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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"

8474 results found.

  1. GRB 051227: optical observation
  2. GRB 051227: P60 Observations
  3. GRB 051227: R-band object in the XRT error circle
  4. GRB 051227: Further analysis of the Swift-BAT burst
  5. GRB 051227: Swift detection of a burst
  6. GRB051117B: optical observation
  7. GRB 051221: Continued fading of optical afterglow
  8. GRB 051221A: RAPTOR Fading Counterpart Constraint
  9. Swift-BAT detection of a possible burst
  10. GRB 051221: Swift/UVOT upper limits
  11. GRB 051221: Swift detection of a bright short burst
  12. GRB051211A: possible optical candidate
  13. GRB 051215: A short GRB in a cluster?
  14. GRB 051211B: Swift XRT confirmation of the afterglow
  15. GRB051211B: Liverpool Telescope observation
  16. GRB 051211b: RTT150 optical observations
  17. GRB 051211B: Swift XRT Observations
  18. GRB 051211B: a possible optical detection by TAROT
  19. An extraordinary long burst on December 3 from SGR1806-20
  20. Possible resuming of the SGR 1806-20 activity
  21. GRB051111: Suzaku WAM observation of the prompt emission
  22. GRB051111: Rc optical observations
  23. GRB 051117A: Refined analysis of the Swift-BAT burst
  24. GRB 051117B: Swift detection of a burst
  25. GRB050925: analysis of the XMM-Newton observation
  26. GRB 051111: Swift-BAT refined analysis
  27. Faulkes Telescope R-band detection of GRB051111
  28. GRB 051109a: IR Detections
  29. GRB051103: MASTER: OT limit and host galaxy candidates
  30. GRB 051105A, 2nd epoch optical observations
  31. GRB051103:_MASTER_optical_observations
  32. GRB 051105: Optical limit
  33. GRB051016B: optical observation
  34. GRB051028: optical observations
  35. GRB051028: confirmation of the afterglow
  36. GRB051028: WHT optical candidate
  37. GRB051028:MASTER observations
  38. GRB051028:MASTER optical observations
  39. GRB051012: Swift-XRT analysis
  40. GRB051021A: Swift XRT refined analysis
  41. GRB051022: Optical Observations
  42. GRB051021b: Magellan IR Imaging
  43. GRB 051021, SMARTS optical/IR observations
  44. GRB 051021B: Swift detection of a burst
  45. GRB 051021: Optical observations
  46. GRB 051021: Optical observations and candidate afterglow
  47. GRB051021.63
  48. GRB051021.6: MASTER optical observation
  49. GRB 051016b: Optical limit
  50. Afterglow candidate of GRB 051016B observed at Lulin
  51. GRB 051016b: Gemini Near IR Observations
  52. GRB 051016: Swift-BAT refined analysis
  53. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  54. GRB050805A: Rc optical observations
  55. GRB051008: optical candidate
  56. GRB051011: MASTER optical observation
  57. GRB051008 - Swift UVOT upper limits
  58. GRB 051008, optical observations
  59. GRB 051008: Swift UVOT Candidate
  60. GRB050925: Swift/XRT limits
  61. GRB050925: Faulkes Telescope North R-band limit
  62. GRB050922C: Optical Observations
  63. GRB050911: Upper limit on X-ray afterglow
  64. Swift-BAT trigger 155072 is probably not a GRB
  65. GRB050914: XRT position probably due to cosmic ray
  66. GRB 050911, optical content of Swift/XRT error box
  67. GRB050911: Swift-XRT position
  68. GRB 050906: Possible X-ray Counterpart
  69. GRB050908 : Swift-XRT refined analysis
  70. GRB 050908: Optical observations
  71. Gemini Spectroscopy of GRB 050908
  72. GRB 050908: P60 Confirmation of Optical Afterglow
  73. GRB 050908: Optical Observations
  74. GRB 050904: Subaru Optical Spectroscopy
  75. GRB 050904: Keck I-band Imaging
  76. GRB 050906: Bright galaxy in BAT error box
  77. GRB 050904: TAROT optical measurements
  78. GRB 050827: Optical Limit
  79. GRB 050826 : Lulin R band observation
  80. GRB 050826: Optical Candidate
  81. GRB050824: MASTER final analysis of the OT observations
  82. GRB050824, I-band imaging
  83. GRB 050824: XRT refined analysis and possible afterglow detection
  84. GRB 050824: BAT refined analysis of a soft weak burst
  85. GRB050824: MASTER:OT decay
  86. GRB 050824 optical candidate
  87. GRB 050820a - corrections to GCN 3846
  88. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  89. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  90. GRB050814: P60 Optical Afterglow Candidate
  91. GRB 050813: Non-fading of afterglow candidate
  92. GRB 050814: Swift detection of a burst
  93. GRB050813, SDSS pre-burst observations
  94. GRB 050813: Possible Short Swift-BAT GRB
  95. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  96. GRB050803: CrAO optical observations, no OT candidate
  97. Detection of an intermediate burst from SGR 1806-20 on August 8
  98. GRB050802: TNG optical observations
  99. GRB 050803: RTT150 optical observations
  100. GRB050803: CrAO optical observations, possible OT candidate

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