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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"

7409 results found.

  1. GRB 130215A: Redshift estimate
  2. GRB 130215: ROTSE-III Detection of Optical Counterpart
  3. GRB 130211A: Swift detection of a burst
  4. GRB 130131A: RATIR optical and infrared upper limits
  5. GRB 130131B: Swift detection of a burst
  6. GRB 130131A - UKIRT afterglow candidate
  7. GRB 130131A: Swift detection of a burst
  8. GRB 130122A: T100 observations
  9. GRB 130122A: Swift detection of a burst with an optical counterpart
  10. GRB 130102A: Swift detection of a burst
  11. GRB 121229A: Swift detection of a burst
  12. GRB 121226A: Swift detection of a burst
  13. GRB 121217A: Swift detection of a burst
  14. GRB 121212A: Swift detection of a burst
  15. GRB 121211A - Faulkes Telescope North afterglow confirmation
  16. GRB 121211A: Swift detection of a burst with an optical counterpart
  17. GRB 121209A: Keck observations
  18. GRB 121209A: CARMA 3mm Observations
  19. GRB 121209A: GROND optical afterglow candidate
  20. GRB 121209A: UVOT Observation
  21. GRB 121128A: Optical Observations
  22. GRB121202A: Swift/UVOT Observations
  23. GRB 121201A: a GRB with an optical counterpart
  24. GRB 121128A: FTN optical afterglow confirmation
  25. GRB 121128A: Swift detection of a burst with an optical counterpart
  26. GRB 121125A: Fermi GBM Observation
  27. GRB 121125A: LOAO Observation
  28. GRB 121125A: Swift detection of a burst with optical counterpart
  29. GRB 121123A: Fermi GBM observation
  30. GRB 121123A: Swift detection of a burst with optical counterpart
  31. GRB 121117A: GROND confirmation of the UVOT afterglow candidate
  32. GRB 121108A: Swift detection of a burst
  33. GRB 121102A: Swift detection of a burst
  34. GRB 121027A: Brightening IR counterpart
  35. GRB 121028A: Swift detection of a burst
  36. GRB 121027A: nIR afterglow candidate with AAT
  37. GRB 121027A: Swift detection of a burst
  38. GRB 121024A: optical observations
  39. GRB 121024A: TAROT Calern observatory optical detection of a bright counterpart
  40. GRB 121024A: Swift detection of a burst with an optical counterpart
  41. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  42. GRB 121017A: Swift detection of a burst
  43. GRB 121011A: optical observations
  44. GRB 121011A: Swift detection of a burst with optical afterglow
  45. Trigger 535747: Swift detection of an outburst from SGR1806-20
  46. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  47. Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
  48. Swift Trigger 535026: Galactic Transient or possible GRB
  49. GRB 120927A: Swift detection of a burst
  50. GRB 120922A: Swift/UVOT Observations
  51. GRB 120923A: Gemini afterglow detection, high-z candidate
  52. GRB 120922A: TAROT La Silla observatory optical observations
  53. GRB 120923A: Swift detection of a burst
  54. GRB 120922A: GROND afterglow candidate
  55. GRB 120922A: Swift detection of a burst
  56. Swift Trigger 534017 is probably not real.
  57. Swift Trigger 533836 is a new Galactic transient
  58. GRB 120913B: TAROT La Silla observatory optical detection
  59. GRB 120907A: ROTSE-III Optical Limits
  60. GRB 120907A: Swift detection of a burst with optical counterpart
  61. GRB 120821A: Swift/XRT observations
  62. GRB 120819A: GROND afterglow confirmation
  63. GRB 120819A: afterglow candidate from NOT
  64. GRB 120819A: Swift detection of a burst
  65. GRB 120816A: optical upper limit
  66. GRB 120816A: Swift detection of a burst
  67. GRB 120805A: Liverpool Telescope optical candidate detection
  68. GRB 120815A: GROND afterglow candidate
  69. GRB 120815A: TAROT La Silla observatory optical observations
  70. GRB 120811C: MASTER-Amur observations of fading OT
  71. GRB 120811C: Swift detection of a burst with an optical counterpart
  72. Trigger 530588: Swift detection of XMM J174457-2850.3
  73. GRB 120807A: Swift detection of a burst
  74. Swift trigger 530214: uncertain if real or not
  75. GRB120805A: Liverpool Telescope observations
  76. GRB 120805A: Swift detection of a burst
  77. GRB 120804A: Swift detection of a short burst
  78. GRB 120803B: FTN possible afterglow candidate
  79. GRB 120803B: Swift detection of a burst
  80. GRB 120803A: Swift detection of a possible burst
  81. GRB 120802A: Swift detection of a burst
  82. GRB120729A - Faulkes Telescope North Optical Afterglow Candidate
  83. GRB 120729A: Swift detection of a burst with an optical afterglow
  84. GRB 120728A: Swift detection of a burst
  85. Swift Trigger 528925 is probably a noise fluctuation
  86. GRB 120724A: FTN optical afterglow candidate
  87. GRB 120724A: Swift detection of a burst
  88. GRB 120709A: Swift re-observation of the field of the X-ray counterpart candidate.
  89. GRB 120722A: VLT/X-shooter redshift of the host galaxy
  90. GRB 120722A: Correction for GCN circ.13500
  91. GRB 120722A: Xinglong TNT optical afterglow candidate
  92. GRB 120722A: Swift detection of a burst
  93. VLT/FORS2 redshift of GRB120716A
  94. GRB 120716A: GROND confirmation of the optical/NIR afterglow
  95. GRB 120716A: Optical decay from NOT
  96. GRB 120716A: Candidate Optical Afterglow from PTF
  97. GRB 120714B: Swift/UVOT Detection
  98. GRB 120714B: GROND confirmation of fading afterglow
  99. GRB 120714B: Position Correction and Candidate Optical Afterglow
  100. GRB120714A: UVOT non-detection

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