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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"

7447 results found.

  1. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  2. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 220403B: Swift detection of a burst with an optical counterpart
  4. Swift Trigger 1100848 is likely not a GRB
  5. GRB 220325A: Swift detection of a burst
  6. GRB 220319A: Swift detection of a burst
  7. GRB 220310A: MITSuME Akeno optical observation
  8. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 220310C: Swift ToO observations
  10. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  11. GRB 220311A: MASTER OT retraction
  12. GRB 220310A: Swift ToO observations
  13. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  14. GRB 220306B: AbAO optical observations, possible afterglow candidate
  15. GRB 220306B: Swift detection of a burst
  16. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  17. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  18. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  19. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  20. GRB 220302A: Swift afterglow detection
  21. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  22. GRB 220219B: Swift-XRT observations
  23. GRB 220219B: Swift ToO observations
  24. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  25. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  26. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  27. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  28. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  29. GRB 210919A: Maidanak optical observations
  30. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  31. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  32. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  33. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  34. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  35. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube-211208A: the optical observation of the candidate PKS0735+178
  37. GRB 220118A: MITSuME Akeno optical observation
  38. GRB 220118A: Swift detection of a burst with an optical counterpart
  39. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  40. AMON IC_HAWC NuEm-220116A: No neutrino counterpart detected with ANTARES
  41. GRB 220117B: Swift detection of a burst
  42. GRB 220117A: Swift detection of a burst
  43. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  44. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  45. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  46. GRB 220107A: MITSuME Akeno optical observation
  47. GRB 220107B: Tiled Swift observations
  48. GRB 220107A: Swift ToO observations
  49. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  50. GRB 211229A: Swift ToO observations
  51. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  52. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  53. GRB 211227A: Swift detection of a burst
  54. GRB 211221A: Swift detection of a burst
  55. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  56. IceCube-211216B: Upper limits from Fermi-GBM Observations
  57. IceCube-211216A: Upper limits from Fermi-GBM Observations
  58. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  59. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  60. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  61. GRB 211211A - Gemini K-band detection
  62. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  63. IceCube-211208A: No neutrino counterpart detected with ANTARES
  64. GRB 211211A: MITSuME Akeno optical observation
  65. GRB 211211A: Nanshan/NEXT optical observations
  66. GRB 211211A: KAIT Optical Afterglow Candidate
  67. GRB 211211A: Swift detection of a bright burst
  68. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  69. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  70. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  71. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  72. GRB 211207A: Swift detection of a burst with an optical counterpart
  73. GRB 211203A: Swift detection of a burst
  74. GRB 211129A: Swift detection of a burst
  75. IceCube-211125A: No neutrino counterpart detected with ANTARES
  76. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  77. IceCube-211123A: Upper limits from Fermi-GBM Observations
  78. IceCube-211117A: not observable by Fermi-GBM
  79. IceCube-211116A: not observable by Fermi-GBM
  80. IceCube-211023A: not observable by Fermi-GBM
  81. HAWC-211123A: not observable by Fermi-GBM
  82. HAWC-211123A: No neutrino counterpart detected with ANTARES
  83. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  84. Trigger_21473: Tiled Swift observations
  85. Search for counterpart to IceCube-211117A with ANTARES
  86. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  87. IceCube-211116A: No neutrino counterpart detected with ANTARES
  88. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 211106A: Swift/UVOT upper limits
  90. Short GRB 211106A: spectroscopy of galaxies in the field
  91. MeerLICHT follow-up of GRB 211106A
  92. GRB 211107B: Swift ToO observations
  93. GRB 211106A: Swift-XRT observations
  94. GRB 211106A: Swift ToO observations
  95. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
  96. Swift Trigger 1082569 is probably not a GRB
  97. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  98. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  99. GRB 211024A: Possible afterglow candidate from GIT
  100. GRB 211024A: Swift ToO observations

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