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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 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  2. Swift XRT on-board boresight update
  3. GRB 061121: ATCA & WSRT Radio Observations
  4. GRB061121: optical observations
  5. GRB 061126: Early Super-LOTIS Observations
  6. GRB 061126: optical observation
  7. RHESSI Spectrum of GRB061126
  8. GRB 061126: Tautenburg afterglow observations
  9. GRB061126: Optical afterglow observations from MIRO
  10. GRB061126: Optical afterglow observations from MIRO
  11. GRB 061126 : SDSS Pre-Burst Observations
  12. GRB 061126: Swift-XRT refined analysis
  13. GRB 061126: Swift/UVOT Observations
  14. GRB 061126, Swift-BAT refined analysis
  15. GRB 061126: SARA Observations
  16. GRB 061126: Early Detection of the IR Afterglow
  17. GRB 061126: Faulkes Telescope North Optical Observations
  18. GRB 061126: Swift/UVOT Afterglow Detection
  19. GRB 061126: XRT position
  20. GRB 061126: Swift detection of a burst
  21. GRB 061121: MDM Continued Monitoring
  22. GRB 061122: Confirmation of X-ray/Optical Afterglow
  23. GRB 061121: MDM Continuing Optical Decay
  24. GRB061121: optical observations
  25. GRB 061122: Candidate Optical Afterglow
  26. GRB 061121: Ep,i - Eiso correlation
  27. GRB 061121: MDM Optical Decay
  28. GRB061122: Swift/UVOT Optical Observations
  29. GRB 061121: ART detection in Ic
  30. GRB061121: P60 Observations
  31. Radio detection of GRB 061121
  32. GRB061122: Swift-XRT position
  33. Konus-Wind observation of GRB 061122
  34. GRB 061121: MDM Optical Observations
  35. GRB 061121 declared "Burst of Interest" by Swift team
  36. RHESSI Spectrum of GRB061121
  37. Konus-Wind and Konus-A observations of GRB 061121
  38. INTEGRAL results on GRB 061122
  39. Swift-BAT trigger 239987 is not a GRB
  40. GRB 061122A: a long GRB detected by INTEGRAL
  41. GRB 061121: Swift/UVOT Observations
  42. GRB 061121: Swift-XRT Team Refined Analysis
  43. GRB 061121, Swift-BAT refined analysis
  44. GRB061121, optical observation
  45. GRB 061121 : Planned XMM-Newton observation
  46. GRB 061121: Optical observation at the KANATA 1.5m telescope
  47. GRB 061121: Faulkes Telescope North Optical Observation
  48. GRB061121: Spectroscopic Redshift
  49. GRB061121: Keck spectroscopic observations
  50. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  51. GRB 061121: Swift detection of a bright burst with an optical counterpart
  52. GRB 060605: NIR Observations
  53. GRB 050915B: optical afterglow
  54. GRB 060111B: Swift UVOT Refined Magnitudes
  55. Swift-BAT triggers 238544 and 238546 are not GRBs
  56. GRB061110A: Correction to GCN5817
  57. GRB 061110A: refined R-band analysis
  58. GRB 061110B: NIR Observations
  59. Swift TOO observations of GRB061110A
  60. Swift/UVOT Upper Limits for GRB061110b
  61. Swift/UVOT Upper Limits for GRB061110a
  62. GRB 061110A - VLT tentative redshift
  63. GRB 061110B: Swift XRT refined analysis
  64. GRB 061110B, Swift-BAT refined analysis
  65. GRB 061110B: VLT redshift
  66. GRB061110B: Optical observations at Crni Vrh
  67. GRB 061110B: NOT optical observations
  68. GRB 061110A: Swift XRT refined analysis
  69. GRB 061110B: Swift/XRT position
  70. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  71. GRB 061110B: Swift-UVOT Initial Observation
  72. GRB 061110A, Swift-BAT refined analysis
  73. GRB 061110B: TAROT Calern observatory optical observations
  74. GRB 061110B: Swift detection of a burst
  75. GRB 061110: NOT observations
  76. GRB 061110: Candidate confirmed
  77. GRB 061110 : Optical afterglow candidate
  78. GRB 061110: ROTSE-III Optical Limits
  79. GRB 061110: Swift detection of a burst
  80. GRB061110A - Optical Non-detection
  81. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  82. GRB 061109: optical observation
  83. GRB 061109: TAROT Calern observatory optical observations
  84. GRB 061109: Swift detection of a possible burst
  85. GRB061028: MAGIC telescope GeV observation
  86. GRB 061027: TAROT La Silla observatory optical observations
  87. GRB 061007: Third Epoch ATCA Radio Observations
  88. GRB061019: second epoch CrAO observations
  89. GRB 061028: Swift/XRT Astrometry Correction
  90. GRB 061102: Swift/UVOT Magnitude Upper Limits
  91. GRB 061102, XRT refined analysis
  92. GRB 061004: Further VLT/NTT observations
  93. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  94. GRB061102B: Super-LOTIS observations
  95. GRB 061028: Optical R passband observations
  96. GRB 061102B: Swift detection of a possible burst
  97. GRB 061102, Swift-BAT refined analysis
  98. GRB 061102: Swift detection of a burst
  99. GRB 061028: VLA Observation
  100. GRB 061004: Swift/XRT Astrometry Correction

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