GCN GRB Coordinates Network GRB Event Reporting Scott

GCN (GRB Coordinates Network) “GRB Event Reporting” Scott Barthelmy NASA-GSFC VOE, Cal. Tech, 13 Apr 05

Table of Contents • Description of the GCN System: – Notices and Circulars • General Principles of Design & Operation • How it collects the information • How it distributes the information • Future Developments VOE, Cal. Tech, 13 Apr 05

Description of the System • GCN is a system of programs with 2 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) – Delivers data to the various instrument teams • These 2 compliment each other – Notices for the real-time observation needs. – Circulars for the humans-in-the-loop after-the-observations. VOE, Cal. Tech, 13 Apr 05

General Principles of Design & Operation • Keep it simple so they need to know as little as possible. • Do all the work, so the end-user does none/little. • Give them what they want -- the customer is always right. – Give them more than what they want; they will find a way. • Know what they want before they want it. – It helps a lot to be a person-in-the-field. • Simple data products and formats • Simple software for the end-user • Simple web pages -- just text, a few plots, a few tables. VOE, Cal. Tech, 13 Apr 05

How GCN Collects Inputs • Interface Programs: – Sockets: integral_ibas_receiver & swift_tdrss_receiver – Email: procmail deposits in import dir gromain periodic checks – Cmd_Files: manually force Test Notices (also param changes) HETE_ops (MIT) the world gromain (GCN) swift_tdrss_receiver ~/import/ gnd proc s/w integral_ibas_receiver ~/import/ ws (gsfc) ws_sim ~/import/ ibas (Europe) Items in grey are representative of other missions. VOE, Cal. Tech, 13 Apr 05

All Encompassing • GCN collects all the information on GRB locations from all the various sources into a single point, and • It transmits that information to all the various sites that want that type. • Each site need only develop & maintain one connection for all their GRB needs. • one-stop shopping VOE, Cal. Tech, 13 Apr 05

All Automatic, so it is fast • All of this collection & distribution of GRB information is done automatically. • There are no humans involved (within the GCN system proper), • So there is minimal delay (<0. 1 sec for HETE, INTEGRAL, and Swift) • And only a 1 -15 sec delay after receipt of the information from the other sources (e. g. IPN & RXTE) • science at the speed of light VOE, Cal. Tech, 13 Apr 05

Distribution Methods • Internet Socket (for the robotic instruments) – 0. 01 -2. 0 sec one-way travel time (~0. 3 sec 98 -percentile) – Imalive packets every 60 sec keep the connection current and it allows both ends to monitor the connection for problems. – Each end can re-initiate the connection if there was a read or write problem. – 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) – 0. 1 -1 minutes – Format is a combination of both human-readable and machine-parsable. • Pagers & Cell-phones (when you’re away from operations) – Uses e-mail – Multiple formats for the various service providers: long, short & subject-only. – You can get beeped by the Universe. • Web site (“pull” technology) – Archive all the Notices & Circulars, Light. Curves, Images, Spectra, etc. VOE, Cal. Tech, 13 Apr 05

Socket Packet Contents • 160 bytes, 40 dwords • • Type number Serial number Packet Time RA, Dec, Error Intensity Trigger_ID Flags Misc Flags Nearly the same content, and the same format across all types. • Plus other type-specific items (box shape, URL, etc) VOE, Cal. Tech, 13 Apr 05

