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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"

28694 results found.

  1. GRB 211025A: Optical Afterglow Detection
  2. GRB211023A: optical afterglow detection from Konkoly Observatory
  3. GRB 211024A: Swift ToO observations
  4. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  5. GRB 211024B: Swift/UVOT detection
  6. GRB 211023A: Mondy optical observations
  7. GRB 211023B: Mondy optical afterglow confirmation
  8. GRB 211023B: Gemini-North Optical Observations
  9. Swift GRB 211025A: Global MASTER-Net observations report
  10. GRB 211023B: LDT Optical Afterglow Detection
  11. Correction to GCN 30965: GRB 211023A: Fermi GBM detection
  12. GRB 211025A: Swift-BAT refined analysis
  13. GRB 211025A: Swift-XRT refined Analysis
  14. GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
  15. GRB 211024B: Swift-XRT refined Analysis
  16. IPN Triangulation of GRB 211019A
  17. Possible Short GRB 211023B: CAHA 2.2m Detection
  18. GRB 211025A: Swift/UVOT Detection
  19. GRB 211023A: 1.5m OSN optical observation
  20. GRB 211024B: Swift-BAT refined analysis
  21. GRB 210610B: Sintesz-Newton/CrAO optical observations
  22. GRB 211024B: Nanshan/NEXT optical afterglow detection
  23. GRB 210919A: FORS2/VLT observations
  24. GRB 211023A: OAJ Bright Afterglow Confirmation
  25. Swift GRB 211024B: Global MASTER-Net observations report
  26. GRB 211023B: Swift-BAT refined analysis
  27. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  28. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  29. GRB 211023B: Swift/UVOT Detection
  30. GRB 211024A: GECAM detection
  31. GRB 211023B: RATIR Optical and NIR Upper Limits
  32. GRB 211023B: TSHAO optical observation
  33. IceCube-211023A: No neutrino counterpart detected with ANTARES
  34. Fermi GRB 211023A: Global MASTER-Net observations report
  35. GRB 211023A: AGILE detection
  36. GRB 211022A: AstroSat CZTI detection
  37. GRB 211023B: Swift-XRT refined Analysis
  38. GRB 211023A: Fermi GBM detection
  39. Swift GRB 211023B: Global MASTER-Net observations report
  40. Fermi GRB 211024A: Global MASTER-Net observations report
  41. GRB 211023A: Fermi-LAT detection
  42. IPN Triangulation of GRB 210927B
  43. GRB 211018A: Swift ToO observations
  44. GRB 211018A: Fermi GBM observation
  45. GRB 211019A: Detection by GRBAlpha
  46. GRB 211018A: Detection by GRBAlpha
  47. Fermi GRB 211019A: Global MASTER-Net observations report
  48. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  49. Swift trigger 1078701: MITSuME Akeno optical upper limits
  50. GRB 210919A: LDT optical observations and candidate host galaxies
  51. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  52. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  53. IceCube-210922A: DESI Observations
  54. Konus-Wind detection of GRB 210928A
  55. Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
  56. GRB 210928A: Kinder SLT-40cm optical limits
  57. GRB 210930A: Swift-BAT refined analysis
  58. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  59. GRB 210928A: Fermi GBM observation
  60. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  61. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  62. GRB 210930A: Swift/UVOT Upper Limits
  63. GRB 210930A: Swift-XRT refined Analysis
  64. Swift GRB 210930A: Global MASTER-Net observations report
  65. Fermi GRB 210929B: Global MASTER-Net observations report
  66. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  67. GRB 210925B: AstroSat CZTI detection
  68. IceCube-210922A: SMA observation for the JCMT candidate
  69. IPN triangulation of GRB 210925B
  70. GRB 210926A: AstroSat CZTI detection
  71. GRB 210919A: iTelescope T-11 upper limits
  72. GRB 210919A OSN 1.5m Source Confirmation
  73. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  74. IceCube-210922A: JCMT/SCUBA2 observations
  75. GRB 210925A: GECAM detection
  76. GRB 210919A: Chandra rapid ToO upper limit
  77. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  78. IceCube-210922A: No significant detection in HAWC
  79. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  80. Retraction of Fermi GBM GRB 210923A: the trigger is not a GRB
  81. IceCube-210922A: Upper limits from Fermi-GBM Observations
  82. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  83. GRB 210919A: DECam Upper Limits
  84. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  85. GRB 210919A: Swift-BAT refined analysis
  86. GRB 210912A: LBT optical observations
  87. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  88. GRB 210919a: Lowell Discovery Telescope upper limits
  89. GRB 210919A: Swift/UVOT Upper Limits
  90. GRB 210919A: LOAO and LSGT optical upper limits
  91. GRB 210919A: MITSuME Akeno optical upper limits
  92. GRB 210919A: Swift-XRT refined Analysis
  93. GRB 210919A: NOT upper limits
  94. GRB 210919A: AbAO optical upper limit
  95. GRB 210919A: LCO Optical Upper Limit
  96. Swift GRB 210919A: Global MASTER-Net observations report
  97. GRB 210812A is not a compelling example of a lensed GRB
  98. GRB 210909A: Detection by GRBAlpha
  99. GRB 210912A: Swift-BAT refined analysis
  100. Konus-Wind observation of the recent SGR 1935+2154 activity

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