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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"

7415 results found.

  1. GRB 070520: Swift detection of a burst
  2. GRB 070510: Swift detection of a possible burst
  3. GRB 070508: OA fading and tentative redshift
  4. GRB 070509: Swift detection of a burst
  5. GRB 070508: TAROT La Silla observatory optical observations
  6. GRB 070508: Swift detection of an intense burst with an optical counterpart
  7. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  8. GRB 070506: Swift detection of a burst with optical afterglow
  9. GRB 070309: Swift-XRT afterglow confirmation
  10. GRB 070429B: Swift detection of a short burst
  11. GRB 070429: Swift detection of a burst
  12. GRB 070420: Swift detection of a burst with optical afterglow
  13. GRB 070419A Swift-BAT Refined Analysis
  14. GRB 070419B: Swift XRT refined analysis
  15. GRB 070419A, Optical observations
  16. GRB 070419B optical afterglow candidate
  17. GRB 070419B: optical afterglow candidate
  18. GRB 070419: P60 Confirmation of Optical Afterglow
  19. GRB 070419B: Swift detection of a burst
  20. GRB 070419 optical afterglow candidate
  21. GRB 070419: Swift detection of a burst
  22. Trigger 276045: Swift detection of a possible burst
  23. GRB 070412: Swift-XRT refined position
  24. GRB 070412: Gemini/GMOS afterglow candidate
  25. GRB 070412: IAC80 optical afterglow candidate
  26. GRB 070412: Swift detection of a burst
  27. GRB 070411 : Liverpool Telescope Observations
  28. GRB 070411: ROTSE-III Detection of Optical Counterpart
  29. GRB 070411: Swift detection of a burst with optical afterglow
  30. GRB 070406: Swift XRT team further analysis
  31. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  32. GRB 070406: Correction to the optical candidate in GCN6253
  33. GRB 070406: further analysis of NOT images.
  34. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  35. GRB 070406: NOT observations
  36. GRB 070406: Optical candidate
  37. GRB 070406: SARA upper limit
  38. GRB 070330: Swift detection of a burst
  39. GRB 070328: Swift/UVOT Upper Limits
  40. GRB 070328: Swift detection of a burst
  41. GRB070318: Swift-XRT refined analysis
  42. GRB 070318: Swift detection of a burst with an optical afterglow
  43. GRB 070309: variability of the XRT afterglow candidate
  44. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  45. GRB 070311: REM candidate afterglow
  46. GRB060901: Candidate optical afterglow
  47. GRB070306: confirmation of near infrared afterglow
  48. GRB 070306: ART-3 early optical and near infrared constraints
  49. GRB 070306: IR observations and candidate afterglow
  50. GRB 070306: Swift detection of a burst
  51. GRB070227: Swift-XRT refined analysis
  52. GRB 070223: Optical Observations
  53. GRB 920925C: optical afterglow candidate
  54. GRB 070224: Optical afterglow confirmation
  55. GRB070224: Swift-XRT Astrometrically Corrected Position
  56. VLA observation of GRB 070223
  57. GRB 070224: WHT K-band imaging
  58. GRB 070224: optical afterglow candidate
  59. GRB 070224: MASTER-Net refind analysis
  60. GRB 070224: MASTER observations
  61. GRB 070224: Swift detection of a burst
  62. GRB 070223: Optical observations
  63. GRB 070223: Swift-XRT Refined Analysis
  64. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  65. GRB070223: Swift burst
  66. GRB 070220: MITSuME Okayama Optical Observation
  67. GRB 070220: Swift detection of a burst
  68. GRB 070219: Swift detection of a burst
  69. GRB 070209: Swift detection of a short hard burst
  70. GRB 070208: Afterglow confirmation from P60
  71. GRB070208: Faulkes Telescope North Afterglow Identification
  72. GRB 070208: Swift detection of a burst
  73. GRB070126: Swift-XRT Observation
  74. GRB 070129: Swift detection of a burst
  75. GRB 070125: MITSuME Okayama optical observation
  76. GRB 070125: PROMPT detections
  77. Possible GRB 070126: Swift/UVOT Upper Limit
  78. GRB 070125: Continued P60 Observations
  79. GRB 070125: SARA detection in R
  80. GRB 070125: P60 Optical Afterglow Candidate
  81. GRB 070110: Continued Detection and Request for Ground Followup
  82. GRB 070110: UVOT Observations of a Candidate Afterglow
  83. GRB070107 Swift/UVOT Observations of a Fading Optical Afterglow
  84. GRB 070110: Swift detection of a burst with a possible optical afterglow
  85. GRB070107: Swift/XRT refined analysis
  86. GRB 070107: Swift detection of a burst
  87. GRB 070103: Swift detection of a burst
  88. GRB 061222A: Confirmation of Gemini Afterglow Candidate
  89. GRB 061222A: Xinglong Optical Limit
  90. GRB 061222A: Gemini Afterglow Candidate
  91. GRB061222A Swift/UVOT: Upper Limits
  92. GRB 061222B: Swift/UVOT Upper limits
  93. GRB061222B: Swift-XRT Refined Analysis
  94. GRB 061222B: SARA upper limit
  95. GRB 061222B: Swift detection of a burst
  96. GRB 061222: Swift detection of a burst
  97. GRB 061217: Astrometry-Corrected XRT Position
  98. GRB 061217: Confirmation of host candidate
  99. GRB 061217, Candidate host galaxy
  100. GRB061217: VLT NIR observations

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