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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"

19534 results found.

  1. GRB 141130A: Swift/UVOT Detection
  2. GRB 141130A: Swift-XRT refined Analysis
  3. GRB 141130A: Enhanced Swift-XRT position
  4. GRB 141130A: Swift detection of a burst with an optical counterpart
  5. GRB 141121A: Continued RATIR Optical Observations
  6. GRB 141121A: Continued RATIR Optical Observations
  7. IPN Triangulation of GRB 141121A (initial episode)
  8. GRB 141121A: SPI-ACS/INTEGRAL observations
  9. GRB 141121A: RATIR Optical and NIR Observations
  10. Konus-Wind observation of GRB 141121A
  11. IPN Triangulation of GRB 141125A (short/hard)
  12. GRB 141121A: Continued RATIR Optical Observations
  13. GRB 141121A: Continued RATIR Optical Observations
  14. GRB 141121A: RATIR Optical Observations - Steeper Fading
  15. GRB 141121A: RATIR Optical Observations - Fading Again
  16. GRB 141121A: LCO-FTN rebrightening confirmation
  17. GRB 141121A: Continued RATIR Optical Observations - Rebrightening
  18. GRB 141121A: Continued RATIR Optical Observations
  19. GRB 141121A: Swift-XRT refined Analysis
  20. GRB 141121A: Swift/UVOT Detections
  21. GRB 141121A: RATIR Optical Observations
  22. GRB 141121A: Swift-BAT refined analysis
  23. GRB 141121A: LCO-FTN observations
  24. GRB 141121A: Enhanced Swift-XRT position
  25. GRB 141121A: GROND Afterglow candidate
  26. GRB141121A: BOOTES-2/TELMA upper limit
  27. GRB 141121A: Swift detection of a burst
  28. IPN Triangulation of GRB 141118A
  29. GRB 141104A: further Swift-XRT observations and afterglow candidate
  30. Swift Trigger 618673: probable noise event
  31. Trigger 618634: Swift detection of Vela X-1
  32. GRB 141109B: optical upper limits
  33. GRB 141015A: TAROT La Silla observatory optical observations
  34. GRB 141022A: TAROT La Silla observatory optical observations
  35. GRB 141031A: TAROT La Silla observatory optical observations
  36. GRB 141109A: TAROT La Silla observatory optical observations
  37. GRB 141109A: AAO optical observations
  38. Swift Trigger 618402: probable noise event
  39. Swift Trigger 618391 is not an astrophysical event
  40. GRB 141109B: Swift/UVOT Upper Limits
  41. GRB 141109A: Swift/UVOT Detection
  42. Konus-Wind observation of GRB 141109A
  43. GRB 141109B: IRAM 30m millimetre observations
  44. GRB 141109B: Swift-XRT refined Analysis
  45. Swift Trigger 618134 is not an astrophysical event
  46. GRB 141109A: Swift-XRT refined Analysis
  47. GRB 141109B: BOOTES-4 and TERSKOL optical upper limit
  48. GRB 141109B: Swift-BAT refined analysis
  49. GRB 141109B: Enhanced Swift-XRT position
  50. GRB 141109A: Swift-BAT refined analysis
  51. GRB 141109A: Enhanced Swift-XRT position
  52. GRB 141109A: GROND afterglow observation
  53. X-shooter redshift of GRB 141109A
  54. GRB 141109B: Swift detection of a burst
  55. GRB 141109A: Swift detection of a burst
  56. GRB 141104A: Swift-XRT observations
  57. GRB 141104A Tiled Swift observations
  58. GRB 141026A: CrAO optical observation
  59. GRB
  60. GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
  61. IPN Triangulation of GRB 141104A (long/very bright)
  62. GRB 141102A possible precursor was another, known source
  63. Konus-Wind observation of GRB 141102A
  64. GRB 141022A: Skynet PROMPT-CTIO Observations
  65. GRB 141102A: Fermi-LAT detection
  66. GRB 141102A: Fermi GBM detection
  67. GRB 141102A found in ground analysis of BAT data
  68. GRB 141031B: RATIR Optical and NIR Observation
  69. GRB 141031B: Swift/UVOT Upper Limits
  70. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  71. GRB 141031B: Swift-XRT refined Analysis
  72. GRB 141031B: Bassano Bresciano Observatory upper limit
  73. GRB 141031B: Swift-BAT refined analysis
  74. GRB 141031A, Swift-BAT refined analysis
  75. GRB 141031B: Enhanced Swift-XRT position
  76. GRB 141031A: Swift/UVOT Upper Limits
  77. GRB 141031A: Swift-XRT refined Analysis
  78. GRB 141031A: Skynet PROMPT-CTIO Observations
  79. GRB 141031A: Fermi GBM detection
  80. GRB 141031B: MASTER early optical observations
  81. GRB 141031B: Swift detection of a burst
  82. GRB 141031A: Enhanced Swift-XRT position
  83. GRB 141031A: GROND detection of a possible optical afterglow candidate
  84. GRB 141031A: Swift detection of a burst
  85. GRB 140509A: GROND afterglow detection
  86. GRB 141028A: Swift/UVOT followup observations
  87. GRB 141028A: Swift-XRT observations
  88. GRB 141029A Tiled Swift observations
  89. GRB 141028A: Swift/UVOT Detection
  90. GRB 141028A: Swift/XRT detection of the X-ray afterglow
  91. GRB 141020A: Continued Mondy Observations, optical upper limit
  92. GRB 141026A: IRAM 30m millimetre observations
  93. GRB 141028A Tiled Swift observations
  94. GRB 141026A: Continued RATIR Optical and NIR Observations
  95. GRB 141028A: Fermi-LAT detection
  96. GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
  97. GRB 141026A: Swift/UVOT Upper Limits
  98. GRB 141026A: Swift-XRT refined Analysis
  99. GRB 141026A: Swift-BAT refined analysis
  100. GRB 141026A: MASTER early optical observations

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