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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"

7396 results found.

  1. GRB 070419 optical afterglow candidate
  2. GRB 070419: Swift detection of a burst
  3. Trigger 276045: Swift detection of a possible burst
  4. GRB 070412: Swift-XRT refined position
  5. GRB 070412: Gemini/GMOS afterglow candidate
  6. GRB 070412: IAC80 optical afterglow candidate
  7. GRB 070412: Swift detection of a burst
  8. GRB 070411 : Liverpool Telescope Observations
  9. GRB 070411: ROTSE-III Detection of Optical Counterpart
  10. GRB 070411: Swift detection of a burst with optical afterglow
  11. GRB 070406: Swift XRT team further analysis
  12. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  13. GRB 070406: Correction to the optical candidate in GCN6253
  14. GRB 070406: further analysis of NOT images.
  15. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  16. GRB 070406: NOT observations
  17. GRB 070406: Optical candidate
  18. GRB 070406: SARA upper limit
  19. GRB 070330: Swift detection of a burst
  20. GRB 070328: Swift/UVOT Upper Limits
  21. GRB 070328: Swift detection of a burst
  22. GRB070318: Swift-XRT refined analysis
  23. GRB 070318: Swift detection of a burst with an optical afterglow
  24. GRB 070309: variability of the XRT afterglow candidate
  25. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  26. GRB 070311: REM candidate afterglow
  27. GRB060901: Candidate optical afterglow
  28. GRB070306: confirmation of near infrared afterglow
  29. GRB 070306: ART-3 early optical and near infrared constraints
  30. GRB 070306: IR observations and candidate afterglow
  31. GRB 070306: Swift detection of a burst
  32. GRB070227: Swift-XRT refined analysis
  33. GRB 070223: Optical Observations
  34. GRB 920925C: optical afterglow candidate
  35. GRB 070224: Optical afterglow confirmation
  36. GRB070224: Swift-XRT Astrometrically Corrected Position
  37. VLA observation of GRB 070223
  38. GRB 070224: WHT K-band imaging
  39. GRB 070224: optical afterglow candidate
  40. GRB 070224: MASTER-Net refind analysis
  41. GRB 070224: MASTER observations
  42. GRB 070224: Swift detection of a burst
  43. GRB 070223: Optical observations
  44. GRB 070223: Swift-XRT Refined Analysis
  45. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  46. GRB070223: Swift burst
  47. GRB 070220: MITSuME Okayama Optical Observation
  48. GRB 070220: Swift detection of a burst
  49. GRB 070219: Swift detection of a burst
  50. GRB 070209: Swift detection of a short hard burst
  51. GRB 070208: Afterglow confirmation from P60
  52. GRB070208: Faulkes Telescope North Afterglow Identification
  53. GRB 070208: Swift detection of a burst
  54. GRB070126: Swift-XRT Observation
  55. GRB 070129: Swift detection of a burst
  56. GRB 070125: MITSuME Okayama optical observation
  57. GRB 070125: PROMPT detections
  58. Possible GRB 070126: Swift/UVOT Upper Limit
  59. GRB 070125: Continued P60 Observations
  60. GRB 070125: SARA detection in R
  61. GRB 070125: P60 Optical Afterglow Candidate
  62. GRB 070110: Continued Detection and Request for Ground Followup
  63. GRB 070110: UVOT Observations of a Candidate Afterglow
  64. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  65. GRB 070110: Swift detection of a burst with a possible optical afterglow
  66. GRB070107: Swift/XRT refined analysis
  67. GRB 070107: Swift detection of a burst
  68. GRB 070103: Swift detection of a burst
  69. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  70. GRB 061222A: Xinglong Optical Limit
  71. GRB 061222A: Gemini Afterglow Candidate
  72. GRB061222A Swift/UVOT: Upper Limits
  73. GRB 061222B: Swift/UVOT Upper limits
  74. GRB061222B: Swift-XRT Refined Analysis
  75. GRB 061222B: SARA upper limit
  76. GRB 061222B: Swift detection of a burst
  77. GRB 061222: Swift detection of a burst
  78. GRB 061217: Astrometry-Corrected XRT Position
  79. GRB 061217: Confirmation of host candidate
  80. GRB 061217, Candidate host galaxy
  81. GRB061217: VLT NIR observations
  82. Swift triggers (#251863) on a possible burst
  83. GRB061217: Swift/UVOT refined analysis.
  84. GRB 061210: MDM Follow-up Observation
  85. GRB061210: Swift/UVOT observations
  86. GRB 061214(?): Swift detection of a possible burst
  87. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  88. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  89. GRB 061201: SOAR Confirmation of Candidate Afterglow
  90. GRB061202: Swift/UVOT Upper Limits
  91. GRB 061202: Swift detection of a burst
  92. GRB 061201: Swift detection of a short hard burst
  93. GRB 061126: Swift/UVOT Afterglow Detection
  94. GRB 061122: Candidate Optical Afterglow
  95. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  96. GRB 061121: Swift detection of a bright burst with an optical counterpart
  97. GRB 061110B: Swift/XRT position
  98. GRB 061110B: Swift-UVOT Initial Observation
  99. GRB 061110: Candidate confirmed
  100. GRB 061110 : Optical afterglow candidate

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