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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').
  1. GRB 060124: XRT position
  2. GRB 060124: Optical Afterglow Candidate from Tautenburg
  3. GRB060124, optical observation
  4. GRB 050124 : Kiso Optical limit
  5. GRB 060124: Optical Observations at Tautenburg
  6. GRB 060117: Suzaku WAM observation of the prompt emission
  7. GRB060124:MASTER optical observation
  8. GRB 060111B: Suzaku WAM observation of the prompt emission
  9. GRB 060124: Swift-BAT detection of a burst
  10. GRB 060116: Radio Detection
  11. GRB 060116: MARGE optical observations
  12. GRB 060121: Swift/UVOT upper limits
  13. GRB 060121: Liverpool Telescopes optical limits
  14. GRB 060121: Swift XRT refined analysis
  15. Konus-Wind observation of GRB 060121
  16. GRB 060121: I-band Limits
  17. GRB 060121: Confirmation of Afterglow
  18. GRB 060121: candidate optical counterpart
  19. GRB 060121: Swift XRT refined position
  20. GRB060121: SARA Observations
  21. GRB 060121: optical observations
  22. GRB 060121: Infrared Observations
  23. GRB 060121: optical observations
  24. GRB 060121: Optical imaging
  25. GRB060121 - SDSS pre-burst observations
  26. GRB 060121: A short-hard GRB in a cluster?
  27. GRB 060121 (=H4010): Results of preliminary spectral analysis
  28. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  29. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  30. HETE Alert 4006: MASTER promt optical limit
  31. GRB 060117: PROMPT Observations
  32. GRB060117 - ATCA 3/6cm radio limits - correction
  33. GRB060117 - ATCA 3/6cm radio limits
  34. GRB 060116: photometric redshift - the farthest GRB?
  35. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  36. Correction to GCN 4542 on GRB 060117
  37. Konus-Wind observation of GRB 060117
  38. GRB 060116: possible I-J dropout
  39. GRB 060116: UKIRT IR Observations
  40. GRB060108: photometric redshift determination
  41. GRB 060117: Refined analysis of the Swift-BAT burst
  42. GRB 060116: PROMPT Observations
  43. GRB 060117: FRAM refined analysis
  44. GRB 060117: FRAM optical afterglow candidate
  45. GRB 060117: nearby galaxy
  46. GRB 060117: Swift-BAT detection of a bright burst
  47. GRB 060116: VLT optical observations
  48. GRB 060116: Refined analysis of the Swift-BAT burst
  49. GRB 060115: PROMPT Observations
  50. GRB 060116: XRT refined analysis
  51. GRB 060116: IR Candidate Afterglow
  52. GRB 060116: Swift/UVOT upper limits
  53. GRB060115: REM observations
  54. GRB 060110: XRT position and analysis
  55. GRB 060116 : Lulin optical limit
  56. GRB 060116: ROTSE-III Optical Limits
  57. GRB060116: XRT position
  58. GRB060116: Faulkes North observation
  59. GRB 060115: absorption redshift
  60. GRB 060116: Swift-BAT detection of a burst
  61. GRB 060115: Refined analysis of the Swift-BAT burst
  62. GRB 060115: OT photometry with MITSuME
  63. GRB 060115: Swift/UVOT upper limits
  64. GRB 060114: REM observations
  65. GRB 060115: Swift XRT refined analysis
  66. GRB 060115: OT finding chart
  67. GRB 060114: Swift/UVOT Observations
  68. GRB060115, optical observation
  69. GRB 060115: MITSuME optical afterglow candidate
  70. GRB 060115: Swift detection of a burst
  71. GRB 060114: Swift XRT upper limit
  72. GRB060114, optical observation
  73. GRB 060114: refined position
  74. GRB 060114: A long GRB detected by INTEGRAL
  75. GRB060114: Faulkes North observation
  76. GRB 060108: IR observations of afterglow
  77. GRB060108: Faulkes North afterglow evidence
  78. GRB 060108: further analysis of VLT images
  79. GRB 060108: Evidence for an XRT Position Offset
  80. GRB 060110: KAIT observations
  81. GRB 060111B: Swift XRT refined analysis
  82. GRB 060111A: refined UVOT anaysis
  83. GRB 060111B: MITSuME detection of optical afterglow
  84. GRB 060111B: TAROT optical observation
  85. GRB060111A: RTT150 optical observations
  86. GRB060111B: RTT150, possible host galaxy
  87. GRB 060111B: Refined analysis of the Swift-BAT burst
  88. GRB 060110: MARGE observations
  89. GRB 060111(a): P60 Observations
  90. GRB 060111B: Gualba observatory limit
  91. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  92. GRB 060111B: Swift detection of a burst
  93. GRB 060111: Swift-BAT Refined Analysis
  94. GRB060111.2:_MASTER optical limit
  95. GRB 060108: VLT K-band observations
  96. GRB 060111: TAROT optical observation
  97. GRB 060111: possible UVOT counterpart
  98. GRB060111 : XRT refined analysis
  99. GRB 060111: ROTSE-III Optical Limits
  100. GRB 060111: Swift detection of a burst

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