1 GCN and SONG Scott Barthelmy GSFC 16-18 Sep 2011, SONG Workshop, Charleston,SC http://gcn.gsfc.nasa.gov Outline: 1) System Description: Functions, Features, & Notice Types 2) How GCN can contribute to SONG 3) How SONG can contribute to GCN GCN (Gamma-ray Coordinates Network) continues to grow and expand to accommodate the needs of the community and to incorporate new sources of transient phenomena. Transitioning into the Transient Astronomy Network (TAN).
Transcript
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GCN and SONG
Scott BarthelmyGSFC
16-18 Sep 2011, SONG Workshop, Charleston,SC
http://gcn.gsfc.nasa.govOutline: 1) System Description: Functions, Features, & Notice Types 2) How GCN can contribute to SONG 3) How SONG can contribute to GCN GCN (Gamma-ray Coordinates Network) continues
to grow and expand to accommodate the needs of the communityand to incorporate new sources of transient phenomena.Transitioning into the Transient Astronomy Network (TAN).
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Description of the GCN System
• GCN is a system of programs with 3 basic activities:– NOTICES: Collects GRB/Transient locations from various space-based & ground-based sources and distributes them to interested parties.
– CIRCULARS: Collects reports from GRB follow-up observers & distributes them to the GRB community.
– REPORTS: Collects full/detailed/final reports from GRB follow-up observers & distributes them to the GRB community.
• These 3 compliment each other:– Notices for the real-time observation needs (all automated, ho humans).
– Circulars for the humans-in-the-loop after-the-observations.– Reports provide the final (full analysis) reference.
System
Provide fast, efficient, and uniform supply of all transient informationto every instrument, operation, and person that wants it.One-stop shopping for all your transient needs.
Notice Basic Contents• Each notice contains:
– RA,Dec location of the burst/transient– Location uncertainty– Time/Date of the event– ID or Serial_number– Intensity (& sometimes Significance)– Event type identity (& sometimes Conf.Level)
– Value-added items (see later slides)
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System
Speed is important.Do not need the full analysis; just need the location.The human can sort out the rest after the observation is done.
Importantpart
History of GCN• Dec 92 With the advent of the C-GRO tape recorder failure…
• Aug 93 First “light” for GCN (called BACODINE at the time).– All C-GRO data transmitted to ground in real-time via TDRSS.– Extract the burst data from BATSE telemetry stream, calculate a position, distribute it to whomever.
– Socket & Phone were the first distribution methods.
• Nov 97 BeppoSAX added (GRB 970228 was a game changer: afterglow).
• Sep 00 IPN error boxes added.• May 01 HETE added.• …. and more things added over the years…. 4
Started out as a GRB-only network,but then opened up with other transients as well – Time Domain Astronomy.
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Distribution Methods• Internet Socket (for the robotic instruments)
– 4 msec to write to 65 socket connections– 0.01-2.0 sec roundtrip travel time (~0.3 sec 98-percentile)– Each end can break/make the connection at will; there are re-try
loops.– Binary & VOEvent formats available.
– Software provided (socket_demo.c & xml_sock_demo.c)• Email-based (for human operations)
– Full-format emails, plus shorter formats for cellphones & pagers (slide 7)
– VOEvent format also available.– 9 msec to generate the ~300 email commands (max load)– 40 sec to execute those 300 commands– 0.1-2 min for the delivery across the internet– Images, spectra, lightcurves available in FITS/GIF/JPEG/PDF as
attachments.
• Web site (“pull” technology)– Archive all the Notices & Circulars, LightCurves, Images, Spectra,
etc.– http://gcn.gsfc.nasa.gov/burst_info.html– Updated within T+3 min.
System
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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, energy band, URL, etc).
• All documented in: http://gcn.gsfc.nasa.gov/gcn/sock_pkt_def_doc.html
Nearly the same content, and the same format across all types.
System
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Email & Pager Format Examples
TITLE: 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.
• Each site specifies the values for each of these 16 filter criteria.
• To receive a given notice, it has to pass all 16 filtering tests.
