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"

2411 results found.

  1. EP250428b: SVOM/VT upper limit
  2. GRB 250424A: SVOM/GRM observation of a long burst
  3. GRB 250424A: SVOM/VT optical observation
  4. GRB 250419a: Continued Liverpool Telescope observations
  5. GRB 250407A: GRBAlpha detection
  6. GRB 250330B: GRBAlpha detection
  7. GRB 250419A: SVOM/ECLAIRs refined analysis
  8. SVOM/sb25042207: XRT observations
  9. SVOM/sb25042207: BOOTES-2 early optical upper limit
  10. SVOM/sb25042207: GOTO optical upper limits
  11. SVOM/sb25042207: SVOM detection of an X-ray transient
  12. GRB250419A: VLA radio detection
  13. GRB 250419A: Mephisto Multi-band Optical Detection
  14. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  15. GRB 250419A: Liverpool Telescope observations
  16. GRB 250419A: LCO optical observation
  17. GRB 250419A: JinShan optical observations
  18. GRB 250419A: SVOM/VT optical continuous observations
  19. GRB 250419A: SVOM/C-GFT optical observations
  20. GRB 250419A: Swift/UVOT Follow up
  21. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  22. GRB 250419A: LCO optical afterglow multi-band observations
  23. GRB 250419A: Mondy and AbAO Optical Observations
  24. GRB 250419A: Liverpool Telescope observations
  25. GRB 250419A: AKO Optical Afterglow Detection
  26. GRB 250419A: MASTER optical afterglow observation
  27. GRB 250419A: Swift-XRT localisation
  28. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  29. GRB 250419A: Swift-XRT refined Analysis
  30. GRB 250419A: GOTO optical counterpart detection
  31. GRB 250419A: KAIT optical afterglow observations
  32. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  33. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  34. GRB 250419A: SVOM detection of a soft burst
  35. Konus-Wind detection of GRB 250403A
  36. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  37. EP250225a: SVOM/VT optical brightening
  38. SVOM/sb25041603 is not a GRB
  39. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  40. SVOM/sb25041603: SVOM detection of an X-ray transient
  41. GRB 250314A: e-MERLIN observations
  42. GRB 250320B: cubesat Avion detection
  43. IPN triangulation of GRB 250407A
  44. GRB 250407A: LCO detection of a fading optical counterpart
  45. Konus-Wind detection of GRB 250407A
  46. GRB 250407A: SVOM/GRM observation of a bright long burst
  47. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  48. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  49. GRB 250403A: AstroSat CZTI detection
  50. GRB 250403A: Montarrenti Observatory optical detection
  51. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  52. GRB 250403A: Fermi GBM observations
  53. GRB 250327B: VIRT Optical Upper Limit
  54. GRB 250403A: Swift/UVOT Detection
  55. GRB 250402A: Swift/UVOT Upper Limits
  56. GRB 250403A: SVOM/VT optical observation
  57. GRB 250403A: REM NIR afterglow detection
  58. GRB 250403A: LCO optical counterpart detection
  59. GRB 250403A: JinShan optical observations
  60. GRB 250402A: EP-FXT afterglow detection
  61. GRB 250403A: Swift-XRT observations
  62. GRB 250402A: NUTTelA-TAO Early Optical Limits
  63. GRB 250403A: 1.6m Mephisto multi-band optical detection
  64. GRB 250402A: Fermi GBM Observation
  65. GRB 250403A: SVOM/C-GFT optical observations
  66. GRB 250403A: GOTO detection of the optical afterglow
  67. GRB 250402A: Swift-XRT observations
  68. GRB 250403A : SVOM detection of a burst
  69. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  70. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  71. GRB 250402A: REM optical/NIR upper limits
  72. GRB 250402A: LCO optical counterpart detection
  73. GRB 250402A: refined SVOM/MXT data analysis
  74. GRB 250402A: SVOM/VT optical counterpart
  75. GRB 250402A: SVOM detection of a burst
  76. GRB 250314A: ALMA detection
  77. GRB 250329B: Swift/UVOT Upper Limit
  78. GRB 250329A: Swift/UVOT Upper Limit
  79. GRB 250327B: Swift/UVOT Detection
  80. GRB 250331E: SVOM/GRM observation
  81. GRB 250327B: Kilonova-Catcher Observations
  82. GRB 250330B: SVOM/GRM observation of a short burst
  83. GRB 250329B: CAHA 2.2m telescope optical limit
  84. Konus-Wind detection of GRB 250327B
  85. GRB 250320C : SVOM detection of a burst through offline search
  86. GRB20250327B: 45th Parallel Observatory upper limit
  87. GRB 250328A: Swift/UVOT Detection
  88. GRB 250328A: Swift-XRT refined Analysis
  89. SVOM/sb25033102 is a false trigger
  90. GRB 250330A: SVOM/VT optical upper limit
  91. SVOM/sb25033102: SVOM detection of an X-ray transient
  92. GRB 250314A: VLA detection
  93. GRB 250328A: 1.6m Mephisto optical observations
  94. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  95. GRB 250329B: Swift-XRT afterglow detection
  96. GRB 250328A: A fading optical afterglow confirmed by SVOM/VT
  97. GRB 250329B: SVOM/C-GFT optical upper limit
  98. GRB 250329B: SVOM/VT optical upper limit
  99. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  100. GRB 250329B: 1.6m Mephisto Optical Upper Limits

Advanced

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