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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 060121: Swift/UVOT upper limits
  2. GRB 060121: Liverpool Telescopes optical limits
  3. GRB 060121: Swift XRT refined analysis
  4. Konus-Wind observation of GRB 060121
  5. GRB 060121: I-band Limits
  6. GRB 060121: Confirmation of Afterglow
  7. GRB 060121: candidate optical counterpart
  8. GRB 060121: Swift XRT refined position
  9. GRB060121: SARA Observations
  10. GRB 060121: optical observations
  11. GRB 060121: Infrared Observations
  12. GRB 060121: optical observations
  13. GRB 060121: Optical imaging
  14. GRB060121 - SDSS pre-burst observations
  15. GRB 060121: A short-hard GRB in a cluster?
  16. GRB 060121 (=H4010): Results of preliminary spectral analysis
  17. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  18. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  19. HETE Alert 4006: MASTER promt optical limit
  20. GRB 060117: PROMPT Observations
  21. GRB060117 - ATCA 3/6cm radio limits - correction
  22. GRB060117 - ATCA 3/6cm radio limits
  23. GRB 060116: photometric redshift - the farthest GRB?
  24. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  25. Correction to GCN 4542 on GRB 060117
  26. Konus-Wind observation of GRB 060117
  27. GRB 060116: possible I-J dropout
  28. GRB 060116: UKIRT IR Observations
  29. GRB060108: photometric redshift determination
  30. GRB 060117: Refined analysis of the Swift-BAT burst
  31. GRB 060116: PROMPT Observations
  32. GRB 060117: FRAM refined analysis
  33. GRB 060117: FRAM optical afterglow candidate
  34. GRB 060117: nearby galaxy
  35. GRB 060117: Swift-BAT detection of a bright burst
  36. GRB 060116: VLT optical observations
  37. GRB 060116: Refined analysis of the Swift-BAT burst
  38. GRB 060115: PROMPT Observations
  39. GRB 060116: XRT refined analysis
  40. GRB 060116: IR Candidate Afterglow
  41. GRB 060116: Swift/UVOT upper limits
  42. GRB060115: REM observations
  43. GRB 060110: XRT position and analysis
  44. GRB 060116 : Lulin optical limit
  45. GRB 060116: ROTSE-III Optical Limits
  46. GRB060116: XRT position
  47. GRB060116: Faulkes North observation
  48. GRB 060115: absorption redshift
  49. GRB 060116: Swift-BAT detection of a burst
  50. GRB 060115: Refined analysis of the Swift-BAT burst
  51. GRB 060115: OT photometry with MITSuME
  52. GRB 060115: Swift/UVOT upper limits
  53. GRB 060114: REM observations
  54. GRB 060115: Swift XRT refined analysis
  55. GRB 060115: OT finding chart
  56. GRB 060114: Swift/UVOT Observations
  57. GRB060115, optical observation
  58. GRB 060115: MITSuME optical afterglow candidate
  59. GRB 060115: Swift detection of a burst
  60. GRB 060114: Swift XRT upper limit
  61. GRB060114, optical observation
  62. GRB 060114: refined position
  63. GRB 060114: A long GRB detected by INTEGRAL
  64. GRB060114: Faulkes North observation
  65. GRB 060108: IR observations of afterglow
  66. GRB060108: Faulkes North afterglow evidence
  67. GRB 060108: further analysis of VLT images
  68. GRB 060108: Evidence for an XRT Position Offset
  69. GRB 060110: KAIT observations
  70. GRB 060111B: Swift XRT refined analysis
  71. GRB 060111A: refined UVOT anaysis
  72. GRB 060111B: MITSuME detection of optical afterglow
  73. GRB 060111B: TAROT optical observation
  74. GRB060111A: RTT150 optical observations
  75. GRB060111B: RTT150, possible host galaxy
  76. GRB 060111B: Refined analysis of the Swift-BAT burst
  77. GRB 060110: MARGE observations
  78. GRB 060111(a): P60 Observations
  79. GRB 060111B: Gualba observatory limit
  80. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  81. GRB 060111B: Swift detection of a burst
  82. GRB 060111: Swift-BAT Refined Analysis
  83. GRB060111.2:_MASTER optical limit
  84. GRB 060108: VLT K-band observations
  85. GRB 060111: TAROT optical observation
  86. GRB 060111: possible UVOT counterpart
  87. GRB060111 : XRT refined analysis
  88. GRB 060111: ROTSE-III Optical Limits
  89. GRB 060111: Swift detection of a burst
  90. GRB 060110: Mitsume optical observations
  91. GRB 060110: Swift-BAT refined analysis
  92. GRB 060109: Swift-BAT refined analysis
  93. GRB 060108: z-band imaging from Gemini-North
  94. GRB 060110a: RAPTOR detection of early optical emission.
  95. GRB 060110: UKIRT K-band observations
  96. GRB 060110: ROTSE-III Confirmation of Optical Counterpart
  97. GRB 060110: IR Candidate Afterglow
  98. GRB060110, optical observation
  99. GRB 060110: Super-LOTIS observations
  100. GRB 060110: Optical observation

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