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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"

27394 results found.

  1. Konus-Wind detection of GRB 211107B
  2. GRB 211115A: MAXI/GSC detection
  3. GRB 211023A: classification and SPI-ACS/INTEGRAL registration
  4. GRB 211106A: Swift/UVOT upper limits
  5. GRB 211110A: AstroSat CZTI detection
  6. Short GRB 211106A: spectroscopy of galaxies in the field
  7. GRB 211110A: GECAM detection
  8. GRB 211107B: Swift-XRT afterglow detection
  9. GRB 211106A, GROND observations
  10. GRB 211106A: Swift-XRT afterglow detection
  11. Fermi GRB 211109B: Global MASTER-Net observations report
  12. GRB 211023A: SAO RAS optical observations
  13. GRB 211107B: Swift-XRT observations
  14. MeerLICHT follow-up of GRB 211106A
  15. GRB 211109C: GECAM detection
  16. Fermi GBM Sub-Threshold Detection of GRB 211106A
  17. GRB 211106A: Swift-XRT observations
  18. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
  19. GRB 211105A: MASTER optical inspection
  20. GRB 211105A: Swift/BAT-GUANO detection outside the coded FOV
  21. GRB 211105A: GECAM detection
  22. Swift Trigger 1082569 is probably not a GRB
  23. GRB 211023A: optical detection by SBT in Ondrejov
  24. GRB 211023B: Subaru optical observation
  25. GRB 211024A: MITSuME Akeno optical observation
  26. GRB 211102B: GECAM detection
  27. GRB 211102B: BALROG localization (Fermi Trigger 657554740 / GRB 211102587)
  28. GRB 211023B: MITSuME Akeno optical upper limits
  29. GRB 211102A: BALROG localization (Fermi Trigger 657533168 / GRB 211102338)
  30. GRB 211024B: Optical afterglow observation by Ondrejov D50
  31. GRB 211024A: 1.3m DFOT observations
  32. IPN triangulation of GRB 211022A
  33. GRB 2121023B: 6 GHz VLA radio upper limit
  34. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  35. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  36. GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  37. GRB 211024A: Possible afterglow candidate from GIT
  38. GRB 211024A: Swift-XRT observations
  39. GRB 211018A: Swift-XRT observations
  40. GRB 211025A: Optical Afterglow Detection
  41. GRB211023A: optical afterglow detection from Konkoly Observatory
  42. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  43. GRB 211023B: Mondy optical afterglow confirmation
  44. GRB 211023B: LDT Optical Afterglow Detection
  45. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  46. GRB 211025A: Swift-BAT refined analysis
  47. GRB 211025A: Swift-XRT refined Analysis
  48. GRB 211024B: Swift-XRT refined Analysis
  49. GRB 211025A: Swift/UVOT Detection
  50. GRB 211024B: Swift-BAT refined analysis
  51. GRB 211025A: Enhanced Swift-XRT position
  52. GRB 211025A: Swift detection of a burst
  53. GECAM detection of a short burst probably from SGR J1555.2-5402
  54. GRB 211024B: Nanshan/NEXT optical afterglow detection
  55. GRB 210919A: FORS2/VLT observations
  56. GRB 211023B: Swift-BAT refined analysis
  57. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  58. GRB 211023B: Swift/UVOT Detection
  59. GRB 211024A: GECAM detection
  60. GRB 211023B: RATIR Optical and NIR Upper Limits
  61. GRB 211023B: TSHAO optical observation
  62. IceCube-211023A: No neutrino counterpart detected with ANTARES
  63. GRB 211022A: AstroSat CZTI detection
  64. GRB 211023B: Swift-XRT refined Analysis
  65. GRB 211023B: Enhanced Swift-XRT position
  66. GRB 211023A: Fermi GBM detection
  67. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  68. IPN Triangulation of GRB 210927B
  69. GRB 211022A: GECAM detection
  70. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  71. GRB 211021A: BALROG localization (Fermi Trigger 656506979 / GRB 211021460)
  72. Fermi trigger No 656506979: Global MASTER-Net observations report
  73. BepiColombo MGNS joins the IPN
  74. Fermi trigger No 656268212: Global MASTER-Net observations report
  75. GRB 211018A: Fermi GBM observation
  76. GRB 211019A: BALROG localization (Fermi Trigger 656315976 / GRB 211019250)
  77. Integral GRB211016.42: Global MASTER-Net observations report
  78. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  79. Swift trigger 1078701: MITSuME Akeno optical upper limits
  80. Fermi trigger No 655673024: Global MASTER-Net observations report
  81. GRB 210919A: LDT optical observations and candidate host galaxies
  82. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  83. Swift Trigger 1078701 is probably not a GRB
  84. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  85. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  86. GRB 210928A: MeerKAT detection
  87. GECAM observation of a burst from SGR J1555.2-5402
  88. GRB 210928A: Kinder SLT-40cm optical limits
  89. GRB 210930A: Swift-BAT refined analysis
  90. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  91. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  92. GRB 210928A: Swift-XRT refined Analysis
  93. GRB 210928A: Fermi GBM observation
  94. GRB 210927B: GECAM detection
  95. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  96. Swift Trigger 1076121 is not a GRB
  97. Swift GRB211001.03: Global MASTER-Net OT detection
  98. GRB 210930A: Swift/UVOT Upper Limits
  99. GRB 210930A: Swift-XRT refined Analysis
  100. Swift GRB 210930A: Global MASTER-Net observations report

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