• The default values for each filter are such so as to pass everything.
System
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Filtering (2of4) Examples:If you have a southern hemisphere telescope, you can restrict the Declinationto what you can observe: CEL_DEC_LIM -90 +30
If you wanted events ONLY in the Galactic Plane, then GAL_LAT_LIM -10.0 +10.0All of these filters specifications can be reversed (negated). The "!" character(as a suffix to the Token) is used to "reverse" the meaning of the filter range.If you want only things off the Plane (i.e. nothing in the Plane) GAL_LAT_LIM! -10.0 +10.0
If you only want items in the Galactic Bulge: GAL_LON_LIM 340.0 +20.0 GAL_LAT_LIM -20.0 +20.0
If you only want items in the LMC: CEL_RA_LIM 75.4 86.5 CEL_DEC_LIM -74 -64
System
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Filtering (3of4)• The next slide shows the complete set of filtering parameters. It also shows which parameters are global in their application and which are type-specific in their application.
• Global filter parameters apply to all Notice Types that the site has selected to be enabled.
• Type-specific filter parameters apply only to the Notice Type that they are attached to (see slide 7).
• 8 of the filter parameters are both global and type-specific. The type-specific value always overrides the global value.
System
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Filter Param Global
Type-specific
Range [units] Default Value
Notice_Type x x n/a all enabled
Error x x 0.0 - 360.0 [deg]
360.0
Time_delay x x 0.001 - 1e17 [hr] 1e17
Intensity x x <mixed units> <all>
Significance x x 0 - inf [sigma] 0
Confidence x x 0 - 100 [%] 0
Trigger_ID x x 0 or 1 0
Observability
x x All, Vis, Night All
Sun_distance x 0.0 - 360.0 [deg]
360.0
Sun_hr_angle x 0.0 - 12.0 [hr] 0
Moon_distance
x 0.0 - 360.0 [deg]
0
Moon_Illum x 0 - 100 [%] 100
Celestial_coords
x 0-360,-90-+90 [deg]
0-360,-90-+90
Galactic_coords
x 0-360,-90-+90 [deg]
0-360,-90-+90
Ecliptic_coords
x 0-360,-90-+90 [deg]
0-360,-90-+90
Time-o-Day_wind
x 00:00-24:00,00:00-24:00
0-24
Filtering (4of4)System
Strawman SONG Site Configuration• Map these functions to something suitable for SONG.
• Can be 1 entry (for the whole network of telescopes), or 2 (for N vs S hemisphere telescopes), or 8 individual entries.
• Choose such that you don’t get things that you have no chance of observing:• Types: The small-errorbox notices: Swift-XRT_Pos, Swift–UVOT_Pos, MOA.
– If allow tiling (say 2x2 or 3x3), then MAXI, INTEGRAL, Swift-BAT_Pos.– No problems for a mini-SONG configuration. These plus a few more.
• Sky Coverage: Dec band: -90 +30 (for South) and -30 +90 (North)• Intensity: Mag limit by type (based on SONG sensitivity and integration
time).• Observability: Night for short-lived transients; Visible for day-long
transients.• Delay: say 12 hours for the GRB types, and infinity for the grav lensing
types.• Some of these filter choices will depend on (a) how fast you can interrupt a
current observation and (b) how long you are willing to observe a given target.
• Of course, you can always do your own filtering. Open up all the filters, receive everything, and make your own filtering choices and observation decisions on a case-by-case basis.
• Distribution Method: Given the automated operations and the fast slewing, the socket method seems best.
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Sites.cfg File Format (1of2)
• The old format for the “sites.cfg” file was compact, but hard for a human to read (and to maintain).
• The new/current format is (see slide 14):– Very human-readable– Allows for easy growth and expansion; adding:• Type-specific filtering function specifications (see slide 11),
• More globally-applied filter function specifications,
• New Notice Types.
• Status: Running since May 2011.
