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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"

7420 results found.

  1. GRB 051221: Swift detection of a bright short burst
  2. GRB051211A: possible optical candidate
  3. GRB 051215: A short GRB in a cluster?
  4. GRB 051211B: Swift XRT confirmation of the afterglow
  5. GRB051211B: Liverpool Telescope observation
  6. GRB 051211b: RTT150 optical observations
  7. GRB 051211B: Swift XRT Observations
  8. GRB 051211B: a possible optical detection by TAROT
  9. GRB051111: Rc optical observations
  10. GRB 051117B: Swift detection of a burst
  11. Faulkes Telescope R-band detection of GRB051111
  12. GRB 051109a: IR Detections
  13. GRB051103: MASTER: OT limit and host galaxy candidates
  14. GRB 051105A, 2nd epoch optical observations
  15. GRB051103:_MASTER_optical_observations
  16. GRB 051105: Optical limit
  17. GRB051016B: optical observation
  18. GRB051028: optical observations
  19. GRB051028: confirmation of the afterglow
  20. GRB051028: WHT optical candidate
  21. GRB051028:MASTER observations
  22. GRB051028:MASTER optical observations
  23. GRB 051022: XRT Refined Spectral and Temporal Analysis
  24. GRB051021A: Swift XRT refined analysis
  25. GRB051021b: Magellan IR Imaging
  26. GRB 051021, SMARTS optical/IR observations
  27. GRB 051021: Optical observations
  28. GRB 051021: Optical observations and candidate afterglow
  29. GRB051021.63
  30. GRB051021.6: MASTER optical observation
  31. GRB 051016b: Optical limit
  32. Afterglow candidate of GRB 051016B observed at Lulin
  33. GRB 051016b: Gemini Near IR Observations
  34. GRB050805A: Rc optical observations
  35. GRB051008: optical candidate
  36. GRB051011: MASTER optical observation
  37. GRB051008 - Swift UVOT upper limits
  38. GRB 051008, optical observations
  39. GRB 051008: Swift UVOT Candidate
  40. grb test
  41. GRB050925: Faulkes Telescope North R-band limit
  42. GRB 050911, optical content of Swift/XRT error box
  43. GRB050911: Swift-XRT position
  44. GRB050908 : Swift-XRT refined analysis
  45. GRB 050908: Optical observations
  46. Gemini Spectroscopy of GRB 050908
  47. GRB 050908: P60 Confirmation of Optical Afterglow
  48. GRB 050908: Optical Observations
  49. GRB 050904: Subaru Optical Spectroscopy
  50. GRB 050906: Swift-BAT refined analysis
  51. GRB 050904: Keck I-band Imaging
  52. GRB 050904: TAROT optical measurements
  53. GRB 050827: Optical Limit
  54. GRB 050826 : Lulin R band observation
  55. GRB 050826: Optical Candidate
  56. GRB050824: MASTER final analysis of the OT observations
  57. GRB050824, I-band imaging
  58. GRB 050824: XRT refined analysis and possible afterglow detection
  59. GRB 050824: BAT refined analysis of a soft weak burst
  60. GRB050824: MASTER:OT decay
  61. GRB 050824 optical candidate
  62. GRB050814: P60 Optical Afterglow Candidate
  63. GRB 050813: Non-fading of afterglow candidate
  64. GRB050803: CrAO optical observations, no OT candidate
  65. GRB050802: TNG optical observations
  66. GRB 050803: RTT150 optical observations
  67. GRB050803: CrAO optical observations, possible OT candidate
  68. GRB 050803, optical observations
  69. GRB 050802: Swift/UVOT optical and UV detections
  70. GRB050801: Optical photometry and decay index
  71. GRB 050730, SMARTS optical/IR afterglow observations
  72. GRB050730: Liverpool Telescope optical observations
  73. GRB 050730, optical candidate
  74. GRB 050721a: Optical Observations
  75. GRB 050714a: Refined XRT analysis and afterglow confirmation
  76. GRB 050716; J-band observations
  77. GRB 050716 - UKIRT identification of candidate afterglow
  78. GRB 050716: Refined XRT analysis.
  79. GRB050716: Faulkes North Telescope observation
  80. GRB 050714B: refined XRT analysis
  81. GRB 050714B: candidate afterglow does not fade
  82. GRB 050709: optical afterglow candidate
  83. GRB 050714, R-band candidate
  84. GRB 050709: Spectroscopy
  85. GRB050713B: Faulkes North Telescope observation
  86. RBO RI observations of GRB 050713A
  87. GRB050709: Candidate X-ray Afterglow from Chandra
  88. GRB 050713: ARC NIR Detections and Identification of Fading
  89. GRB050712: UVOT candidate optical counterpart
  90. GRB 050626: Swift XRT observations
  91. GRB 050607: MDM Observations
  92. GRB 050603: Swift XRT Position
  93. GRB050528: BOOTES optical candidate (retraction)
  94. GRB050528: BOOTES optical candidate
  95. Possible GRB050528: no candidate from Liverpool Telescope
  96. GRB050525: Super-LOTIS observations
  97. GRB 050525a: Gemini/GMOS Spectra
  98. GRB050306: optical afterglow not confirmed
  99. GRB050525: Optical observations
  100. GRB 050525: Optical observation

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