Various spectral services have been implemented.
SSA Services
Simple Spectral Access Protocol (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.
SSA Services on Max-Planck-Institut für extraterrestrische Physik(MPE) Spectra
GAVO provides SSA services on the spectra from various projects in which MPE scientists participate. The following spectra are available via GAVo services:
CDFS Optical Spectra
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.
zCOSMOS Bright Spectroscopic Observations Data Release DR2
The global COSMOS project is aimed at understanding the evolution of galaxies and active galactic nuclei, and in particular the role of the galactic environment in that evolution. It is built around observations of a single equatorial 1.7 deg2 field corresponding to transverse dimensions of 100 x 100 Mpc2. The zCOSMOS redshift survey is a major project (ESO Large Program 175.A-0839) that is using 600 hours of observing time with the VIMOS spectrograph on the VLT UT3, spread over five observing seasons (2005-2009). It consists of two parts (see Lilly et al., 2007, for details): the first, "zCOSMOS-bright", obtains spectra of about 20,000 galaxies selected to have IAB < 22.5 across the full 1.7 deg2 of the COSMOS field.
The zCOSMOS-bright sample was designed to yield a high and fairly uniform sampling rate (about 70%), with a high success rate in measuring redshifts (approaching 100% at 0.5 < z < 0.8), and with sufficient velocity accuracy (about 100 km/s) to efficiently map the environments of galaxies down to the scale of galaxy groups out to redshifts z ~ 1.
The second part, the "zCOSMOS-deep", will consist of about 10,000 spectra of higher redshift galaxies, colour-selected to have redshifts in the 1.4 < z < 3.0 range, and lying in the central 1 deg2 region of the COSMOS field.
After the first two zCOSMOS observing seasons in 2005 and 2006, about a half of the zCOSMOS-bright observations had been completed, yielding a total of over 10,500 spectra from which redshift measurements have been made. This sample, the so-called "10k-sample" (Lilly et al., 2008, The Messenger, vol. 134, p. 35-40 ), is the one released here (DR2).
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.