Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

37745 results found.

  1. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  2. Swift GRB 251230A: Global MASTER-Net observations report
  3. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  4. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  5. GRB 251226A: Glowbug gamma-ray detection
  6. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  7. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  8. Fermi GRB 251228A: Global MASTER-Net observations report
  9. GRB 251228A: Fermi GBM Final Real-time Localization
  10. GRB 251226A: SVOM/GRM observation
  11. GRB 251226A: GECAM-B detection
  12. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  13. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  14. GRB 251222A: NUTTelA-TAO Early Measurements
  15. GRB 251222A/EP251222b: Optical detection with Kinder observations
  16. GRB 251221A: Swift-BAT refined analysis
  17. GRB 251222A/EP251222b: FTW optical and NIR observations
  18. GRB 251205A: Kilonova-Catcher optical afterglow detection
  19. GRB 251222A: AbAO optical observations
  20. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  21. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  22. GRB 251222A: ZTSH BVRI optical observations
  23. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  24. GRB 251222A: Continued 1.3m DFOT optical observation
  25. GRB 251222A: Fermi GBM Observation
  26. EP251220a: CrAO ZTSh optical observations
  27. GRB 251222A / EP251222b: GECAM-B observation
  28. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  29. Konus-Wind detection of GRB 251222A / EP251222b
  30. GRB 251222A: Swift-XRT afterglow detection
  31. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  32. GRB 251222A / EP251222b: GOTO optical counterpart detection
  33. GRB 251222A / EP251222b: LCO optical observations
  34. GRB 251222A: 1.3m DFOT optical detection
  35. GRB251221A: 7DT optical upper limits
  36. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  37. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  38. EP251222b/GRB 251222A: SVOM/GRM observation
  39. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  40. GRB 251222A: PRIME near-infrared detection
  41. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  42. GRB 251222A: NOT optical observations
  43. IPN triangulation of GRB 251220B (short)
  44. GRB 251222A: Swift ToO observations
  45. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  46. GRB 251222A: SVOM/VT optical candidate
  47. GRB 251222A: SVOM detection of a long burst
  48. GRB 251222A: Fermi GBM Final Real-time Localization
  49. GRB 251221A: PRIME near-infrared observation
  50. GRB 251221A: UAFO and Mondy optical upper limit
  51. GRB 251221A: Swift-XRT refined Analysis
  52. GRB 251221A: Swift/UVOT Upper Limits
  53. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  54. GRB 251221A: Enhanced Swift-XRT position
  55. GRB 251221A: Fermi GBM Observation
  56. GRB 251221B: Fermi GBM Final Real-time Localization
  57. GRB 251220B: SVOM/GRM observation of a short burst
  58. GRB 251221A: COLIBRÍ detection of the optical counterpart
  59. GRB 251221A: Swift detection of a burst
  60. GRB 251221A: Fermi GBM Final Real-time Localization
  61. GRB 251220B: Fermi GBM Final Real-time Localization
  62. GRB 251219A: SVOM/GRM observation of a short burst
  63. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  64. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  65. GRB 251220A: MAXI/GSC detection
  66. GRB 251215A: Swift-XRT afterglow detection
  67. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 251214B: VIRT Optical Upper Limit
  69. Fermi trigger No 787736968: Global MASTER-Net observations report
  70. Fermi GRB 251217A: Global MASTER-Net observations report
  71. GRB 251217A: Fermi GBM Final Real-time Localization
  72. GRB 251215A: Swift/UVOT Upper LImits
  73. GRB 251215A: Fermi GBM Observation
  74. Fermi GRB 251216A: Global MASTER-Net observations report
  75. GRB 251202A/EP251202a: Koshka optical upper limit
  76. GRB 251214B: Mondy optical upper limit
  77. GRB 251215A: COLIBRÍ optical upper limit
  78. GRB 251216A: Fermi GBM Final Real-time Localization
  79. EP251214b: KAIT optical upper limit
  80. GRB 251215A: Swift-XRT observations
  81. Fermi GRB 251215A: Global MASTER-Net observations report
  82. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  83. GRB 251215A: Glowbug gamma-ray detection
  84. GRB 251214B: UAFO optical upper limit
  85. GRB 251214B: VLT/X-shooter observations
  86. GRB 251213A: GRID-10B observation
  87. GRB 251214B: Swift-BAT refined analysis
  88. GRB 251202A: radio detection with the VLA
  89. GRB 251214B: AbAO optical observations
  90. GRB 251214B: LCO detection of the optical counterpart
  91. GRB 251209A: GECAM-B observation of a long burst
  92. GRB 251214D: GECAM-B observation of a long burst
  93. GRB 251214B: Fermi GBM Observation
  94. GRB 251209A: Insight-HXMT/HE detection
  95. GRB 251215A: Swift ToO observations
  96. GRID detection of GRB 251213A
  97. GRB 251203B: AbAO optical observations
  98. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  99. GRB 251214B: GECAM-B observation of a long burst
  100. GRB 251214B: Swift-XRT refined Analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov