voe, caltech, 13apr05 gcn (grb coordinates network) grb event reporting scott barthelmy nasa-gsfc

VOE, CalTech, 13Apr05

GCN(GRB Coordinates Network)

“GRB Event Reporting”

Scott BarthelmyNASA-GSFC


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


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.


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.


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)

gromain(GCN)

swift_tdrss_receiver

integral_ibas_receiver

~/import/

ws_sim

ws (gsfc)

~/import/

~/import/

~/import/

ibas (Europe)

gnd proc s/w

Items in grey are representative of other missions.

HETE_ops (MIT)

theworld


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


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


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, LightCurves, Images, Spectra, etc.


Socket Packet Contents

• 160 bytes, 40 dwords

• Type number• Serial number• Packet Time• RA, Dec, Error• Intensity• Trigger_ID Flags• Misc Flags

• Plus other type-specific items (box shape, URL, etc)

Nearly the same content, and the same format across all types.


Email & Pager Format ExamplesTITLE: GCN/SWIFT NOTICENOTICE_DATE: Sat 04 Sep 04 19:42:25 UTNOTICE_TYPE: Swift-BAT GRB PositionTRIGGER_NUM: 100002, Seg_Num: 0GRB_RA: 68.95d {+04h 35m 47s} (J2000), 68.99d {+04h 35m 57s} (current), 68.50d {+04h 34m 01s} (1950)GRB_DEC: -37.30d {-37d 18' 13"} (J2000), -37.29d {-37d 17' 39"} (current), -37.40d {-37d 24' 16"} (1950)GRB_ERROR: 4.00 [arcmin radius, statistical only]GRB_INTEN: 4591 [cnts] Peak=933 [cnts/sec]BKG_INTEN: 6455 [cnts]BKG_TIME: 45384.00 SOD {12:36:24.00} UTGRB_DATE: 13243 TJD; 239 DOY; 04/08/26GRB_TIME: 45400.44 SOD {12:36:40.44} UTGRB_PHI: 154.14 [deg]GRB_EL: 43.60 [deg]TRIGGER_INDEX: 127SOLN_STATUS: 3RATE_SIGNIF: 18.63 [sigma]IMAGE_SIGNIF: 14.79 [sigma]MERIT_PARAMS: +1 +0 +0 +0 +3 +33 +0 +0 +6 +1SUN_POSTN: 155.52d {+10h 22m 05s} +10.18d {+10d 11' 02"}SUN_DIST: 93.43 [deg]MOON_POSTN: 286.97d {+19h 07m 53s} -27.40d {-27d 23' 53"}MOON_DIST: 106.13 [deg]GAL_COORDS: 239.98,-42.17 [deg] galactic lon,lat of the burst directionECL_COORDS: 57.00,-58.36 [deg] ecliptic lon,lat of the burst directionCOMMENTS: SWIFT-BAT GRB Coordinates.COMMENTS: This is a rate trigger.COMMENTS: A point_source was found.COMMENTS: This does not match any source in the on-board catalog.COMMENTS: This does not match any source in the ground catalog.COMMENTS: This is a GRB.

GCN/SWIFT-BATGRB PositionRA=68.988d DEC=-37.295dERROR=4.0arcminTIME: 12:36:40.44 UTR_Signif=18.6I_Signif=14.8

Nearly the same content, and the same format across all types.


Filtering Methods• Source Type

– Swift, INTEGRAL, HETE, BeppoSAX, 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.


Data Products

Mission N_Inst N_Notices Comment

GRO 3 6 original

ALEXIS 1 1 Ex-UV

RXTE 2 4 GRBs & Trans

IPN “1” 2 Delays

HETE 2 3 1st r-t & small

beppoSAX 1 1

INTEGRAL 1 6+1

Swift 3 14+2+5 w/Attachments


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;

all functions, capabilities, formats, protocols, etc.


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 ([email protected] or

128.183.16.43:5112)– Do they want to receive:

• Socket-disconnect warnings• daily socket reports


Person’s Configuration for Circulars

• You must be pre-registered to submit a Circular– 6 pieces of information needed:

• Full Name John Doe• Institutional affiliation[/project] State University[/Swift]• Email login/account name (1) johnd• Email domain (1) su.edu• Email address you want to receive Circulars [email protected]• Do you want to receive or not (1 or 0) 1

– Multiple entries are allowed (ie different logins, machines, institutions, whatever)

(1) These two fields used in the vetting check during a submission.


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, 512MB RAM, 320 GB disk, Router, and an UPS


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.


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.


990123--> GCN--> ROTSE• GCN achieved its original design goal;

non- observations while still bursting.

• Combination of real-time data processing & fast-slewing, wide-FOV, automated instruments

• GCN to ROTSE at T+4sec.

• ROTSE’s 1st observation at T+22sec.

• 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 x1054 ergs (2mOc2)

• Top 0.3% by fluence; top 2% by intensity

• Z=1.6, halfway to the edge of the Universe

C.Akerlof, et al., Nature, 398, Apr99

Since then, there have beenSeveral other simul-detections.


GCN/Swift Data Products

•Raw (16):– BAT: Alert, Position, No_Position, Lightcurve, Scaled_map– XRT: Position, No_Position, Image, Spectrum, Lightcurve– UVOT: Finding_Chart, Dark_Burst_Image– FOM: Will/Wont_Observe, Will/Wont_Slew– MOC: 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.


GRB BASICS

• Flashes of gamma-rays (0.05 to 1.5 MeV)• 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: HyperNova/Collapsar (for the long), NS/BH mergers (short)

voe, caltech, 13apr05 gcn (grb coordinates network) grb event reporting scott barthelmy nasa-gsfc

Documents

system gcn

rotse gcn

13apr05 description

gcn system proper

grb locations

grb needs

world slide

shopping slide