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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. Radio detection of GRB 061121
  2. GRB061122: Swift-XRT position
  3. Konus-Wind observation of GRB 061122
  4. GRB 061121: MDM Optical Observations
  5. GRB 061121 declared "Burst of Interest" by Swift team
  6. RHESSI Spectrum of GRB061121
  7. Konus-Wind and Konus-A observations of GRB 061121
  8. INTEGRAL results on GRB 061122
  9. Swift-BAT trigger 239987 is not a GRB
  10. GRB 061122A: a long GRB detected by INTEGRAL
  11. GRB 061121: Swift/UVOT Observations
  12. GRB 061121: Swift-XRT Team Refined Analysis
  13. GRB 061121, Swift-BAT refined analysis
  14. GRB061121, optical observation
  15. GRB 061121 : Planned XMM-Newton observation
  16. GRB 061121: Optical observation at the KANATA 1.5m telescope
  17. GRB 061121: Faulkes Telescope North Optical Observation
  18. GRB061121: Spectroscopic Redshift
  19. GRB061121: Keck spectroscopic observations
  20. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  21. GRB 061121: Swift detection of a bright burst with an optical counterpart
  22. GRB 060605: NIR Observations
  23. GRB 050915B: optical afterglow
  24. GRB 060111B: Swift UVOT Refined Magnitudes
  25. Swift-BAT triggers 238544 and 238546 are not GRBs
  26. GRB061110A: Correction to GCN5817
  27. GRB 061110A: refined R-band analysis
  28. GRB 061110B: NIR Observations
  29. Swift TOO observations of GRB061110A
  30. Swift/UVOT Upper Limits for GRB061110b
  31. Swift/UVOT Upper Limits for GRB061110a
  32. GRB 061110A - VLT tentative redshift
  33. GRB 061110B: Swift XRT refined analysis
  34. GRB 061110B, Swift-BAT refined analysis
  35. GRB 061110B: VLT redshift
  36. GRB061110B: Optical observations at Crni Vrh
  37. GRB 061110B: NOT optical observations
  38. GRB 061110A: Swift XRT refined analysis
  39. GRB 061110B: Swift/XRT position
  40. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  41. GRB 061110B: Swift-UVOT Initial Observation
  42. GRB 061110A, Swift-BAT refined analysis
  43. GRB 061110B: TAROT Calern observatory optical observations
  44. GRB 061110B: Swift detection of a burst
  45. GRB 061110: NOT observations
  46. GRB 061110: Candidate confirmed
  47. GRB 061110 : Optical afterglow candidate
  48. GRB 061110: ROTSE-III Optical Limits
  49. GRB 061110: Swift detection of a burst
  50. GRB061110A - Optical Non-detection
  51. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  52. GRB 061109: optical observation
  53. GRB 061109: TAROT Calern observatory optical observations
  54. GRB 061109: Swift detection of a possible burst
  55. GRB061028: MAGIC telescope GeV observation
  56. GRB 061027: TAROT La Silla observatory optical observations
  57. GRB 061007: Third Epoch ATCA Radio Observations
  58. GRB061019: second epoch CrAO observations
  59. GRB 061028: Swift/XRT Astrometry Correction
  60. GRB 061102: Swift/UVOT Magnitude Upper Limits
  61. GRB 061102, XRT refined analysis
  62. GRB 061004: Further VLT/NTT observations
  63. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  64. GRB061102B: Super-LOTIS observations
  65. GRB 061028: Optical R passband observations
  66. GRB 061102B: Swift detection of a possible burst
  67. GRB 061102, Swift-BAT refined analysis
  68. GRB 061102: Swift detection of a burst
  69. GRB 061028: VLA Observation
  70. GRB 061004: Swift/XRT Astrometry Correction
  71. GRB 060801: Swift/XRT Astrometry Correction
  72. GRB 061028: Futher P200 Observations
  73. GRB 061028: MDM Observations
  74. GRB 061028: P200 Observations
  75. GRB 061028: SARA upper limit
  76. GRB 061028: z band imaging
  77. GRB061028: XRT refined analysis
  78. GRB 061028: Swift/UVOT Observations
  79. GRB 061028, Swift-BAT refined analysis
  80. GRB 061028: TAROT Calern observatory late optical observations
  81. GRB 061028: TAROT Calern observatory optical observations
  82. GRB 061028: Swift detection of a burst
  83. GRB 061027, Swift refined analysis of a possible burst
  84. GRB 061027: Swift detection of a possible burst
  85. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  86. GRB061025: Swift XRT refined analysis
  87. GRB061025: Swift/UVOT observations
  88. GRB 061019: MITSuME upper limits
  89. GRB 061025: REM observations
  90. GRB 061025: Gemini-S observations
  91. GRB061025: Swift XRT position
  92. GRB 061025: ROTSE-III Optical Limits
  93. GRB 061025: a long GRB detected by INTEGRAL
  94. Swift XRT boresight update
  95. GRB 061021, Swift-BAT Lag analysis
  96. Konus-Wind observation of GRB 061021
  97. GRB 061021 - VLT spectrum without lines
  98. GRB 061021: Swift-XRT refined analysis
  99. GRB 061021: Swift/UVOT Observation
  100. GRB 061021, Swift-BAT refined analysis

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