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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"

18435 results found.

  1. GRB 121027A: sub-mm upper limit
  2. GRB 121031A: Swift-BAT refined analysis
  3. GRB 121031A: Prompt enhanced Swift-XRT position
  4. GRB 121031A: Swift detection of a burst
  5. Swift Quick-look and HEASARC are back online
  6. GRB 121027A: Swift/UVOT Possible Detection
  7. GRB 121028A: near-IR observations at Calar Alto
  8. GRB 121028A: RAPTOR Limits During Gamma-Ray Emitting Interval
  9. Swift Quick-look and HEASARC will be offline for due to hurricane Sandy
  10. GRB 121027A: MASTER early prompt optical limit
  11. GRB 121027A: Swift-XRT refined Analysis
  12. GRB 121027A: Brightening IR counterpart
  13. GRB 121028A: Swift-XRT refined Analysis
  14. GRB 121028A: Enhanced Swift-XRT position
  15. GRB 121028A: Swift-BAT refined analysis
  16. GRB 121027A: Enhanced Swift-XRT position
  17. GRB 121028A: Swift detection of a burst
  18. GRB 121011A: optical observations
  19. GRB 121027A: nIR afterglow candidate with AAT
  20. GRB 121027A: Swift-BAT refined analysis
  21. GRB 121025A: Swift-XRT observation
  22. GRB 121027A: MAXI/GSC detection 40 minutes after the Swift Trigger
  23. GRB 121027A: Swift detection of a burst
  24. Swift Quick-look and HEASARC will be offline for 24 hours this weekend
  25. Swift-BAT trigger 536502 is not astrophysical
  26. GRB 121024A: Swift/UVOT Observations
  27. GRB 121024A: Swift-BAT refined analysis
  28. GRB 121024A: Enhanced Swift-XRT position
  29. GRB 121024A: PAIRITEL NIR Detection
  30. GRB 121024A: Swift-XRT refined Analysis
  31. GRB 121024A: GROND Detection of the Optical/NIR Afterglow
  32. Skynet PROMPT/Dolomiti observations of GRB121024A
  33. GRB 121024A: TAROT Calern observatory optical detection of a bright counterpart
  34. GRB 121024A: Swift detection of a burst with an optical counterpart
  35. Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
  36. GRB 121011A: early optical light curve
  37. GRB 121017A: Swift/UVOT Upper Limits
  38. GRB 121017A: Swift-XRT refined Analysis
  39. GRB 121017A: GROND Observations
  40. GRB 121017A: Swift-BAT refined analysis
  41. GRB 121017A: Enhanced Swift-XRT position
  42. GRB 121017A: 1.23m CAHA R-band observations
  43. GRB 121017A: BOOTES-2/TELMA observations
  44. GRB 121017A: Swift detection of a burst
  45. GRB 121011A Suzaku WAM observation of the prompt emission
  46. GRB 121014A: Swift-BAT refined analysis
  47. GRB 121014A: Swift detection of a burst
  48. GRB 121011A: Swift/UVOT Detection
  49. GRB 121011A: Fermi GBM observation
  50. GRB 121011A: Fermi-LAT detection of a burst
  51. Swift-BAT trigger 535733 is not astrophysical
  52. GRB 121011A: Swift-XRT refined Analysis
  53. GRB 121011A: optical observations
  54. GRB 121011A, Swift-BAT refined analysis
  55. Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
  56. GRB 121011A: Enhanced Swift-XRT position
  57. GRB 121011A: MASTER-Net early OT light curve
  58. GRB 121011A: Swift detection of a burst with optical afterglow
  59. Trigger 535747: Swift detection of an outburst from SGR1806-20
  60. Trigger 535733: Swift possible detection of SAX J1828.5-1037
  61. GRB 120927A: optical upper limit
  62. GRB 120804A: Late-time Chandra observation
  63. GRB 121001A: GROND Afterglow Confirmation
  64. GRB 121001A: Swift/UVOT Upper Limits
  65. GRB 121001A: Swift-XRT refined Analysis
  66. GRB 121001A: Enhanced Swift-XRT Position
  67. Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
  68. Swift Trigger 535026: Optical decay confirmation with IAC80 and BOOTES-2/TELMA.
  69. GRB 121001A: MASTER optical observations
  70. GRB 121001A: possible optical counterpart
  71. Swift Trigger 535026: ROTSE-III Optical Limits
  72. Swift Trigger 535026: Galactic Transient or possible GRB
  73. GRB 120927A: Swift/UVOT Upper Limits
  74. GRB 120927A, Swift-BAT refined analysis
  75. GRB 120927A: GROND upper limits
  76. GRB 120927A: Swift-XRT refined Analysis
  77. GRB 120927A: Enhanced Swift-XRT position
  78. GRB 120927A: Swift detection of a burst
  79. Further Swift-XRT observations of the GRB 120919A field.
  80. GRB 120923A: optical upper limit
  81. GRB 120923A: RAPTOR Early Afterglow Limits
  82. GRB 120916A Suzaku WAM observation of the prompt emission
  83. GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval
  84. GRB 120923A: CARMA Observations
  85. GRB 120923A: EVLA Observations
  86. GRB 120923A: Swift-XRT refined Analysis
  87. GRB 120923A: GROND Upper limits
  88. GRB 120922A: Fermi GBM detection
  89. GRB 120922A: Swift/UVOT Detection
  90. GRB 120923A: Swift-BAT refined analysis
  91. GRB 120922A: Swift-BAT refined analysis
  92. GRB 120923A: Swift/UVOT Upper Limit
  93. GRB 120922A: Swift-XRT refined Analysis
  94. GRB 120922A: Swift/UVOT Observations
  95. GRB 120923A: Enhanced Swift-XRT position
  96. GRB 120922A: Enhanced Swift-XRT position
  97. GRB 120922A: TAROT La Silla observatory optical observations
  98. GRB 120923A: TAROT La Silla observatory optical observations
  99. GRB 120923A: ROTSE-III Optical Limits
  100. GRB 120923A: Swift detection of a burst

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