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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-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  2. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  3. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  4. GRB 201001A: TSHAO optical upper limit
  5. GRB 201001A: Xinglong-2.16m optical upper limit
  6. GRB 201001A: MITSuME Akeno optical upper limits
  7. IceCube-200926A: JCMT/SCUBA2 observations
  8. IceCube-200929A: No significant detection in HAWC
  9. GRB 201001A: Swift-BAT refined analysis
  10. GRB 201001A: Swift-XRT refined Analysis
  11. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  12. GRB 201001A: Fermi GBM observation
  13. Swift-XRT observations of IceCube 200929A
  14. GRB 201001A: Enhanced Swift-XRT position
  15. GRB 201001A: Swift detection of a burst
  16. GRB 201001A: Fermi GBM Final Real-time Localization
  17. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  18. IceCube-200929A: Upper limits from Fermi-GBM Observations
  19. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  20. IceCube-200926B: No significant detection in HAWC
  21. GRB 200928B: Insight-HXMT/HE detection
  22. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  23. IceCube-200926B: Upper limits from Fermi-GBM Observations
  24. IceCube-200926A: Upper limits from Fermi-GBM Observations
  25. IceCube Alert 200929.74: Global MASTER-Net observations report
  26. IceCube-200926A: No significant detection in HAWC
  27. Fermi GRB 200929A: Global MASTER-Net observations report
  28. GRB 200928B: AstroSat CZTI detection
  29. GRB 200929A: Fermi GBM Final Real-time Localization
  30. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  31. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  33. GRB 200928B: Fermi GBM Final Real-time Localization
  34. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  35. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  36. GRB 200928A: Fermi GBM Final Localization
  37. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  38. IceCube Alert 200926.94: Global MASTER-Net observations report
  39. Swift-XRT observations of IceCube 200926A
  40. Konus-Wind detection of GRB 200920B
  41. Fermi-LAT Gamma-ray Observations of IceCube-200926A
  42. GRB 200925B: Swift-XRT refined analysis update
  43. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  44. IceCube Alert 200926.33: Global MASTER-Net observations report
  45. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  46. GRB 200925B: Swift-XRT refined Analysis
  47. GRB 200925B: Swift/UVOT Detection
  48. GRB 200925B: Swift-BAT refined analysis
  49. GRB 200922A: Chilescope optical observations
  50. IceCube-200926A: IceCube observation of a high-energy neutrino candidate event
  51. GRB 200925B: Enhanced Swift-XRT position
  52. Swift GRB 200925B: Global MASTER-Net OT detection
  53. GRB 200925B: OSN Afterglow Candidate Discovery
  54. GRB 200925B: Prompt enhanced Swift-XRT position
  55. GRB 200925B: Swift detection of a burst
  56. Swift GRB200925.91: Global MASTER-Net observations report
  57. Fermi GRB 200925A: Global MASTER-Net observations report
  58. GRB 200925A: Fermi GBM Final Real-time Localization
  59. Konus-Wind observation of GRB 200914A
  60. Fermi GRB 200924A: Global MASTER-Net observations report
  61. GRB 200924B: Fermi GBM Final Localization
  62. GRB 200922A: chance superposition between optical afterglow and archival star
  63. Fermi trigger No 622618714: Global MASTER-Net observations report
  64. GRB 200922A: Insight-HXMT/HE detection
  65. GRB 200924A: Fermi GBM Final Real-time Localization
  66. Fermi GRB 200923A: Global MASTER-Net observations report
  67. IceCube Alert 200921.80: Global MASTER-Net observations report
  68. GRB 200923A: Fermi GBM Final Real-time Localization
  69. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 200922A: Swift-BAT refined analysis
  71. Improved enhanced Swift-XRT position of GRB 200922A
  72. GRB 200922A: Swift/UVOT Detection
  73. Fermi-LAT Gamma-ray Observations of IceCube-200921A and detection of a new gamma-ray source, Fermi J1256.9+2630
  74. IceCube-200921A: no significant detection in HAWC observations
  75. Fermi GRB 200922B: Global MASTER-Net observations report
  76. GRB 200922A: LCO observations
  77. Swift GRB 200922A: Global MASTER-Net observations report
  78. GRB 200922A: Swift-XRT refined Analysis
  79. GRB 200917A: Swift/UVOT Upper Limits
  80. GRB 200922B: Fermi GBM Final Real-time Localization
  81. GRB 200922A: Enhanced Swift-XRT position
  82. GRB 200919C: Insight-HXMT/HE detection
  83. GRB 200922A: Swift detection of a burst with possible optical counterpart
  84. IceCube-200921A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  85. IceCube-200921A: Upper limits from Fermi-GBM Observations
  86. IceCube-200921A: IceCube observation of a high-energy neutrino candidate event
  87. IPN triangulation of GRB 200920B (short)
  88. GRB 200914A: Swift-XRT further observations
  89. IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
  90. GRB 200920B: AGILE/MCAL detection of a burst
  91. GRB 200920A: Fermi GBM Final Real-time Localization
  92. Fermi GRB 200919C: Global MASTER-Net observations report
  93. GRB 200919C: Fermi GBM Final Real-time Localization
  94. GRB 200919A: CrAO/ZTSh early optical upper limit
  95. Fermi GRB 200919B: Global MASTER-Net observations report
  96. GRB 200919A: Swift-BAT refined analysis
  97. GRB 200919B: Fermi GBM Final Real-time Localization
  98. GRB 200916B: MASTER optical observation
  99. Swift GRB200919.08: Global MASTER-Net observations report
  100. GRB 200919A: Swift detection of a burst

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