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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"

28057 results found.

  1. GRB 221120A: GIT upper limits on optical afterglow
  2. GRB 221119A: Fermi GBM detection
  3. GRB 221119A: Detection by GRBAlpha
  4. GRB 221119A: Fermi-LAT detection
  5. GRB 221009A: Japanese VLBI Network observation
  6. GRB 221115B: LCOGT Optical Upper Limits
  7. GRB 221115B : MeerLICHT upper limits
  8. GRB 221115A: Fermi GBM detection
  9. GRB 221115B: Swift/BAT-GUANO arcminute localization
  10. GRB 221115A: Swift/BAT-GUANO detection
  11. GRB 221110A: GRANDMA observations
  12. GRB 221110A: COATLI Second-Epoch Upper Limits
  13. GRB 221009A: GRANDMA/Kilonova-Catcher observations
  14. GRB 221110A: GMG upper limit
  15. GRB 221110A: Swift/UVOT Detection and Corrected UVOT Position
  16. GRB 221110A: Swift-BAT refined analysis
  17. GRB 221110A: Swift-XRT refined Analysis
  18. GRB 221110A: Enhanced Swift-XRT position
  19. GRB 221110A: COATLI Afterglow detection
  20. GRB 221110A: LCOGT Optical Afterglow Detection
  21. GRB 221110A: Swift detection of a burst with an optical counterpart
  22. Swift GRB221110.10: Global MASTER-Net OT detection
  23. GRB 221009A: Hubble Space Telescope observations
  24. GRB 221107A: Fermi GBM Observation
  25. GRB 221107A: Swift/BAT-GUANO detection outside the coded FOV
  26. IceCube-221104A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi-LAT gamma-ray observations of IceCube-221104A
  28. GRB 221027B: GRANDMA observations
  29. GRB 221028A: Detection by VZLUSAT-2
  30. GRB 221029A: Fermi GBM observation
  31. GRB 221029A: Fermi GBM Final Localization
  32. GRB 221028A: Swift-XRT refined Analysis
  33. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  34. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  35. GRB 221028A: Correction to GCN 32893 - Fluence and flux are for 50-150 keV
  36. GRB 221028A, Swift-BAT refined analysis
  37. GRB 221027B: Swift-BAT refined analysis
  38. GRB 221029A: Swift/BAT-GUANO detection outside the coded FOV
  39. GRB 221028A: CrAO/ZTSh optical upper limit
  40. GRB 221028A: COATLI Upper Limits
  41. Trigger 1132968: Swift trigger is the Crab
  42. GRB 221028A: MITSuME Okayama optical upper limits
  43. GRB 221028B: MAXI/GSC detection
  44. GRB 221028A: LCOGT Optical Upper Limits
  45. GRB 221027B: COATLI Upper Limits
  46. GRB 221028A: GIT optical upper limit
  47. GRB 221027B: Swift/UVOT Upper Limits
  48. GRB 221028A: Swift detection of a burst
  49. GRB 221027B: Swift-XRT refined Analysis
  50. GRB 221027B: BOOTES-1 optical upper limit
  51. GRB 221027B: Enhanced Swift-XRT position
  52. GRB 221027B: Swift detection of a burst
  53. GRB 221027A: Fermi GBM detection
  54. GRB 221024A: Mondy optical observations
  55. GRB 221027A: Fermi-LAT detection
  56. GRB 221024A: GRANDMA observations
  57. IPN triangulation of GRB 221022C (short)
  58. GRB 221023A: AGILE/GRID analysis
  59. GRB 221024A: Swift-BAT refined analysis
  60. GRB 221025A: AstroSat CZTI detection
  61. GRB 221009A: SARA-RM 1m Optical Afterglow Detection
  62. GRB 221025A: Fermi GBM Observation
  63. GRB 221024A: Swift/UVOT UV upper limits
  64. GRB 221022A: Swift-XRT observations
  65. GRB 221024A: Swift-XRT refined Analysis
  66. GRB 221023A: Fermi GBM Observation
  67. GRB 221025A: Fermi-LAT detection
  68. IPN triangulation of GRB 221022B (long)
  69. GRB 221024A: GIT confirmation of the optical afterglow
  70. GRB 221024A: Enhanced Swift-XRT position
  71. GRB 221024A: D50 candidate afterglow
  72. GRB 221022A: Fermi GBM detection
  73. GRB 221023A: Fermi-LAT detection
  74. GRB 221022B: Fermi GBM detection
  75. GRB 221021A: Fermi GBM observation
  76. GRB 221024A: Swift detection of a burst
  77. GRB 221023A: Fermi GBM Final Localization
  78. GRB 221022A: Swift/BAT-GUANO detection
  79. GRB 221022B: Swift/BAT-GUANO detection outside the coded FOV
  80. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  81. GRB 221021A: Swift/BAT-GUANO detection outside the coded FOV
  82. SGR 1935+21542: VZLUSAT-2 and GRBAlpha joint detection
  83. GRB221009A: LBT optical imaging
  84. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  85. GRB 221017A: Swift-XRT observations
  86. GRB 221009A: TNG NIR detection
  87. GRB 221009A: BOAO NIR detections
  88. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  89. GRB 221013B: Swift/BAT-GUANO detection
  90. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  91. GRB 221009A: GRANDMA observations
  92. The probability of observing GRB 221009A at z = 0.151
  93. GRB 221009A: Medicina Radio Telescope observations
  94. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  95. GRB 221009A: Second epoch of NuSTAR data
  96. GRB 221016A: Swift-BAT refined analysis
  97. GRB 221016A: Swift/UVOT Detection
  98. GRB 221016A: Swift-XRT refined Analysis
  99. GRB 221016A: Fermi GBM observation
  100. GRB 221009A: A type I BdHN of exceptional energetics

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