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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"

27393 results found.

  1. GRB 140413A: Swift-XRT observations
  2. GRB 140413A: GROND afterglow candidate
  3. Swift Trigger 595616: a possible GRB
  4. GRB 140412A: Swift detection of a burst
  5. Swift Trigger 595345 is not an astrophysical source
  6. Swift-BAT trigger 595162 is noise
  7. Fermi418277210: iPTF optical observations
  8. GRB 140408A: RATIR Optical Upper Limits
  9. GRB 140408A: Swift-BAT refined analysis
  10. GRB 140408A: GROND Detection of an Afterglow Candidate
  11. GRB 140408A: Swift/UVOT Upper Limits
  12. GRB 140408A: Swift-XRT refined Analysis
  13. GRB 140408A: Fermi GBM detection
  14. Swift Trigger 595162: a possible GRB
  15. GRB 140408A: Swift detection of a burst
  16. GRB 140406A: Fermi GBM observation
  17. GRB 140402A: Deep limit on the optical afterglow from Magellan observations
  18. GRB 140402A: Swift/UVOT Upper Limits
  19. GRB 140331A: Continued RATIR Optical and NIR Observations
  20. GRB 140402A: Swift-XRT observations
  21. GRB 140402A: MASTER optical observations
  22. GRB 140402A BAT refined analysis
  23. GRB 140402A: Marginal BAT detection
  24. GRB 140402A: Fermi GBM detection
  25. GRB 140402A: Fermi-LAT detection of a burst
  26. Swift trigger 594286: Is likely a noise trigger
  27. GRB 140330A: Fermi GBM observation
  28. GRB 140331A: Swift-XRT refined Analysis
  29. GRB 140301A: Zadko observatory - Gingin optical observations
  30. GRB 140331A: Swift-BAT refined analysis
  31. Retraction of the Fermi/LAT high-energy counterpart for GRB 140330A
  32. GRB 140331A: Swift/UVOT Upper Limits
  33. GRB 140302A: TAROT La Silla observatory optical observations
  34. GRB 140323A: Zadko observatory - Gingin optical observations
  35. GRB 140330A: intense and persistent gamma-ray emission detected by AGILE
  36. GRB 140331A: Zadko observatory - Gingin optical observations
  37. IPN triangulation of GRB 130330A
  38. GRB 140331A: RATIR Optical and NIR Observations
  39. GRB 140331A: Swift detection of a burst
  40. GRB 140330A: Fermi-LAT Detection
  41. GRB 140329A: Fermi-LAT detection
  42. MAXI ID=745548350 is UV Ceti
  43. GRB 140329A: Fermi GBM observation of a bright burst
  44. Swift trigger 593744: detection of a flare from UV Cet
  45. GRB 140323A : Suzaku WAM observation of the prompt emission
  46. Fermi Gamma-ray Burst Monitor trigger 417486540 / 140326020 is not a GRB
  47. GRB 140226A/iPTF14yb: Mondy optical observations
  48. Konus-Wind observation of GRB 140323A
  49. GRB 140323A: Fermi-LAT detection
  50. GRB 140323A: Swift-XRT refined Analysis
  51. GRB 140323A: Fermi GBM observation
  52. GRB 140323A: BOOTES-3 optical upper limit.
  53. GRB 140323A: Swift/UVOT Upper Limits
  54. GRB 140323A: Swift-BAT refined analysis
  55. GRB 140323A: Swift detection of a burst
  56. GRB 140320A: RATIR Optical and NIR Observations
  57. GRB 140320B: P60 detection of a very red afterglow
  58. IPN Triangulation of very intense GRB 140320D
  59. GRB 140320C: Mini-GWAC prompt observation
  60. GRB 140320C: Swift/UVOT Upper Limits
  61. GRB 140320A: Swift-BAT refined analysis
  62. GRB 140320B: Swift/UVOT Upper Limits
  63. GRB 140320A: Swift/UVOT Upper Limits
  64. GRB 140320C: Swift-XRT observations
  65. GRB 140320A: Confirmation of a fading X-ray afterglow
  66. GRB 140320C: Swift-XRT detection of the X-ray afterglow
  67. GRB 140320A: Fermi GBM detection
  68. GRB 140320B: Swift-XRT detection of the afterglow
  69. GRB 140320A: Swift-XRT detection of an afterglow candidate
  70. GRB 140320C: MASTER optical observations
  71. GRB 140320C: FTN optical observations
  72. GRB 140320B: FTN optical afterglow candidate
  73. Swift Trigger 592558 is not an astrophysical source
  74. GRB 140320A: Fermi GBM observations suggest a short GRB
  75. GRB 140320A: Swift detection of a burst
  76. GRB 140318A: Continued RATIR Optical and NIR Observations
  77. GRB 140318A: Swift/UVOT Upper Limits
  78. GRB 140318A: Swift-BAT refined analysis
  79. GRB 140318A: Swift-XRT refined Analysis
  80. GRB 140318A: Liverpool Telescope optical observations
  81. GRB 140318A: RATIR Optical and NIR Detections
  82. GRB140318A: Discovery Channel Telescope Optical Detection
  83. GRB 140318A: WHT spectroscopy
  84. GRB 140318A: NOT detection of the afterglow
  85. GRB 140318A: Swift detection of a burst
  86. GRB 140311C: Swift-XRT and UVOT observations
  87. GRB 140311C: MASTER before, during and after trigger optical observations
  88. GRB 140311B: Swift-BAT refined analysis
  89. GRB 140311A: RATIR Optical and NIR Detection
  90. GRB 140311C: Fermi GBM Detection
  91. GRB 140311A: Montarrenti Observatory optical upper limit
  92. GRB 140311B: Fermi GBM Detection
  93. GRB 140311A: Kottamia I-band observation
  94. GRB 140311A: Swift/UVOT Upper Limits
  95. GRB 140311B: Swift/UVOT Upper Limits
  96. Fermi416242156: possible iPTF counterpart
  97. GRB 140311B: RATIR Optical and NIR Observations
  98. GRB 140311A: Bassano Bresciano Observatory optical upper limit
  99. GRB 140311A: Swift-XRT refined Analysis
  100. GRO J1744-28: Fermi GBM observation

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