Transcript Section 7.2: Science Operation Group

GLAST LAT Project
Gamma-ray Large
Area Space
Telescope
GLAST Large Area Telescope
ISOC Peer Review
7.2 Science Operations Group
Seth W. Digel
HEPL, Stanford Univ.
ISOC Peer Review - March 2, 2004
Section 7.2 - 1
GLAST LAT Project
Topics
• Definition of the Science Operations Group (SOG)
– Organization
• Responsibilities
• Implementation of the SOG
– Current status
– Transition from I&T
– Timeline - synchronizing with the GRTs
ISOC Peer Review - March 2, 2004
Section 7.2 - 2
GLAST LAT Project
Functional Organization of the ISOC
•
•
•
LOF – LAT operations and
monitoring, and flight
software and instrument
testbed
SAS – Development,
maintenance, and support
of ground software, from
instrument simulation to
science analysis tools to
the processing pipelines
SOG
– Instrument calibration
– Performance
optimization
– Operation of pipelines
(data processing &
transient source alerts)
– Data distribution
ISOC Peer Review - March 2, 2004
Section 7.2 - 3
GLAST LAT Project
Responsibilities – Instrument Calibration
•
•
See 7.1 for specifics about calibration of the LAT and ground
operations for calibration
The SOG shall…
– Maintain the data and the body of knowledge gained by I&T from
the engineering models and the beam tests
• N.B. I&T will transition to SOG, as has already been mentioned
– Use flight data on an ongoing basis to maintain calibration of the
LAT
• E.g. (not exhaustive), Gain calibrations of ACD PMTs,
pedestals and gains for PINs in CAL, dead/hot strips in TKR
• N.B. In-flight Calibration relies on a Collaboration-wide effort
and leadership from ISOC
– In flight Calibration Tasks are identified in LAT-MD-00446
• TBRs have to do with whether data are reduced on-orbit and
the frequency of recalibrations
• The TBRs will be removed as we develop and test ISOC
concepts and as hands-on experience is gained in I&T
ISOC Peer Review - March 2, 2004
Section 7.2 - 4
GLAST LAT Project
Instrument Calibration (2)
– Optimize the settings of the LAT in flight
• This will be in response to in-flight changes in the
hardware – e.g., silicon strips becoming ‘hot’ or dead
– Generate LAT response functions
• The response functions are the high-level
characterizations of the performance of the LAT; these
are central to the high-level data analysis
• As needed, in response to change in LAT performance
or update of reconstruction/classification of events
ISOC Peer Review - March 2, 2004
Section 7.2 - 5
GLAST LAT Project
Responsibilities – Operation of Processing
Pipelines
•
•
Whatever tasks that sensibly can be automated will be
– A general purpose processing server is being developed by SAS
(§ 4.3)
The SOG shall (using the pipeline processing system) …
– Back-up all data products (cf §4.3)
– Perform Level 1 processing
• Unpacking L0 LAT science data
• Assessment of science data quality & generation of
diagnostics for the LOF
• Reconstruction & classification of events
– Search for transient sources & monitoring of selected sources
• LAT team has the responsibility to monitor for blazar flares
• By agreement with the project, fluxes for a short list of
blazars will be made publicly available regularly and
promptly during the sky survey (Phase 1)
ISOC Peer Review - March 2, 2004
Section 7.2 - 6
GLAST LAT Project
Operation of Processing Pipelines (2)
•
– Process LAT GRB transient alerts
• When the associated event data will arrive is still TBD
(might be able to have it travel with realtime telemetry
during a contact)
– Automatically monitor the calibration
• E.g., fluxes of standard, steady sources
– Generate Monte Carlo data sets of simulated LAT data
• These will generally be major processing undertakings
authorized by the LISC in support of studies of
reconstruction, background rejection or response
functions
• Update to the response functions will be required after
recon or classification are updated by SAS
Supporting reprocessing in any of these areas as required
ISOC Peer Review - March 2, 2004
Section 7.2 - 7
GLAST LAT Project
Responsibilities – Data Distribution
• The SOG shall…
– Maintain the Level 1 database of processed events along
with intermediate-level results (the ‘Level 0.5’ database)
– Maintain the the other high-level databases needed by the
standard analysis environment
• Ref. Standard Analysis Environment design report
(http://www-glast.slac.stanford.edu/sciencetools/reviews/sept02/)
• Pointing/livetime/mode history, response functions
– Distribute data according to established ICDs to the GSSC,
to LAT mirror analysis sites, and directly to LAT
collaborators
ISOC Peer Review - March 2, 2004
Section 7.2 - 8
GLAST LAT Project
Interfaces to SOG
• SOG-centric view of data flow to and from the SOG, i.e., the
interfaces with the LOF, SAS, the LAT Collab. and the GSSC
LAT Science Data, alert
messages
High-level diagnostics
Config. of LAT
SOG
LOF
Instrument simulation
Science tools
Pipeline server
SAS
LAT HK
ISOC
Data products
Response functions
Instrument simulation
Science tools
Support for LAT collab.
GSSC
ISOC Peer Review - March 2, 2004
LAT Collab.
Section 7.2 - 9
GLAST LAT Project
Implementation of the SOG
• Some of the functions of the SOG are distributed across the
collaboration
– In particular, expertise with the calibrations of the LAT
subsystems lies with the developers of the subsystems
• Core functions of the SOG will be coordinated by a dedicated
group at SU/SLAC
– In particular, pipeline operations (data processing, transient
alerts) and data distribution
• The SOG activities at SU/SLAC will be co-located with the LOF
ISOC Peer Review - March 2, 2004
Section 7.2 - 10
GLAST LAT Project
Implementation (2)
• Overall oversight of the SOG will be by the LAT Instrument
Steering Committee (LISC)
– The LISC will represent the science interests of the LAT
collaboration
– It will also have oversight over reprocessing, including
decisions about when reprocessing data in response to
changes of instrument performance or event reconstruction
ISOC Peer Review - March 2, 2004
Section 7.2 - 11
GLAST LAT Project
Summary
• The SOG serves science needs of the collaboration, in terms of
pipeline processing, instrument optimization, and calibration
• It also distributes processed data to the GSSC
• The interfaces internal and external to the ISOC are understood
and detailed requirements are being developed
• The transition from I&T to SOG is being developed as well.
ISOC Peer Review - March 2, 2004
Section 7.2 - 12