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"

24368 results found.

  1. GRB 260102A: Swift-XRT afterglow detection
  2. GRB 260109A: Fermi GBM Final Real-time Localization
  3. GRB 260104A: Swift-BAT refined analysis
  4. GRB 260101A: Swift-BAT refined analysis
  5. Swift GRB 251230A: Global MASTER-Net OT detection
  6. Fermi GRB 260107A: Global MASTER-Net observations report
  7. GRB 260107A: Fermi GBM Final Real-time Localization
  8. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  9. The EP-WXT trigger 01709251112 is likely a flaring star
  10. Fermi GRB 260105A: Global MASTER-Net observations report
  11. GRB 260105B: Fermi GBM Detection
  12. EP260105a: FTW optical observations
  13. EP260104a: FTW optical observations
  14. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  15. GRB 260105A: SVOM/GRM observation
  16. GRB 260105B: SVOM/GRM observation
  17. The EP-WXT trigger 01709251028 is likely a flaring star
  18. Fermi GRB 260105B: Global MASTER-Net observations report
  19. EP260105a: SVOM/VT optical upperlimit
  20. GRB 260105B: Fermi GBM Final Real-time Localization
  21. GRB 260105A: Fermi GBM Final Real-time Localization
  22. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  23. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  24. EP260104a: Global MASTER-Net observations report
  25. EP260105a: Global MASTER-Net observations report
  26. GRB 260104C: Fermi GBM Final Real-time Localization
  27. Fermi GRB 260104B: Global MASTER-Net observations report
  28. Swift GRB 260104A: Global MASTER-Net observations report
  29. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  30. GRB 260104A: Swift-XRT refined Analysis
  31. GRB 260103A: GECAM-B observation of a burst
  32. GRB 260104B: Fermi GBM Final Localization
  33. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  34. SVOM GRB260103.08: Global MASTER-Net observations report
  35. GRB 260102B: Fermi GBM Final Real-time Localization
  36. SVOM GRB260102A: Global MASTER-Net observations report
  37. Fermi GBM Sub-Threshold Detection of GRB 260102A
  38. GRB 260102A: EP-FXT follow-up observation
  39. EP260101a: Global MASTER-Net observations report
  40. GRB 260102A: LCO optical upper limits
  41. GRB 260102A: Swift-XRT observations
  42. GRB 260102A: SVOM/VT optical counterpart
  43. GRB 260101A: Fermi GBM Observation
  44. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  45. GRB 260102A: SVOM detection of a burst
  46. GRB 260101A: NOT spectroscopic observations
  47. GRB 260101A: SVOM/GRM observation
  48. GRB 260101A: Swift-XRT refined Analysis
  49. Swift GRB 260101A: Global MASTER-Net observations report
  50. GRB 260101A: Fermi GBM Final Real-time Localization
  51. SVOM GRB251231.57: Global MASTER-Net observations report
  52. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  53. GRB 251230A: GRANDMA/TAROT Early Detection
  54. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  55. EP251229a: Optical upper limit with Kinder observations
  56. GRB 251230A: 1.3m DFOT optical upper limit
  57. GRB 251231A: Fermi GBM Final Real-time Localization
  58. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  59. GRB251230A: 7DT optical upper limits
  60. EP251229a: BOOTES-2 early optical upper limit
  61. GRB 251230A / EP251230a: SVOM/VT optical observation
  62. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  63. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  64. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  65. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  66. Swift GRB 251230A: Global MASTER-Net observations report
  67. EP251229a: Global MASTER-Net observations report
  68. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  69. Fermi GRB 251228A: Global MASTER-Net observations report
  70. The EP-WXT trigger 01709250662 is likely a flaring star
  71. GRB 251228A: Fermi GBM Final Real-time Localization
  72. GRB 251226A: SVOM/GRM observation
  73. GRB 251226A: GECAM-B detection
  74. SVOM GRB251227.07: Global MASTER-Net observations report
  75. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  76. The EP-WXT trigger 01709250617 is likely a flaring star
  77. IceCube Alert 251225.84: Global MASTER-Net observations report
  78. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 251222A: NUTTelA-TAO Early Measurements
  80. GRB 251222A/EP251222b: Optical detection with Kinder observations
  81. GRB 251221A: Swift-BAT refined analysis
  82. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  83. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  84. GRB 251222A: Continued 1.3m DFOT optical observation
  85. EP251220a: 3.6m DOT optical afterglow detection
  86. GRB 251222A: Fermi GBM Observation
  87. EP251222a: Global MASTER-Net observations report
  88. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  89. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  90. Konus-Wind detection of GRB 251222A / EP251222b
  91. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  92. EP251222a: GOTO optical upper limit
  93. GRB 251222A / EP251222b: LCO optical observations
  94. GRB 251222A: 1.3m DFOT optical detection
  95. GRB251221A: 7DT optical upper limits
  96. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  97. EP251222b/GRB 251222A: SVOM/GRM observation
  98. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  99. The EP-WXT trigger 01709250397 is likely a flaring star
  100. EP251221a: Global MASTER-Net observations report

Advanced

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