Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

37604 results found.

  1. GRB 260321A: SVOM detection of a burst
  2. GRB 260310A / AT2026fgk: ABObservatory and NOCTIS new optical observations
  3. GRB 260318A: Glowbug gamma-ray detection
  4. GRB 260310A / AT 2026fgk: KAIT optical observations
  5. GRB 260320A: NuSTAR detection of prompt emission
  6. GRB 260310A / AT2026fgk: NuSTAR follow-up detection
  7. EP-WXT trigger 01709258989: KAIT confirmation of a stellar flare
  8. GRB 260310A / AT 2026fgk: FTW optical and NIR observations show no rebrightening
  9. GRB 260310A: no evidence of re-brightening up to 9.6 days in optical observation at Mondy
  10. GRB 260310A / AT 2026fgk: COLIBRÍ evidence of a late rebrightening
  11. GRB 260310A/AT2026fgk: LBT near-infrared observations
  12. NOEMA Detection of GRB 260310A / AT 2026fgk
  13. GRB 260318A: SVOM/GRM observation
  14. GRB 260310A: classification as long GRB based on Eiso, Ep, and T_90
  15. GRB 260318A: GECAM-B observation
  16. GRB260310A/AT2026fgk: Further optical observation from 1.3m DFOT
  17. Fermi GRB 260318A: Global MASTER-Net observations report
  18. GRB 260318A: Fermi GBM Final Real-time Localization
  19. Fermi Gamma-ray Burst Monitor trigger 795096033/260312500 (GRB 260313A) is unlikely to be a GRB
  20. GRB 260316A / EP260316a: COLIBRÍ optical followup of counterpart candidate
  21. GRB 260310A / AT 2026fgk: radio detection with the VLA
  22. GRB 260310A / AT2026fgk: SVOM/VT optical observations
  23. GRB 260310A / AT2026fgk: LCO optical observations
  24. GRB 260317A: Fermi GBM Final Localization
  25. GRB 260316B: GECAM-B observation
  26. GRB 260316B: SVOM/GRM observation
  27. EP260316a / GRB 260316A: SVOM/VT optical upper limits
  28. EP260316a: COLIBRÍ faint optical counterpart candidate
  29. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  30. GRB 260316B: AstroSat CZTI detection
  31. EP260316a: refined analysis of the EP-WXT and EP-FXT observations
  32. GRB 260316B: Fermi GBM Final Real-time Localization
  33. EP260316a / GRB 260316A : Fermi-GBM Sub-Threshold Detection
  34. GRB 260314A: Glowbug gamma-ray detection
  35. GRB 260310A / AT2026fgk: 1.3m DFOT optical observations
  36. GRB 260310A / AT2026fgk: ABObservatory and NOCTIS optical observations
  37. GRB 260310A / AT 2026fgk: iTelescope optical observations
  38. GRID detection of GRB 260312B
  39. IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
  40. Fermi trigger No 795185313: Global MASTER-Net observations report
  41. GRB 260314A: GECAM-B observation of a burst
  42. Fermi Gamma-ray Burst Monitor trigger 795185313/260314534 is not a GRB
  43. GRB 260310A / AT2026fgk: SAO RAS optical observations
  44. GRB 260310A/AT2026fgk: radio detection at 15GHz
  45. GRB 260310A / AT2026fgk: TNG NIR detection
  46. GRB 260310A / AT2026fgk: OASDG optical observations
  47. GRB 260310A / AT2026fgk: Multiband optical follow-up with Kinder observations
  48. GRB 260310A / AT 2026fgk: COLIBRÍ continuing optical observations
  49. GRB 260310A / AT2026fgk: further CAHA 1.23m telescope optical observations suggest shallow decay
  50. Fermi GRB 260314A: Global MASTER-Net observations report
  51. Fermi GRB 260313A: Global MASTER-Net observations report
  52. GRB 260314A: Fermi GBM Final Real-time Localization
  53. GRB 260310A/AT 2026fgk: WINTER NIR Detections
  54. GRB 260313A: A Correction to the Fermi GBM Final Localization
  55. GRB 260310A: Einstein Probe Follow-up X-ray Telescope (FXT) Detection
  56. GRB 260310A/AT 2026fgk: J-band observations by the SYSU 80 cm infrared telescope
  57. GRB 260310B: Insight-HXMT/HE detection
  58. GRB 260310A/AT 2026fgk: DDOTI Optical Detection
  59. GRB 260310A: NOT optical polarimetry
  60. GRB 260312B: AstroSat CZTI detection
  61. Swift BAT trigger 1500295: A solar flare
  62. GRB 260313A: Fermi GBM Final Real-time Localization
  63. GRB 260310A/AT 2026fgk: Bok spectroscopic observation
  64. Swift BAT trigger 1500287: A solar flare
  65. GRB 260310A / AT2026fgk: OSIRIS+/GTC spectroscopy confirms redshift z = 0.153
  66. GRB 260308A: Insight-HXMT/HE detection
  67. GRB 260307A: CALET Gamma-Ray Burst Monitor detection
  68. GRB 260310A / AT 2026fgk: Location in the Epeak - Eiso diagram
  69. GRB 260310A / AT 2026fgk: COLIBRÍ optical observations
  70. GRB 260310A / AT2026fgk: CAHA 1.23m telescope optical observations
  71. GRB 260310A / AT2026fgk : MASTER OT rebrightening during 7h observations
  72. GRB260310A / AT2026fgk: P200 Spectroscopy
  73. GRB 260312B: Glowbug gamma-ray detection
  74. GRB 260310A: Fermi GBM Observation
  75. GRB 260310A: potential optical counterpart
  76. Fermi GRB 260312B: Global MASTER-Net observations report
  77. Fermi GRB 260311B: Global MASTER-Net observations report
  78. Swift BAT trigger 1500148: A solar flare
  79. GRB 260312B: BALROG localization (Fermi Trigger 795001611 / GRB 260312407)
  80. GRB 260312B: Fermi GBM Final Real-time Localization
  81. GRB 260310B: GECAM-B observation of a burst
  82. Retraction of GCN 43965: GRB is actually solar flare
  83. GRB 260312A: Swift detection of a burst
  84. GRB 260311B: Fermi GBM Final Real-time Localization
  85. GRB 260131A/B: radio detection with the VLA
  86. GRB260307A: GECAM-B observation of a burst
  87. GRB 260308A: SVOM/GRM observation of a short GRB
  88. EP260306a: Mondy optical upper limit
  89. GRB 260310A: AstroSat CZTI detection of a long burst
  90. GRB 260311A: Fermi GBM Final Real-time Localization
  91. Fermi GRB 260310B: Global MASTER-Net observations report
  92. GRB 260310B: Fermi GBM Final Real-time Localization
  93. Fermi GRB 260310A: Global MASTER-Net observations report
  94. GRB 260307B: SVOM/ECLAIRs refined analysis
  95. GRB 260208A: radio detection with the VLA
  96. GRB 260310A: Fermi GBM Final Real-time Localization
  97. GRB 260307A: Glowbug gamma-ray detection
  98. GRB 260308A: Fermi GBM Final Real-time Localization
  99. Fermi GBM Sub-Threshold Detection of GRB 260307B
  100. GRB 260307B: Mephisto optical upper limits

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