Email & Pager Format Examples TITLE: NOTICE_DATE: NOTICE_TYPE: TRIGGER_NUM: GRB_RA: GRB_DEC: GRB_ERROR: GRB_INTEN: BKG_TIME: GRB_DATE: GRB_TIME: GRB_PHI: GRB_EL: TRIGGER_INDEX: SOLN_STATUS: RATE_SIGNIF: IMAGE_SIGNIF: MERIT_PARAMS: SUN_POSTN: SUN_DIST: MOON_POSTN: MOON_DIST: GAL_COORDS: ECL_COORDS: COMMENTS: COMMENTS: GCN/SWIFT NOTICE Sat 04 Sep 04 19: 42: 25 UT Swift-BAT GRB Position 100002, Seg_Num: 0 68. 95 d {+04 h 35 m 47 s} (J 2000), 68. 99 d {+04 h 35 m 57 s} (current), 68. 50 d {+04 h 34 m 01 s} (1950) -37. 30 d {-37 d 18' 13"} (J 2000), -37. 29 d {-37 d 17' 39"} (current), -37. 40 d {-37 d 24' 16"} (1950) 4. 00 [arcmin radius, statistical only] 4591 [cnts] Peak=933 [cnts/sec] 6455 [cnts] 45384. 00 SOD {12: 36: 24. 00} UT 13243 TJD; 239 DOY; 04/08/26 45400. 44 SOD {12: 36: 40. 44} UT 154. 14 [deg] 43. 60 [deg] 127 3 18. 63 [sigma] 14. 79 [sigma] +1 +0 +0 +0 +3 +33 +0 +0 +6 +1 155. 52 d {+10 h 22 m 05 s} +10. 18 d {+10 d 11' 02"} 93. 43 [deg] 286. 97 d {+19 h 07 m 53 s} -27. 40 d {-27 d 23' 53"} 106. 13 [deg] 239. 98, -42. 17 [deg] galactic lon, lat of the burst direction 57. 00, -58. 36 [deg] ecliptic lon, lat of the burst direction SWIFT-BAT GRB Coordinates. This is a rate trigger. A point_source was found. This does not match any source in the on-board catalog. This does not match any source in the ground catalog. This is a GRB. GCN/SWIFT-BAT GRB Position RA=68. 988 d DEC=-37. 295 d ERROR=4. 0 arcmin TIME: 12: 36: 40. 44 UT R_Signif=18. 6 I_Signif=14. 8 Nearly the same content, and the same format across all types. VOE, Cal. Tech, 13 Apr 05

Filtering Methods • Source Type – Swift, INTEGRAL, HETE, Beppo. SAX, IPN, RXTE, ALEXIS, …. – Sub-type selection (instruments, saw/no_saw, etc) • Visibility – All, Visible, Nighttime, and Customized • Location Uncertainty Size – 1 arcsec to 360 deg (match your FOV/tiling capability) • Time Delay (time since burst) – 1 sec to 40 days • Sites get the logical-AND of the 4 filtering conditions • Special filtering to accommodate mission-teams • There used to be intensity filtering, but multi-missions make that difficult. VOE, Cal. Tech, 13 Apr 05

Data Products Mission GRO ALEXIS RXTE IPN HETE beppo. SAX INTEGRAL Swift N_Inst 3 1 2 N_Notices 6 1 4 Comment original Ex-UV GRBs & Trans “ 1” 2 1 1 3 2 3 1 6+1 14+2+5 Delays 1 st r-t & small w/Attachments VOE, Cal. Tech, 13 Apr 05

WEB SITE CONTENTS • • http: //gcn. gsfc. nasa. gov/gcn GRB Notices pages for each S/C (r-t updated) Circulars Archive (r-t updated) Bursts-of-Special Interest (r-t updated) – Circulars grouped by burst • Technical Description of the GCN system – All information about the GCN system; capabilities, formats, protocols, etc. all functions, VOE, Cal. Tech, 13 Apr 05

Site’s Configuration for Notices • A Notice “site” is specified by ~60 pieces of information – – – – Site_name, Longitude, Latitude Dis/enables for each of the ~40 Types Error_size limit and Time_delay limit Trigger_ID filtering Test Notices (5 types) Distribution method Attachment format (FITS, GIF, JPEG, Postscript, Text) Destination address (scott@milkyway. gsfc. nasa. gov or 128. 183. 16. 43: 5112) – Do they want to receive: • Socket-disconnect warnings • daily socket reports VOE, Cal. Tech, 13 Apr 05

