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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. IceCube-200929A: No significant detection in HAWC
  2. GRB 201001A: Swift-BAT refined analysis
  3. GRB 201001A: Swift-XRT refined Analysis
  4. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  5. GRB 201001A: Fermi GBM observation
  6. Swift-XRT observations of IceCube 200929A
  7. GRB 201001A: Enhanced Swift-XRT position
  8. GRB 201001A: Swift detection of a burst
  9. GRB 201001A: Fermi GBM Final Real-time Localization
  10. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  11. IceCube-200929A: Upper limits from Fermi-GBM Observations
  12. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  13. IceCube-200926B: No significant detection in HAWC
  14. GRB 200928B: Insight-HXMT/HE detection
  15. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  16. IceCube-200926B: Upper limits from Fermi-GBM Observations
  17. IceCube-200926A: Upper limits from Fermi-GBM Observations
  18. IceCube Alert 200929.74: Global MASTER-Net observations report
  19. IceCube-200926A: No significant detection in HAWC
  20. Fermi GRB 200929A: Global MASTER-Net observations report
  21. GRB 200928B: AstroSat CZTI detection
  22. GRB 200929A: Fermi GBM Final Real-time Localization
  23. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  24. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  25. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  26. GRB 200928B: Fermi GBM Final Real-time Localization
  27. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  28. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  29. GRB 200928A: Fermi GBM Final Localization
  30. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  31. IceCube Alert 200926.94: Global MASTER-Net observations report
  32. Swift-XRT observations of IceCube 200926A
  33. Konus-Wind detection of GRB 200920B
  34. Fermi-LAT Gamma-ray Observations of IceCube-200926A
  35. GRB 200925B: Swift-XRT refined analysis update
  36. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  37. IceCube Alert 200926.33: Global MASTER-Net observations report
  38. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  39. GRB 200925B: Swift-XRT refined Analysis
  40. GRB 200925B: Swift/UVOT Detection
  41. GRB 200925B: Swift-BAT refined analysis
  42. GRB 200922A: Chilescope optical observations
  43. IceCube-200926A: IceCube observation of a high-energy neutrino candidate event
  44. GRB 200925B: Enhanced Swift-XRT position
  45. Swift GRB 200925B: Global MASTER-Net OT detection
  46. GRB 200925B: OSN Afterglow Candidate Discovery
  47. GRB 200925B: Prompt enhanced Swift-XRT position
  48. GRB 200925B: Swift detection of a burst
  49. Swift GRB200925.91: Global MASTER-Net observations report
  50. Fermi GRB 200925A: Global MASTER-Net observations report
  51. GRB 200925A: Fermi GBM Final Real-time Localization
  52. Konus-Wind observation of GRB 200914A
  53. Fermi GRB 200924A: Global MASTER-Net observations report
  54. GRB 200924B: Fermi GBM Final Localization
  55. GRB 200922A: chance superposition between optical afterglow and archival star
  56. Fermi trigger No 622618714: Global MASTER-Net observations report
  57. GRB 200922A: Insight-HXMT/HE detection
  58. GRB 200924A: Fermi GBM Final Real-time Localization
  59. Fermi GRB 200923A: Global MASTER-Net observations report
  60. IceCube Alert 200921.80: Global MASTER-Net observations report
  61. GRB 200923A: Fermi GBM Final Real-time Localization
  62. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  63. GRB 200922A: Swift-BAT refined analysis
  64. Improved enhanced Swift-XRT position of GRB 200922A
  65. GRB 200922A: Swift/UVOT Detection
  66. Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
  67. IceCube-200921A: no significant detection in HAWC observations
  68. Fermi GRB 200922B: Global MASTER-Net observations report
  69. GRB 200922A: LCO observations
  70. Swift GRB 200922A: Global MASTER-Net observations report
  71. GRB 200922A: Swift-XRT refined Analysis
  72. GRB 200917A: Swift/UVOT Upper Limits
  73. GRB 200922B: Fermi GBM Final Real-time Localization
  74. GRB 200922A: Enhanced Swift-XRT position
  75. GRB 200919C: Insight-HXMT/HE detection
  76. GRB 200922A: Swift detection of a burst with possible optical counterpart
  77. IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  78. IceCube-200921A: Upper limits from Fermi-GBM Observations
  79. IceCube-200921A: IceCube observation of a high-energy neutrino candidate event
  80. IPN triangulation of GRB 200920B (short)
  81. GRB 200914A: Swift-XRT further observations
  82. IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
  83. GRB 200920B: AGILE/MCAL detection of a burst
  84. GRB 200920A: Fermi GBM Final Real-time Localization
  85. Fermi GRB 200919C: Global MASTER-Net observations report
  86. GRB 200919C: Fermi GBM Final Real-time Localization
  87. GRB 200919A: CrAO/ZTSh early optical upper limit
  88. Fermi GRB 200919B: Global MASTER-Net observations report
  89. GRB 200919A: Swift-BAT refined analysis
  90. GRB 200919B: Fermi GBM Final Real-time Localization
  91. GRB 200916B: MASTER optical observation
  92. Swift GRB200919.08: Global MASTER-Net observations report
  93. GRB 200919A: Swift detection of a burst
  94. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  95. IceCube-200916A: Upper limits from a search for additional neutrino events in IceCube
  96. GRB 200916B: AstroSat CZTI detection
  97. GRB 200917A: GROWTH-India Telescope optical upper limit.
  98. Swift-XRT observations of IceCube 200916A
  99. IceCube-200916A: No significant detection in HAWC
  100. GRB 200917A: Swift-BAT refined analysis

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