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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. GRB 061217: Swift detection of a short hard burst
  2. GRB 061210: MDM Follow-up Observation
  3. GRB061210: Swift/UVOT observations
  4. Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
  5. GRB 061210: Optical sources near XRT positions
  6. GRB 061210: Swift XRT analysis - Possible counterparts
  7. GRB 061210 : Faulkes North Telescope optical limit
  8. GRB 061214(?): ROTSE-III Optical Limits
  9. GRB 061214(?): Swift detection of a possible burst
  10. GRB 061210: Suzaku WAM observation of the prompt emission
  11. Swift/BAT trigger #250033 is due to a known source during loss of
  12. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  13. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  14. GRB 061213: MASTER-VWF-Kislovodsk observations
  15. GRB 061210: Gemini/GMOS Observations
  16. GRB 061126: Radio Observations
  17. GRB061210: Radio Observations
  18. GRB061201, VLT optical decay: correction
  19. GRB 061126: a GRB detected off-axis by INTEGRAL
  20. GRB 061202: Suzaku WAM observation of the prompt emission
  21. GRB 061210: MDM Observation
  22. GRB 061210, Swift-BAT refined analysis of the SHB
  23. GRB 061210: Swift-BAT detection of a short burst
  24. Optical Afterglow observations of GRB 061126
  25. GRB061126: optical observations
  26. GRB 060926: MASTER: discovery of the optical flare
  27. GRB061126: update on the Swift-XRT afterglow light curve
  28. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  29. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  30. GRB 061202: TORTOREM optical upper limits
  31. GRB 061201: VLT optical decay
  32. GRB 061201: SOAR Confirmation of Candidate Afterglow
  33. GRB061126 : NMSU 1.0m observations
  34. GRB 061202: Swift XRT refined analysis
  35. GRB061202: FRAM early follow-up limit
  36. GRB061202 optical limit by "Pi of the Sky"
  37. Konus-Wind observation of GRB 061201
  38. GRB061202: optical/NIR observations with REM
  39. GRB061202: Swift/UVOT Upper Limits
  40. GRB 061202, Swift-BAT refined analysis
  41. GRB 061202: Swift detection of a burst
  42. GRB 061201: Swift XRT Team refined analysis
  43. GRB 061201: VLT optical observations
  44. GRB 061201: Initial UVOT Observations
  45. GRB 061201, Swift-BAT refined analysis of the SHB
  46. GRB 061201: Swift detection of a short hard burst
  47. GRB 061201: Coincidence with a Galaxy Cluster
  48. GRB 061122: GETS observation
  49. GRB 061121, SMARTS optical/IR observations
  50. GRB 061121: flattening of the decay
  51. INT+WFC observations of GRB 061126
  52. GRB 061126: Possible Jet Break
  53. GRB 061121: Second Epoch ATCA Radio Observations
  54. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  55. Swift XRT on-board boresight update
  56. GRB 061121: ATCA & WSRT Radio Observations
  57. GRB061121: optical observations
  58. GRB 061126: Early Super-LOTIS Observations
  59. GRB 061126: optical observation
  60. RHESSI Spectrum of GRB061126
  61. GRB 061126: Tautenburg afterglow observations
  62. GRB061126: Optical afterglow observations from MIRO
  63. GRB061126: Optical afterglow observations from MIRO
  64. GRB 061126 : SDSS Pre-Burst Observations
  65. GRB 061126: Swift-XRT refined analysis
  66. GRB 061126: Swift/UVOT Observations
  67. GRB 061126, Swift-BAT refined analysis
  68. GRB 061126: SARA Observations
  69. GRB 061126: Early Detection of the IR Afterglow
  70. GRB 061126: Faulkes Telescope North Optical Observations
  71. GRB 061126: Swift/UVOT Afterglow Detection
  72. GRB 061126: XRT position
  73. GRB 061126: Swift detection of a burst
  74. GRB 061121: MDM Continued Monitoring
  75. GRB 061122: Confirmation of X-ray/Optical Afterglow
  76. GRB 061121: MDM Continuing Optical Decay
  77. GRB061121: optical observations
  78. GRB 061122: Candidate Optical Afterglow
  79. GRB 061121: Ep,i - Eiso correlation
  80. GRB 061121: MDM Optical Decay
  81. GRB061122: Swift/UVOT Optical Observations
  82. GRB 061121: ART detection in Ic
  83. GRB061121: P60 Observations
  84. Radio detection of GRB 061121
  85. GRB061122: Swift-XRT position
  86. Konus-Wind observation of GRB 061122
  87. GRB 061121: MDM Optical Observations
  88. GRB 061121 declared "Burst of Interest" by Swift team
  89. RHESSI Spectrum of GRB061121
  90. Konus-Wind and Konus-A observations of GRB 061121
  91. INTEGRAL results on GRB 061122
  92. Swift-BAT trigger 239987 is not a GRB
  93. GRB 061122A: a long GRB detected by INTEGRAL
  94. GRB 061121: Swift/UVOT Observations
  95. GRB 061121: Swift-XRT Team Refined Analysis
  96. GRB 061121, Swift-BAT refined analysis
  97. GRB061121, optical observation
  98. GRB 061121 : Planned XMM-Newton observation
  99. GRB 061121: Optical observation at the KANATA 1.5m telescope
  100. GRB 061121: Faulkes Telescope North Optical Observation

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