Person’s Configuration for Circulars • You must be pre-registered to submit a Circular – 6 pieces of information needed: • • • Full Name Institutional affiliation[/project] Email login/account name (1) Email domain (1) Email address you want to receive Circulars Do you want to receive or not (1 or 0) John Doe State University[/Swift] johnd su. edu johnd@astro. su. edu 1 – Multiple entries are allowed (ie different logins, machines, institutions, whatever) (1) These two fields used in the vetting check during a submission. VOE, Cal. Tech, 13 Apr 05

Some GCN Statistics • Notices: – 460+ "sites" involving ~500 researchers. – “sites” are: robotic telescopes, human-ops telescopes, pro’s & amateurs, theorists, people with an interest. • Up-time is 99. 7% (in the last 2 yr; 98. 6% over 13 yr) • ~3000 observations on ~600 GRBs • Communications Traffic (for 2002): – 7000 automated notices/packets were distributed. – 600 manual e-mails were received from the "sites" & – 500 e-mails were sent back in reply by the GCN operator. • Circulars: – 860+ recipients – 3200+ distributed • Both run on a LINUX PC – 3 GHz, 512 MB RAM, 320 GB disk, Router, and an UPS VOE, Cal. Tech, 13 Apr 05

Aggressive Campaign for Participation • GCN is open to anyone with an interest in GRBs. • The Circulars are also open to everyone. • Always looking for new sources of GRB locations; looking for other sources. VOE, Cal. Tech, 13 Apr 05

The Future • GLAST (Launch in 2007) • AGILE (Launch in 200? ) • Optical/Radio/X-G Counterpart Notices – Feeds back to the robotic systems what the follow-up people found. • MILAGRO events • Speech-synthesized phone calls – Dial your phone and TELL you where the burst is. VOE, Cal. Tech, 13 Apr 05

990123 --> GCN--> ROTSE • GCN achieved its original design goal; non -g observations while still bursting. • Combination of real-time data processing & fast-slewing, wide-FOV, automated instruments • GCN to ROTSE at T+4 sec. • ROTSE’s 1 st observation at T+22 sec. • mag 11. 7, 8. 9, 10. 0, 11. 9, 13. 1, 13. 8, 14. 3 • at T+ 22, 47, 73, 157, 281, 447, 612 s. • Few x 1054 ergs (2 m. Oc 2) • Top 0. 3% by fluence; top 2% by intensity • Z=1. 6, halfway to the edge of the Universe Since then, there have been Several other simul-detections. VOE, Cal. Tech, 13 Apr 05 C. Akerlof, et al. , Nature, 398, Apr 99

GCN/Swift Data Products • Raw (16): – – – BAT: XRT: UVOT: FOM: MOC: Alert, Position, No_Position, Lightcurve, Scaled_map Position, No_Position, Image, Spectrum, Lightcurve Finding_Chart, Dark_Burst_Image Will/Wont_Observe, Will/Wont_Slew Initial_Full_Data_Arrival, Updated_Full_Data_Arrival • Processed (5): – BAT: Lightcurve – XRT: Image, Spectrum – UVOT: Finding_Chart, Dark_Burst_Image • Warning/Error (7): – – – BAT: Short_Alarm, Long_Alarm XRT: Emergency UVOT: Emergency FOM: PPT_Argument_Error, Safe_Pointing, & Slew_Abort This is a back-up capability to the primary PSU MOC notification operation. VOE, Cal. Tech, 13 Apr 05

GRB BASICS • • Flashes of gamma-rays (0. 05 to 1. 5 Me. V) Random locations; Isotropically distributed Random times; Never repeat Very brief: 0. 01 to 100 sec Intense: brighter than the rest of the Universe Cosmological distances: z= 0. 1 to 4. 5 Sources: Hyper. Nova/Collapsar (for the long), NS/BH mergers (short) VOE, Cal. Tech, 13 Apr 05