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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 061202: TORTOREM optical upper limits
  2. GRB 061201: VLT optical decay
  3. GRB 061201: SOAR Confirmation of Candidate Afterglow
  4. GRB061126 : NMSU 1.0m observations
  5. GRB 061202: Swift XRT refined analysis
  6. GRB061202: FRAM early follow-up limit
  7. GRB061202 optical limit by "Pi of the Sky"
  8. Konus-Wind observation of GRB 061201
  9. GRB061202: optical/NIR observations with REM
  10. GRB061202: Swift/UVOT Upper Limits
  11. GRB 061202, Swift-BAT refined analysis
  12. GRB 061202: Swift detection of a burst
  13. GRB 061201: Swift XRT Team refined analysis
  14. GRB 061201: VLT optical observations
  15. GRB 061201: Initial UVOT Observations
  16. GRB 061201, Swift-BAT refined analysis of the SHB
  17. GRB 061201: Swift detection of a short hard burst
  18. GRB 061201: Coincidence with a Galaxy Cluster
  19. GRB 061122: GETS observation
  20. GRB 061121, SMARTS optical/IR observations
  21. GRB 061121: flattening of the decay
  22. INT+WFC observations of GRB 061126
  23. GRB 061126: Possible Jet Break
  24. GRB 061121: Second Epoch ATCA Radio Observations
  25. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  26. Swift XRT on-board boresight update
  27. GRB 061121: ATCA & WSRT Radio Observations
  28. GRB061121: optical observations
  29. GRB 061126: Early Super-LOTIS Observations
  30. GRB 061126: optical observation
  31. RHESSI Spectrum of GRB061126
  32. GRB 061126: Tautenburg afterglow observations
  33. GRB061126: Optical afterglow observations from MIRO
  34. GRB061126: Optical afterglow observations from MIRO
  35. GRB 061126 : SDSS Pre-Burst Observations
  36. GRB 061126: Swift-XRT refined analysis
  37. GRB 061126: Swift/UVOT Observations
  38. GRB 061126, Swift-BAT refined analysis
  39. GRB 061126: SARA Observations
  40. GRB 061126: Early Detection of the IR Afterglow
  41. GRB 061126: Faulkes Telescope North Optical Observations
  42. GRB 061126: Swift/UVOT Afterglow Detection
  43. GRB 061126: XRT position
  44. GRB 061126: Swift detection of a burst
  45. GRB 061121: MDM Continued Monitoring
  46. GRB 061122: Confirmation of X-ray/Optical Afterglow
  47. GRB 061121: MDM Continuing Optical Decay
  48. GRB061121: optical observations
  49. GRB 061122: Candidate Optical Afterglow
  50. GRB 061121: Ep,i - Eiso correlation
  51. GRB 061121: MDM Optical Decay
  52. GRB061122: Swift/UVOT Optical Observations
  53. GRB 061121: ART detection in Ic
  54. GRB061121: P60 Observations
  55. Radio detection of GRB 061121
  56. GRB061122: Swift-XRT position
  57. Konus-Wind observation of GRB 061122
  58. GRB 061121: MDM Optical Observations
  59. GRB 061121 declared "Burst of Interest" by Swift team
  60. RHESSI Spectrum of GRB061121
  61. Konus-Wind and Konus-A observations of GRB 061121
  62. INTEGRAL results on GRB 061122
  63. Swift-BAT trigger 239987 is not a GRB
  64. GRB 061122A: a long GRB detected by INTEGRAL
  65. GRB 061121: Swift/UVOT Observations
  66. GRB 061121: Swift-XRT Team Refined Analysis
  67. GRB 061121, Swift-BAT refined analysis
  68. GRB061121, optical observation
  69. GRB 061121 : Planned XMM-Newton observation
  70. GRB 061121: Optical observation at the KANATA 1.5m telescope
  71. GRB 061121: Faulkes Telescope North Optical Observation
  72. GRB061121: Spectroscopic Redshift
  73. GRB061121: Keck spectroscopic observations
  74. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  75. GRB 061121: Swift detection of a bright burst with an optical counterpart
  76. GRB 060605: NIR Observations
  77. GRB 050915B: optical afterglow
  78. GRB 060111B: Swift UVOT Refined Magnitudes
  79. Swift-BAT triggers 238544 and 238546 are not GRBs
  80. GRB061110A: Correction to GCN5817
  81. GRB 061110A: refined R-band analysis
  82. GRB 061110B: NIR Observations
  83. Swift TOO observations of GRB061110A
  84. Swift/UVOT Upper Limits for GRB061110b
  85. Swift/UVOT Upper Limits for GRB061110a
  86. GRB 061110A - VLT tentative redshift
  87. GRB 061110B: Swift XRT refined analysis
  88. GRB 061110B, Swift-BAT refined analysis
  89. GRB 061110B: VLT redshift
  90. GRB061110B: Optical observations at Crni Vrh
  91. GRB 061110B: NOT optical observations
  92. GRB 061110A: Swift XRT refined analysis
  93. GRB 061110B: Swift/XRT position
  94. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  95. GRB 061110B: Swift-UVOT Initial Observation
  96. GRB 061110A, Swift-BAT refined analysis
  97. GRB 061110B: TAROT Calern observatory optical observations
  98. GRB 061110B: Swift detection of a burst
  99. GRB 061110: NOT observations
  100. GRB 061110: Candidate confirmed

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