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"

12170 results found.

  1. GRB 251010A: AstroSat CZTI detection
  2. GRB 251011A: AstroSat CZTI detection
  3. GRB 251011B: Swift detection of a burst
  4. SVOM/sb25101004: SVOM detection of a stellar flare
  5. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  6. IceCube Alert 251008A: Global MASTER-Net observations report
  7. GRB 251006B: Fermi GBM Observation
  8. GRB 251007A: AstroSat CZTI detection
  9. GRB 250917B: iTelescope T-26 upper limit
  10. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  11. GRB 251007A: Swift-XRT refined Analysis
  12. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  13. GRB 251006B/EP251006a: EP-WXT detection
  14. Fermi GRB 251006B: Global MASTER-Net observations report
  15. GRB 251006B: BALROG localization (Fermi Trigger 781473909 / GRB 251006837)
  16. GRB 251006B: Fermi GBM Final Real-time Localization
  17. GRB 251003A: LAST optical observations
  18. GRB 251002A: LAST optical observations
  19. GRB 251005C: AstroSat CZTI detection
  20. GRB 251002A: Fermi GBM Observation
  21. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  22. GRB 251002A: AKO Early Optical Afterglow Detection
  23. GRB 251003A: Kilonova-Catcher optical afterglow detection
  24. GRB 251002A: Swift-XRT afterglow detection
  25. GRB 251002A: Kilonova-Catcher optical afterglow detection
  26. GRB 251002A: J band observations by SYSU 80cm infrared telescope
  27. GRB 251002A: VLT/X-shooter spectroscopic redshift z = 2.178
  28. GRB 251003A: Swift detection of a burst
  29. Swift GRB251003A: Global MASTER-Net observations report
  30. Fermi/SVOM GRB 251002A : MASTER OT earlier detection in 2 polarization filters
  31. GRB 251002A: BOOTES-6 early optical detection
  32. GRB 251002A: SAO RAS optical observations
  33. GRB 251002A: ULL-ASTRO-MASTER early detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  34. GRB 251002A: FRAM-ORM afterglow detection
  35. Fermi GRB 251002A: Global MASTER-Net observations report
  36. GRB 251001B: Swift-BAT refined analysis
  37. GRB 251001B: Swift/UVOT Detection
  38. GRB 251001B: Swift-XRT refined Analysis
  39. GRB 250930A: Fermi GBM Final Localization
  40. GRB 251001B: Swift detection of a burst
  41. GRB 250910A / EP250910a: VLT/X-shooter host galaxy redshift z = 0.592
  42. Fermi GRB 250929A: Global MASTER-Net observations report
  43. GRB 250929A: Fermi GBM Final Real-time Localization
  44. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  45. GRB 250924A: SVOM/GRM observation
  46. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  47. Fermi trigger No 780609036: Global MASTER-Net observations report
  48. GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
  49. GRB 250926A: AstroSat CZTI detection
  50. GRB 250925A: Mondy and AbAO optical observations
  51. Fermi GRB 250926A: Global MASTER-Net observations report
  52. GRB250925A: Liverpool Telescope optical observations
  53. GRB 250924A: Swift-BAT refined analysis
  54. GRB 250925A: Swift detection of a burst
  55. GRB 250924A: SAO RAS optical observations
  56. GRB 250924A: AstroSat CZTI detection
  57. GRB 250914A: AstroSat CZTI detection
  58. GRB 250920B: AstroSat CZTI detection
  59. GRB 250920C: TRT optical observation
  60. Konus-Wind detection of GRB 250920C
  61. GRB 250920C: SALT redshift confirmation
  62. GRB 250922C: AstroSat CZTI detection of a short burst
  63. Fermi GRB 250922B: Global MASTER-Net observations report
  64. Fermi trigger No 780156732: Global MASTER-Net observations report
  65. Konus-Wind detection of GRB 250920B
  66. Konus-Wind detection of GRB 250920A
  67. Konus-Wind detection of GRB 250911A
  68. GRB 250920B: Glowbug gamma-ray detection
  69. GRB 250916A: CrAO ZTSh R-band optical observations
  70. GRB 250920C: Swift-XRT refined Analysis
  71. GRB 250920B: Kitab-ISON optical upper limit
  72. GRB 250920C: GROWTH-India Telescope optical observations
  73. GRB 250920B: Fermi GBM Observation
  74. GRB 250920A: Fermi GBM Detection
  75. GRB 250920C: Fermi GBM Observation
  76. Swift GRB 250920C: Global MASTER-Net observations report
  77. GRB 250920B: FTW optical and NIR observations of the counterpart
  78. GRB 250920C: Optical counterpart detection by LCO
  79. GRB250920C: LCOGT Optical Detection
  80. GRB 250920B: Swift-XRT refined Analysis
  81. GRB 250920B: SVOM/C-GFT optical observations
  82. GRB 250920C: GOTO optical counterpart candidate
  83. Konus-Wind detection of GRB 250919A
  84. GRB 250920C: Fermi GBM Final Real-time Localization
  85. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
  86. Swift GRB 250920B: Global MASTER-Net observations report
  87. GRB 250920A: AstroSat CZTI detection
  88. GRB 250920B: Fermi GBM Final Real-time Localization
  89. GRB 250920A: BALROG localization (Fermi Trigger 780029651 / GRB 250920121)
  90. GRB 250920A: Fermi GBM Final Localization
  91. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  92. GRB 250919A: Swift-XRT afterglow detection
  93. GRB 250919A: Fermi-LAT detection
  94. EP250919a: Einstein Probe detection of an X-ray transient
  95. GRB 250912A: SVOM/ECLAIRs refined analysis
  96. GRB 250916A: MAO/AZT-22 optical observations
  97. GRB 250916A: SAO RAS optical observations
  98. GRB 250917B: Fermi GBM Observation
  99. GRB 250916A: AstroSat CZTI detection of a bright long burst
  100. GRB 250910A: SVOM/ECLAIRs 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