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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"

7444 results found.

  1. GRB 130511A: Swift detection of a burst with an optical counterpart
  2. GRB 130508A: Swift detection of a probable burst
  3. GRB 130505B: Swift Candidate Afterglow
  4. GRB 130504A: IAC80 optical candidate
  5. GRB 130505A: Swift detection of a burst with optical afterglow
  6. GRB 130504A: Bassano Bresciano Observatory optical upper limit
  7. GRB 130504A, Swift-BAT refined analysis
  8. Swift-XRT X-ray afterglow candidate for GRB 130504A (BAT trigger 555096)
  9. Trigger 555096: Swift detection of a possible burst
  10. GRB 130502A: Swift/UVOT Upper Limits
  11. GRB 130502B: P60 Observations
  12. GRB 130502A: TNG candidate counterpart
  13. GRB 130502A: Swift detection of a burst
  14. GRB 130427B: Swift detection of a burst with optical counterpart
  15. Swift Trigger 554135 is probably not a GRB or transient
  16. GRB 130420B: Swift detection of a burst
  17. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  18. GRB 130420A: Swift detection of a burst with an optical counterpart
  19. GRB 130420A: Faulkes Telescope North candidate
  20. GRB 130418A: Bassano Bresciano Observatory optical observations
  21. GRB 130418A: Swift detection of a burst with an optical counterpart
  22. GRB 130408A: Swift/UVOT Detection of the Optical Afterglow
  23. GRB 130408A: Liverpool Telescope Optical candidate detection
  24. GRB 130407A Tiled Swift observations
  25. GRB 130211A: Retraction of afterglow candidate
  26. GRB 130310A: RATIR Observations
  27. Swift Trigger 552142: a possible GRB
  28. GRB 130325A Tiled Swift observations
  29. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  30. GRB 130327A: Swift detection of a burst
  31. GRB 130315A: GROND afterglow candidate
  32. GRB130313A: GTC early optical limits
  33. GRB 130315A: Swift detection of a burst
  34. GRB 130313A: Swift detection of a short burst
  35. Swift XRT RETRACTION of GRB 130310A afterglow detection
  36. GRB 130215A: Redshift estimate
  37. GRB 130215: ROTSE-III Detection of Optical Counterpart
  38. GRB 130211A: Swift detection of a burst
  39. GRB 130131A: RATIR optical and infrared upper limits
  40. GRB 130131B: Swift detection of a burst
  41. GRB 130131A - UKIRT afterglow candidate
  42. GRB 130131A: Swift detection of a burst
  43. GRB 130122A: T100 observations
  44. GRB 130122A: Swift detection of a burst with an optical counterpart
  45. GRB 130102A: Swift detection of a burst
  46. GRB 121229A: Swift detection of a burst
  47. GRB 121226A: Swift detection of a burst
  48. GRB 121217A: Swift detection of a burst
  49. GRB 121212A: Swift detection of a burst
  50. GRB 121211A - Faulkes Telescope North afterglow confirmation
  51. GRB 121211A: Swift detection of a burst with an optical counterpart
  52. GRB 121209A: Keck observations
  53. GRB 121209A: CARMA 3mm Observations
  54. GRB 121209A: GROND optical afterglow candidate
  55. GRB 121209A: UVOT Observation
  56. GRB 121128A: Optical Observations
  57. GRB121202A: Swift/UVOT Observations
  58. GRB 121201A: a GRB with an optical counterpart
  59. GRB 121128A: FTN optical afterglow confirmation
  60. GRB 121128A: Swift detection of a burst with an optical counterpart
  61. GRB 121125A: Fermi GBM Observation
  62. GRB 121125A: LOAO Observation
  63. GRB 121125A: Swift detection of a burst with optical counterpart
  64. GRB 121123A: Fermi GBM observation
  65. GRB 121123A: Swift detection of a burst with optical counterpart
  66. GRB 121117A: GROND confirmation of the UVOT afterglow candidate
  67. GRB 121108A: Swift detection of a burst
  68. GRB 121102A: Swift detection of a burst
  69. GRB 121027A: Brightening IR counterpart
  70. GRB 121028A: Swift detection of a burst
  71. GRB 121027A: nIR afterglow candidate with AAT
  72. GRB 121027A: Swift detection of a burst
  73. GRB 121024A: optical observations
  74. GRB 121024A: TAROT Calern observatory optical detection of a bright counterpart
  75. GRB 121024A: Swift detection of a burst with an optical counterpart
  76. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  77. GRB 121017A: Swift detection of a burst
  78. GRB 121011A: optical observations
  79. GRB 121011A: Swift detection of a burst with optical afterglow
  80. Trigger 535747: Swift detection of an outburst from SGR1806-20
  81. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  82. Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
  83. Swift Trigger 535026: Galactic Transient or possible GRB
  84. GRB 120927A: Swift detection of a burst
  85. GRB 120922A: Swift/UVOT Observations
  86. GRB 120923A: Gemini afterglow detection, high-z candidate
  87. GRB 120922A: TAROT La Silla observatory optical observations
  88. GRB 120923A: Swift detection of a burst
  89. GRB 120922A: GROND afterglow candidate
  90. GRB 120922A: Swift detection of a burst
  91. Swift Trigger 534017 is probably not real.
  92. Swift Trigger 533836 is a new Galactic transient
  93. GRB 120913B: TAROT La Silla observatory optical detection
  94. GRB 120907A: ROTSE-III Optical Limits
  95. GRB 120907A: Swift detection of a burst with optical counterpart
  96. GRB 120821A: Swift/XRT observations
  97. GRB 120819A: GROND afterglow confirmation
  98. GRB 120819A: afterglow candidate from NOT
  99. GRB 120819A: Swift detection of a burst
  100. GRB 120816A: optical upper limit

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