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"

41680 results found.

  1. IPN triangulation of GRB 260601A (short/hard)
  2. GRB 260610A: Fermi GBM Final Real-time Localization (duplicate submission)
  3. EP260610a: COLIBRÍ optical upper limits
  4. EP260610a: Einstein Probe detection of a fast X-ray transient
  5. Konus-Wind detection of GRB 260604C
  6. GRB 260608A: Fermi GRB Observation
  7. GRB 260604C: AstroSat CZTI detection
  8. IPN triangulation of GRB 260601B / EP260601a
  9. GRB 260604C: SVOM/ECLAIRs refined analysis
  10. GRB 260608A: SVOM/ECLAIRs refined analysis
  11. Konus-Wind detection of GRB 260607B
  12. GRB 260607B: GECAM-B observation
  13. GRB 260608C: Fermi GBM Final Real-time Localization (duplicate submission)
  14. GRB 260604C: further SAO RAS optical observations
  15. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  16. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  17. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  18. GRB 260604C: SVOM/C-GFT upper limit
  19. GRB 260607B: AstroSat CZTI detection
  20. GRB 260608A: SVOM detection of a burst
  21. GRB 260608A: Fermi GBM Final Real-time Localization (duplicate submission)
  22. EP260605a: EP-FXT follow-up observation
  23. GRB 260607A: TRT optical observations
  24. GRB 260604C: GRANDMA further observations
  25. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  26. GRB 260604A: SVOM/GRM detection
  27. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  28. GRB 260607B: Fermi GBM Observation
  29. GRB 260607B: Fermi-LAT detection
  30. GRB 260607B: Fermi GBM Final Localization Correction
  31. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  32. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  33. GRB 260607A: Fermi GBM Final Real-time Localization (duplicate submission)
  34. GRB 260604C: GECAM-B observation
  35. GRB 260604C: 6 GHz VLA observations
  36. GRB 260604C: SAO RAS optical observations
  37. GRB 260604C: GRANDMA observations
  38. GRB 260604B: SVOM/GRM detection
  39. GRB 260605A: Insight-HXMT/HE detection
  40. GRB260603A: SVOM/ECLAIRs refined analysis
  41. EP260605a: Einstein Probe detection of a fast X-ray transient
  42. EP260603a: COLIBRÍ optical upper limit
  43. GRB 260604A: Glowbug gamma-ray detection
  44. GRB 260604C: LCO optical upper limit
  45. GRB 260604C: Liverpool Telescope optical detection
  46. The EP-WXT trigger 01709267001 is likely a flaring star
  47. EP260602d: EP-FXT follow-up observation
  48. EP260602c: EP-FXT follow-up observation
  49. GRB 260601B / EP260601a: AstroSat CZTI detection
  50. GRB 260527A/EP260527a: 6 GHz VLA observations
  51. GRB 260604C: GOTO detections of the optical afterglow
  52. GRB 260604C: Correction to GCN 44828
  53. GRB 260604C: Kilonova-Catcher optical afterglow detection
  54. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  55. The EP-WXT trigger 01709266798 is likely a flaring star
  56. GRB 260604C: Jinshan optical observations
  57. GRB 260604C: Fermi GBM Observation
  58. EP260602d: J-band upper limit with WINTER
  59. EP260602b: J-band upper limit with WINTER
  60. GRB 260604C: LAST detection of optical counterpart candidate
  61. GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
  62. Fermi GRB 260604C: Global MASTER-Net observations report
  63. Fermi GRB 260604C: Global MASTER-Net observations report
  64. SVOM GRB260604.85: Global MASTER-Net observations report
  65. GRB 260604C: SVOM detection of a long burst
  66. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  67. GRB 260603A: NOT optical observations
  68. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  69. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  70. EP260602a: EP-FXT follow-up observation
  71. EP260603a: Global MASTER-Net observations report
  72. EP260603a: Einstein Probe detection of a fast X-ray transient
  73. EP260602d: Optical Upper limits with kinder observations
  74. EP260602b: Liverpool Telescope observations
  75. EP260602a: Liverpool Telescope optical upper limits
  76. EP260602b: Liverpool Telescope and LCO observations
  77. EP260602a: GTC and Liverpool Telescope optical observations
  78. Konus-Wind detection of GRB 260601B/EP260601a
  79. GRB 260603A: EP-FXT follow-up observation
  80. EP260601a/GRB 260601B: EP-FXT follow-up observation
  81. GRB 260601B / EP260601a: Mondy optical upper limit
  82. EP260602b: EP-FXT follow-up observation
  83. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  84. GRB 260603A: Kilonova-Catcher optical upper limit
  85. GRB 260603A: SVOM/VT optical observations
  86. EP260602a: NOT NIR J-band observations
  87. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  88. EP260602d: Einstein Probe detection of a fast X-ray transient
  89. Fermi trigger No 802141998: Global MASTER-Net observations report
  90. EP260602a: SVOM/VT optical magnitudes correction
  91. GRB 260601A: SVOM/GRM observation of a short burst
  92. EP260602c: Einstein Probe detection of a fast X-ray transient
  93. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  94. EP260602a: COLIBRÍ optical observations
  95. GRB260601B/EP260601a: NOT near-infrared observations
  96. SVOM GRB260603.23: Global MASTER-Net observations report
  97. GRB 260603A: SVOM detection of a burst
  98. EP260602b: Einstein Probe detection of a fast X-ray transient
  99. GRB 260601B/EP260601a: Insight-HXMT detection
  100. Fermi GRB 260602B: 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