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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"

24385 results found.

  1. GRB 061214(?): ROTSE-III Optical Limits
  2. GRB 061210: Suzaku WAM observation of the prompt emission
  3. Swift/BAT trigger #250033 is due to a known source during loss of
  4. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  5. GRB 061213: MASTER-VWF-Kislovodsk observations
  6. GRB 061210: Gemini/GMOS Observations
  7. GRB 061210, Swift-BAT refined analysis of the SHB
  8. Optical Afterglow observations of GRB 061126
  9. GRB 060926: MASTER: discovery of the optical flare
  10. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  11. GRB 061201: SOAR Confirmation of Candidate Afterglow
  12. GRB 061202: Swift XRT refined analysis
  13. Konus-Wind observation of GRB 061201
  14. GRB061202: optical/NIR observations with REM
  15. GRB061202: Swift/UVOT Upper Limits
  16. GRB 061202, Swift-BAT refined analysis
  17. GRB 061201: Swift XRT Team refined analysis
  18. GRB 061201, Swift-BAT refined analysis of the SHB
  19. GRB 061121, SMARTS optical/IR observations
  20. GRB061121: optical observations
  21. GRB 061126: optical observation
  22. RHESSI Spectrum of GRB061126
  23. GRB 061126: Swift/UVOT Observations
  24. GRB 061126, Swift-BAT refined analysis
  25. GRB 061126: SARA Observations
  26. GRB 061126: Faulkes Telescope North Optical Observations
  27. GRB 061121: MDM Continued Monitoring
  28. GRB 061121: MDM Continuing Optical Decay
  29. GRB061121: optical observations
  30. GRB 061122: Candidate Optical Afterglow
  31. GRB 061121: MDM Optical Decay
  32. GRB061122: Swift/UVOT Optical Observations
  33. Konus-Wind observation of GRB 061122
  34. GRB 061121: MDM Optical Observations
  35. RHESSI Spectrum of GRB061121
  36. INTEGRAL results on GRB 061122
  37. GRB 061122A: a long GRB detected by INTEGRAL
  38. GRB 061121: Swift/UVOT Observations
  39. GRB 061121, Swift-BAT refined analysis
  40. GRB061121, optical observation
  41. GRB 061121: Optical observation at the KANATA 1.5m telescope
  42. GRB 061121: Faulkes Telescope North Optical Observation
  43. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  44. GRB 050915B: optical afterglow
  45. GRB 060111B: Swift UVOT Refined Magnitudes
  46. Swift/UVOT Upper Limits for GRB061110b
  47. Swift/UVOT Upper Limits for GRB061110a
  48. GRB 061110A - VLT tentative redshift
  49. GRB 061110B, Swift-BAT refined analysis
  50. GRB 061110A: Swift XRT refined analysis
  51. GRB 061110B: Swift/XRT position
  52. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  53. GRB 061110A, Swift-BAT refined analysis
  54. GRB 061110: ROTSE-III Optical Limits
  55. GRB 061109: optical observation
  56. GRB061028: MAGIC telescope GeV observation
  57. GRB 061028: Swift/XRT Astrometry Correction
  58. GRB 061004: Further VLT/NTT observations
  59. GRB 061028: Optical R passband observations
  60. GRB 061102B: Swift detection of a possible burst
  61. GRB 061102, Swift-BAT refined analysis
  62. GRB 061004: Swift/XRT Astrometry Correction
  63. GRB 060801: Swift/XRT Astrometry Correction
  64. GRB 061028, Swift-BAT refined analysis
  65. GRB 061027, Swift refined analysis of a possible burst
  66. GRB061025: Swift/UVOT observations
  67. GRB 061025: ROTSE-III Optical Limits
  68. GRB 061025: a long GRB detected by INTEGRAL
  69. Swift XRT boresight update
  70. GRB 061021 - VLT spectrum without lines
  71. GRB 061021: Swift/UVOT Observation
  72. GRB 061021, Swift-BAT refined analysis
  73. GRB060904b: optical observations
  74. GRB061019: optical observations
  75. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  76. GRB 061019: SMARTS afterglow confirmation
  77. GRB061019: Swift XRT refined analysis
  78. GRB 061019, Swift-BAT refined analysis
  79. GRB061019: Swift/XRT position
  80. GRB 060825: GORT Observations
  81. GRB 061007: RHESSI Spectral Fit
  82. GRB 061007: Suzaku/WAM observation of the prompt emission
  83. Konus-Wind observation of GRB 061007
  84. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  85. GRB061007: Swift UVOT followup observations
  86. GRB 061006 : Suzaku/WAM observation of the prompt emission
  87. GRB 061007: Swift-BAT refined analysis
  88. GRB 061006: Swift/UVOT optical observations
  89. GRB 061007 - FTS early brightening and power law decay
  90. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  91. GRB 061007: ROTSE-III Detection of Optical Counterpart
  92. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  93. GRB 061006: Swift-XRT Team Refined Analysis
  94. GRB 060930: near-IR afterglow candidate retraction
  95. GRB 061004: Swift-XRT Team Refined Analysis
  96. GRB 061004, Swift BAT refined analysis
  97. Konus-Wind observation of GRB 060928
  98. GRB 060928: Suzaku/WAM observation of the prompt emission
  99. GRB 060928: Swift observations
  100. GRB 060928: RHESSI Spectral Fit

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