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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: optical observations
  2. GRB 060121: Infrared Observations
  3. GRB 060121: optical observations
  4. GRB 060121: Optical imaging
  5. GRB060121 - SDSS pre-burst observations
  6. GRB 060121: A short-hard GRB in a cluster?
  7. GRB 060121 (=H4010): Results of preliminary spectral analysis
  8. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  9. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  10. HETE Alert 4006: MASTER promt optical limit
  11. GRB 060117: PROMPT Observations
  12. GRB060117 - ATCA 3/6cm radio limits - correction
  13. GRB060117 - ATCA 3/6cm radio limits
  14. GRB 060116: photometric redshift - the farthest GRB?
  15. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  16. Correction to GCN 4542 on GRB 060117
  17. Konus-Wind observation of GRB 060117
  18. GRB 060116: possible I-J dropout
  19. GRB 060116: UKIRT IR Observations
  20. GRB060108: photometric redshift determination
  21. GRB 060117: Refined analysis of the Swift-BAT burst
  22. GRB 060116: PROMPT Observations
  23. GRB 060117: FRAM refined analysis
  24. GRB 060117: FRAM optical afterglow candidate
  25. GRB 060117: nearby galaxy
  26. GRB 060117: Swift-BAT detection of a bright burst
  27. GRB 060116: VLT optical observations
  28. GRB 060116: Refined analysis of the Swift-BAT burst
  29. GRB 060115: PROMPT Observations
  30. GRB 060116: XRT refined analysis
  31. GRB 060116: IR Candidate Afterglow
  32. GRB 060116: Swift/UVOT upper limits
  33. GRB060115: REM observations
  34. GRB 060110: XRT position and analysis
  35. GRB 060116 : Lulin optical limit
  36. GRB 060116: ROTSE-III Optical Limits
  37. GRB060116: XRT position
  38. GRB060116: Faulkes North observation
  39. GRB 060115: absorption redshift
  40. GRB 060116: Swift-BAT detection of a burst
  41. GRB 060115: Refined analysis of the Swift-BAT burst
  42. GRB 060115: OT photometry with MITSuME
  43. GRB 060115: Swift/UVOT upper limits
  44. GRB 060114: REM observations
  45. GRB 060115: Swift XRT refined analysis
  46. GRB 060115: OT finding chart
  47. GRB 060114: Swift/UVOT Observations
  48. GRB060115, optical observation
  49. GRB 060115: MITSuME optical afterglow candidate
  50. GRB 060115: Swift detection of a burst
  51. GRB 060114: Swift XRT upper limit
  52. GRB060114, optical observation
  53. GRB 060114: refined position
  54. GRB 060114: A long GRB detected by INTEGRAL
  55. GRB060114: Faulkes North observation
  56. GRB 060108: IR observations of afterglow
  57. GRB060108: Faulkes North afterglow evidence
  58. GRB 060108: further analysis of VLT images
  59. GRB 060108: Evidence for an XRT Position Offset
  60. GRB 060110: KAIT observations
  61. GRB 060111B: Swift XRT refined analysis
  62. GRB 060111A: refined UVOT anaysis
  63. GRB 060111B: MITSuME detection of optical afterglow
  64. GRB 060111B: TAROT optical observation
  65. GRB060111A: RTT150 optical observations
  66. GRB060111B: RTT150, possible host galaxy
  67. GRB 060111B: Refined analysis of the Swift-BAT burst
  68. GRB 060110: MARGE observations
  69. GRB 060111(a): P60 Observations
  70. GRB 060111B: Gualba observatory limit
  71. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  72. GRB 060111B: Swift detection of a burst
  73. GRB 060111: Swift-BAT Refined Analysis
  74. GRB060111.2:_MASTER optical limit
  75. GRB 060108: VLT K-band observations
  76. GRB 060111: TAROT optical observation
  77. GRB 060111: possible UVOT counterpart
  78. GRB060111 : XRT refined analysis
  79. GRB 060111: ROTSE-III Optical Limits
  80. GRB 060111: Swift detection of a burst
  81. GRB 060110: Mitsume optical observations
  82. GRB 060110: Swift-BAT refined analysis
  83. GRB 060109: Swift-BAT refined analysis
  84. GRB 060108: z-band imaging from Gemini-North
  85. GRB 060110a: RAPTOR detection of early optical emission.
  86. GRB 060110: UKIRT K-band observations
  87. GRB 060110: ROTSE-III Confirmation of Optical Counterpart
  88. GRB 060110: IR Candidate Afterglow
  89. GRB060110, optical observation
  90. GRB 060110: Super-LOTIS observations
  91. GRB 060110: Optical observation
  92. GRB 060110: Correction
  93. Correction to GRB 060109 XRT analysis
  94. GRB 050110: IR Observations
  95. GRB 060110: Optical limit
  96. GRB 060110: Swift-BAT detection of a burst
  97. GRB 060109: Refined Swift-XRT analysis
  98. GRB 060109: Swift/UVOT upper limits
  99. GRB060109, optical observation
  100. GRB 060108: ISAS early observations and near IR upper limit

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