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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. Trigger 779762: Swift detection of Vela X-1
  2. Trigger 779351: Swift detection of Swift J0243.6+6124
  3. Search for counterpart to IceCube-171015A with ANTARES
  4. INTEGRAL SPI-ACS observation of IceCube-171015A
  5. Swift trigger 779171 is probably a noise fluctuation
  6. IceCube-171015A - IceCube observation of a high-energy neutrino candidate event
  7. GRB 171010A: VLA Observations
  8. GRB 171010A: VLA Detection
  9. GRB 171010A: A detection of a radio source by AMI
  10. GRB 171010A : Optical observations from HCT
  11. GRB 171010A: RATIR Optical and NIR Observations
  12. BAT trigger 778435 is not a GRB.
  13. GRB 171010B: Swift-XRT observations
  14. GRB 171013A: TAROT Calern observatory optical observations
  15. GRB 171013A: Swift detection of a possible burst
  16. GRB 171011A: Swift-BAT refined analysis
  17. Konus-Wind observation of GRB 171011B
  18. GRB 171010A: Swift/UVOT Detection
  19. Konus-Wind observation of GRB 171010A
  20. GRB 171010A: ePESSTO NTT spectroscopic redshift
  21. GRB 171010A: MITSuME Akeno Optical Observation
  22. GRB 171010A: NOT optical observations
  23. GRB 171010B: Fermi GBM detection
  24. IPN Triangulation of GRB 171011B (long/very bright)
  25. GRB 171010B: Swift ToO observations
  26. GRB 171011A: TAROT Calern observatory optical observations
  27. GRB 171010B: Swift detection of a burst
  28. GRB 171011A: MASTER-SAAO optical observations
  29. GRB 171011A: Swift detection of a burst
  30. GRB 171010A: Fermi GBM observation
  31. GRB 171010A: LCO 1m telescope observations
  32. GRB171010A: AstroSat CZTI detection
  33. GRB 171010A: Swift-XRT afterglow detection
  34. GRB 171010A: optical observations
  35. GRB 171010A: OT, spectrum, and possible host galaxy
  36. GRB 171010A: Swift ToO observations
  37. GRB 171010A: Fermi-LAT detection
  38. GRB 171007A: Swift/UVOT Upper Limits
  39. LIGO/Virgo G298048/GW170817: updated localization from parameter estimation
  40. LIGO/Virgo G298048: Mid-Infrared Spitzer/IRAC Observations at 3.6 and 4.5 microns
  41. GRB 171007A: Swift-BAT refined analysis
  42. GRB 171007A: Fermi GBM observation
  43. GRB 171007A: Enhanced Swift-XRT position
  44. GRB 171007A: Swift-XRT refined Analysis
  45. GRB 171007A: RATIR Optical and NIR Observations
  46. GRB 171007A: Swift detection of a burst
  47. LIGO/Virgo G298048: LWA radio observations
  48. GRB 171004A: Swift/UVOT Upper Limits
  49. GRB 171004A: Swift-BAT refined analysis
  50. GRB 171004A: Correction to RATIR Astrometry and Photometry
  51. GRB 171004A: Swift-XRT refined Analysis
  52. GRB 171004A: Enhanced Swift-XRT position
  53. LIGO/Virgo G299232: SWASP optical imaging coverage
  54. GRB 171004A: RATIR Optical and NIR Observations
  55. GRB 170710A: LCO Observations
  56. GRB 171004A: Swift detection of a burst
  57. GRB 171003A: Enhanced Swift-XRT position
  58. LIGO/Virgo G299232: MAGIC Cherenkov Telescopes observations
  59. Swift Trigger 775946 is a Galactic transient, not GRB 171003
  60. LIGO/Virgo G299232: LOFAR follow-up
  61. GRB 171003A: LT early optical observations
  62. GRB 171003A: Swift detection of a burst or a Galactic Transient
  63. GRB 171001A: RATIR Optical and NIR Observations
  64. GRB 171001A: Swift-BAT refined analysis
  65. GRB 171001A: Nanshan-0.36m optical afterglow detections
  66. GRB 171001A: Swift-XRT refined Analysis
  67. GRB 171001A: Swift/UVOT Detection
  68. GRB 171001A: IRSF Observation
  69. GRB171001A: D50 optical limit
  70. GRB 171001A: Enhanced Swift-XRT position
  71. GRB 170921A: 15 GHz upper limits from AMI
  72. GRB 170903A: 15 GHz upper limits from AMI
  73. GRB 170906C: 15 GHz upper limits from AMI
  74. GRB 170823A: 15 GHz upper limits from AMI
  75. GRB 170822A: 15 GHz upper limits from AMI
  76. GRB 171001A: Swift detection of a burst
  77. LIGO/VIRGO G299232: AMI-LA Observations of the optical transient Swift J014008.5+343403.6
  78. Fermi Gamma-ray Burst Monitor trigger 528508320/170930994 is not a GRB
  79. Fermi Gamma-ray Burst Monitor trigger 528330888/170929011 is not a GRB
  80. 3.6m Devasthal Optical Telescope observations of GRB 170428A
  81. Further Swift-XRT observations of IceCube 170922A
  82. LIGO/Virgo G298048: Record of all e-MERLIN results to date on SSS17a
  83. LIGO/Virgo G298048: Further European VLBI Network (EVN) observations of SSS17a
  84. LIGO/Virgo G299232/GW170825: serendipitous XMM-Newton slew observations
  85. LIGO/Virgo G298936/GW170823: serendipitous XMM-Newton slew observations
  86. Fermi-GBM GRB misclassifications
  87. LIGO/VIRGO G298048: VLA detection of the radio counterpart at 6 GHz
  88. LIGO/Virgo G297595/GW170814: updated localization from parameter estimation
  89. LIGO/VIRGO G298048: Further MeerKAT observations of SSS17a
  90. GRB 170728B: Kottamia R-band observation
  91. LIGO/Virgo G298048: Summary of Pi of the Sky observations
  92. IceCube-170922A: Swift-XRT observations
  93. LIGO/VIRGO G298048: Latest 3 GHz Detection of Radio Counterpart to SSS17a
  94. LIGO/Virgo G298048: Limits from further FRB searches of SSS17a
  95. LIGO/Virgo G298048: MWA Observations of Error Region
  96. Konus-Wind observation of GRB 170921B
  97. Correction to GCN Circular 21919: GRB 170921C: Insight-HXMT detection
  98. IceCube-170922A: HAWC follow-up
  99. Search for counterpart to IceCube-170922A with ANTARES
  100. GRB 170921B: AstroSat CZTI detection

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