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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"

28055 results found.

  1. INT+WFC observations of GRB 061126
  2. Swift XRT on-board boresight update
  3. GRB 061126: optical observation
  4. GRB 061126: Tautenburg afterglow observations
  5. GRB061126: Optical afterglow observations from MIRO
  6. GRB061126: Optical afterglow observations from MIRO
  7. GRB 061126 : SDSS Pre-Burst Observations
  8. GRB 061126: Swift-XRT refined analysis
  9. GRB 061126: Swift/UVOT Observations
  10. GRB 061126, Swift-BAT refined analysis
  11. GRB 061126: Early Detection of the IR Afterglow
  12. GRB 061126: Swift/UVOT Afterglow Detection
  13. GRB 061122: Candidate Optical Afterglow
  14. GRB 061121: Ep,i - Eiso correlation
  15. GRB061122: Swift/UVOT Optical Observations
  16. GRB061121: P60 Observations
  17. Radio detection of GRB 061121
  18. GRB061122: Swift-XRT position
  19. INTEGRAL results on GRB 061122
  20. Swift-BAT trigger 239987 is not a GRB
  21. GRB 061121: Swift/UVOT Observations
  22. GRB 061121: Swift-XRT Team Refined Analysis
  23. GRB 061121, Swift-BAT refined analysis
  24. GRB061121, optical observation
  25. GRB 061121: Optical observation at the KANATA 1.5m telescope
  26. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  27. GRB 061121: Swift detection of a bright burst with an optical counterpart
  28. GRB 060605: NIR Observations
  29. GRB 050915B: optical afterglow
  30. Swift-BAT triggers 238544 and 238546 are not GRBs
  31. Swift/UVOT Upper Limits for GRB061110b
  32. Swift/UVOT Upper Limits for GRB061110a
  33. GRB 061110B, Swift-BAT refined analysis
  34. GRB061110B: Optical observations at Crni Vrh
  35. GRB 061110A: Swift XRT refined analysis
  36. GRB 061110A, Swift-BAT refined analysis
  37. GRB 061110B: TAROT Calern observatory optical observations
  38. GRB 061110B: Swift detection of a burst
  39. GRB 061110: Candidate confirmed
  40. GRB 061110 : Optical afterglow candidate
  41. GRB 061110: ROTSE-III Optical Limits
  42. GRB 061110: Swift detection of a burst
  43. GRB061110A - Optical Non-detection
  44. GRB 061109: optical observation
  45. GRB 061109: TAROT Calern observatory optical observations
  46. GRB 061027: TAROT La Silla observatory optical observations
  47. GRB 061028: Swift/XRT Astrometry Correction
  48. GRB 061102: Swift/UVOT Magnitude Upper Limits
  49. GRB 061102, XRT refined analysis
  50. GRB061102B: Super-LOTIS observations
  51. GRB 061028: Optical R passband observations
  52. GRB 061102B: Swift detection of a possible burst
  53. GRB 061102, Swift-BAT refined analysis
  54. GRB 061102: Swift detection of a burst
  55. GRB 061028: VLA Observation
  56. GRB 061004: Swift/XRT Astrometry Correction
  57. GRB 060801: Swift/XRT Astrometry Correction
  58. GRB 061028: Futher P200 Observations
  59. GRB 061028: P200 Observations
  60. GRB 061028: SARA upper limit
  61. GRB 061028: z band imaging
  62. GRB061028: XRT refined analysis
  63. GRB 061028: Swift/UVOT Observations
  64. GRB 061028, Swift-BAT refined analysis
  65. GRB 061028: TAROT Calern observatory optical observations
  66. GRB 061028: Swift detection of a burst
  67. GRB 061027, Swift refined analysis of a possible burst
  68. GRB 061027: Swift detection of a possible burst
  69. GRB061025: Swift XRT refined analysis
  70. GRB061025: Swift/UVOT observations
  71. GRB 061025: REM observations
  72. GRB 061025: ROTSE-III Optical Limits
  73. GRB 061025: a long GRB detected by INTEGRAL
  74. Swift XRT boresight update
  75. GRB 061021: Swift/UVOT Observation
  76. GRB 061021, Swift-BAT refined analysis
  77. GRB 061021: Swift detection of a burst
  78. GRB061019: optical observations
  79. GRB 061019: SARA upper limit
  80. GRB 061019: Swift/UVOT upper limit
  81. GRB 061019: SMARTS afterglow confirmation
  82. GRB061019: Swift XRT refined analysis
  83. GRB 061019, Swift-BAT refined analysis
  84. GRB 061019: TAROT La Silla observatory optical observations
  85. GRB 061019: REM K-band candidate afterglow
  86. GRB 061007: Second Epoch ATCA Radio Observations
  87. GRB 061007: Suzaku/WAM observation of the prompt emission
  88. GRB 061006: astrometry-corrected XRT position
  89. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  90. GRB 061007: ATCA Radio Observations
  91. GRB061007: Swift UVOT followup observations
  92. GRB 061006: optical afterglow
  93. GRB 061007: OA fading and VLT redshift
  94. GRB 061007: Correction to GCN 5712
  95. GRB 061007: Swift-BAT refined analysis
  96. GRB 061007: Swift XRT refined analysis
  97. GRB 061006: Swift/UVOT optical observations
  98. GRB 061007: Swift detection of a burst with an optical counterpart
  99. GRB 061007: ROTSE-III Detection of Optical Counterpart
  100. GRB 061006: VLT observation

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