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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. GRB111022B: D50 optical limit
  2. GRB 111020A: Chandra Observation
  3. GRB 111022B: BTA Optical Observations
  4. GRB 111022A: MITSuME Akeno Optical upper limits
  5. GRB 111024A: MAXI/GSC detection of a burst
  6. GRB 111022B: Swift/UVOT upper limits
  7. GRB 111022A: Swift/UVOT Upper Limits
  8. GRB 111016A: optical upper limit
  9. GRB 111022B, Swift-BAT refined analysis
  10. GRB 111022B: Swift-XRT refined Analysis
  11. GRB 111022A: RIzY Observation
  12. GRB 111022A: Swift-XRT refined Analysis
  13. GRB 111022B: Gemini infrared observations
  14. GRB 111022B: MITSuME Akeno Optical upper limits
  15. GRB 111022B: NOT observations
  16. GRB 111022B: Enhanced Swift-XRT position
  17. GRB 111020A Spectral lag analysis
  18. GRB 111022A: Swift-BAT refined analysis
  19. GRB 111022B: MASTER-Net early limit
  20. GRB 111022A: Preliminary UVOT TDRSS Non-Detection
  21. GRB 111022A: MASTER-Net early limit
  22. GRB 111022B: Swift detection of a burst
  23. GRB 111022A: Swift detection of a burst
  24. GRB 111020A: Gemini-South additional observations and limit on an optical afterglow
  25. GRB 111020A: EVLA observations
  26. GRB 111020A: Swift-XRT refined Analysis
  27. GRB 111020A: Gemini-South i-band observations
  28. GRB 111020A: Swift/UVOT Upper Limits
  29. GRB 111020A: Faulkes Telescope South observations
  30. GRB 111020A: Swift-BAT refined analysis
  31. GRB 111020A: Enhanced Swift-XRT position
  32. GRB 111020A: BOOTES-3 Optical Upper Limit.
  33. GRB 111020A: Planned XMM-Newton observation
  34. GRB 111020A: Swift detection of a short burst
  35. GRB 111018A: Swift/UVOT Upper Limits
  36. GRB 110918A: Optical light curve for days 1.4 to 16.3
  37. GRB 111018A: Swift-BAT refined analysis
  38. Konus-Wind observation of GRB 111016B
  39. GRB 111018A: Swift-XRT refined Analysis
  40. GRB 111018A: GROND Upper Limits
  41. GRB 111018A: Enhanced Swift-XRT position
  42. IPN Triangulation of GRB 111016B (long duration, intense)
  43. GRB111016A : WIYN 3.5m NIR observations
  44. GRB 111018A: Swift detection of a burst
  45. GRB 111017A: Fermi GBM Detection
  46. GRB111016A: D50 optical limit
  47. GRB 111016A: Gemini Detection of the NIR Counterpart
  48. GRB 111016A: Swift/UVOT Detection of a Source
  49. GRB 111016A: Swift-BAT refined analysis
  50. GRB 111016A: P60 Afterglow Candidate
  51. GRB 111016A: MITSuME Akeno Optical upper limits
  52. GRB 111016A: Swift-XRT refined Analysis
  53. GRB 111016A: Enhanced Swift-XRT position
  54. GRB 111016A: Swift-XRT observations
  55. GRB 111016A: Swift detection of a burst
  56. GRB 110921A: optical observations
  57. GRB 111008A : miniTAO/ANIR NIR observations
  58. EVLA 22 GHz Detection of GRB 111008A
  59. GRB 111005A: ATCA 18 GHz decay
  60. GRB 111008A: Swift/UVOT Upper Limits
  61. Konus-Wind observation of GRB 111008A
  62. GRB 111008A: IAC80 I-band observations
  63. GRB 111008A: VLT/X-shooter spectroscopy
  64. GRB 111008A: Swift-XRT refined Analysis
  65. GRB 111008A: Gemini spectroscopic redshift
  66. GRB 111008A, GROND observations
  67. GRB 111008A: NOT optical observation
  68. GRB 111008A: Gemini optical counterpart
  69. GRB 111008A: Enhanced Swift-XRT position
  70. GRB 111008A, Swift-BAT refined analysis,
  71. GRB 111008A: Swift detection of a burst
  72. GRB 111005A: ATCA 18 GHz detection
  73. GRB 111005A: ATCA radio upper limit
  74. GRB 111005A : miniTAO/ANIR NIR observations
  75. GRB 111005A: EVLA Observations
  76. GRB 111005A: VLT optical observations
  77. GRB 111005A: GROND NIR observations
  78. GRB 111005A: VLT IR observations
  79. GRB 111005A: Swift-BAT refined analysis
  80. GRB 111005A: bright galaxy in error circle
  81. GRB 111005A: Swift detection of a burst
  82. GRB 111003A: Fermi GBM detection
  83. GRB 110905A / MAXI J1836-194: optical monitoring
  84. GRB 110921A: MITSuME-Akeno Optical photometry
  85. Skynet/Dolomiti observations of GRB 110928A
  86. Skynet observations of GRB 110928A
  87. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  88. GRB 110928A: Swift/UVOT Upper Limits
  89. Trigger 504307: Swift detection of MAXI J1836-194
  90. GRB 110928A: Swift-XRT refined Analysis
  91. GRB 110825A: GROND Observations
  92. GRB 110928A: Enhanced Swift-XRT position
  93. GRB 110928A: P60 Observations
  94. GRB 110928A: Further PAIRITEL NIR Observations
  95. GRB 110928A: Swift-BAT refined analysis
  96. GRB 110928A: Swift-XRT observations
  97. GRB 110928A: Swift/UVOT finding chart observation
  98. GRB 110928A: PAIRITEL NIR Observations
  99. GRB 110928A: ROTSE-III Optical Limits
  100. GRB 110928A: Swift detection of a burst

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