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"

36235 results found.

  1. GRB 261108C: SVOM/VT early optical upper limits
  2. GRB 261108C: LCO optical upper limits
  3. GRB 261108D: SVOM detection of an X-ray transient
  4. GRB 261108C: SVOM detection of a burst
  5. GRB 261108A: Fermi GBM Observation
  6. Konus-Wind detection of GRB 261024A
  7. GRB 261108B: Fermi GBM Final Localization Correction
  8. GRB 261108A: SVOM/C-GFT optical upper limit
  9. GRB 261108A: SVOM/VT optical upper limits
  10. GRB 261108A: LCO optical upper limits
  11. GRB 261108A: FRAM-Auger optical limits
  12. GRB 261103A: SVOM/VT optical upper limits
  13. GRB 261108A: SVOM detection of a burst
  14. GRB 261108A: Fermi GBM Final Real-time Localization
  15. GRB 261029C: SVOM/GRM detection of a short burst
  16. GRB 261103A: SVOM/ECLAIRs refined analysis
  17. Konus-Wind detection of GRB 261024D
  18. Konus-Wind detection of GRB 261029C (short / bright)
  19. GRB 261104A：EP-FXT follow-up observation
  20. GRB 261104A: DECam Detection of an Optical Counterpart Candidate
  21. GRB 261104A: SVOM/ECLAIRs refined analysis
  22. GRB 261104A: SVOM/VT optical upper limits
  23. IPN triangulation of GRB 261029C (short / bright)
  24. IPN triangulation of GRB 261025B (short)
  25. GRB 261103A: SVOM/C-GFT optical upper limit
  26. IPN triangulation of GRB 261024A
  27. GRB 261104A: LCO optical upper limits
  28. GRB 261104A: SVOM detection of burst
  29. GRB 260924A: CrAO ZTSh optical observations
  30. GRB 261029A : MITSuME Akeno optical afterglow detection
  31. GRB 261030C: AstroSat CZTI detection
  32. GRB 261029A: VST/OmegaCAM detection of the optical afterglow at 3 days
  33. GRB 261029A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  34. GRB 261103A: LCO optical upper limits
  35. GRB 261103A: SVOM/ECLAIRs detection of a burst through on-ground search
  36. Konus-Wind detection of GRB 261029A
  37. GRB 261029A: SAO RAS optical observations
  38. EP261015a/SN 2026ahoa: VLT/FORS2 discovery of a pre-peak type Ic-BL supernova at a tentative spectroscopic redshift z=0.31
  39. GRB 261102A: Fermi GBM Detection
  40. GRB 261029C: AstroSat CZTI detection of a short burst
  41. GRB 261102A: Fermi GBM Final Real-time Localization
  42. GRB 261101B: BALROG localization (Fermi Trigger 815240277 / GRB 261101651)
  43. GRB 261101B: Fermi GBM Final Real-time Localization
  44. GRB 261101A: Fermi GBM Final Real-time Localization
  45. GRB 261030A: Fermi GBM Detection
  46. Fermi GRB 261030B: Global MASTER-Net observations report
  47. GRB 261030B: Fermi GBM Final Real-time Localization
  48. GRB 261029A: SVOM/ECLAIRs refined analysis
  49. The EP-WXT trigger 01709321980: KAIT confirmation of a stellar flare
  50. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  51. GRB 261030A: Fermi GBM Final Real-time Localization
  52. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  53. GRB 261029A: Glowbug gamma-ray detection
  54. GRB 261024D: SVOM/GRM observation
  55. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  56. GRB 261029A : SVOM/GWAC-F60 observations
  57. GRB 261029A: GECAM-B detection of a bright burst
  58. GRB 261029A: WFST optical observations
  59. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  60. GRB 261029A: Ondrejov D50 optical observations, possible rebrightening
  61. GRB 261029A: Liverpool Telescope observations
  62. GRB 261029A: NuSTAR detection of bright prompt emission
  63. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  64. GRB 261029A: Fermi GBM Observation
  65. GRB 261029A: FRAM-ORM and FRAM-Auger optical afterglow light curve
  66. GRB 261029A: SVOM/GRM observation of a bright burst
  67. GRB 261029A: CALET Gamma-Ray Burst Monitor detection
  68. IPN triangulation of GRB 261024D
  69. GRB261029A: Infrared fading detected with MDM/MIRAGE
  70. GRB 261029A: SVOM/VT optical observation
  71. GRB 261029B : AstroSat CZTI detection
  72. GRB 261029A / AT2026ahaw: r- and i-band optical follow-up with the PKU 60cm Telescope
  73. GRB 261029A : AstroSat CZTI detection
  74. GRB 261029A: SVOM/C-GFT optical observations
  75. GRB 261029A: EP-FXT follow-up observation
  76. GRB 261029A: Fermi-LAT detection
  77. GRB 261029A: LCO optical observations (correction to GCN 46082)
  78. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  79. GRB 261029A: LCO optical observations
  80. GRB 261029A: NOT imaging and spectroscopic redshift z = 3.27
  81. GRB261029A: Early infrared detection with MDM/MIRAGE
  82. GRB 261029A: KAIT optical observations
  83. GRB 261029A: TRT optical observations
  84. GRB 261029B: Fermi GBM Final Real-time Localization
  85. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  86. GRB 261029A: GOTO optical counterpart candidate
  87. GRB 261029A: SVOM detection of a burst
  88. GRB 261029A: Fermi GBM Final Real-time Localization
  89. GRB 261021A: Glowbug gamma-ray detection
  90. GRB 261028A: Fermi GBM Final Localization
  91. GRB 261026A: SVOM/ECLAIRs refined analysis
  92. GRB 261024C: GECAM-B observation
  93. GRB 261026B: AstroSat CZTI detection
  94. GRB 261024D: Insight-HXMT/HE detection
  95. GRB261026A: Infrared detection with MDM/MIRAGE
  96. GRB 261026A: SVOM/VT optical blue bump
  97. GRB 261026A: SAO RAS optical observations
  98. GRB 261024D: GECAM-B observation
  99. GRB 261026A: EP-FXT follow-up observation
  100. GRB 261024A: SVOM/GRM observation

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