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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 221027B: Swift-XRT refined Analysis
  2. GRB 221027B: BOOTES-1 optical upper limit
  3. GRB 221027B: Enhanced Swift-XRT position
  4. GRB 221027B: Swift detection of a burst
  5. GRB 221027A: Fermi GBM detection
  6. IPN triangulation of GRB 221025A (short)
  7. Konus-Wind detection of GRB 221022B
  8. GRB 221024A: Mondy optical observations
  9. GRB 221027A: Fermi-LAT detection
  10. GRB 221027A: Fermi GBM Final Real-time Localization
  11. GRB 221009A: Further Gemini-South Infrared Observations
  12. GRB 221024A: GRANDMA observations
  13. Fermi Gamma-ray Burst Monitor trigger 688431261/221025954 is not a GRB
  14. IPN triangulation of GRB 221022C (short)
  15. GRB 221023A: AGILE/GRID analysis
  16. SGR 1935+2154: AstroSat CZTI Detections
  17. GRB 221024A: Swift-BAT refined analysis
  18. GRB 221025A: AstroSat CZTI detection
  19. GRB 221009A: SARA-RM 1m Optical Afterglow Detection
  20. GRB 221025A: Fermi GBM Observation
  21. GRB 221009A: spectroscopic confirmation of SN in LBT spectra
  22. Konus-Wind detection of GRB 221023A
  23. GRB 221024A: Swift/UVOT UV upper limits
  24. GRB 221022A: Swift-XRT observations
  25. GRB 221024A: Swift-XRT refined Analysis
  26. GRB 221023A: Fermi GBM Observation
  27. GRB 221022B: Detection by GRBAlpha
  28. GRB 221025A: Fermi-LAT detection
  29. IPN triangulation of GRB 221022B (long)
  30. GRB 221024A: GIT confirmation of the optical afterglow
  31. LAT GRB221025.04: Global MASTER-Net observations report
  32. GRB 221024A: Enhanced Swift-XRT position
  33. GRB 221024A: D50 candidate afterglow
  34. GRB 221022B: AstroSat CZTI detection
  35. GRB 221022A: Fermi GBM detection
  36. GRB 221022A: Swift ToO observations
  37. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  38. GRB 221023A: Fermi-LAT detection
  39. GRB 221022B: Fermi GBM detection
  40. GRB 221021A: Fermi GBM observation
  41. GRB 221009A: Determination of the black holes mass and spin
  42. GRB 221024A: Swift detection of a burst
  43. GRB 221023A: Fermi GBM Final Localization
  44. GRB 221023A: AGILE detection of a burst
  45. GRB 221022A: Swift/BAT-GUANO detection
  46. GRB 221022B: Swift/BAT-GUANO detection outside the coded FOV
  47. GRB 221022B: AGILE detection
  48. GRB 221009A: James Webb Space Telescope Observations
  49. GRB 221022B: Fermi GBM Final Real-time Localization
  50. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  51. GRB 221009A: optical observations, SN photometric evidence
  52. GRB 221021A: Swift/BAT-GUANO detection outside the coded FOV
  53. GRB 221022A: Fermi GBM Final Real-time Localization
  54. GRB 221020A: Detection by GRBAlpha
  55. SGR 1935+21542: VZLUSAT-2 and GRBAlpha joint detection
  56. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  57. GRB 221021A: Fermi GBM Final Real-time Localization
  58. GRB 221009A: 1.3m DFOT Optical Observations
  59. Fermi GBM trigger 687320613 / 221013100 (GRB 221013B) is not a GRB
  60. GRB221009A: LBT optical imaging
  61. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  62. GRB 221017A: Swift-XRT observations
  63. GRB 221020A: Fermi GBM Final Real-time Localization
  64. Improved IPN localization for GRB 221009A (BepiColombo-MGNS light curve)
  65. GRB 221009A: TNG NIR detection
  66. GRB 221009A: BOAO NIR detections
  67. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  68. AGILE detection of a burst from SGR J1935+2154 reported by VZLUSAT-2
  69. GRB 221009A: Spectroscopic detection of emerging SN features
  70. GRB 221009A: Continued LDT Afterglow Monitoring
  71. GRB 221013B: Swift/BAT-GUANO detection
  72. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  73. AGILE detection of the 2022 October 17 burst from SGR J1935+2154 reported by Konus-Wind
  74. GRB 221009A: GRANDMA observations
  75. SGR 1935+2154: Detection by GRBAlpha
  76. The probability of observing GRB 221009A at z = 0.151
  77. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17
  78. GRB 221009A: Medicina Radio Telescope observations
  79. GRB 221017A: Swift ToO observations
  80. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  81. GRB 221009A: Second epoch of NuSTAR data
  82. IPN triangulation of GRB 221017A (long)
  83. GRB 221016A: Swift-BAT refined analysis
  84. GRB 221016A: Swift/UVOT Detection
  85. GRB 221016A: Swift-XRT refined Analysis
  86. Konus-Wind detection of GRB 221016A
  87. GRB 221016A: Fermi GBM observation
  88. GRB 220926B: Detection by GRBAlpha
  89. GRB 221009A: A type I BdHN of exceptional energetics
  90. MAXI GRB221017.24: Global MASTER-Net observations report
  91. GRB 221016A: z-band upper limit, possible afterglow brightening
  92. GRB 221017A: MAXI/GSC detection
  93. GRB 221016A: Enhanced Swift-XRT position
  94. GRB 221016A: LCOGT Optical Afterglow Detection
  95. GRB 221016A: Swift detection of a burst
  96. GRB 221016A: Fermi GBM Final Real-time Localization
  97. Swift GRB221016.99: Global MASTER-Net observations report
  98. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  99. Konus-Wind detection of a short burst coincident with a bright radio burst from SGR 1935+2154
  100. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence

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