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Downtime expected shortly as all LEDAS services are moved to a new server.

Dec 2003: HEASoft updated to version 5.3

The latest version of the HEASARC X-ray data reduction/analysis software package HEASoft (version 5.3) is now available for download. HEASoft 5.3 contains FTOOLS 5.3, fv 4.0, XIMAGE 4.2, XRONOS 5.20 and XSPEC 11.3.

Nov 2003: PIMMS upgraded to v3.4, Swift AO-1 support

The interactive X-ray mission simulator software PIMMS has been updated to the latest version PIMMS 3.4, which has effective area curves for Swift AO-1 proposal preparation.

Sept 2003: BLASTA now supports 2MASS All-Sky Data Release

The BLASTA search engine now supports online searches of the 2MASS All-Sky Data Release Point Source Catalog (~470 million sources, released 2003 March).

Sept 2003: BLASTA, SIMBAD, ViZieR services moved

The BLASTA search engine, SIMBAD bibliography search and ViZieR gateway have been moved to a new server. The existing server ledas-svc will be retired shortly. Please update your bookmarks accordingly.

August 2003: CIAO 3.0 and CALDB 2.23 available for download

The latest version of the Chandra data reduction software (CIAO 3.0) and calibration database (CALDB 2.23) are now available for download from LEDAS.

July 2003: WebChaSeR interactive search engine

WebChaSeR, a java-based interactive search interface to the Chandra Data Archive, is now available locally as a LEDAS service.

July 2003: AGASC available for download

The full AGASC (AXAF Guide and Acquisition Star Catalog) is now available for download from LEDAS via FTP. No portable catalog reading software is available, but the individual FITS files can be accessed with e.g. FTOOLS. CXC provides a search interface to the AGASC here.

June 2003: LEDAS Newsletter #17

The latest LEDAS newsletter is now available. If you would like to be added to the mailing list to receive future newsletters, please email <ledas-request@star.le.ac.uk>.

June 2003: WebPIMMS upgraded to latest version v3.3

The X-ray mission simulator software WebPIMMS as been upgraded to the latest version v3.3, incorporating calibration data for Chandra Cycle-5 and XMM AO-3 proposals.

May 2003: Scripted access to DSS image service

Users can now access the DSS image service directly, by submitting a URL of the form:-


where the parameters are as follows:-

  • coordinates: position of field centre in decimal hours/degrees
  • pixelsize: size of pixels in output image
  • punits: pixel size units ( sec | min )
  • equinox: coordinate equinox
  • fieldsize: output image field size
  • funits: output image size units ( sec | min | deg | pix )

May 2003: New web address for LEDAS

LEDAS is now available at the new URL http://www.ledas.ac.uk/. The existing URL will continue to work, but we would advise users to update their bookmarks.

May 2003: Latest CFITSIO (v2.460) library now available for download

The latest version of the FITS access library CFITSIO (v2.460) is now available for download from LEDAS. This revision adds support for proxy HTTP servers when reading FITS files via HTTP. For more information, see the changelog.

May 2003: ARNIE5 supports interactive plotting of search results

The new LEDAS catalogue search interface ARNIE5 now supports interactive plotting and filtering of search results using VOPlot, a Java applet developed by Persistent Systems and the IUCAA. The applet is started by clicking on the 'Display in VOPlot' link in the ARNIE5 search results page. For more information, please see the VOPlot Help Page.

April 2003: XMM Serendipitous Source Catalogue available from LEDAS

1XMM is the first comprehensive catalogue of serendipitous X-ray sources from the European Space Agency's (ESA) XMM-Newton observatory, and has been constructed by the XMM-Newton Survey Science Centre (SSC) on behalf of ESA. Most (> 80%) of the entries have not previously been reported as
X-ray sources.

The catalogue contains source detections drawn from 585 XMM-Newton EPIC observations made between 2000 March 1 and 2002 May 5; all datasets were publicly available by 2003 January 31 but not all public observations are included in this catalogue. Net exposure times in these observations range
from < 1000 up to ~100000 seconds. The total area of the catalogue fields is ~90 deg^2, but taking account of the substantial overlaps between observations, the net sky area covered independently is ~50 deg^2. The observations sample, albeit sparsely, most of the sky, with the exception of a 'hole' centred in the Cygnus region caused by spacecraft observing constraints.

The processing to generate the catalogue is based closely on the data processing system used by the SSC in routine processing of XMM-Newton data on behalf of ESA to produce data products for observers and the archive. Considerable effort has been expended to 'calibrate' the catalogue in terms of understanding such issues as errors, biases, sensitivity and sky coverage.

The catalogue source detection and parametrisation technique is optimised for point-like sources, and has been performed across several photon-energy bands and using data from each of the three EPIC cameras - PN, MOS1, MOS2.

The catalogue content includes the source-detection parameters (likelihood, position coordinates, counts, count rate, flux, hardness ratio, background estimates, errors ...); the results of cross-correlation with a large number of archival catalogues (SIMBAD, NED, USNO, GSC, APM, ROSAT ...); quality 'flags' resulting from visual screening, and 'metadata' relating to the observation.

The catalogue contains 33026 X-ray source detections with likelihood values >8 and summary quality flag >0, together with a further 23685 detections with lower likelihood values and/or summary quality flag=0
indicating that the detection may be spurious. The 33026 X-ray source detections relate to 28279 unique X-ray sources.

The median flux (in the total photon energy band 0.2-12 keV) of the catalogue sources is ~3e-14 erg cm^-2 s^-1; ~12% have fluxes below 1e-14 erg cm^-2 s^-1.

The positional accuracy of the catalogue sources is generally ~0.5-2 arcsec (68% confidence radius) for detections with likelihood >8. The flux estimates from the three EPIC cameras are overall in agreement to ~2% for on-axis sources, and ~6% off-axis.

In association with the catalogue itself, various data products are also available (images, exposure maps, sensitivity maps, extracts from archival catalogues and databases ...).

LEDAS provides a Web-based user interface allowing filtering and searching of the catalogue, and links to associated data products from the XMM Science Archive at ESA Vilspa.

The catalogue is also available from other servers:

- the XSA, at ESA's XMM-Newton SOC

- the XCAT-DB, at the SSC institute, OA Strasbourg

- the SSC Home Page, at the SSC institute, University of Leicester

- Vizier, at CDS Strasbourg

February 2003: BLASTA now supports searches of USNO-B1.0

The database browser BLASTA now supports searches of USNO-B1.0, the latest catalogue producedby the PMM project at USNO Flagstaff. USNO-B1.0 is a full-sky catalogue which includes positions, proper motions, magnitudes in various optical passbands and star/galaxy IDs for ~109 objects. The catalogue is complete down to V=21 and has 0.3mag photometric accuracy in up to five colours.

February 2003: Chandra CALDB 2.21 now available for download

The latest version of the Chandra calibration database (CALDB 2.21) is now available for download from LEDAS. It includes a corrected version of the ACIS CTI-corrected response functions (CTI-corrected FEF version N0002), new CTI-corrected ACIS blank field (background) files, and -1 order HETG LSF parameter files.

January 2003: Chandra Cycle-5 proposal packages are available for download.

The proposal planning tools for Cycle 5 are now available for download. The software includes a range of useful command-line tools for Chandra observations including the flux calculator PIMMS, and the observation visualiser (obsvis) to display instrument fields of view.