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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"

19594 results found.

  1. Swift Trigger 618402: probable noise event
  2. Swift Trigger 618391 is not an astrophysical event
  3. GRB 141109B: Swift/UVOT Upper Limits
  4. GRB 141109A: Swift/UVOT Detection
  5. Konus-Wind observation of GRB 141109A
  6. GRB 141109B: IRAM 30m millimetre observations
  7. GRB 141109B: Swift-XRT refined Analysis
  8. Swift Trigger 618134 is not an astrophysical event
  9. GRB 141109A: Swift-XRT refined Analysis
  10. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  11. GRB 141109B: Swift-BAT refined analysis
  12. GRB 141109B: Enhanced Swift-XRT position
  13. GRB 141109A: Swift-BAT refined analysis
  14. GRB 141109A: Enhanced Swift-XRT position
  15. GRB 141109A: GROND afterglow observation
  16. X-shooter redshift of GRB 141109A
  17. GRB 141109B: Swift detection of a burst
  18. GRB 141109A: Swift detection of a burst
  19. GRB 141104A: Swift-XRT observations
  20. GRB 141104A Tiled Swift observations
  21. GRB 141026A: CrAO optical observation
  22. GRB
  23. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  24. IPN Triangulation of GRB 141104A (long/very bright)
  25. GRB 141102A possible precursor was another, known source
  26. Konus-Wind observation of GRB 141102A
  27. GRB 141022A: Skynet PROMPT-CTIO Observations
  28. GRB 141102A: Fermi-LAT detection
  29. GRB 141102A: Fermi GBM detection
  30. GRB 141102A found in ground analysis of BAT data
  31. GRB 141031B: RATIR Optical and NIR Observation
  32. GRB 141031B: Swift/UVOT Upper Limits
  33. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  34. GRB 141031B: Swift-XRT refined Analysis
  35. GRB 141031B: Bassano Bresciano Observatory upper limit
  36. GRB 141031B: Swift-BAT refined analysis
  37. GRB 141031A, Swift-BAT refined analysis
  38. GRB 141031B: Enhanced Swift-XRT position
  39. GRB 141031A: Swift/UVOT Upper Limits
  40. GRB 141031A: Swift-XRT refined Analysis
  41. GRB 141031A: Skynet PROMPT-CTIO Observations
  42. GRB 141031A: Fermi GBM detection
  43. GRB 141031B: MASTER early optical observations
  44. GRB 141031B: Swift detection of a burst
  45. GRB 141031A: Enhanced Swift-XRT position
  46. GRB 141031A: GROND detection of a possible optical afterglow candidate
  47. GRB 141031A: Swift detection of a burst
  48. GRB 140509A: GROND afterglow detection
  49. GRB 141028A: Swift/UVOT followup observations
  50. GRB 141028A: Swift-XRT observations
  51. GRB 141029A Tiled Swift observations
  52. GRB 141028A: Swift/UVOT Detection
  53. GRB 141028A: Swift/XRT detection of the X-ray afterglow
  54. GRB 141020A: Continued Mondy Observations, optical upper limit
  55. GRB 141026A: IRAM 30m millimetre observations
  56. GRB 141028A Tiled Swift observations
  57. GRB 141026A: Continued RATIR Optical and NIR Observations
  58. GRB 141028A: Fermi-LAT detection
  59. GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
  60. GRB 141026A: Swift/UVOT Upper Limits
  61. GRB 141026A: Swift-XRT refined Analysis
  62. GRB 141026A: Swift-BAT refined analysis
  63. GRB 141026A: MASTER early optical observations
  64. GRB 141026A: Enhanced Swift-XRT position
  65. GRB 141026A: GROND observations
  66. GRB 141026A: RATIR Optical Observations
  67. GRB 141026A: P60 early observations
  68. GRB 141026A: Swift detection of a burst
  69. GRB 141020A: AAO optical upper limit
  70. GRB 141020A: Khureltogot optical upper limit
  71. GRB141022A: Fermi GBM Detection
  72. GRB 141022A: Swift/UVOT Upper Limits
  73. GRB 141020A: Mondy optical observations
  74. GRB 141022A: Swift-BAT refined analysis
  75. GRB 141022A: Swift-XRT refined Analysis
  76. GRB141015A iTelescope observation
  77. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  78. GRB 141022A: Swift detection of a burst
  79. GRB 141004A: RATIR Late Time Optical and NIR Observations
  80. GRB 141020A: Swift-BAT refined analysis
  81. GRB 141020A: Swift-XRT refined Analysis
  82. GRB 141020A: 1.4 GHZ observation
  83. GRB 141020A: Swift/UVOT Detection
  84. GRB 141020A: Enhanced Swift-XRT position
  85. GRB 141020B: MAXI/GSC detection
  86. Konus-Wind observation of GRB 141017A
  87. GRB 141020A: Swift detection of a burst with an optical counterpart
  88. GRB 141017A, Swift-BAT refined analysis
  89. GRB 141017A: GROND Afterglow Confirmation
  90. GRB 141015A: Swift-XRT afterglow confirmation and refined Analysis
  91. GRB 141017A: Swift/UVOT Detection
  92. GRB 141017A: Swift-XRT refined Analysis
  93. GRB 141017A: Enhanced Swift-XRT position
  94. GRB 141017A: Zadko observatory - Gingin optical observations
  95. GRB 141017A: Swift detection of a burst
  96. GRB 141015A: Swift/UVOT Upper Limits
  97. GRB 141015A: Swift-BAT refined analysis
  98. GRB 141015A: RATIR Optical Upper Limits
  99. GRB 141015A: Enhanced Swift-XRT position
  100. GRB 141015A: Super-LOTIS early observations

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