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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"

8476 results found.

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

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