SiteName -76.80 39.00 -1 360.1 48.0 C80 20E 3FEF FB71 0 0 0 0 0 0 0 f 0 207F 0 0 ALL FITS EMAIL [email protected] D C ; 25jun01 29jun09
An example of the new “configuration” formatis shown to the right. It contains all theinformation of the old format (shown on slide 13), plus it shows some of the new filtering functionsdescribed in slides 8-11.
There are 3 sections within each site’s configuration:a) The Administrative stuff about the site:b) Global filtering specifications,c) Notice Type specifications (with Type-specific filtering params)
System
Active GRB Notice Types (1of2)NAME RATE [/yr]
ERROR COMMENT
Swift_BAT_QL 90 3’ RA,Dec only; 3 sec before the BAT_Pos
Swift_BAT_Pos 90 3’ BAT Position (initial trigger for Swift NFIs).
Swift_BAT_Slew_Pos 4 4’ Off-line analysis to find burst during Swift slews.
Swift_BAT_Lightcurve 90 3’ Light curve
Swift_FOM 90 3’ What is the Figure-of-Merit for this trigger.
Swift_Slew 90 3’ Will the s/c slewing (or not) to this trigger.
Swift_XRT_Pos 80 5” XRT Position.
Swift_XRT_Pos_Nack 10 n/a XRT did not find a real-time position.
Swift_XRT_Image 90 n/a XRT Image used to find the position.
Swift_UVOT_SrcList 90 n/a UVOT Sources within an 8x8’ image.
POINTING DIRECTION: Follow along (be on target before/during T0).
Swift 27,000 n/a Fermi 9,000 n/a Every hour. INTEGRAL 100’s n/a Episodic. AGILE 9,000 n/a Every hour.TEST: Provide practice notices; exercise your
system. Swift-BAT, Fermi-GBM/-LAT
3000 , 3000 n/a
INTEGRAL-all, AGILE
1500 , 3000 n/a
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System
*
*
* SONG compatible: location uncertainty is less than SONG FoV. - mini-SONG compatible.
*-
**
Value-Added Services for Observers
• Temporal and Spatial coincidences between missions and instruments in real-time.– These appear in the “COMMENTS” field of the full-format email
notices.
• Galaxy associations (4875 nearby galaxies).– If it is in/near one of these galaxies, then a flag bit is set. (&
COMMENT in emails)
• SIMBAD & NED searches on all the small error box burst/transient position types. (This is a separate Notice Type)
• Sun & Moon distances and Moon phase.• Near-by bright stars (<6.5 mag, 9054 stars) within 12’.
• Galactic and Ecliptic coordinates.
COMMENTS: NOTE: This INTEGRAL event is temporally(21.0<100sec) coincident with the FERMI_GBM event (trignum=336710376).
Information calculated by GCN to aid follow-up observersin planning their observations:
System
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Near-by Galaxy Associations
• Full-format emails now contain a comment when the burst location overlaps a near-by galaxy.
• The NGC2000 catalog used to make the GCN-NGC catalog:– Only the 4875 galaxies that have sizes specified are included.
– Even though most are elliptical in shape, they are assumed to be circular when making the proximity comparison.
– All non-galaxy entries were eliminated (nebulae, clusters, etc):
• Since there is a <0.05% probability that this would happen by chance, the association of a given burst with the galaxy is almost certainly real.
• Two scenarios are tested and reported:
BAT Error CircleGalaxy
P1
P2
Galaxy (eg M31)Major Dia.
Bursts Position
Position circle smaller than GalaxyGalaxy smaller & inside Position Circle
System
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Bright Star Notification
• Full-format emails now contain a comment when there is a bright star near the burst location.– There are 9054 stars in the search dbase,– Brighter than 6.5 mag.– The proximity match must be closer than 12 arcmin (radius).
– Actual mag and actual distance to the burst location are also specified in the full-format email notice.
– Done for all burst/trans_position-containing Notice types.
• This helps follow-up observers to know when there will be a bright star complicating their observations.
System
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Recently Added Notice Types (1of2)
• Fermi-LAT_Monitor (26 Aug 11)– Flares from the 168 sources routinely monitored by LAT. About 25 per year. – 10-60 arcmin radius error circles (95% containment). Delays: 1 day to 1 week.
