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| Interactively Explore the Extended Groth Strip | |
| There are now two different interactive tools that you can use to explore the Extended Groth Strip: | |
| The Keck SkyTrekker tool: | |
| This tool, developed at Keck Observatory, allows you to explore full resolution Hubble Space Telescope images of the Extended Groth Strip. You select an image tile from the tile map, then interactively move through a high resolution image of the tile. This tools runs through a normal browser window. Take me there! | |
| Google Sky: | |
| You can also explore the multiwavelength AEGIS dataset through Google Sky. The file linked at the bottom of this page allow you to zoom through X-ray, ultraviolet, visible, and infrared images from AEGIS. These images come from three of NASA's Great Observatories: the Chandra X-ray Observatory, the Hubble Space Telescope, and the Spitzer Space Telescope, as well as NASA's GALEX ultraviolet satellite. | |
| Google Sky's interactive interface allows you to pan through AEGIS and zoom in on any object of interest. You can blink back and forth between the different wavelengths or make one image semi-transparent so that you can view two images simultaneously. This makes it easy to investigate how galaxies that look similar in visible light have very different infrared, ultraviolet, or X-ray properties. | |
| The images are scaled to show what the sky might look like if you had eyes sensitive to a particular type of light -- an object that appears 'blue' in the infrared may be 'red' in the ultraviolet or visible-light images. Each picture gives us different information about objects in the distant Universe. For instance, the infrared Spitzer image provides a measure of the number of stars in a galaxy, the visible-light Hubble image reveals the galaxy's detailed shape, the ultraviolet GALEX image probes how quickly new stars are forming, while the X-ray Chandra image can indicate the presence of black holes hidden within otherwise normal-looking galaxies. Small dots that look like stars turn out to have powerful X-ray signals---they are not stars, they are "quasi stellar objects" (more familiarly known as "quasars"), extremely massive black holes at the centers of galaxies that are swallowing up gas and outshining their host galaxies! | |
| Google Sky for Astronomers: | |
| The Google Sky interface can also be useful to professional astronomers. You can use the Google Sky interface to pan through the AEGIS images of the Extended Groth Strip. Circles indicate the locations of objects in the DEEP2 spectroscopic catalog. Clicking on these objects pulls up information from the AEGIS photometric and spectroscopic database, along with links to the 1D spectra and additional target information. | |
| Using Google Sky: | |
| Using Google Sky to explore the AEGIS dataset requires that you download Google Earth and install it on your computer. You can download Google Earth here. | |
| Once you have installed Google Earth, open the application. First, under the "View" menu, select "Switch to Sky". Then download the file to your computer and open it, either with the 'Open' option in the File menu within Google Earth, or by double-clicking the file's icon. | |
| By default, only the AEGIS Hubble image will be shown. However, by clicking the appropriate checkbox within the 'Places' pane at the left side of the screen, you can show any of the other AEGIS images on top of it. | |
| Multiwavelength interactive Google Sky file: multiwavelength_aegis.kml | |
| In addition, we also have: | |
| Ground-based CFHTLS image of AEGIS (covers a larger area): aegis_cfhtls.kml | |
| Further instructions on how to navigate Google Sky can be found in the Google Earth User's Guide. You can get further help using Google Earth at the Google Earth help group, or participate in a discussion about the AEGIS data set at the Google Sky community forum. | |
| Notes for Astronomers: | |
| Chandra: The image has been binned and smoothed to below the resolution of the Chandra / ACIS camera; watch this space for a higher-resolution version. The color coding indicates X-ray hardness (bluer = harder; i. e., with more high-energy photons compared to low-energy). Integration time is 200 ksec / pointing. | |
| GALEX: The GALEX image was constructed by using the Far Ultraviolet (FUV) image for the blue channel, a composite of the FUV and Near Ultraviolet (NUV) images for the green channel, and the NUV image for the red channel. Total exposure time is 120 ksec in the FUV and 237 ksec in the NUV. | |
| Hubble: This image is a color composite using ACS F606W images for the blue channel, a composite of F606W and F814W for green, and F814W for red. The base Google Sky image in AEGIS is a lower-resolution version from STScI; there are minor astrometry errors. Watch this space for full-resolution, improved-astrometry HST images for Google Sky. Integration time is ~2.2 ksec per pointing in each filter. | |
| Spitzer: This image is a color composite using IRAC Channel 1 (3.6 microns) for the blue channel, Channel 2 (4.5 microns) for green, and Channel 2 (5.8 microns) for red. Integration time is 9.7 ksec per pointing. | |
| DEEP2: Note that only redshift qualities 3 and 4 are considered secure (95% and 99.5% correct in tests); redshifts for all other objects are arbitrary, other than stars (which have z quality = -1). See http://deep.berkeley.edu/DR3 for details. | |
| Google Sky Image Credits: | |
| Chandra image: NASA / K. Nandra (Imperial College, London) | |
| GALEX image: NASA / JPL / C. Martin (California Institute of Technology) | |
| Hubble image: NASA / ESA / M. Davis (UC Berkeley) | |
| Spitzer image: NASA / JPL-Caltech / G. Fazio (Harvard-Smithsonian Center for Astrophysics) | |
| Keck SkyTrekker & AEGIS DEEP2 Catalog: | |
| Shui Hung Kwok, Jeff Mader (Keck Observatory) using data from the DEEP2 Collaboration | |