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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"

8474 results found.

  1. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  2. IceCube-211208A: No neutrino counterpart detected with ANTARES
  3. GRB 211211A: MITSuME Akeno optical observation
  4. GRB 211211A: Nanshan/NEXT optical observations
  5. GRB 211211A: KAIT Optical Afterglow Candidate
  6. GRB 211211A: Swift detection of a bright burst
  7. IceCube-211208A: No significant detection in HAWC
  8. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  9. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  10. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 211207A: Swift detection of a burst with an optical counterpart
  13. Fermi GBM Upper limits for GRB 211203A
  14. GRB 211203A: Swift detection of a burst
  15. IceCube-211125A: No significant detection in HAWC
  16. IceCube-Cascade 211128A: Upper limits from a search for additional neutrino events in IceCube
  17. IceCube-211125A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 211129A: Swift detection of a burst
  19. IceCube-211125A: No neutrino counterpart detected with ANTARES
  20. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube-211123A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube-211123A: Upper limits from Fermi-GBM Observations
  23. IceCube-211117A: not observable by Fermi-GBM
  24. IceCube-211116A: not observable by Fermi-GBM
  25. IceCube-211023A: not observable by Fermi-GBM
  26. HAWC-211123A: not observable by Fermi-GBM
  27. HAWC-211123A: No neutrino counterpart detected with ANTARES
  28. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  29. Trigger_21473: Tiled Swift observations
  30. Search for counterpart to IceCube-211117A with ANTARES
  31. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
  33. IceCube-211116A: No neutrino counterpart detected with ANTARES
  34. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  35. GRB 211106A: Swift/UVOT upper limits
  36. Short GRB 211106A: spectroscopy of galaxies in the field
  37. MeerLICHT follow-up of GRB 211106A
  38. GRB 211107B: Swift ToO observations
  39. Fermi GBM Sub-Threshold Detection of GRB 211106A
  40. GRB 211106A: Swift-XRT observations
  41. GRB 211106A: Swift ToO observations
  42. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
  43. Swift Trigger 1082569 is probably not a GRB
  44. GRB 211023B: Subaru optical observation
  45. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  46. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  47. GRB 211024A: Possible afterglow candidate from GIT
  48. GRB 211024A: Swift ToO observations
  49. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  50. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 211025A: Swift detection of a burst
  52. GRB 210919A: FORS2/VLT observations
  53. GRB 211023A: OAJ Bright Afterglow Confirmation
  54. GRB 211023B: TSHAO optical observation
  55. IceCube-211023A: No neutrino counterpart detected with ANTARES
  56. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  57. IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event
  58. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  59. GRB 211018A: Swift ToO observations
  60. GRB 211019A: Detection by GRBAlpha
  61. GRB 210919A: LDT optical observations and candidate host galaxies
  62. Swift Trigger 1078701 is probably not a GRB
  63. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  64. GRB 210928A: Fermi-LAT detection
  65. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  66. GRB 210930A: CAHA 2.2m telescope optical limit
  67. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  68. Swift Trigger 1076121 is not a GRB
  69. GRB 210930A: Swift detection of a burst
  70. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  71. IceCube-210922A: SMA observation for the JCMT candidate
  72. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  73. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  74. IceCube-210922A: JCMT/SCUBA2 observations
  75. GRB 210919A: Chandra rapid ToO upper limit
  76. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  77. IceCube-210922A: No significant detection in HAWC
  78. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  79. IceCube-210922A: Upper limits from a search for additional neutrino events in IceCube
  80. IceCube-210922A: Upper limits from Fermi-GBM Observations
  81. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  82. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 September 22
  83. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  84. GRB 210919A: Swift detection of a short burst
  85. Swift trigger 1073821: detection of IGR J16418-4532
  86. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  87. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  88. GRB 210912A: Host-galaxy candidate in PanSTARRS
  89. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  90. Fermi GBM observation of a bright flare in the direction of SGR 1935+2154
  91. GRB 210826A: further Swift-XRT observations
  92. Swift detection of a burst from SGR Swift J1555.2-5402
  93. Fermi GBM Sub-Threshold Detection of GRB 210905A
  94. GRB 210905A: Swift detection of a burst
  95. Fermi GBM observation of a burst from SGR J1555.2-5402
  96. GRB 210901A: Swift detection of a burst
  97. GRB 210827A: further Swift-XRT observations
  98. GRB 210827A: Swift/UVOT Upper Limits
  99. GRB 210827A: Swift ToO observations
  100. GRB 210826A: Swift/UVOT Upper Limits

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