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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 211212A: Fermi GBM Final Real-time Localization
  2. GRB 211211A: Fermi GBM observation
  3. GRB 211211A: Swift-BAT refined analysis
  4. Fermi GRB 211211B: Global MASTER-Net observations report
  5. GRB 211211B: Fermi GBM Final Real-time Localization
  6. Fermi GRB 211211A: Global MASTER-Net observations report
  7. GRB 211211A: Enhanced Swift-XRT position
  8. GRB 211207A: Swift/UVOT Detection
  9. GRB 211211A: KAIT Optical Afterglow Candidate
  10. GRB 211211A: Swift detection of a bright burst
  11. GRB 211211A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 660868196: Global MASTER-Net observations report
  13. IceCube-211208A: No significant detection in HAWC
  14. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  15. Fermi trigger No 660736561: Global MASTER-Net observations report
  16. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  17. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  19. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  20. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211209A
  21. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  22. IceCube Alert 211208.84: Global MASTER-Net observations report
  23. GRB 211207A: Swift-BAT refined analysis
  24. GRB 211207A: VLT/X-shooter redshift
  25. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  26. GRB 211204C: Fermi GBM detection
  27. GRB 211207A: Swift-XRT refined Analysis
  28. GRB 211207A: Enhanced Swift-XRT position
  29. Swift GRB 211207A: Global MASTER-Net observations report
  30. GRB 211207A: Swift detection of a burst with an optical counterpart
  31. GRB 211206A: Not observable by Fermi-GBM
  32. GRB 211206A: AstroSat CZTI detection
  33. GRB 211206B: AstroSat CZTI detection
  34. GRB 211204C: AstroSat CZTI detection
  35. IPN triangulation of GRB 211204C
  36. GRB 211206A: Swift/BAT-GUANO detection outside the coded FOV
  37. GRB 211206A: AGILE/MCAL detection of a burst
  38. GRB 211204C: Swift/BAT-GUANO detection outside the coded FOV
  39. GRB 211204C: GECAM detection
  40. Fermi GRB 211204C: Global MASTER-Net observations report
  41. GRB 211204C: Fermi GBM Final Real-time Localization
  42. Fermi GRB 211204B: Global MASTER-Net observations report
  43. GRB 211204B: Fermi GBM Final Real-time Localization
  44. Fermi GRB 211204A: Global MASTER-Net observations report
  45. GRB 211204A: Fermi GBM Final Real-time Localization
  46. GRB 211124A: Fermi GBM Observation
  47. Swift Trigger 1086826 (possible GRB 211203A) is likely not an astrophysical event
  48. Swift GRB 211203A: Global MASTER-Net observations report
  49. Fermi GBM Upper limits for GRB 211203A
  50. Konus-Wind detection of GRB 211130A
  51. IPN triangulation of GRB 211130A
  52. GRB 211203A: Swift detection of a burst
  53. GRB 211201A: GECAM detection
  54. GRB 211201A: Swift/BAT-GUANO detection likely outside the coded FOV
  55. GRB 211106A: Second HST Observation
  56. Fermi GRB 211201A: Global MASTER-Net observations report
  57. GRB 211201A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 211130A: Global MASTER-Net observations report
  59. IceCube-211125A: No significant detection in HAWC
  60. GRB 211130A: BALROG localization (Fermi Trigger 659978192 / GRB 211130636)
  61. GRB 211130A: Fermi GBM Final Real-time Localization
  62. GRB 211106A: GECAM detection
  63. GRB 211129A: Swift-BAT refined analysis
  64. GRB 211129A: Swift-XRT refined Analysis
  65. GRB 211129A: Swift/UVOT Upper Limits
  66. GRB 211106A: HST Observations
  67. GRB 211106A: Chandra Observations
  68. IceCube-Cascade 211128A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube-211125A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 211129A: Fermi GBM observation
  71. Swift GRB 211129A: Global MASTER-Net observations report
  72. GRB 211129A: Nanshan/NEXT optical upper limit
  73. GRB 211129A: Enhanced Swift-XRT position
  74. IPN triangulation of GRB 211118A
  75. GRB 211129A: MITSuME Akeno optical upper limits
  76. GRB 211129A: Swift detection of a burst
  77. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  78. GRB 211023A: Xinglong 2.16m optical observations
  79. GRB 211023A: Xinglong 2.16m optical observations
  80. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  81. GRB 211120548: Fermi GBM observation
  82. Konus-Wind detection of GRB 211120A
  83. IPN triangulation of GRB 211120A
  84. IceCube-211125A: No neutrino counterpart detected with ANTARES
  85. Chandra observations of GRB 210905A
  86. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  87. GRB 211118A: Fermi GBM detection
  88. IceCube Alert 211125.27: Global MASTER-Net observations report
  89. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  90. IceCube-211123A: Upper limits from a search for additional neutrino events in IceCube
  91. IceCube-211123A: INTEGRAL was inactive at the time of the event
  92. IceCube-211123A: Upper limits from Fermi-GBM Observations
  93. IceCube-211117A: not observable by Fermi-GBM
  94. IceCube-211116A: not observable by Fermi-GBM
  95. IceCube-211023A: not observable by Fermi-GBM
  96. IPN triangulation of GRB 211124A (short)
  97. HAWC-211123A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  98. HAWC-211123A: not observable by Fermi-GBM
  99. GRB 211124A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  100. IceCube Alert 211123.60: Global MASTER-Net observations report

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