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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"

8477 results found.

  1. Swift-BAT trigger 175653 is not an astrophysical source
  2. GRB051211B: optical observations
  3. GRB 051221B: Optical Observations with Kuiper 1.54m
  4. GRB 051227: optical observation
  5. GRB 051227: P60 Observations
  6. GRB 051227: R-band object in the XRT error circle
  7. GRB 051227: Further analysis of the Swift-BAT burst
  8. GRB 051227: Swift detection of a burst
  9. GRB051117B: optical observation
  10. GRB 051221: Continued fading of optical afterglow
  11. GRB 051221A: RAPTOR Fading Counterpart Constraint
  12. Swift-BAT detection of a possible burst
  13. GRB 051221: Swift/UVOT upper limits
  14. GRB 051221: Swift detection of a bright short burst
  15. GRB051211A: possible optical candidate
  16. GRB 051215: A short GRB in a cluster?
  17. GRB 051211B: Swift XRT confirmation of the afterglow
  18. GRB051211B: Liverpool Telescope observation
  19. GRB 051211b: RTT150 optical observations
  20. GRB 051211B: Swift XRT Observations
  21. GRB 051211B: a possible optical detection by TAROT
  22. An extraordinary long burst on December 3 from SGR1806-20
  23. Possible resuming of the SGR 1806-20 activity
  24. GRB051111: Suzaku WAM observation of the prompt emission
  25. GRB051111: Rc optical observations
  26. GRB 051117A: Refined analysis of the Swift-BAT burst
  27. GRB 051117B: Swift detection of a burst
  28. GRB050925: analysis of the XMM-Newton observation
  29. GRB 051111: Swift-BAT refined analysis
  30. Faulkes Telescope R-band detection of GRB051111
  31. GRB 051109a: IR Detections
  32. GRB051103: MASTER: OT limit and host galaxy candidates
  33. GRB 051105A, 2nd epoch optical observations
  34. GRB051103:_MASTER_optical_observations
  35. GRB 051105: Optical limit
  36. GRB051016B: optical observation
  37. GRB051028: optical observations
  38. GRB051028: confirmation of the afterglow
  39. GRB051028: WHT optical candidate
  40. GRB051028:MASTER observations
  41. GRB051028:MASTER optical observations
  42. GRB051012: Swift-XRT analysis
  43. GRB051021A: Swift XRT refined analysis
  44. GRB051022: Optical Observations
  45. GRB051021b: Magellan IR Imaging
  46. GRB 051021, SMARTS optical/IR observations
  47. GRB 051021B: Swift detection of a burst
  48. GRB 051021: Optical observations
  49. GRB 051021: Optical observations and candidate afterglow
  50. GRB051021.63
  51. GRB051021.6: MASTER optical observation
  52. GRB 051016b: Optical limit
  53. Afterglow candidate of GRB 051016B observed at Lulin
  54. GRB 051016b: Gemini Near IR Observations
  55. GRB 051016: Swift-BAT refined analysis
  56. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  57. GRB050805A: Rc optical observations
  58. GRB051008: optical candidate
  59. GRB051011: MASTER optical observation
  60. GRB051008 - Swift UVOT upper limits
  61. GRB 051008, optical observations
  62. GRB 051008: Swift UVOT Candidate
  63. GRB050925: Swift/XRT limits
  64. GRB050925: Faulkes Telescope North R-band limit
  65. GRB050922C: Optical Observations
  66. GRB050911: Upper limit on X-ray afterglow
  67. Swift-BAT trigger 155072 is probably not a GRB
  68. GRB050914: XRT position probably due to cosmic ray
  69. GRB 050911, optical content of Swift/XRT error box
  70. GRB050911: Swift-XRT position
  71. GRB 050906: Possible X-ray Counterpart
  72. GRB050908 : Swift-XRT refined analysis
  73. GRB 050908: Optical observations
  74. Gemini Spectroscopy of GRB 050908
  75. GRB 050908: P60 Confirmation of Optical Afterglow
  76. GRB 050908: Optical Observations
  77. GRB 050904: Subaru Optical Spectroscopy
  78. GRB 050904: Keck I-band Imaging
  79. GRB 050906: Bright galaxy in BAT error box
  80. GRB 050904: TAROT optical measurements
  81. GRB 050827: Optical Limit
  82. GRB 050826 : Lulin R band observation
  83. GRB 050826: Optical Candidate
  84. GRB050824: MASTER final analysis of the OT observations
  85. GRB050824, I-band imaging
  86. GRB 050824: XRT refined analysis and possible afterglow detection
  87. GRB 050824: BAT refined analysis of a soft weak burst
  88. GRB050824: MASTER:OT decay
  89. GRB 050824 optical candidate
  90. GRB 050820a - corrections to GCN 3846
  91. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  92. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  93. GRB050814: P60 Optical Afterglow Candidate
  94. GRB 050813: Non-fading of afterglow candidate
  95. GRB 050814: Swift detection of a burst
  96. GRB050813, SDSS pre-burst observations
  97. GRB 050813: Possible Short Swift-BAT GRB
  98. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  99. GRB050803: CrAO optical observations, no OT candidate
  100. Detection of an intermediate burst from SGR 1806-20 on August 8

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