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

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