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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 061121: ATCA & WSRT Radio Observations
  2. GRB061121: optical observations
  3. GRB 061126: Early Super-LOTIS Observations
  4. GRB 061126: optical observation
  5. RHESSI Spectrum of GRB061126
  6. GRB 061126: Tautenburg afterglow observations
  7. GRB061126: Optical afterglow observations from MIRO
  8. GRB061126: Optical afterglow observations from MIRO
  9. GRB 061126 : SDSS Pre-Burst Observations
  10. GRB 061126: Swift-XRT refined analysis
  11. GRB 061126: Swift/UVOT Observations
  12. GRB 061126, Swift-BAT refined analysis
  13. GRB 061126: SARA Observations
  14. GRB 061126: Early Detection of the IR Afterglow
  15. GRB 061126: Faulkes Telescope North Optical Observations
  16. GRB 061126: Swift/UVOT Afterglow Detection
  17. GRB 061126: XRT position
  18. GRB 061126: Swift detection of a burst
  19. GRB 061121: MDM Continued Monitoring
  20. GRB 061122: Confirmation of X-ray/Optical Afterglow
  21. GRB 061121: MDM Continuing Optical Decay
  22. GRB061121: optical observations
  23. GRB 061122: Candidate Optical Afterglow
  24. GRB 061121: Ep,i - Eiso correlation
  25. GRB 061121: MDM Optical Decay
  26. GRB061122: Swift/UVOT Optical Observations
  27. GRB 061121: ART detection in Ic
  28. GRB061121: P60 Observations
  29. Radio detection of GRB 061121
  30. GRB061122: Swift-XRT position
  31. Konus-Wind observation of GRB 061122
  32. GRB 061121: MDM Optical Observations
  33. GRB 061121 declared "Burst of Interest" by Swift team
  34. RHESSI Spectrum of GRB061121
  35. Konus-Wind and Konus-A observations of GRB 061121
  36. INTEGRAL results on GRB 061122
  37. Swift-BAT trigger 239987 is not a GRB
  38. GRB 061122A: a long GRB detected by INTEGRAL
  39. GRB 061121: Swift/UVOT Observations
  40. GRB 061121: Swift-XRT Team Refined Analysis
  41. GRB 061121, Swift-BAT refined analysis
  42. GRB061121, optical observation
  43. GRB 061121 : Planned XMM-Newton observation
  44. GRB 061121: Optical observation at the KANATA 1.5m telescope
  45. GRB 061121: Faulkes Telescope North Optical Observation
  46. GRB061121: Spectroscopic Redshift
  47. GRB061121: Keck spectroscopic observations
  48. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  49. GRB 061121: Swift detection of a bright burst with an optical counterpart
  50. GRB 060605: NIR Observations
  51. GRB 050915B: optical afterglow
  52. GRB 060111B: Swift UVOT Refined Magnitudes
  53. Swift-BAT triggers 238544 and 238546 are not GRBs
  54. GRB061110A: Correction to GCN5817
  55. GRB 061110A: refined R-band analysis
  56. GRB 061110B: NIR Observations
  57. Swift TOO observations of GRB061110A
  58. Swift/UVOT Upper Limits for GRB061110b
  59. Swift/UVOT Upper Limits for GRB061110a
  60. GRB 061110A - VLT tentative redshift
  61. GRB 061110B: Swift XRT refined analysis
  62. GRB 061110B, Swift-BAT refined analysis
  63. GRB 061110B: VLT redshift
  64. GRB061110B: Optical observations at Crni Vrh
  65. GRB 061110B: NOT optical observations
  66. GRB 061110A: Swift XRT refined analysis
  67. GRB 061110B: Swift/XRT position
  68. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  69. GRB 061110B: Swift-UVOT Initial Observation
  70. GRB 061110A, Swift-BAT refined analysis
  71. GRB 061110B: TAROT Calern observatory optical observations
  72. GRB 061110B: Swift detection of a burst
  73. GRB 061110: NOT observations
  74. GRB 061110: Candidate confirmed
  75. GRB 061110 : Optical afterglow candidate
  76. GRB 061110: ROTSE-III Optical Limits
  77. GRB 061110: Swift detection of a burst
  78. GRB061110A - Optical Non-detection
  79. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  80. GRB 061109: optical observation
  81. GRB 061109: TAROT Calern observatory optical observations
  82. GRB 061109: Swift detection of a possible burst
  83. GRB061028: MAGIC telescope GeV observation
  84. GRB 061027: TAROT La Silla observatory optical observations
  85. GRB 061007: Third Epoch ATCA Radio Observations
  86. GRB061019: second epoch CrAO observations
  87. GRB 061028: Swift/XRT Astrometry Correction
  88. GRB 061102: Swift/UVOT Magnitude Upper Limits
  89. GRB 061102, XRT refined analysis
  90. GRB 061004: Further VLT/NTT observations
  91. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  92. GRB061102B: Super-LOTIS observations
  93. GRB 061028: Optical R passband observations
  94. GRB 061102B: Swift detection of a possible burst
  95. GRB 061102, Swift-BAT refined analysis
  96. GRB 061102: Swift detection of a burst
  97. GRB 061028: VLA Observation
  98. GRB 061004: Swift/XRT Astrometry Correction
  99. GRB 060801: Swift/XRT Astrometry Correction
  100. GRB 061028: Futher P200 Observations

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