of the XID programme
Processing Subsystem (PPS) for XMM,
which will be run at
Leicester University by the SSC,
will produce a number of products for each XMM observation. Besides being
delivered to the XMM Science Operations Centre (SOC), they will also be
stored at Leicester for the XID programme.
PPS products for the EPIC images contain a list of the X-ray sources found
in that observation, with all potentially useful information (position,
extracted spectrum, etc.).
primary source list is then cross-correlated with an extensive list of
existing catalogues built in the Archival Multiwavelength Database (AMW-DB)
Astronomique de Strasbourg), which includes APM and
SuperCOSMOS (when available)
scans of the optical sky survey plates. This allows the possibility of
tweaking the astrometry of every particular EPIC observation to an absolute
reference frame. These source lists will be used for the XID programme.
XID activities, other than the cross-correlation work with catalogues,
are coordinated and supported by the SSC node at the Mullard Space Science
In short MSSL is responsible for the overall coordination of the XID programme
and maintenance of the XID database which will ingest all the data resulting
from observing runs within the XID programme. It will also provide assistance
in terms of source lists, quality standards for the observations, etc.
Access to the non-proprietary data is granted to the whole SSC consortium.
of the optical programme
XID programme is expected to include collaborators from outside the Survey
Science Centre, who participate in it on a collaborative basis.
of the XID programme will imply the following tasks:
particular observing runs to observers (from the SSC or collaborators),
based on availability and expertise in the use of similar instrumentation.
As a general rule, two observers, if possible from the same Institute,
will attend each run.
sure that the observers have available the target lists and
set by the XID programme in terms of calibration (including photometric
or spectrophotometric standards to use, etc.).
sure that the observing log, raw data and reduced data are posted to the
XID database at the Mullard Space Science Laboratory in the required timescales
(1 day, 1 week and 3 months at the latest, respectively).
that all the SSC members have access to all the data obtained in our observing
runs through the XID-DB.
Summary information (sources/fields observed,
magnitudes, redshifts, etc.) of our runs will be available to the whole
SSC consortium at all times. However, the data itself (both raw and reduced)
will only be available to the full SSC consortium after 12 months of the
observing date. This is the policy expected to apply to all observing runs
in the framework of the XID programme.
scientific exploitation of the data within the
SSC consortium and its external
collaborators, in terms of spin-off results, will be overseen by the XID
plan is based on our previous experience. A number of members of the SSC
have participated in international collaborations (RIXOS,
EMSS, RBS, etc,). Lessons learned from these previous experiences of special
relevance to the XID programme include:
observations tend to be heterogeneous as they are performed by different
observing teams. This applies both to target selections and to calibration
policy (flats, arcs, standards, etc.). Both issues will be agreed previously
by the whole collaboration and managed by the XID team leader. This ensures
that the data obtained will not be biased towards a particular class of
objects and that the quality of the data will be more uniform.
be reduced by the observing teams themselves within a short timescale (3
months) and following standard procedures that guarantee the usefulness
of the data for the XID programme.
exploitation of the data obtained within the XID programme is open to all
members of the SSC (and to the external collaborators when they provide
data), with the oversight of the XID Working group.
10th March 2000
Text based on
AXIS proposal by X.Barcons and the SSC consortium.
by J.Verdon and maintained by firstname.lastname@example.org