex background regions. Saturation affects photometry for sources brighter than approximately 8.1, 6.7, 3.8 and -0.4 mag at 3.4, 4.6, 12 and 22 m, respectively.
Measurement quality flags, image artifact contamination flags, extended source and variability flags, and association information cross-referencing WISE sources with the 2MASS Point and Extended Source Catalogs.
Relative photometric calibration for WISE source photometry is made using measurements of a
network of calibration standard stars near the ecliptic poles. The WISE bandpasses and relative
spectral response curves are available in Section IV.4.h.v of the WISE All-Sky Release
Explanatory Supplement.
See section II.2 of the WISE All-Sky Release Explanatory Supplement for more information
about the content, format, and properties of the Source Catalog.
Ancillary Products
In addition to the Image Atlas, Source Catalog and Explanatory Supplement, the WISE All-Sky
Release includes several ancillary data products.
Reject Table - Database of 283,887,651 "source" detections from the Atlas Images that are not included in the Source Catalog because they have flux signal-to-noise ratios
Tabular Data - Simple and complex queries on WISE tabular data products including the Source Catalog, Single-exposure source database, and image metadata tables can be made using the IRSA/GATOR general catalog query engine.
Image Data Access - The IRSA/WISE Image Service enables viewing and downloading WISE Atlas and Single-exposure image sets using position/area-based and object named queries. Custom projection, re-sampling and small mosaics of WISE images can be obtained using the IRSA Image Mosaic service.
Solar System Object Searches - A special capability of the IRSA services is the ability to search for WISE Single-exposure image and extracted source data for solar system objects. Searches can be made for either known objects, or in a "pre-covery" mode for newly-discovered objects via user-specified orbital elements.
See section I.3 of the WISE All-Sky Release Explanatory Supplement for a complete description
of how to access WISE data products.
Standard Acknowledgment for Use of WISE Data in Publications
Please include the following in any published material that makes use of the WISE data products:
"This publication makes use of data products from the Wide-field Infrared Survey Explorer,
which is a joint project of the University of California, Los Angeles, and the Jet Propulsion
Laboratory/California Institute of Technology, funded by the National Aeronautics and Space
Administration."
Thank you very much.
March 14, 2012 - Mapping the Infrared Universe: The Entire
WISE Sky
This is a mosaic of the images covering the entire sky as observed by
the Wide-field Infrared Survey Explorer (WISE), part of its All-Sky
Data Release.
The sky can be thought of as a sphere that surrounds us in three
dimensions. To make a map of the sky, astronomers project it into
two dimensions. Many different methods can be used to project a
spherical surface into a 2-D map. The projection used in this image of
the sky is called Aitoff, named after the geographer who invented it.
It takes the 3-D sky sphere and slices open one hemisphere, and then
flattens the whole thing out into an oval shape.
More
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A set of hands-on and demonstration activities from NASAs SOFIA
mission designed to complement instruction on the electromagnetic
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Size & Scale of the Universe
The Universe is very, very big. One cannot reasonably create a scale
model of the Universe that includes all of its componentsfrom people
to superclustersand simultaneously scales their distances and sizes.
This activity attempts to overcome that difficulty by examining the
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Realms of the Universe Activity (pdf) Size and Scale Glossary (pdf) Size and Scale Presentation (pptx) Realms of the Universe Activity Worksheet (pdf) Room Size Conversion Calculator (xlsx)