• Fermi-LAT_Transient (26 Aug 11)– Detections by LAT of previously unknown sources, specifically not GRBs). About 5-
10 per year.– 10-60 arcmin radius error circles (95% containment). Delays: 1 day to 1 week
• Fermi-LAT_Ground (02 Aug 11)– GRBs found during automated off-line ground processing. About 5 per year.– 10-60 arcmin radius error circles (95% containment). Delays: 6-24 hours.
• MOA Gravitational Lensing Events (01 Aug 11)– Alerts about upcoming gravitational lensing events from the MOA project. – About 2/3 are issued before the peak in the lensing lightcurve.– About 60/month. Quiescent mag: 14-22 (90 percentile). About 50% have a delta_mag
brightening of 2 or more.– Position errors less than 1 arcsec.
• Day-of-Week-Time-of-Day (13 Jun 11)– Receive a notice at specific time-of-day and on the days-of-the-week of your
choosing. It allows you to monitor your connectivity – especially useful for cellphone/pager recipients.
• Fermi-GBM_Final (07 Jun 11)– Humain-in-the-loop ground processing to improve the location determinations: 1-3°
stat + 3° sys.– Delays: 0.2-2 hours.– Issued for the 20% brightest GBM bursts (ie ~50 per year).
• MAXI_Known (12 Apr 11)– Detections of flares from previously known sources. ~52 per year.– Location errors: 30-60 arcmin (radius, stat+sys, 90% containment). Delays:
2-3 hours.
• INTEGRAL_Weak (24 Feb 11)– The regular threshold has been lowered from 8 to 6.5 sigma for these “weak”
triggers.– Location error is 4 arcmin radius.– These can be issued (a) just before the normal Wakeup/Update/Final sequence,
or (b) all by itself.
• Swift-BAT_Monitor (23 Feb 10)– Alerts the recipient of outbursts from any of the 741 sources routinely
monitored by BAT during the course of its hard x-ray survey.– The Notice contains: the Source_name, RA,Dec location, the Date/Time, the
Current and Baseline flux values, and the outburst increase in sigma units (ie significance).
• Swift-BAT_QuickLook (11 Jan 10)– Has only the RA,Dec,Time of the bursts and transients detected by BAT.– But it arrives 0-6 sec (ave=3.0 sec) sooner than the regular BAT_Position
Notice. This is suitable for robotic telescopes so they can be “on target” 0-6 sec sooner. (It is available only to socket-based sites; not to email-based sites -- 6 sec sooner for a human-read email is not worth the effort.)
System
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VOEvents (as of Apr 08)
• As part of the IVO Association and the VOEvent subgroup, GCN has implemented the VOEvent format (an XML-based format).
• It follows the VOEvent protocol and formats.– See http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/IvoaVOEvent
• VOEvents are being distributed for all the GCN Notice types.– They are available via the XML_SOCKET distribution method. The XML_SOCKET method is very similar to the original (binary) SOCKET distribution method.
– They are available via the EMAIL method, both as the body of the email or as an attachment.
• They are also forwarded to the Caltech/SkyAlert broker, which then distributes them to interested parties.
• In the near future (few months), the GCN VOEvents will be distributed directly by a GCN VOEvent server/broker (next slide).
GCN Outside the Box• GCN is going outside the Goddard firewall.• Goddard’s firewall rules preclude operation of a true
server, i.e. an unknown (outside) client initiating a connection to a server inside Goddard. (HEASARC is the only exception & GCN will not be given a similar exception.)
• To overcome that prohibition, I am working on establishing a true server operation outside of Goddard. Work has begun using the Atlantic Net cloud service provider.
• Both the original 160-byte binary socket packet format and the VOEvent XML socket message format are being supported. (appropriate socket_demo programs will be provided)
• Both the original (current) GCN and the outside GCN will be operated in parallel (i.e. no need to migrate if you don’t want to).
• The next slide shows the existing GCN operation (black text) and the future new GCN operation (blue text).
