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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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 221009A: TNG NIR detection
  2. GRB 221009A: BOAO NIR detections
  3. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  4. AGILE detection of a burst from SGR J1935+2154 reported by VZLUSAT-2
  5. GRB 221009A: Spectroscopic detection of emerging SN features
  6. GRB 221009A: Continued LDT Afterglow Monitoring
  7. GRB 221013B: Swift/BAT-GUANO detection
  8. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  9. AGILE detection of the 2022 October 17 burst from SGR J1935+2154 reported by Konus-Wind
  10. GRB 221009A: GRANDMA observations
  11. SGR 1935+2154: Detection by GRBAlpha
  12. The probability of observing GRB 221009A at z = 0.151
  13. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17
  14. GRB 221009A: Medicina Radio Telescope observations
  15. GRB 221017A: Swift ToO observations
  16. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  17. GRB 221009A: Second epoch of NuSTAR data
  18. IPN triangulation of GRB 221017A (long)
  19. GRB 221016A: Swift-BAT refined analysis
  20. GRB 221016A: Swift/UVOT Detection
  21. GRB 221016A: Swift-XRT refined Analysis
  22. Konus-Wind detection of GRB 221016A
  23. GRB 221016A: Fermi GBM observation
  24. GRB 220926B: Detection by GRBAlpha
  25. GRB 221009A: A type I BdHN of exceptional energetics
  26. MAXI GRB221017.24: Global MASTER-Net observations report
  27. GRB 221016A: z-band upper limit, possible afterglow brightening
  28. GRB 221017A: MAXI/GSC detection
  29. GRB 221016A: Enhanced Swift-XRT position
  30. GRB 221016A: LCOGT Optical Afterglow Detection
  31. GRB 221016A: Swift detection of a burst
  32. GRB 221016A: Fermi GBM Final Real-time Localization
  33. Swift GRB221016.99: Global MASTER-Net observations report
  34. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  35. Konus-Wind detection of a short burst coincident with a bright radio burst from SGR 1935+2154
  36. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  37. Konus-Wind observation of the recent SGR 1935+2154 activity
  38. GRB 221009A: LEIA X-ray Afterglow Detection
  39. GRB 221009A: ATCA radio spectrum
  40. GRB 221009A: VLT spectroscopic detection of the host galaxy
  41. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  42. GRB 221009A: ATCA detection
  43. GRB 221009A: Armchair Energetics
  44. GRB 221009A: ALMA and ACA detections
  45. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  46. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  47. GRB 221009A: Pan-STARRS optical photometry
  48. GRB 221009A: VLA detection
  49. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  50. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  51. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  52. GRB 221009A: OHP optical observations
  53. GRB221009A: RTT-150 optical observations
  54. GRB 221009A: HEBS detection
  55. GRB 221009A: Gemini-South Infrared Afterglow Detection
  56. GRB221009A: Gemini-South Optical Afterglow Detection
  57. GRB 221009A: a 397.7 GeV photon observed by Fermi-LAT at 0.4 day after the GBM trigger
  58. GRB 221014A: Fermi GBM Final Real-time Localization
  59. GRB 221009A: Gamma-ray Detection by SIRI-2
  60. GRB221009A: Ionospheric disturbance observed in India
  61. GRB221009A: Detection as sudden ionospheric disturbances (SID)
  62. GRB221009A: RTT-150 optical observations
  63. MAXI GRB 221006A: Redshifts of the possible host galaxies
  64. GRB 221009A: search for neutrinos with KM3NeT
  65. GRB 221009A: MeerKAT detection
  66. GRB 221009A: Lowell Discovery Telescope Afterglow Detection
  67. GRB221009A: LCOGT Continued Observations - Optical Upper Limits
  68. Fermi Gamma-ray Burst Monitor continues to detect SGR 1935+2154
  69. GRB 221009A/Swift J1913.1+1946: low-frequency ASKAP observations
  70. Fermi trigger No 687345829: Global MASTER-Net observations report
  71. Fermi trigger No 687344475: Global MASTER-Net observations report
  72. Fermi trigger No 687340841: Global MASTER-Net observations report
  73. Fermi trigger No 687337536: Global MASTER-Net observations report
  74. GRB 221006A: Swift-XRT afterglow detection
  75. GRB 221009A: MITSuME Okayama optical observation
  76. GRB 221009A: Sayan observatory 1.6-m telescope observations
  77. Fermi trigger No 687281393: Global MASTER-Net observations report
  78. GRB 221009A: GMG observation
  79. GRB 221013B: Fermi GBM Final Real-time Localization
  80. Integral GRB221013.04: Global MASTER-Net observations report
  81. GRB 221013A: Fermi GBM Final Real-time Localization
  82. Integral GRB221013.00: Global MASTER-Net observations report
  83. Integral GRB221012.99: Global MASTER-Net observations report
  84. Integral GRB221012.94: Global MASTER-Net observations report
  85. Integral GRB221012.91: Global MASTER-Net observations report
  86. Integral GRB221012.88: Global MASTER-Net observations report
  87. Integral GRB221012.87: Global MASTER-Net observations report
  88. Integral GRB221012.77: Global MASTER-Net observations report
  89. Integral GRB221012.74: Global MASTER-Net observations report
  90. Integral GRB221012.72: Global MASTER-Net observations report
  91. Integral GRB221012.71: Global MASTER-Net observations report
  92. Integral GRB221012.68: Global MASTER-Net observations report
  93. Integral GRB221012.68: Global MASTER-Net observations report
  94. Integral GRB221012.98: Global MASTER-Net observations report
  95. Afterglow limits of GRB 221006A from OHP
  96. GRB221009A: optical afterglow measurements from Konkoly Observatory
  97. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  98. GRB 221009A/Swift J1913.1+1946: SMA observations
  99. INTEGRAL shows increasing activity in SGR J1935+2154
  100. GRB 221009A: COATLI Continued Monitoring of the Afterglow

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