GCN: Recent & Future Improvements Taka Sakamoto for Scott Barthelmy GSFC Apr 2009, Egypt...

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  • GCN:Recent & Future ImprovementsTaka SakamotoforScott BarthelmyGSFCApr 2009, EgyptOutline:1) GCN System Description. 2) GCN Status and Statistics.3) Recently Added New Functions and Features.4) Near-Future Functions and Features.

    Egypt, Apr09

  • What is GCN?Its The Gamma ray bursts Coordinates Network.

    Egypt, Apr09

  • Description of the GCN SystemGCN is a system of programs with 3 basic activities:NOTICES: Collect GRB locations from various s/c and distribute them to interested parties.CIRCULARS: Collect reports from burst follow-up observers & distribute them to the GRB community. (Easy, Cheap, and Fast) REPORTS: Collect full/detailed/final reports from burst follow-up observers & distribute them to the GRB community.These 3 compliment each otherNotices for the real-time observation needs.Circulars for the humans-in-the-loop after-the-observations.Reports provide the final (full analysis) reference.

    Egypt, Apr09

  • Distribution MethodsInternet Socket (for the robotic instruments)4 msec to write to 65 sockets0.01-2.0 sec roundtrip travel time (~0.3 sec 98-percentile)Each end can break/make the connection at will; there are re-try loops.Software provided (socket_demo.c from the web site).E-mail (for the human-based operations)9 msec to generate the ~250 email commands40 sec to execute those commands0.1-2 min for deliveryPagers & Cell-phones (when youre away from operations)Uses e-mailMultiple formats for the various service providers: long, short & subject-only.Web site (pull technology)Archive all the Notices & Circulars, LightCurves, Images, Spectra, etc.Updated by T+3 min.

    Egypt, Apr09

  • Status and Statistics561 Sites (Notices):119 socket-based (~65 routinely connected)442 email-based (full-format, pager, cellphone)995 Circulars/Reports recipientsSwift Statistics:409 bursts detected & distributed (as of 25mar09)False Positive Rate is 2% (since after May 06)Other Statistics:110 Fermi-GBM bursts 6 Fermi-LAT bursts 52 INTEGRAL bursts 8 SuperAGILE bursts 21 IPN_Raw bursts

    Egypt, Apr09

  • New: FERMI & AGILEFERMI:GBM Notices available (as of 17 Oct 08).AlertHeads-up; timestamp and trigger number.Flight_Position1-N on-board calculated position.Ground_Position1-N ground-calculated position.Propagation delay ~8-10 sec (only 0.3 sec within GCN).LAT Notices available (as of 28 Feb 09):Updated_Position1-N updated on-board calculated positions.AGILE (as of July 08):Wakeup0-1 per burst, initial on-board position.Ground-calc_Position0-1 per burst, improved gnd algorithms.Refined_Position0-1 per burst, human-in-the-loop.

    Egypt, Apr09

  • New (Apr 08): Swift-BAT Slew BurstsSlew Sources:GRBs found during the time when Swift is slewing.Capture BAT event-by-event data during slews.Processed on the ground (1-7 hrs later) to find the bursts.Developed by Antonio Copete et al (Harvard).Location uncertainties 3-4 arcmin.9 GRBs found and distributed.Swift TOOs are typically done to get XRT/UVOT results2-12 hrs after the burst

    Egypt, Apr09

  • New (Jun 08): Auto-Processed LightcurvesURL: http://gcn.gsfc.nasa.gov/gcn/swift_gnd_ana.htmlBAT & XRT lightcurves (UVOT images & spectra in the future)BAT: Mask-weighted (background subtracted)XRT: On-going afterglowAutomatically processed and updated as more data is downlinked.Available in plots and in text (64-msec binning; can be rebinned to suit your needs).Suitable for inclusion into your papers (citations to Swift encouraged).Example BAT PlotExample XRT PlotExample Text file (XRT)

    Egypt, Apr09

  • New (Apr 08): VOEventsAs part of the IVO Association and the VOEvent subgroup, GCN has developed a new way of distributing burst & transient information.It uses the VOEvent protocol and formats.XML messages for all the GCN Notice types are being distributed.Through eSTAR; and soon NOAO & Caltech and GCN-direct!

    Egypt, Apr09

  • New (Nov 07): Improved Site ConfigurationWebpage-based configuration specification.Works for:1) a brand new site creation.2) requesting a modification to an existing site.3) just getting an english-version listing of your own site on your own demand.URL: http://gcn.gsfc.nasa.gov/config_builder.html

    Egypt, Apr09

  • New (Oct 07): Near-by Galaxy AssociationsFull-format emails now contain a comment when the burst location is in a near-by galaxy.NGC catalog used:Only the 4875 galaxies that have sizes specified are included.All non-galaxy entries were eliminated (nebulae, clusters, etc):Since there is a
  • New (May 07): Bright Star NotificationFull-format emails now contain a comment when there is a bright star near the burst location.There are 9054 stars in the search dbase,Greater than 6.5 mag.Closer than 12 arcmin (radius).Actual mag and actual distance to the burst location are also specified.Done for all burst_position-containing Notice types.This helps follow-up observers know when there will be a bright star complicating their observations.

