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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 061214(?): ROTSE-III Optical Limits
  2. GRB 061214(?): Swift detection of a possible burst
  3. GRB 061210: Suzaku WAM observation of the prompt emission
  4. Swift/BAT trigger #250033 is due to a known source during loss of
  5. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  6. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  7. GRB 061213: MASTER-VWF-Kislovodsk observations
  8. GRB 061210: Gemini/GMOS Observations
  9. GRB 061126: Radio Observations
  10. GRB061210: Radio Observations
  11. GRB061201, VLT optical decay: correction
  12. GRB 061126: a GRB detected off-axis by INTEGRAL
  13. GRB 061202: Suzaku WAM observation of the prompt emission
  14. GRB 061210: MDM Observation
  15. GRB 061210, Swift-BAT refined analysis of the SHB
  16. GRB 061210: Swift-BAT detection of a short burst
  17. Optical Afterglow observations of GRB 061126
  18. GRB061126: optical observations
  19. GRB 060926: MASTER: discovery of the optical flare
  20. GRB061126: update on the Swift-XRT afterglow light curve
  21. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  22. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  23. GRB 061202: TORTOREM optical upper limits
  24. GRB 061201: VLT optical decay
  25. GRB 061201: SOAR Confirmation of Candidate Afterglow
  26. GRB061126 : NMSU 1.0m observations
  27. GRB 061202: Swift XRT refined analysis
  28. GRB061202: FRAM early follow-up limit
  29. GRB061202 optical limit by "Pi of the Sky"
  30. Konus-Wind observation of GRB 061201
  31. GRB061202: optical/NIR observations with REM
  32. GRB061202: Swift/UVOT Upper Limits
  33. GRB 061202, Swift-BAT refined analysis
  34. GRB 061202: Swift detection of a burst
  35. GRB 061201: Swift XRT Team refined analysis
  36. GRB 061201: VLT optical observations
  37. GRB 061201: Initial UVOT Observations
  38. GRB 061201, Swift-BAT refined analysis of the SHB
  39. GRB 061201: Swift detection of a short hard burst
  40. GRB 061201: Coincidence with a Galaxy Cluster
  41. GRB 061122: GETS observation
  42. GRB 061121, SMARTS optical/IR observations
  43. GRB 061121: flattening of the decay
  44. INT+WFC observations of GRB 061126
  45. GRB 061126: Possible Jet Break
  46. GRB 061121: Second Epoch ATCA Radio Observations
  47. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  48. Swift XRT on-board boresight update
  49. GRB 061121: ATCA & WSRT Radio Observations
  50. GRB061121: optical observations
  51. GRB 061126: Early Super-LOTIS Observations
  52. GRB 061126: optical observation
  53. RHESSI Spectrum of GRB061126
  54. GRB 061126: Tautenburg afterglow observations
  55. GRB061126: Optical afterglow observations from MIRO
  56. GRB061126: Optical afterglow observations from MIRO
  57. GRB 061126 : SDSS Pre-Burst Observations
  58. GRB 061126: Swift-XRT refined analysis
  59. GRB 061126: Swift/UVOT Observations
  60. GRB 061126, Swift-BAT refined analysis
  61. GRB 061126: SARA Observations
  62. GRB 061126: Early Detection of the IR Afterglow
  63. GRB 061126: Faulkes Telescope North Optical Observations
  64. GRB 061126: Swift/UVOT Afterglow Detection
  65. GRB 061126: XRT position
  66. GRB 061126: Swift detection of a burst
  67. GRB 061121: MDM Continued Monitoring
  68. GRB 061122: Confirmation of X-ray/Optical Afterglow
  69. GRB 061121: MDM Continuing Optical Decay
  70. GRB061121: optical observations
  71. GRB 061122: Candidate Optical Afterglow
  72. GRB 061121: Ep,i - Eiso correlation
  73. GRB 061121: MDM Optical Decay
  74. GRB061122: Swift/UVOT Optical Observations
  75. GRB 061121: ART detection in Ic
  76. GRB061121: P60 Observations
  77. Radio detection of GRB 061121
  78. GRB061122: Swift-XRT position
  79. Konus-Wind observation of GRB 061122
  80. GRB 061121: MDM Optical Observations
  81. GRB 061121 declared "Burst of Interest" by Swift team
  82. RHESSI Spectrum of GRB061121
  83. Konus-Wind and Konus-A observations of GRB 061121
  84. INTEGRAL results on GRB 061122
  85. Swift-BAT trigger 239987 is not a GRB
  86. GRB 061122A: a long GRB detected by INTEGRAL
  87. GRB 061121: Swift/UVOT Observations
  88. GRB 061121: Swift-XRT Team Refined Analysis
  89. GRB 061121, Swift-BAT refined analysis
  90. GRB061121, optical observation
  91. GRB 061121 : Planned XMM-Newton observation
  92. GRB 061121: Optical observation at the KANATA 1.5m telescope
  93. GRB 061121: Faulkes Telescope North Optical Observation
  94. GRB061121: Spectroscopic Redshift
  95. GRB061121: Keck spectroscopic observations
  96. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  97. GRB 061121: Swift detection of a bright burst with an optical counterpart
  98. GRB 060605: NIR Observations
  99. GRB 050915B: optical afterglow
  100. GRB 060111B: Swift UVOT Refined Magnitudes

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