Various spectral services have been implemented.
SSAP Services
SSAP is a HTTP-based query protocol on one-dimensional spectra. The query returns a list of candidate spectra with description and location of the actual spectral data. The actual spectral data can be retrieved at the URL given in the "Access Reference" field. For further information how to use the service, please look at our Help pages which can be accessed from the main service pages.
We also offer browser based service applications that can be reached via the buttons below.
CDFS - SSA
GAVO has implemented a service compliant to the Simple Spectral Access Protocol (SSAP) on a set of optical spectra that were the result of the spectroscopic follow-up of X-ray sources in the Chandra Deep Field South (R. Giacconi et. al.).
The nominal aim point of the data set is RA = 3hr32m28s.0(53.1167 deg), and DEC = -27o48'30''(-27.8083 deg) (J2000) covering the 1Msec Chandra X-Ray observation. It was carried out with VLT/FORS in the time frame of October 2000 to December 2001. There are 296 spectra available.
TheoSSA
A prototype of the Simple Spectra Access Protocol was implemented focussing on synthetic spectra. The first data set which is available at the moment is TMAP by Thomas Rauch in Tuebingen. This is an example of a "distributed" service: The spectral data is physically stored at Tuebingen, whereas metadata and search application are implemented at ARI, Heidelberg.
This service accepts all HTTP requests with mandatory parameters as they are defined in the version 1.01 of the SSAP specification. However, since this service specializes on theoretical spectra, some of the parameters (POS, SIZE, TIME) are not applicable to this kind of data and will lead to empty results if specified. (Therefore the user interface in our browser based application does not offer edit fields for these parameters.) Additional parameters which this service offers are: TEMP (effective temperature), TEMP_TOLERANCE (tolerance range), GRAVITY (surface gravity), GRAVITY_TOLERANCE (tolerance range) and FRACTION0..FRACTION7, VALUE0 ..VALUE7 (mass fractions for up to eight different elements).
There are two different ways to access this service: the "plain" HTTP access is used by central VO registries to enable search for synthetic spectra in various archives simultaneously. Some sample HTTP requests are listed below.
The second way is via the browser based application which offers a user interface to simplify search and download of synthetical spectra.
Sample HTTP requests:
http://vo.ari.uni-heidelberg.de/ssatr-0.01/ssatr?request=queryData&format=metadata
Returns all input and output parameters of this service in votable format. This request is only used by VO registries to find out the capabilities of this service and is therefore not included in our user interface.
Returns a list with descriptions of candidate spectra that have a temperature of 120000+/-1000, a gravity of 6+/-1, one of the following formats: votable, xml, text/plain, text/html. This list is returned in votable format since no returnformat is specified.
Returns a list with descriptions of candidate spectra that have a temperature of 120000K, a gravity of 9cm/s2, wavelengths between 0 and 1 m,a mass fraction of about 0.5 for hydrogen and of about 0.5 for helium.
Returns the same list as above but in html format.