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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. GRB 141121A: Enhanced Swift-XRT position
  2. GRB 141118A: iPTF Optical Observations
  3. GRB 141121A: GROND Afterglow candidate
  4. GRB 141121A: MAXI/GSC detection
  5. GRB141121A: BOOTES-2/TELMA upper limit
  6. GRB 141121A: Swift detection of a burst
  7. Konus-Wind observation of GRB 141118A
  8. IPN Triangulation of GRB 141118A
  9. GRB 141109A: further VLA observations
  10. GRB 141104A: further Swift-XRT observations and afterglow candidate
  11. GRB 141109A: VLA detection
  12. Swift Trigger 618673: probable noise event
  13. Trigger 618634: Swift detection of Vela X-1
  14. GRB 141109B: optical upper limits
  15. GRB 141015A: TAROT La Silla observatory optical observations
  16. GRB 141022A: TAROT La Silla observatory optical observations
  17. GRB 141031A: TAROT La Silla observatory optical observations
  18. GRB 141109A: TAROT La Silla observatory optical observations
  19. GRB 141109A: AAO optical observations
  20. Swift Trigger 618402: probable noise event
  21. Swift Trigger 618391 is not an astrophysical event
  22. GRB 141109A: Terskol photometry
  23. GRB 141109B: Swift/UVOT Upper Limits
  24. GRB 141109A: Swift/UVOT Detection
  25. GRB 141109A: NOT r-band observation
  26. Konus-Wind observation of GRB 141109A
  27. GRB 141109B: MITSuME Akeno upper limits
  28. GRB141109A : Xinglong TNT optical observation
  29. GRB 141109B: IRAM 30m millimetre observations
  30. GRB 141109B: Swift-XRT refined Analysis
  31. Swift Trigger 618134 is not an astrophysical event
  32. GRB 141109A: MITSuME Ishigakijima upper limits
  33. GRB 141109A: Swift-XRT refined Analysis
  34. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  35. GRB 141109B: Swift-BAT refined analysis
  36. GRB 141109B: Enhanced Swift-XRT position
  37. GRB 141109A: Swift-BAT refined analysis
  38. GRB 141109A: Enhanced Swift-XRT position
  39. GRB 141109A: CQUEAN Detection at 0.85 - 1.05 micron
  40. GRB 141109A: GROND afterglow observation
  41. X-shooter redshift of GRB 141109A
  42. GRB 141109A: REM NIR candidate afterglow
  43. GRB 141109B: Swift detection of a burst
  44. GRB 141109A: Swift detection of a burst
  45. GRB 141104A: Swift-XRT observations
  46. GRB 141028A: Mondy optical observations
  47. GRB 141104A Tiled Swift observations
  48. GRB 141026A: CrAO optical observation
  49. GRB
  50. GRB 141026A: Gemini-North optical and NIR imaging
  51. GRB 141028A: TShAO optical observation
  52. GRB 141031B: TShAO optical observations
  53. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  54. Konus-Wind observation of GRB 141104A
  55. IPN Triangulation of GRB 141104A (long/very bright)
  56. GRB 141102A possible precursor was another, known source
  57. Konus-Wind observation of GRB 141102A
  58. GRB 141022A: Skynet PROMPT-CTIO Observations
  59. GRB 141102A: Fermi-LAT detection
  60. GRB 141102A: Fermi GBM detection
  61. GRB 141102A found in ground analysis of BAT data
  62. GRB 141026A: VLA observations
  63. GRB 141031B: RATIR Optical and NIR Observation
  64. GRB 141031B: Swift/UVOT Upper Limits
  65. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  66. GRB 141031B: Swift-XRT refined Analysis
  67. GRB 141031B: Bassano Bresciano Observatory upper limit
  68. GRB 141031B: NOT optical observations
  69. GRB 141031B: MITSuME Ishigakijima upper limits
  70. GRB 141031B: Swift-BAT refined analysis
  71. GRB 141031A, Swift-BAT refined analysis
  72. GRB 141031B: Enhanced Swift-XRT position
  73. GRB 141031A: Swift/UVOT Upper Limits
  74. GRB 141031B: TShAO optical upper limit
  75. GRB 141031B: 1.23m CAHA I-band observations
  76. GRB 141031A: Swift-XRT refined Analysis
  77. GRB 141031A: Skynet PROMPT-CTIO Observations
  78. GRB 141004A: Continued Late Time RATIR Optical and NIR Observations
  79. GRB 141031A: VLT/X-shooter optical observations
  80. GRB 141031A: Fermi GBM detection
  81. GRB 141031B: Nanshan optical upper limit
  82. GRB 141031B: MASTER early optical observations
  83. GRB 141031B: Swift detection of a burst
  84. GRB 141031A: Enhanced Swift-XRT position
  85. GRB 141031A: GROND detection of a possible optical afterglow candidate
  86. GRB 141031A: Swift detection of a burst
  87. GRB 141029A: Nanshan optical upper limit
  88. GRB 141028A: SAO RAS Zeiss-1000 photometry
  89. GRB 140509A: GROND afterglow detection
  90. GRB 141028A: Continued RATIR Observations
  91. GRB 141028A: Swift/UVOT followup observations
  92. GRB 141028A: P60 Observations and Decay Index
  93. IPN triangulation of GRB 141029B
  94. GRB 141029B: Fermi GBM detection
  95. GRB 141028A: Swift-XRT observations
  96. GRB 141028A: LCOGTN observations
  97. GRB 141029A Tiled Swift observations
  98. GRB 141028A: VLT/X-shooter redshift of z=2.33
  99. GRB141028A: Gemini-North redshift
  100. GRB 141029A: MAXI/GSC detection

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