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System
Architecture: Current & Future
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Import
Filter &Distribute
160B binarysocket packetVOEvent
XML Socket
email
SwiftFermiINTEGRALMAXIAGILEMOAothers
sitesconfigs
OutsideGCN
(AtlanticCloud) VOEvent XML
socket server
160B packet socket server
GSFC
Firewall
world
world
world
world
world
System
Some contributors use socket connection to GCN, some use email method to get their data to GCN.
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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 Type 65 sent (SWIFT_FOM_2OBSAT) out of 1 1 Type 66 sent (SWIFT_FOSC_2OBSAT) out of 1 1 Type 67 sent (SWIFT_XRT_POSITION) out of 1 0 Type 68 sent (SWIFT_XRT_SPECTRUM) out of 2 1 Type 69 sent (SWIFT_XRT_IMAGE) out of 1 1 Type 70 sent (SWIFT_XRT_LC) out of 1 0 Type 71 sent (SWIFT_XRT_CENTROID) out of 0 1 Type 72 sent (SWIFT_UVOT_DBURST) out of 1 1 Type 73 sent (SWIFT_UVOT_FCHART) out of 1 0 Type 74 sent (SWIFT_FULL_DATA_INIT) out of 0 0 Type 75 sent (SWIFT_FULL_DATA_UPDATE) out of 0 0 Type 76 sent (SWIFT_BAT_GRB_LC_PROC) out of 0 0 Type 77 sent (SWIFT_XRT_SPECTRUM_PROC) out of 2 0 Type 78 sent (SWIFT_XRT_IMAGE_PROC) out of 1 0 Type 79 sent (SWIFT_UVOT_DBURST_PROC) out of 1 0 Type 80 sent (SWIFT_UVOT_FCHART_PROC) out of 1 0 Type 81 sent (SWIFT_UVOT_POS) out of 0 0 Type 82 sent (SWIFT_BAT_GRB_POS_TEST) out of 8 62 Type 83 sent (SWIFT_POINTDIR) out of 62 0 Type 84 sent (SWIFT_BAT_TRANS) out of 0 0 Were received back with some sort of error.
//////////// RECORD OF PROGRAM OPERATIONS /////////////////////05/12/10 19:26:30.472 GMT: Starting gromain.
//////////// RECORD OF SOCKET OPERATIONS //////////////////////05/12/10 19:25:10.983 GMT: Attempting to send KILL packet to XYZ...05/12/10 19:25:11.093 GMT: The shutdown of XYZ worked OK.05/12/10 19:26:31.263 GMT: Client socket to xyz.univ.edu XYZ is up.
//////////// RECORD OF PACKET ERRORS //////////////////////////There were no packet errors today.
System
Helps you monitor andmanage your GCN operation.
There is also a similar versionfor the email-based clients.
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Daily Report: (2of2) Histo of Roundtrip Times:
All Packets
//////////// HISTOGRAMS OF ROUNDTRIP TIMES ////////////////////Attached below are histograms of the roundtrip travel timesof the packets between the GCN system (capella) and SLOTISthat were received back in the proper order & with valid contents.The range of the histos is from 0.00sec to 100sec with0.25sec per bin resolution. Underflows (there should not be any)and overflows are also tabulated.The 6 histos are for the 4 packet type subclasses (0,1,2,3): 0) All_Position_Notices+INTEGRAL_Test (that pass your filter criteria), 1) All_Non-Pos_Swift_Notices. 2) All_Test_Notices(Type=2&44) (if enabled), 3) Type=Imalives (1440+-few per 24 hrs). 4) Type=<all_types>, 5) Type=<all_types_from_all_sites>.
Header[5]: Roundtrip of All pkt Types for all sites for 12/10 UT
• GCN is always looking for new Notice Types to add. Let GCN distribute your timely data to others in the world so they can make timely follow-up observations of your targets.• GCN has 500+ customers ready to accept your
transients. Many robotic operations are looking for other targets in between GRBs.
• GCN is not just GRBs – it is all transient phenomena (ie TAN = Transient Astronomy Network).
• GCN wants to do: SN, Novae, CV, optical transients (known & unknown). All wave-bands and all particles.
