An Introduction to MAST

Today we have a guest post from Scott Fleming. Scott is a scientist at the Space Telescope Science Institute, located in Baltimore, MD, USA, where he works on the data archives.  His research interests include eclipsing binaries, stellar astrophysics, brown dwarfs, and extrasolar planets. Today Scott is here to tell you a more about MAST, the online public data archive where the Planet Hunters team obtain the Kepler light curves that are processed and eventually show up on the Planet Hunters site for you to classify.

The Mikulski Archive for Space Telescopes (MAST) is the official archive of data from NASA-funded space telescopes.  We primarily house data from ultraviolet and optical space telescopes.  Some of the missions we support include GALEX, the Hubble Space Telescope, the James Webb Space Telescope (after it launches), and of course, Kepler.  We also archive, and plan to archive, data from many other missions that have launched over the past 40 years, ranging from the 1970’s to future space and ground-based telescopes.

 Our role in the Kepler mission is to serve as the Data Management Center.  This means that, in addition to some data processing, we archive the lightcurve data itself (the timestamps, fluxes, flux uncertainties), as well as information related to each observation that’s required for calibration purposes, and catalog information that contains data on the host stars (their brightness in different wavelengths, estimates of their temperatures and sizes, etc).  We primarily serve professional researchers by facilitating access to the data, enabling powerful search capabilities so they can locate the data they need for their research, and providing tools that allow the scientists to preview and visualize the data before they download it to their machines for further analysis.  However, we do have some online tools that are used by educators and amateur astronomers as well.

Our newest tool is the MAST Discovery Portal.  This online search interface allows users to enter coordinates or target names and do a search for data across many missions all at once.  This is kind of like a “Google” for astronomical data, where users can discover observations that may have been taken on their objects, even if they weren’t aware of its existence beforehand.   You can enter the coordinates or name of a Kepler star, for example, and discover what other data exist by searching “All MAST Observations” or the “All Virtual Observatory Collections” in the top-left menu.  The Virtual Observatory is an online service that provides access to data from other astronomical archives around the world.  This allows users to search not only the ultraviolet and optical data at MAST, but also data in the radio, infrared, x-ray, and gamma-ray.


MAST Discovery Portal Astroviewer (image credit: Scott Fleming)

The Discovery Portal includes an AstroViewer.  Using background images of the sky created from ground-based surveys, users can see the “footprints” (i.e., the field-of-view) of a given piece of data, and see exactly where your objects lie inside.  If you’d like to try it out, do a search on “Kepler 2”.  In the AstroViewer on the right-hand-side of the screen you will see lots of footprints appear.  The small squares around stars in the field are from Kepler; they show which stars Kepler looked at in the field.  Our target, Kepler 2, is automatically centered in the AstroViewer.  You will notice larger squares around it, which are the footprints of data observed with the Hubble Space Telescope.  If you zoom out to larger scales using the “minus” button on the lower-left corner of the AstroViewer, you will start to see very large squares and circles.  The biggest squares come from the Swift space telescope, while the large circle is an observation from the ultraviolet GALEX space telescope.  You can see how this visualization of data from many missions allows users to discover new data on their targets, and look for cross-mission overlap that can enable new kinds of science when multiple instruments observe the same target.

 Feel free to try out the Discovery Portal for yourself.  There is no registration or login required.  You can follow MAST online on Facebook and follow us on Twitter @MAST_News.  Although our posts are directed at professional astronomers to alert them when new data and tools are available at MAST, it’s still a way to keep up-to-tabs on what new projects are happening in the professional astronomy circles.


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