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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"
  1. GRB141124A: MASTER Detection of New Flare of QSO NVSS J075043+790917 During the Fermi Error Box inspection
  2. GRB 141118A: Fermi GBM Detection
  3. GRB 141121A: Mondy optical observations
  4. GRB 141121A: LCO-FTN rebrightening confirmation
  5. GRB 141121A: MITSuME Ishigakijima Optical Observation
  6. GRB 141121A: Continued RATIR Optical Observations - Rebrightening
  7. GRB 141121A: AAO optical observations
  8. GRB 141121A: MITSuME Akeno Optical observation
  9. GRB 141121A: Continued RATIR Optical Observations
  10. GRB 141121A: Swift-XRT refined Analysis
  11. GRB 141121A: Swift/UVOT Detections
  12. GRB 141121A: RATIR Optical Observations
  13. GRB 141121A: Swift-BAT refined analysis
  14. GRB 141121A: LCO-FTN observations
  15. GRB 141121A: Keck redshift
  16. GRB 141121A: Enhanced Swift-XRT position
  17. GRB 141118A: iPTF Optical Observations
  18. GRB 141121A: GROND Afterglow candidate
  19. GRB 141121A: MAXI/GSC detection
  20. GRB141121A: BOOTES-2/TELMA upper limit
  21. GRB 141121A: Swift detection of a burst
  22. Konus-Wind observation of GRB 141118A
  23. IPN Triangulation of GRB 141118A
  24. GRB 141109A: further VLA observations
  25. GRB 141104A: further Swift-XRT observations and afterglow candidate
  26. GRB 141109A: VLA detection
  27. Swift Trigger 618673: probable noise event
  28. Trigger 618634: Swift detection of Vela X-1
  29. GRB 141109B: optical upper limits
  30. GRB 141015A: TAROT La Silla observatory optical observations
  31. GRB 141022A: TAROT La Silla observatory optical observations
  32. GRB 141031A: TAROT La Silla observatory optical observations
  33. GRB 141109A: TAROT La Silla observatory optical observations
  34. GRB 141109A: AAO optical observations
  35. Swift Trigger 618402: probable noise event
  36. Swift Trigger 618391 is not an astrophysical event
  37. GRB 141109A: Terskol photometry
  38. GRB 141109B: Swift/UVOT Upper Limits
  39. GRB 141109A: Swift/UVOT Detection
  40. GRB 141109A: NOT r-band observation
  41. Konus-Wind observation of GRB 141109A
  42. GRB 141109B: MITSuME Akeno upper limits
  43. GRB141109A : Xinglong TNT optical observation
  44. GRB 141109B: IRAM 30m millimetre observations
  45. GRB 141109B: Swift-XRT refined Analysis
  46. Swift Trigger 618134 is not an astrophysical event
  47. GRB 141109A: MITSuME Ishigakijima upper limits
  48. GRB 141109A: Swift-XRT refined Analysis
  49. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  50. GRB 141109B: Swift-BAT refined analysis
  51. GRB 141109B: Enhanced Swift-XRT position
  52. GRB 141109A: Swift-BAT refined analysis
  53. GRB 141109A: Enhanced Swift-XRT position
  54. GRB 141109A: CQUEAN Detection at 0.85 - 1.05 micron
  55. GRB 141109A: GROND afterglow observation
  56. X-shooter redshift of GRB 141109A
  57. GRB 141109A: REM NIR candidate afterglow
  58. GRB 141109B: Swift detection of a burst
  59. GRB 141109A: Swift detection of a burst
  60. GRB 141104A: Swift-XRT observations
  61. GRB 141028A: Mondy optical observations
  62. GRB 141104A Tiled Swift observations
  63. GRB 141026A: CrAO optical observation
  64. GRB
  65. GRB 141026A: Gemini-North optical and NIR imaging
  66. GRB 141028A: TShAO optical observation
  67. GRB 141031B: TShAO optical observations
  68. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  69. Konus-Wind observation of GRB 141104A
  70. IPN Triangulation of GRB 141104A (long/very bright)
  71. GRB 141102A possible precursor was another, known source
  72. Konus-Wind observation of GRB 141102A
  73. GRB 141022A: Skynet PROMPT-CTIO Observations
  74. GRB 141102A: Fermi-LAT detection
  75. GRB 141102A: Fermi GBM detection
  76. GRB 141102A found in ground analysis of BAT data
  77. GRB 141026A: VLA observations
  78. GRB 141031B: RATIR Optical and NIR Observation
  79. GRB 141031B: Swift/UVOT Upper Limits
  80. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  81. GRB 141031B: Swift-XRT refined Analysis
  82. GRB 141031B: Bassano Bresciano Observatory upper limit
  83. GRB 141031B: NOT optical observations
  84. GRB 141031B: MITSuME Ishigakijima upper limits
  85. GRB 141031B: Swift-BAT refined analysis
  86. GRB 141031A, Swift-BAT refined analysis
  87. GRB 141031B: Enhanced Swift-XRT position
  88. GRB 141031A: Swift/UVOT Upper Limits
  89. GRB 141031B: TShAO optical upper limit
  90. GRB 141031B: 1.23m CAHA I-band observations
  91. GRB 141031A: Swift-XRT refined Analysis
  92. GRB 141031A: Skynet PROMPT-CTIO Observations
  93. GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
  94. GRB 141031A: VLT/X-shooter optical observations
  95. GRB 141031A: Fermi GBM detection
  96. GRB 141031B: Nanshan optical upper limit
  97. GRB 141031B: MASTER early optical observations
  98. GRB 141031B: Swift detection of a burst
  99. GRB 141031A: Enhanced Swift-XRT position
  100. GRB 141031A: GROND detection of a possible optical afterglow candidate

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