• Please contact me to discuss setting up your Notice Type within GCN/TAN:• [email protected]• +1 301-286-3106
• People wishing to receive GCN Notices can read about the basic information needed to set up a new site at: http://gcn.gsfc.nasa.gov/invitation.html Then go to: http://gcn.gsfc.nasa.gov/config_builder.html– And then select “1” (create a new
site).
• Existing sites can use the same webpage to:– Modify their existing configurations
(select “2”).– Request a copy of your configuration
be emailed to you (select “3”),• You can also find out about signing
GCN SONG (1of2)• SONG is an extensive network of robotic telescopes that can make follow-up observations of the GRB &Transients distributed by GCN.– Notified in 1-15 minutes of the GRB/Transients. Mini-SONG in 10-30 sec.
• SONG has some time in between its stellar oscillation observations to make rapid-response follow-up observations:– Gap-less coverage with the full network; better than space-based coverage because no Earth occultations. (Fill in that first-orbit gap.)
– GRB afterglow detection: Swift-XRT_Position, -UVOT_Position; and MAXI-Unknown/-Known, Swift-BAT_Position, INTEGRAL if willing to do 2x2 or 3x3 tiling.• Check against catalogs (DSS) for the “new” source; revisits are necessary to detect fading if no prior identification (w/in a few hours is sufficient if early in the lightcurve).
– Spectroscopy might also be possible; UVOT accuracy is sub-arcsec, about half your slit width. (Lines; or at least L cut-off for z ~ 3.5 - 5.5.)
– MOA Gravitational lensing events (well suited since half of your telescopes are southern hemisphere)
• Just slip the GCN Notices into your observing queue(s).30
UVOT V MagGRB Afterglows
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12.7
17.8
26 GRB Lightcurves
79 GRB Mags at T<500sec, 37%
And there are few notables:990123 peaked at 9 mag,080319B peaked at 5.8 mag.
V Mag
Oates,MNRAS,2009
Roming,ApJ,2009
XRT Positions available in 70-120 sec (90%), UVOT in 100-400 sec.
MOA Events• 2/3 are available before the peak in the lightcurve.
• 50% have a delta_mag brightening of 2 mags.
• Mean baseline mag is 18.
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GCN SONG (2of2)• GCN provides software (both 160 byte packet & VOEvent XML).– Use the code directly in your control, or as examples of code segments you can paste into your control program.
– Or you can use the email-based method if you prefer.
• Let GCN know of any new data type you would like to see.– I can arrange with that source provider to get it incorporated into GCN.• Then you have to maintain only one interface.
– And chances are other GCN customers would also like to subscribe.
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SONG GCN• And the direction of information flow can be reversed.• SONG has a large amount of time coverage.• SONG can make discoveries of GRB afterglows and Transients.
• These discoveries can be fed back into GCN for distribution:– GCN/COUNTERPART for the GRB afterglows, & also the Circulars.– New GCN Notices; call them “SONG_Trans”, for the Transients.– New Gravitation micro-lensing events (separate from MOA and OGLE); call them “SONG_Lens” notices.
– GCN offers ability to send internal Notices only to SONG Team members.
– GCN offers SONG to control who can receive Notices (ie partial public).
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Typical Process for Setting up a Feed into GCN
• Decide on what product(s) and contents.• Decide on import method into GCN: socket or email.• Decide on format (and fine tune the contents).• Get both ends coded up.• Run some test/fake message into GCN.• Distribute only to me & SONG Team members.• I make up GCN/SONG webpage, archive page, and Announcement.
– Comments from you, iterate, and ultimate final approval from you.
• Run some real SONG message (full end-to-end test).• Send out Announcement to GCN customer list.• Add SONG Notice types to those customers that want them.• We’re running SONG --> GCN --> the world.
Summary• GCN has the data types SONG & mini-SONG needs to increase its science productivity.
• GCN has the methods to get it to you quickly.
• And GCN can receive anything you might produce and distribute it to the world.
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BACKUP and DUP SLIDES
Circulars• Observations and results from follow-up observers.
