For a brief introduction of the process by which data entered the archive, and a discussion regarding the structure of the ROSAT data archive at GSFC, see ftp://heasarc.gsfc.nasa.gov/rosat/doc/archive/archive_intro.html
Contents
- Introduction
- Accessing the US ROSAT Public Data Archive (USRPDA)
- Accessing the ROSAT Data Archives at MPE and Leicester
- For more Information
Introduction
Release of Data to the ROSAT DATA ARCHIVES: What Users should Know
ROSAT pointed-phase data has a proprietary period of 1 year after the completed dataset has been received by the principal investigator. After that, the data are released into the ROSAT Data Archives (RDA). The ROSAT Data Archives are located at the Goddard Space Flight Center (GSFC) in the US, at the Max-Planck-Institute fuer Extraterrestrische Physik (MPE) in Germany, and at Leicester University in the UK. The US ROSAT Data Processing Center is responsible for the release of data obtained by US PI's, while MPE is responsible for the release of data obtained by European PI's. Although every effort is made to have all public data available at each archive site, inevitable delays in data exchange between the US and Germany mean that European data will often appear first in the MPE archives, while US data generally appear first in the GSFC archive. Thus, oftentimes, public European data which may be "missing" from the US archive can be accessed from the MPE archive, and vice-versa.A Brief Word about ROSAT Data Formats
Until the start of REV2 processing in 1994, ROSAT data produced at the US Data Center at GSFC and data processed at the German Data Center at MPE were in different formats. That is to say, the files output used FITS as the basic file structure, but the details of the file structure differed depending on where the data were processed. These differences came about naturally as a result of the different analysis tools used on either side of the Atlantic: primarily MIDAS/EXSAS in Europe, and primarily IRAF/PROS in the US. As these data became public, they were released into the ROSAT Data Archives, with the result that tools which might work on one form of archived data might not work on the other form. This could cause some inconvenience to archive users who, for example, might want to compare US and German observations of the same object.With the start of REV2 processing, data were produced at the US and German data centers using a common data format, called the "Rationalized Data File" format. The RDF format uses FITS as the basic file structure, while specifying the details using approved multi-mission data structures and keywords. The REV2 data in RDF format represents the final ROSAT archive product. Eventually, all ROSAT data in all ROSAT Data archives will be in RDF format. That is to say, data previously released will be re-processed into the RDF format, and re-released to the archive, and the pre-RDF versions will be removed from the archives.
Until the reprocessing is completed and all the reprocessed data are ingested into the ROSAT ARCHIVE, the archive will contain a mix of RDF and non-RDF data. Users should be aware of this mix of data formats and use the appropriate analysis package, or be ready to make the appropriate data conversions if necessary.
Accessing the US ROSAT Public Data Archive (USRPDA)
Public Data access using Browse
The ROSAT PUBLIC DATA lists can be accessed as a searchable data table using the HEASARC BROWSE interface. The ROSAT PUBLIC data table is called ROSPUBLIC in BROWSE. Users can:Use the HEASARC BROWSE WEB interface Browse to BROWSE the ROSPUBLIC database.
To do this:
- connect to the URLhttp://heasarc.gsfc.nasa.gov/W3Browse
- click the ROSAT button to select ROSAT searches
- Either enter a source name or position and press the basic search button, or press the advanced search button to selectively search ROSAT tables and catalogues; archived datasets are available by searching the ROSMASTER or ROSPUBLIC catalogues
A list of publically available sequences which have been archived in the US Data Archive will be returned. You can then download selected data sets and data products by following the Browse instructions.
Public data via anonymous ftp from heasarc.gsfc.nasa.gov
Users can also access public ROSAT data directly from the anonymous ftp account.
- rosat/data/pspc/processed_data - public ROSAT datasets by sequence id. Data is divided into subdirectories from 100000 to 900000 based on the sequence id of the data. Thus the dataset rp500065n00, a PSPC pointing at Crab nebula, can be found in rosat/data/pspc/processed_data/500000/rp500065n00
- rosat/data/hri/processed_data - public ROSAT datasets by sequence id. Data is divided into subdirectories from 100000 to 900000 based on the sequence id of the data. Thus the dataset rh400344n00, an HRI pointing at the Vela Pulsar, can be found in rosat/data/hri/processed_data/400000/rh400344n00/
- rosat/doc/archive- archive user guide, archive data lists
Accessing the ROSAT Data Archives at MPE and Leicester
- The ROSAT Data Archive at MPE can be accessed online from the MPE ROSAT Science Data Center page, http://www.rosat.mpe-garching.mpg.de. The MPE ROSAT Archive Data Browser offers a quick way to search the MPE archive for public ROSAT data.
- The ROSAT Data Archive at Leicester can be accessed online from the UK ROSAT Guest Observer Center page( http://ledas-www.star.le.ac.uk/rosat-goc/index.html).
For more Information
- use anonymous ftp; connect to heasarc.gsfc.nasa.gov, cd to rosat/doc/archive and download archive_intro.tex (LaTeX version) or archive_intro.ps (postscript version)
- Report problems or questions via e-mail to the rosat help desk at rosathelp@oheasarc.gsfc.nasa.gov
Page Author: Dr. Mike Corcoran
Last modified 2001-10-25