    Egypt, Apr09

  • New (Oct 06) : REPORTSAre more detailed than the Circulars.Are more complete; more accurate.168 GRBs have these Reports (all of them Swift so far)Encourage non-Swift observers to submit Reports.

    Egypt, Apr09

  • Near-Future: Swift-BAT SubthresholdBAT is currently testing triggers below the normal 6.5 sigma level. ~60 triggers to date; 1 was real GRB.These extra triggers are a separate Notice type within GCN (so that recipients can elect to separately enable them).~2 triggers per day (the above-threshold rate is 2 per week).There are two distribution times:Immediately for the SubThreshold type (to those that sign up).Lots of fasle-positives; suitable for robotic telescopes.Delayed (5-20 min) until the XRT_POS message can be processed by the UL auto-pipeline. If an XRT position is found, then GCN will promote the trigger to a BAT_POS-series of Notices and distribute them to the world.If you have signed up for BAT/XRT_Pos, then you will get these too.

    Egypt, Apr09

  • New: Misc StuffIPN_RAW Notices (Sep 08):Timestamp-only: GRB detections by a single s/cAnnulus: GRB detection by 2 s/cThis is the first step in automating the cross-correlations.SIMBAD-NED Search Notices (Aug 08)Available for the small-error-circle Position Notices (Swift, AGILE, Fermi-LAT, INTEGRAL)MIME-compliant/capable Circulars (Sep 08)Strips out all that messy HTML -- just the true text distributed.Handle Circulars Subject-lines that were longWrapping now handled correctly -- no longer truncated.socket_demo.c updated for AGILE & Fermi types. (Sep 08)

    Egypt, Apr09

  • POINTING DIRECTION NOTICESSome Missions provide their observing plan pointing direction as a function of time.GCN has turned this information into Notices.This allows robotic telescopes to follow along:This minimizes slewing time by minimizing slew distance.It allows for pre burst trigger_time images.Missions with Pointing_Dir Notices:SwiftINTEGRALAGILE (new as of Jul 08)FERMI (new as of Feb 09)

    Egypt, Apr09

  • Data Products by Mission

    MissionN_InstN_NoticesCommentGRO36originalALEXIS11Ex-UVHETE231st r-t & smallbeppoSAX11RXTE24GRBs & TransIPN12not r-tINTEGRAL16+1Swift314+2+5w/AttachmentsAGILE13Fermi23+1GBM is public

    Egypt, Apr09

  • Backup Slides

    Egypt, Apr09

  • How GCN Collects InputsInterface Programs: Sockets: integral_ibas_receiver, swift_tdrss_receiver, and fermi_receiverEmail: procmail deposits in import dir gromain periodic checksCmd_Files: manually force Test Notices (also param changes)

    gromain(GCN)swift_tdrss_receiverintegral_ibas_receiver~/import/ws_simws (gsfc)~/import/~/import/~/import/ibas (Europe)gnd proc s/wfermi_receiver (GSFC)theworldEmail:IPNAGLERXTEBAP (gsfc)

    Egypt, Apr09

  • Socket Packet Contents160 bytes, 40 dwords

    Type numberSerial numberPacket TimeRA, Dec, ErrorIntensityTrigger_ID FlagsMisc Flags

    Plus other type-specific items (box shape, URL, etc)Nearly the same content, and the same format across all types.

    Egypt, Apr09

  • Daily Socket Connection Report (1of2)For the UT day 12/10 2005:

    0 failed attempts to connect were made. 1 successful connections were made. 1 disconnects from the GCN end.

    1547 Total packets sent (types 2-4,39,40-44,51-55,60-84): 0 Type 2 sent (Test Coords) out of 8 1437 Type 3 sent (Imalive) out of 1437 1 Type 4 sent (Kill pkts) out of 1 0 Type 39 sent (IPN_POS) out of 0 0 Type 40 sent (HETE_ALERT) out of 0 0 Type 41 sent (HETE_UPDATE) out of 0 0 Type 42 sent (HETE_FINAL) out of 0 0 Type 43 sent (HETE_GNDANA) out of 0 8 Type 44 sent (HETE_TEST) out of 8 31 Type 51 sent (INTEGRAL_PNTDIR) out of 39 0 Type 52 sent (INTEGRAL_SPIACS) out of 39 0 Type 53 sent (INTEGRAL_WAKEUP) out of 39 0 Type 54 sent (INTEGRAL_REFINED) out of 39 0 Type 55 sent (INTEGRAL_OFFLINE) out of 39 0 Type 60 sent (SWIFT_BAT_GRB_ALERT) out of 0 1 Type 61 sent (SWIFT_BAT_GRB_POS_ACK) out of 1 0 Type 62 sent (SWIFT_BAT_GRB_POS_NACK) out of 0 1 Type 63 sent (SWIFT_BAT_GRB_LC) out of 1 1