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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. GRB060124 optical observations
  2. GRB 060121: Probable Detection of NIR Afterglow
  3. GRB060124: optical observation
  4. GRB 060116 HST observations
  5. GRB 060124: HETE detection and spectrum of the main peak
  6. Refined XRT Position for GRB 060123
  7. Konus-Wind observation of GRB 060124
  8. GRB060124: detailed XRT analysis
  9. GRB 060124 Optical Observations
  10. GRB 060124: ART optical limits during the burst
  11. GRB060123: Optical and IR Imaging
  12. GRB 060123: P200 Observations
  13. GRB 060124: Keck optical spectrum
  14. GRB 060124: Keck Absorption Redshift
  15. GRB 060124: MDM Optical Spectrum
  16. GRB 060124: XRT refined analysis
  17. GRB 060124: R band Observations
  18. GRB 060124 : Optical observation at Xinglong and Kiso
  19. GRB060124: optical observations at Asiago
  20. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  21. GRB060123: SDSS pre-burst observations
  22. GRB 060123: Swift detection of a very long, faint burst
  23. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  24. GRB 060121: OHP optical limits
  25. GRB 060124: TAROT optical limits
  26. GRB 060124: Swift/UVOT Observation
  27. GRB 060124: Confirmation of the Afterglow
  28. GRB 060124: XRT position
  29. GRB 060124: Optical Afterglow Candidate from Tautenburg
  30. GRB060124, optical observation
  31. GRB 050124 : Kiso Optical limit
  32. GRB 060124: Optical Observations at Tautenburg
  33. GRB 060117: Suzaku WAM observation of the prompt emission
  34. GRB060124:MASTER optical observation
  35. GRB 060111B: Suzaku WAM observation of the prompt emission
  36. GRB 060124: Swift-BAT detection of a burst
  37. GRB 060116: Radio Detection
  38. GRB 060116: MARGE optical observations
  39. GRB 060121: Swift/UVOT upper limits
  40. GRB 060121: Liverpool Telescopes optical limits
  41. GRB 060121: Swift XRT refined analysis
  42. Konus-Wind observation of GRB 060121
  43. GRB 060121: I-band Limits
  44. GRB 060121: Confirmation of Afterglow
  45. GRB 060121: candidate optical counterpart
  46. GRB 060121: Swift XRT refined position
  47. GRB060121: SARA Observations
  48. GRB 060121: optical observations
  49. GRB 060121: Infrared Observations
  50. GRB 060121: optical observations
  51. GRB 060121: Optical imaging
  52. GRB060121 - SDSS pre-burst observations
  53. GRB 060121: A short-hard GRB in a cluster?
  54. GRB 060121 (=H4010): Results of preliminary spectral analysis
  55. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  56. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  57. HETE Alert 4006: MASTER promt optical limit
  58. GRB 060117: PROMPT Observations
  59. GRB060117 - ATCA 3/6cm radio limits - correction
  60. GRB060117 - ATCA 3/6cm radio limits
  61. GRB 060116: photometric redshift - the farthest GRB?
  62. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  63. Correction to GCN 4542 on GRB 060117
  64. Konus-Wind observation of GRB 060117
  65. GRB 060116: possible I-J dropout
  66. GRB 060116: UKIRT IR Observations
  67. GRB060108: photometric redshift determination
  68. GRB 060117: Refined analysis of the Swift-BAT burst
  69. GRB 060116: PROMPT Observations
  70. GRB 060117: FRAM refined analysis
  71. GRB 060117: FRAM optical afterglow candidate
  72. GRB 060117: nearby galaxy
  73. GRB 060117: Swift-BAT detection of a bright burst
  74. GRB 060116: VLT optical observations
  75. GRB 060116: Refined analysis of the Swift-BAT burst
  76. GRB 060115: PROMPT Observations
  77. GRB 060116: XRT refined analysis
  78. GRB 060116: IR Candidate Afterglow
  79. GRB 060116: Swift/UVOT upper limits
  80. GRB060115: REM observations
  81. GRB 060110: XRT position and analysis
  82. GRB 060116 : Lulin optical limit
  83. GRB 060116: ROTSE-III Optical Limits
  84. GRB060116: XRT position
  85. GRB060116: Faulkes North observation
  86. GRB 060115: absorption redshift
  87. GRB 060116: Swift-BAT detection of a burst
  88. GRB 060115: Refined analysis of the Swift-BAT burst
  89. GRB 060115: OT photometry with MITSuME
  90. GRB 060115: Swift/UVOT upper limits
  91. GRB 060114: REM observations
  92. GRB 060115: Swift XRT refined analysis
  93. GRB 060115: OT finding chart
  94. GRB 060114: Swift/UVOT Observations
  95. GRB060115, optical observation
  96. GRB 060115: MITSuME optical afterglow candidate
  97. GRB 060115: Swift detection of a burst
  98. GRB 060114: Swift XRT upper limit
  99. GRB060114, optical observation
  100. GRB 060114: refined position

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