Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

37512 results found.

  1. GRB 251222A / EP251222b: LCO optical observations
  2. GRB 251222A: 1.3m DFOT optical detection
  3. GRB251221A: 7DT optical upper limits
  4. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  5. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  6. EP251222b/GRB 251222A: SVOM/GRM observation
  7. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  8. GRB 251222A: PRIME near-infrared detection
  9. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  10. GRB 251222A: NOT optical observations
  11. IPN triangulation of GRB 251220B (short)
  12. GRB 251222A: Swift ToO observations
  13. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  14. GRB 251222A: SVOM/VT optical candidate
  15. GRB 251222A: SVOM detection of a long burst
  16. GRB 251222A: Fermi GBM Final Real-time Localization
  17. GRB 251221A: PRIME near-infrared observation
  18. GRB 251221A: UAFO and Mondy optical upper limit
  19. GRB 251221A: Swift-XRT refined Analysis
  20. GRB 251221A: Swift/UVOT Upper Limits
  21. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  22. GRB 251221A: Enhanced Swift-XRT position
  23. GRB 251221A: Fermi GBM Observation
  24. GRB 251221B: Fermi GBM Final Real-time Localization
  25. GRB 251220B: SVOM/GRM observation of a short burst
  26. GRB 251221A: COLIBRÍ detection of the optical counterpart
  27. GRB 251221A: Swift detection of a burst
  28. GRB 251221A: Fermi GBM Final Real-time Localization
  29. GRB 251220B: Fermi GBM Final Real-time Localization
  30. GRB 251219A: SVOM/GRM observation of a short burst
  31. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  32. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  33. GRB 251220A: MAXI/GSC detection
  34. GRB 251215A: Swift-XRT afterglow detection
  35. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 251214B: VIRT Optical Upper Limit
  37. Fermi trigger No 787736968: Global MASTER-Net observations report
  38. Fermi GRB 251217A: Global MASTER-Net observations report
  39. GRB 251217A: Fermi GBM Final Real-time Localization
  40. GRB 251215A: Swift/UVOT Upper LImits
  41. GRB 251215A: Fermi GBM Observation
  42. Fermi GRB 251216A: Global MASTER-Net observations report
  43. GRB 251202A/EP251202a: Koshka optical upper limit
  44. GRB 251214B: Mondy optical upper limit
  45. GRB 251215A: COLIBRÍ optical upper limit
  46. GRB 251216A: Fermi GBM Final Real-time Localization
  47. EP251214b: KAIT optical upper limit
  48. GRB 251215A: Swift-XRT observations
  49. Fermi GRB 251215A: Global MASTER-Net observations report
  50. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  51. GRB 251215A: Glowbug gamma-ray detection
  52. GRB 251214B: UAFO optical upper limit
  53. GRB 251214B: VLT/X-shooter observations
  54. GRB 251213A: GRID-10B observation
  55. GRB 251214B: Swift-BAT refined analysis
  56. GRB 251202A: radio detection with the VLA
  57. GRB 251214B: AbAO optical observations
  58. GRB 251214B: LCO detection of the optical counterpart
  59. GRB 251209A: GECAM-B observation of a long burst
  60. GRB 251214D: GECAM-B observation of a long burst
  61. GRB 251214B: Fermi GBM Observation
  62. GRB 251209A: Insight-HXMT/HE detection
  63. GRB 251215A: Swift ToO observations
  64. GRID detection of GRB 251213A
  65. GRB 251203B: AbAO optical observations
  66. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  67. GRB 251214B: GECAM-B observation of a long burst
  68. GRB 251214B: Swift-XRT refined Analysis
  69. GRB 251213A: SVOM/GRM observation
  70. EP251214a: KAIT optical upper limit
  71. GRB 251214D: AstroSat CZTI detection of a long burst
  72. GRB 251213A: AstroSat CZTI detection
  73. GRB 251214A: AstroSat CZTI detection
  74. GRB 251213A: GECAM-B detection
  75. GRB 251214B: Swift/UVOT Detection
  76. GRB 251215A: Fermi GBM Final Real-time Localization
  77. GRB 251214B: COLIBRÍ observations of the afterglow
  78. GRB 251214A: GECAM-B observation of a likely long burst
  79. GRB 251214B: 1.3m DFOT optical detection
  80. GRB 251214B: Enhanced Swift-XRT position
  81. GRB 251214B: Xinglong-2.16m optical observation
  82. GRB 251214C: Fermi GBM Final Localization
  83. GRB 251214B : MASTER optical afterglow detection
  84. Fermi trigger No 787396657: Global MASTER-Net observations report
  85. GRB 251214B: SVOM/C-GFT optical observations
  86. EP251214a: COLIBRÍ optical upper limit
  87. Swift GRB 251214B: Global MASTER-Net observations report
  88. GRB 251214B: Swift detection of a burst with an optical counterpart
  89. GRB 251214B: Fermi GBM Final Real-time Localization
  90. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  91. Fermi GRB 251214A: Global MASTER-Net observations report
  92. GRB 251214A: Fermi GBM Final Real-time Localization
  93. EP251212a: KAIT optical upper limit
  94. EP251212a / GRB 251212A: AstroSat CZTI detection
  95. GRB 251211B: AstroSat CZTI detection
  96. GRB 251209A: NuSTAR detection of prompt emission
  97. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  98. Fermi GRB 251211B: Global MASTER-Net observations report
  99. GRB 251211B: Fermi GBM Final Real-time Localization
  100. GRB 251211A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov