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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"

7420 results found.

  1. GRB 060306: Swift detection of a bright burst
  2. GRB 060223B: Swift XRT possible afterglow
  3. GRB 060223: Swift detection of a burst
  4. GRB060218: Radio Afterglow Discovery
  5. GRB 060219: Swift-BAT detection of a weak burst
  6. Brightening of the Optical Counterpart of the Possible GRB 060218
  7. GRB 060218: MDM Observations
  8. GRB 060218: Pre-burst detection of a possible host galaxy
  9. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  10. GRB 060218: Swift-BAT detection of a possible burst
  11. GRB 060213: optical afterglow not confirmed
  12. Swift UVOT observations of GRB060213
  13. GRB 060213: optical afterglow candidate
  14. GRB060213: Swift XRT observations and possible afterglow candidate
  15. GRB060213: MASTER final result
  16. GRB060213:_MASTER_optical_observation
  17. GRB 050826: Optical Afterglow and Host Galaxy
  18. GRB 060210: Optical Observations
  19. GRB060211.7: MASTER_optical_observation under the snow
  20. GRB 060211B: Swift-BAT detection of a burst
  21. GRB 060211: Swift detection of a long burst
  22. GRB060210:Faulkes Telescope North Afterglow Confirmation
  23. GRB 060210: candidate afterglow
  24. GRB 060210: Swift detection of a burst
  25. GRB060209A: MASTER optical observation
  26. GRB 060209(?): Swift-BAT detection of a possible burst
  27. GRB 060203: Swift/UVOT upper limits
  28. Retraction of orphan GRB afterglow candidate
  29. Orphan GRB Afterglow candidate
  30. GRB 060204A: ROSAT Pointing
  31. GRB060206: Liverpool Telescope observation
  32. GRB 060206: RAPTOR observations of afterglow candidate variability.
  33. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  34. GRB060206: Swift-BAT detection of a burst
  35. GRB 060204b: Keck/LRIS Afterglow Confirmation
  36. GRB 060204C: Liverpool Telescopes optical limit
  37. GRB 060204C: Swift-BAT detection of a burst
  38. GRB060204B: Faulkes OT candidate
  39. GRB 060204B: Swift detection of a burst
  40. GRB 060203: P60 Confirmation of Optical Afterglow
  41. Possible GRB 060203: candidate optical counterpart
  42. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  43. GRB 060202: Swift/UVOT upper limits
  44. GRB060202: Faulkes North observation
  45. GRB 060202: Swift detection of a burst
  46. GRB 051211A: MDM Observations
  47. GRB050121b: optical observation
  48. GRB 060124: Confirmation of the Afterglow
  49. GRB 060124: XRT position
  50. GRB 060124: Optical Afterglow Candidate from Tautenburg
  51. GRB 060124: Optical Observations at Tautenburg
  52. GRB060124:MASTER optical observation
  53. GRB 060121: Liverpool Telescopes optical limits
  54. GRB 060121: candidate optical counterpart
  55. GRB 060116: PROMPT Observations
  56. GRB 060117: FRAM refined analysis
  57. GRB 060117: FRAM optical afterglow candidate
  58. GRB 060117: nearby galaxy
  59. GRB 060116: VLT optical observations
  60. GRB 060116: IR Candidate Afterglow
  61. GRB060116: Faulkes North observation
  62. GRB 060116: Swift-BAT detection of a burst
  63. GRB 060115: OT photometry with MITSuME
  64. GRB 060115: Swift/UVOT upper limits
  65. GRB 060115: MITSuME optical afterglow candidate
  66. GRB 060115: Swift detection of a burst
  67. GRB060114: Faulkes North observation
  68. GRB060108: Faulkes North afterglow evidence
  69. GRB 060111A: refined UVOT anaysis
  70. GRB 060111B: MITSuME detection of optical afterglow
  71. GRB060111A: RTT150 optical observations
  72. GRB 060111B: Swift detection of a burst
  73. GRB060111.2:_MASTER optical limit
  74. GRB 060111: possible UVOT counterpart
  75. GRB 060111: Swift detection of a burst
  76. GRB 060110: Mitsume optical observations
  77. GRB 060110: IR Candidate Afterglow
  78. GRB 060110: Super-LOTIS observations
  79. GRB 060110: Optical observation
  80. GRB 060110: Correction
  81. GRB 060110: Optical limit
  82. GRB 060109: Swift Detection of a long burst
  83. GRB060108: Faulkes Telescope observation
  84. GRB060108: Swift detection of its 100th GRB
  85. GRB 060105: Swift/UVOT upper limits
  86. GRB 060102 - no XRT afterglow
  87. GRB060105 : Kiso optical observation
  88. GRB060105: Swift detection of a bright long burst
  89. Swift-BAT trigger 175653 is not an astrophysical source
  90. GRB051211B: optical observations
  91. GRB 051221B: Optical Observations with Kuiper 1.54m
  92. GRB 051227: optical observation
  93. GRB 051227: P60 Observations
  94. GRB 051227: R-band object in the XRT error circle
  95. GRB 051227: Swift detection of a burst
  96. GRB051117B: optical observation
  97. GRB 051221: Continued fading of optical afterglow
  98. GRB 051221A: RAPTOR Fading Counterpart Constraint
  99. Swift-BAT detection of a possible burst
  100. GRB 051221: Swift/UVOT upper limits

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