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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"

28051 results found.

  1. GRB061126: Optical afterglow observations from MIRO
  2. GRB061126: Optical afterglow observations from MIRO
  3. GRB 061126 : SDSS Pre-Burst Observations
  4. GRB 061126: Swift-XRT refined analysis
  5. GRB 061126: Swift/UVOT Observations
  6. GRB 061126, Swift-BAT refined analysis
  7. GRB 061126: Early Detection of the IR Afterglow
  8. GRB 061126: Swift/UVOT Afterglow Detection
  9. GRB 061122: Candidate Optical Afterglow
  10. GRB 061121: Ep,i - Eiso correlation
  11. GRB061122: Swift/UVOT Optical Observations
  12. GRB061121: P60 Observations
  13. Radio detection of GRB 061121
  14. GRB061122: Swift-XRT position
  15. INTEGRAL results on GRB 061122
  16. Swift-BAT trigger 239987 is not a GRB
  17. GRB 061121: Swift/UVOT Observations
  18. GRB 061121: Swift-XRT Team Refined Analysis
  19. GRB 061121, Swift-BAT refined analysis
  20. GRB061121, optical observation
  21. GRB 061121: Optical observation at the KANATA 1.5m telescope
  22. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  23. GRB 061121: Swift detection of a bright burst with an optical counterpart
  24. GRB 060605: NIR Observations
  25. GRB 050915B: optical afterglow
  26. Swift-BAT triggers 238544 and 238546 are not GRBs
  27. Swift/UVOT Upper Limits for GRB061110b
  28. Swift/UVOT Upper Limits for GRB061110a
  29. GRB 061110B, Swift-BAT refined analysis
  30. GRB061110B: Optical observations at Crni Vrh
  31. GRB 061110A: Swift XRT refined analysis
  32. GRB 061110A, Swift-BAT refined analysis
  33. GRB 061110B: TAROT Calern observatory optical observations
  34. GRB 061110B: Swift detection of a burst
  35. GRB 061110: Candidate confirmed
  36. GRB 061110 : Optical afterglow candidate
  37. GRB 061110: ROTSE-III Optical Limits
  38. GRB 061110: Swift detection of a burst
  39. GRB061110A - Optical Non-detection
  40. GRB 061109: optical observation
  41. GRB 061109: TAROT Calern observatory optical observations
  42. GRB 061027: TAROT La Silla observatory optical observations
  43. GRB 061028: Swift/XRT Astrometry Correction
  44. GRB 061102: Swift/UVOT Magnitude Upper Limits
  45. GRB 061102, XRT refined analysis
  46. GRB061102B: Super-LOTIS observations
  47. GRB 061028: Optical R passband observations
  48. GRB 061102B: Swift detection of a possible burst
  49. GRB 061102, Swift-BAT refined analysis
  50. GRB 061102: Swift detection of a burst
  51. GRB 061028: VLA Observation
  52. GRB 061004: Swift/XRT Astrometry Correction
  53. GRB 060801: Swift/XRT Astrometry Correction
  54. GRB 061028: Futher P200 Observations
  55. GRB 061028: P200 Observations
  56. GRB 061028: SARA upper limit
  57. GRB 061028: z band imaging
  58. GRB061028: XRT refined analysis
  59. GRB 061028: Swift/UVOT Observations
  60. GRB 061028, Swift-BAT refined analysis
  61. GRB 061028: TAROT Calern observatory optical observations
  62. GRB 061028: Swift detection of a burst
  63. GRB 061027, Swift refined analysis of a possible burst
  64. GRB 061027: Swift detection of a possible burst
  65. GRB061025: Swift XRT refined analysis
  66. GRB061025: Swift/UVOT observations
  67. GRB 061025: REM observations
  68. GRB 061025: ROTSE-III Optical Limits
  69. GRB 061025: a long GRB detected by INTEGRAL
  70. Swift XRT boresight update
  71. GRB 061021: Swift/UVOT Observation
  72. GRB 061021, Swift-BAT refined analysis
  73. GRB 061021: Swift detection of a burst
  74. GRB061019: optical observations
  75. GRB 061019: SARA upper limit
  76. GRB 061019: Swift/UVOT upper limit
  77. GRB 061019: SMARTS afterglow confirmation
  78. GRB061019: Swift XRT refined analysis
  79. GRB 061019, Swift-BAT refined analysis
  80. GRB 061019: TAROT La Silla observatory optical observations
  81. GRB 061019: REM K-band candidate afterglow
  82. GRB 061007: Second Epoch ATCA Radio Observations
  83. GRB 061007: Suzaku/WAM observation of the prompt emission
  84. GRB 061006: astrometry-corrected XRT position
  85. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  86. GRB 061007: ATCA Radio Observations
  87. GRB061007: Swift UVOT followup observations
  88. GRB 061006: optical afterglow
  89. GRB 061007: OA fading and VLT redshift
  90. GRB 061007: Correction to GCN 5712
  91. GRB 061007: Swift-BAT refined analysis
  92. GRB 061007: Swift XRT refined analysis
  93. GRB 061006: Swift/UVOT optical observations
  94. GRB 061007: Swift detection of a burst with an optical counterpart
  95. GRB 061007: ROTSE-III Detection of Optical Counterpart
  96. GRB 061006: VLT observation
  97. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  98. GRB 061006: Swift-XRT Team Refined Analysis
  99. GRB061006 (Swift 232585) might be a short-hard GRB
  100. GRB 060930: near-IR afterglow candidate retraction

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