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"

12096 results found.

  1. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  2. Swift GRB260120B: Global MASTER-Net observations report
  3. GRB 260120B: Fermi GBM Final Real-time Localization
  4. Fermi trigger No 790601190: Global MASTER-Net observations report
  5. Fermi trigger No 790570272: Global MASTER-Net observations report
  6. GRB 260120A: Fermi GBM Final Real-time Localization
  7. EP260119a: update of EP-FXT follow-up observation
  8. SVOM GRB260119.90: Global MASTER-Net observations report
  9. EP260116a: COLIBRÍ detection of a fading optical source
  10. EP260119a: Global MASTER-Net observations report
  11. GRB 260117A: ZTSh optical upper limit
  12. EP260119a: COLIBRÍ optical counterpart candidate
  13. EP260119a: preliminary result from the EP-FXT observation
  14. GRB 260110A: SVOM detection of a burst through offline search
  15. EP260119a: EP-WXT detection of a fast X-ray transient
  16. Swift GRB260118.48: Global MASTER-Net observations report
  17. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  18. GRB 260117A: SVOM detection of a long faint burst
  19. EP260116a: Einstein Probe detection of an X-ray transient
  20. IceCube Alert 260115.73: Global MASTER-Net observations report
  21. Fermi GRB 260115A: Global MASTER-Net observations report
  22. Konus-Wind detection of GRB 260114A
  23. GRB 260114A: Swift-XRT refined Analysis
  24. Konus-Wind detection of GRB 251230A / EP251230a
  25. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  26. GRB 260114A: Swift detection of a short burst
  27. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  28. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  29. Konus-Wind detection of GRB 260101A
  30. GRB 260112B: Fermi GBM Final Real-time Localization
  31. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube Alert 260111A: Global MASTER-Net observations report
  33. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  34. EP260110a: SVOM/C-GFT upper limit
  35. EP260110a: BOOTES-5/JGU optical upper limit
  36. EP260110a: Einstein Probe detection of an X-ray transient
  37. Fermi GRB 260107A: Global MASTER-Net observations report
  38. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  39. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  40. EP260104a: Einstein Probe detection of a fast X-ray transient
  41. EP260105a: Einstein Probe detection of an X-ray transient
  42. Fermi GRB 260104B: Global MASTER-Net observations report
  43. GRB 260104A: Swift-XRT refined Analysis
  44. GRB 260104A: Swift detection of a burst
  45. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  46. SVOM GRB260103.08: Global MASTER-Net observations report
  47. EP260101a: Einstein Probe detection of an X-ray transient
  48. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  49. EP251229a: Optical upper limit with Kinder observations
  50. GRB 251230A: Swift-XRT refined Analysis
  51. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  52. GRB 251230A: Swift/UVOT detection
  53. GRB251230A: 7DT optical upper limits
  54. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  55. EP251229a: BOOTES-2 early optical upper limit
  56. GRB 251230A / EP251230a: SVOM/VT optical observation
  57. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  58. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  59. EP251229a: Global MASTER-Net observations report
  60. EP251229a: Einstein Probe detection of an X-ray transient
  61. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  62. Fermi GRB 251228A: Global MASTER-Net observations report
  63. SVOM GRB251227.07: Global MASTER-Net observations report
  64. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  65. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 251222A/EP251222b: Optical detection with Kinder observations
  67. EP251222a: Optical upper limit with Kinder observations
  68. GRB 251205A: Kilonova-Catcher optical afterglow detection
  69. EP251220a: CrAO ZTSh optical observations
  70. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  71. Konus-Wind detection of GRB 251222A / EP251222b
  72. GRB 251222A: Swift-XRT afterglow detection
  73. GRB 251222A: 1.3m DFOT optical detection
  74. GRB251221A: 7DT optical upper limits
  75. EP251222b/GRB 251222A: SVOM/GRM observation
  76. EP251222a: Einstein Probe detection of an X-ray transient
  77. EP251221a: Einstein Probe detection of a fast X-ray transient
  78. EP251220a: EP-FXT follow-up observation
  79. EP 251220a: GOTO optical counterpart detection
  80. Swift GRB251221A: Global MASTER-Net observations report
  81. EP251220a: Global MASTER-Net observations report
  82. EP251220a: EP detection of a fast X-ray transient
  83. SVOM GRB251220.98: Global MASTER-Net observations report
  84. GRB 251220B: Fermi GBM Final Real-time Localization
  85. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  86. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  87. GRB 251220A: MAXI/GSC detection
  88. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  89. SVOM GRB251219.11: Global MASTER-Net observations report
  90. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  91. IceCube Alert 251218.85: Global MASTER-Net observations report
  92. Fermi GRB 251217A: Global MASTER-Net observations report
  93. Fermi GRB 251215A: Global MASTER-Net observations report
  94. EP251214a: Optical upper limit with Kinder observations
  95. EP251214b : Einstein Probe detection of a fast X-ray transient
  96. EP251214b : Einstein Probe detection of a fast X-ray transient
  97. EP251214b (EP trigger 01709250023): LCO optical limits
  98. GRB 251203B: AbAO optical observations
  99. GRB 251214B: Swift-XRT refined Analysis
  100. GRB 251214D: AstroSat CZTI detection of a long burst

Advanced

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