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TITLE: GCN CIRCULARNUMBER: 12284SUBJECT: GRB 110818A: Optical afterglow and redshift from VLT/X-shooterDATE: 11/08/19 07:49:47 GMTFROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <[email protected]>
P. D'Avanzo (INAF/Brera), M. Sparre, D. Watson, J. P. U. Fynbo, D. Malesani, B. Milvang-Jensen (DARK/NBI), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), V. D'Elia (INAF/Rome), and N. R. Tanvir (U. Leicester), report on behalf of the X-shooter GTO GRB collaboration:
We observed the field of GRB 110818A (Markwardt et al. GCN 12279) with the ESO VLT equipped with X-shooter. Observations started on 2011-08-19 at 02:47 UT (6.15 hr after the GRB).
The acquisition image shows an optical afterglow candidate inside the XRT error circle (Markwardt et al. GCN 12279) at the following coordinates (J2000): RA = 21:09:21.04 Dec = -63:58:52.3with an uncertainty of about 0.5". The object has a magnitude R ~ 22.3, calibrated assuming R = 19.2 for the USNO-B1 star 0260-0726657(RA, Dec = 21:09:23.14, -63:58:33.0).
A total spectroscopic exposure of 4x1200 s was obtained, covering the spectral range from 300 to 2500 nm.
We report a redshift of z = 3.36 based on detection of absorption features from Si II, C IV, Al II, Ca H, Ca K and Mg I. Emission from the [O III] doublet is also observed.
We would like to thank the staff at the VLT, in particular, Alain Smette,Patricia Guajardo and Dimitri Gadotti for carrying out the observations.
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REPORTS• Are more detailed than the Circulars.• Are more complete; more accurate.• 295 GRBs have these Reports (all of them Swift so far) (as of
14Sep11)– “Initial” available in 24-36 hours (Discontinued by the Swift Team).– “Final” available after the last of the XRT/UVOT follow-ups. (days-weeks)
• Encourage non-Swift observers to submit Reports.
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New Notice Types• The following new Notice Types will be added to the GCN system. Discussions and/or work has begun with all these sources of transient events:
• KAIT, PTF, PIOTS, OGLE, <sn>, <cv>
Near-TermFuture New
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Swift Data Products• BAT: Position and Lightcurve 15-30 sec
• XRT: Position (or nack) and Image (2x2’)80-120– Spectrum and Lightcurves on the web page
• UVOT: Image and SourceList 300-400– 200 sec V band, 2.7x2.7’ and 8x8’– Raw and Processed forms
• S/C Observe and Slew (or not) 15-30• S/C Pointing Direction (so you can follow along)
• Test
• Circulars on each burst:– 1st has BAT/XRT/UVOT initial findings & interpretation.– 2nd has “refined” results & analysis by each instrument.
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XRT Images (2x2’)
CosmicRay
GRB050421
GRB 051227GRB 060105
PSF=7.6 pixHPD
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Raw UVOT Image & Source List
2.7x2.7 arcmin 8x8 arcmin
Raw = no coordinates, no catalog matching
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Processed UVOT Image & Source List
sw00173904_0274uvot_field_image.ps.gz10-100 sec after the raw versions.
BAT Er
ror Ci
rcle,
90+% C
L
2.7x2.7 arcmin 8x8 arcmin
UVOT Source ListUVOT Image
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Swift GRBs Web Table
Archive of the Notices.Get plots of lightcurves & spectra, images (GIF, JPEG, PDF, PS).Get the FITS files.
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The “Tables” pageon the GCN web site.These are all thearchives of the activeand discontinuedmissions.
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Auto-Processed Lightcurves• These “auto-processed” are different than the real-
time TDRSS lightcurves. The use the full data set. They have the full ground-analysis applied.
• BAT, XRT, & UVOT lightcurves– BAT: Mask-weighted (background subtracted)– XRT & UVOT: On-going afterglow– Automatically processed and updated as more data is downlinked.
– Available in plot-form and in text-form.– Suitable for inclusion into your papers.
