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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"

7405 results found.

  1. GRB 070429: Swift detection of a burst
  2. GRB 070420: Swift detection of a burst with optical afterglow
  3. GRB 070419A Swift-BAT Refined Analysis
  4. GRB 070419B: Swift XRT refined analysis
  5. GRB 070419A, Optical observations
  6. GRB 070419B optical afterglow candidate
  7. GRB 070419B: optical afterglow candidate
  8. GRB 070419: P60 Confirmation of Optical Afterglow
  9. GRB 070419B: Swift detection of a burst
  10. GRB 070419 optical afterglow candidate
  11. GRB 070419: Swift detection of a burst
  12. Trigger 276045: Swift detection of a possible burst
  13. GRB 070412: Swift-XRT refined position
  14. GRB 070412: Gemini/GMOS afterglow candidate
  15. GRB 070412: IAC80 optical afterglow candidate
  16. GRB 070412: Swift detection of a burst
  17. GRB 070411 : Liverpool Telescope Observations
  18. GRB 070411: ROTSE-III Detection of Optical Counterpart
  19. GRB 070411: Swift detection of a burst with optical afterglow
  20. GRB 070406: Swift XRT team further analysis
  21. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  22. GRB 070406: Correction to the optical candidate in GCN6253
  23. GRB 070406: further analysis of NOT images.
  24. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  25. GRB 070406: NOT observations
  26. GRB 070406: Optical candidate
  27. GRB 070406: SARA upper limit
  28. GRB 070330: Swift detection of a burst
  29. GRB 070328: Swift/UVOT Upper Limits
  30. GRB 070328: Swift detection of a burst
  31. GRB070318: Swift-XRT refined analysis
  32. GRB 070318: Swift detection of a burst with an optical afterglow
  33. GRB 070309: variability of the XRT afterglow candidate
  34. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  35. GRB 070311: REM candidate afterglow
  36. GRB060901: Candidate optical afterglow
  37. GRB070306: confirmation of near infrared afterglow
  38. GRB 070306: ART-3 early optical and near infrared constraints
  39. GRB 070306: IR observations and candidate afterglow
  40. GRB 070306: Swift detection of a burst
  41. GRB070227: Swift-XRT refined analysis
  42. GRB 070223: Optical Observations
  43. GRB 920925C: optical afterglow candidate
  44. GRB 070224: Optical afterglow confirmation
  45. GRB070224: Swift-XRT Astrometrically Corrected Position
  46. VLA observation of GRB 070223
  47. GRB 070224: WHT K-band imaging
  48. GRB 070224: optical afterglow candidate
  49. GRB 070224: MASTER-Net refind analysis
  50. GRB 070224: MASTER observations
  51. GRB 070224: Swift detection of a burst
  52. GRB 070223: Optical observations
  53. GRB 070223: Swift-XRT Refined Analysis
  54. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  55. GRB070223: Swift burst
  56. GRB 070220: MITSuME Okayama Optical Observation
  57. GRB 070220: Swift detection of a burst
  58. GRB 070219: Swift detection of a burst
  59. GRB 070209: Swift detection of a short hard burst
  60. GRB 070208: Afterglow confirmation from P60
  61. GRB070208: Faulkes Telescope North Afterglow Identification
  62. GRB 070208: Swift detection of a burst
  63. GRB070126: Swift-XRT Observation
  64. GRB 070129: Swift detection of a burst
  65. GRB 070125: MITSuME Okayama optical observation
  66. GRB 070125: PROMPT detections
  67. Possible GRB 070126: Swift/UVOT Upper Limit
  68. GRB 070125: Continued P60 Observations
  69. GRB 070125: SARA detection in R
  70. GRB 070125: P60 Optical Afterglow Candidate
  71. GRB 070110: Continued Detection and Request for Ground Followup
  72. GRB 070110: UVOT Observations of a Candidate Afterglow
  73. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  74. GRB 070110: Swift detection of a burst with a possible optical afterglow
  75. GRB070107: Swift/XRT refined analysis
  76. GRB 070107: Swift detection of a burst
  77. GRB 070103: Swift detection of a burst
  78. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  79. GRB 061222A: Xinglong Optical Limit
  80. GRB 061222A: Gemini Afterglow Candidate
  81. GRB061222A Swift/UVOT: Upper Limits
  82. GRB 061222B: Swift/UVOT Upper limits
  83. GRB061222B: Swift-XRT Refined Analysis
  84. GRB 061222B: SARA upper limit
  85. GRB 061222B: Swift detection of a burst
  86. GRB 061222: Swift detection of a burst
  87. GRB 061217: Astrometry-Corrected XRT Position
  88. GRB 061217: Confirmation of host candidate
  89. GRB 061217, Candidate host galaxy
  90. GRB061217: VLT NIR observations
  91. Swift triggers (#251863) on a possible burst
  92. GRB061217: Swift/UVOT refined analysis.
  93. GRB 061210: MDM Follow-up Observation
  94. GRB061210: Swift/UVOT observations
  95. GRB 061214(?): Swift detection of a possible burst
  96. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  97. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  98. GRB 061201: SOAR Confirmation of Candidate Afterglow
  99. GRB061202: Swift/UVOT Upper Limits
  100. GRB 061202: Swift detection of a burst

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