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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"

21466 results found.

  1. GRB 070107, Swift-BAT refined analysis
  2. GRB 070107: Swift/XRT position
  3. GRB 070107: Swift detection of a burst
  4. VLA observation of GRB 061222B
  5. VLA detection of GRB 061222A
  6. GRB070103: APO SPIcam i' and z' limits
  7. GRB070103: KPNO 4m+FLAMINGOS J limit
  8. GRB 070103: Swift/UVOT Upper limits
  9. GRB070103: Swift XRT refined analysis
  10. GRB 070103, Swift-BAT refined analysis
  11. GRB 070103: TAROT Calern observatory optical observations
  12. GRB 070103: Swift detection of a burst
  13. Retractions of previous Swift-BAT triggers
  14. GRB061222a: optical observations
  15. Konus-Wind observation of GRB 061222A
  16. GRB 061210: Swift/XRT Astrometry Correction
  17. GRB 050826: MDM Redshift
  18. GRB 061222A: MITSuME Akeno optical upper limits
  19. GRB 061222A: Gemini Afterglow Candidate
  20. GRB 061222B, Swift-BAT refined analysis
  21. GRB061222A Swift/UVOT: Upper Limits
  22. GRB 061222B: Swift/UVOT Upper limits
  23. GRB061222B: Swift-XRT Refined Analysis
  24. GRB 061222A: Observation with the KANATA 1.5m telescope
  25. GRB 061222B: BOOTES-IR optical observations
  26. GRB 061222B: SARA upper limit
  27. GRB 061222A: Swift-XRT refined analysis
  28. GRB 061222A, Swift-BAT refined analysis
  29. GRB 061222B: TAROT La Silla observatory optical observations
  30. GRB 061222B: Swift detection of a burst
  31. GRB 061222b: optical afterglow
  32. GRB 061222A: Prompt ROTSE-III Optical Limits
  33. GRB 061222: Swift detection of a burst
  34. GRB 061217: Astrometry-Corrected XRT Position
  35. GRB 061217: Confirmation of host candidate
  36. GRB 061217: Object ib GCN 5948 is a star
  37. GRB 061217: Extended object in the revised XRT error circle
  38. GRB 061217, Candidate host galaxy
  39. GRB 061217 - Swift/XRT position correction
  40. GRB 061210: Possible Host Galaxy (S2-G2) Keck Spectrum
  41. GRB 061218: TAROT La Silla observatory optical observations
  42. GRB 061217: TAROT Calern observatory optical observations
  43. GRB 061218, Swift-BAT refined analysis
  44. GRB061217: VLT NIR observations
  45. Swift triggers (#251863) on a possible burst
  46. GRB061217: Swift/UVOT refined analysis.
  47. GRB 061217: optical observations at Calar Alto
  48. GRB061217 - Swift/XRT refined analysis
  49. GRB 061217, Further Swift-BAT refined analysis of the short hard burst
  50. GRB 061217, Swift-BAT refined analysis
  51. GRB 061217: ROTSE-III Optical Limits
  52. GRB 061217: Swift detection of a short hard burst
  53. GRB 061210: MDM Follow-up Observation
  54. GRB061210: Swift/UVOT observations
  55. Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
  56. GRB 061210: Optical sources near XRT positions
  57. GRB 061210: Swift XRT analysis - Possible counterparts
  58. GRB 061210 : Faulkes North Telescope optical limit
  59. GRB 061214(?): ROTSE-III Optical Limits
  60. GRB 061214(?): Swift detection of a possible burst
  61. Swift/BAT trigger #250033 is due to a known source during loss of
  62. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  63. GRB 061213: MASTER-VWF-Kislovodsk observations
  64. GRB 061210: MDM Observation
  65. GRB 061210, Swift-BAT refined analysis of the SHB
  66. GRB 061210: Swift-BAT detection of a short burst
  67. Optical Afterglow observations of GRB 061126
  68. GRB 060926: MASTER: discovery of the optical flare
  69. GRB061126: update on the Swift-XRT afterglow light curve
  70. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  71. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  72. GRB061126 : NMSU 1.0m observations
  73. GRB 061202: Swift XRT refined analysis
  74. GRB061202: FRAM early follow-up limit
  75. GRB061202 optical limit by "Pi of the Sky"
  76. Konus-Wind observation of GRB 061201
  77. GRB061202: optical/NIR observations with REM
  78. GRB061202: Swift/UVOT Upper Limits
  79. GRB 061202, Swift-BAT refined analysis
  80. GRB 061202: Swift detection of a burst
  81. GRB 061201: Swift XRT Team refined analysis
  82. GRB 061201: VLT optical observations
  83. GRB 061201: Initial UVOT Observations
  84. GRB 061201, Swift-BAT refined analysis of the SHB
  85. GRB 061201: Swift detection of a short hard burst
  86. GRB 061201: Coincidence with a Galaxy Cluster
  87. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  88. Swift XRT on-board boresight update
  89. GRB 061126: Early Super-LOTIS Observations
  90. GRB061126: Optical afterglow observations from MIRO
  91. GRB061126: Optical afterglow observations from MIRO
  92. GRB 061126: Swift-XRT refined analysis
  93. GRB 061126: Swift/UVOT Observations
  94. GRB 061126, Swift-BAT refined analysis
  95. GRB 061126: Faulkes Telescope North Optical Observations
  96. GRB 061126: Swift/UVOT Afterglow Detection
  97. GRB 061126: XRT position
  98. GRB 061126: Swift detection of a burst
  99. GRB 061122: Confirmation of X-ray/Optical Afterglow
  100. GRB 061122: Candidate Optical Afterglow

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