Here are instructions and links to help you follow along the National Virtual Observatory workshop.
Exercise 1: Using a Web Service
Go to the NED VO services: NED web services Lets try ObjByName, that will return the coordinates of an object based on its name - along with alternate names. Try it out.
Project 1: Finding Supernovae with SDSS Skyserver
The SDSS first images the sky and then uses those images to decide which spectra to take. We will do a search for spectra that are 2 magnitudes fainter than we expected to look for potetial supernovae. Go to the SDSS image list tool SDSS image list tool. Click on "Use query to fill form", then enter the following SQL in the form.Project 2: Creating a Multiwavelength Image Composite of Centaurus A
SELECT top 100 specobjid as name, ra, dec
FROM SpecObj
WHERE (fiberMag_r - mag_2) < -2.0
Look through the list, I see two obvious supernovae.
The galaxy Centaurus A is a great example of how observations at many wavelengths are neccessary to build up a complete picture of an object. The NVO provides a consistent way to access these various surveys, reatly facilitatig this type of analyis. We will go to the NVO DataScope to discover what type of information is availble for Cen A : DataScope . Enter Cen A and wait for the results to come back. We want images: I selected Chandra, DSS1 and SUMSS. After making your selections click analyse data with Aladin. Wait for the images to downloan and then create your composite. Here's mine:
One of the first three science prototypes for the NVO was Gamma Ray burst follow up service. Check it out here
We will use the VO Spctrum Services to access the spectra. Go here VO Spectrum Services click on search and the conesearch. But we need coordinates for our objects - let's get them from the SDSS Skysrever . Click on Search and the SQL. Let's enter the following query :Exercise 3: How far is far
SELECT top 3 ra, dec, z
FROM SpecObj
WHERE z > 5 and zConf > 0.75
when you get back the coordiates enter them in the conesearch with a search radius of 0.1
These are among the most distant objects in the universe ever measured - but how distant?
We can use a web service - the Cosmic Distances web service- to figure out the distance to our high redshift quasars. Go here Cosmic Distances Web Service Of course in cosmology there are many ways to measure distance. Let's try ComovingLineOfSight.Excercise 4: OpenSkyQuery, SkyQuery.net and ADQL
OK, great finally lets look at the Open Sky Query site. This is a service that just came online a couple of weeks ago. This is perhaps the best example of what the NVO will be. You have the ability to cross match daa from several surveys and a new query language has been created ADQL (the Astronomy Data Query Language) to deal with the peculiarities of matchinging different astronomical catlogs on the sky. Poke about and try out ome sample queries here SkyQuery.net in the tme we hve leftSome Other Links:
NVO Click on the Summer School to get software and developers packages.
SDSS Skyserver
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