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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"

7301 results found.

  1. GRB 220107B: Tiled Swift observations
  2. GRB 220107A: Swift ToO observations
  3. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  4. GRB 211229A: Swift ToO observations
  5. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  6. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  7. GRB 211227A: Swift detection of a burst
  8. GRB 211221A: Swift detection of a burst
  9. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  10. IceCube-211216B: Upper limits from Fermi-GBM Observations
  11. IceCube-211216A: Upper limits from Fermi-GBM Observations
  12. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  13. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  14. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  15. GRB 211211A - Gemini K-band detection
  16. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  17. IceCube-211208A: No neutrino counterpart detected with ANTARES
  18. GRB 211211A: MITSuME Akeno optical observation
  19. GRB 211211A: Nanshan/NEXT optical observations
  20. GRB 211211A: KAIT Optical Afterglow Candidate
  21. GRB 211211A: Swift detection of a bright burst
  22. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  23. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  24. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  25. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  26. GRB 211207A: Swift detection of a burst with an optical counterpart
  27. GRB 211203A: Swift detection of a burst
  28. GRB 211129A: Swift detection of a burst
  29. IceCube-211125A: No neutrino counterpart detected with ANTARES
  30. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  31. IceCube-211123A: Upper limits from Fermi-GBM Observations
  32. IceCube-211117A: not observable by Fermi-GBM
  33. IceCube-211116A: not observable by Fermi-GBM
  34. IceCube-211023A: not observable by Fermi-GBM
  35. HAWC-211123A: not observable by Fermi-GBM
  36. HAWC-211123A: No neutrino counterpart detected with ANTARES
  37. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  38. Trigger_21473: Tiled Swift observations
  39. Search for counterpart to IceCube-211117A with ANTARES
  40. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  41. IceCube-211116A: No neutrino counterpart detected with ANTARES
  42. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  43. GRB 211106A: Swift/UVOT upper limits
  44. Short GRB 211106A: spectroscopy of galaxies in the field
  45. MeerLICHT follow-up of GRB 211106A
  46. GRB 211107B: Swift ToO observations
  47. GRB 211106A: Swift-XRT observations
  48. GRB 211106A: Swift ToO observations
  49. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
  50. Swift Trigger 1082569 is probably not a GRB
  51. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  52. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  53. GRB 211024A: Possible afterglow candidate from GIT
  54. GRB 211024A: Swift ToO observations
  55. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  56. GRB 211025A: Swift detection of a burst
  57. GRB 210919A: FORS2/VLT observations
  58. GRB 211023A: OAJ Bright Afterglow Confirmation
  59. IceCube-211023A: No neutrino counterpart detected with ANTARES
  60. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  61. IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event
  62. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  63. GRB 211018A: Swift ToO observations
  64. GRB 210919A: LDT optical observations and candidate host galaxies
  65. Swift Trigger 1078701 is probably not a GRB
  66. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  67. GRB 210928A: MeerKAT detection
  68. GRB 210928A: Fermi-LAT detection
  69. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  70. GRB 210930A: CAHA 2.2m telescope optical limit
  71. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  72. Swift Trigger 1076121 is not a GRB
  73. GRB 210930A: Swift detection of a burst
  74. IceCube-210922A: SMA observation for the JCMT candidate
  75. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  76. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  77. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  78. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  79. IceCube-210922A: Upper limits from Fermi-GBM Observations
  80. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  81. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  82. GRB 210919A: Swift detection of a short burst
  83. Swift trigger 1073821: detection of IGR J16418-4532
  84. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  85. GRB 210912A: Host-galaxy candidate in PanSTARRS
  86. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  87. GRB 210826A: further Swift-XRT observations
  88. Swift detection of a burst from SGR Swift J1555.2-5402
  89. GRB 210905A: Swift detection of a burst
  90. GRB 210901A: Swift detection of a burst
  91. GRB 210827A: further Swift-XRT observations
  92. GRB 210827A: Swift/UVOT Upper Limits
  93. GRB 210827A: Swift ToO observations
  94. GRB 210826A: Swift/UVOT Upper Limits
  95. POLAR detection of a SGR-like burst
  96. GRB 210826A: Swift-XRT observations
  97. GRB 210826A: Tiled Swift observations
  98. Swift detection of an outburst from SGR Swift J1555.2-5402
  99. GRB 210824A: Swift detection of a burst
  100. GRB 210822A: Swift detection of a burst with an optical afterglow

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