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"

27824 results found.

  1. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  2. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  3. GRB 250215A: Swift-XRT refined Analysis
  4. EP250215a / GRB 250215A: AstroSat CZTI detection
  5. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  6. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  7. GRB 250215A: Fermi GBM Final Real-time Localization
  8. EP250207b: Xinglong optical upper limit
  9. GRB 250213A: Swift ToO observations
  10. GRB 250214A: Fermi GBM Final Real-time Localization
  11. EP250212a: Xinglong optical upper limit
  12. GRB 250213A: SVOM detection of a burst
  13. GRB 250205A: VIRT Optical Upper Limit
  14. GRB 250205A: Leavitt Observatory optical upper limit
  15. GRB 250210A: GRBAlpha detection
  16. LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies
  17. EP250212a: Liverpool Telescope optical upper limits
  18. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  19. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  20. GRB 250211A: Swift ToO observations
  21. GRB 250212A: Fermi GBM Final Real-time Localization
  22. GRB 250207A: Fermi GBM Observation
  23. GRB 250205A / EP250205A: radio detection with the VLA
  24. IceCube-250207A: One candidate from the Zwicky Transient Facility
  25. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  26. Konus-Wind detection of GRB 250207A
  27. Konus-Wind detection of GRB 250206A
  28. EP250207b: Liverpool Telescope possible optical counterpart
  29. Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
  30. GRB 250207A: Skynet optical afterglow observations
  31. LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy
  32. GRB 241128A: VIRT Optical Upper Limit
  33. GRB 250210A: INTEGRAL SPI-ACS detection
  34. GRB 250210A: AstroSat CZTI detection
  35. EP250207b: a new X-ray transient detected by Einstein Probe
  36. LIGO/Virgo/KAGRA S250206dm: MASTER detection AT2025bbo
  37. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  38. GRB 250210A: Fermi GBM Final Real-time Localization
  39. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  40. GRB 250204B: GRBAlpha detection
  41. GRB 250204A: GRBAlpha detection
  42. GRB 250207A: 1.3m DFOT Optical observations
  43. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  44. GRB 250206A: Swift-XRT observations
  45. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  46. GRB 250129A: GRANDMA Continued Afterglow Detection
  47. GRB 250207A: Swift-BAT refined analysis
  48. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  49. GRB 250205A: 1.3m DFOT optical upper limit
  50. GRB 250206A: Tiled Swift observations
  51. GRB 250206A: EIRSAT-1 GMOD Detection
  52. GRB 250206A: Fermi-LAT detection
  53. GRB 250207B: Swift-XRT observations
  54. LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
  55. GRB 250208A: Fermi GBM Final Real-time Localization
  56. EP250207a: EP-WXT detection and XRT follow-up observation
  57. GRB 250207A: Swift-XRT refined Analysis
  58. GRB 250207A: Enhanced Swift-XRT position
  59. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  60. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  61. GRB 250207A: REM IR afterglow detection
  62. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  63. GRB 250207A: FRAM-Auger optical detection
  64. GRB 250207B: Tiled Swift observations
  65. Konus-Wind detection of GRB 250204B
  66. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 250207A: REM optical afterglow detection
  68. GRB 250207A: Swift/UVOT Detection
  69. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  70. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  71. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  72. GRB 250207B: MAXI/GSC detection
  73. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  74. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  75. GRB 250207A: Swift detection of a burst with optical counterpart
  76. GRB 250207A: Fermi GBM Final Real-time Localization
  77. GRB 250206A: Fermi GBM Final Real-time Localization
  78. GRB 250205A: Fermi GBM Observation
  79. GRB 250205A: Swift/UVOT Upper Limits
  80. EP250205a/GRB 250205A: Einstein Probe observation
  81. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  82. GRB 250205A: Swift/XRT detection
  83. GRB250205A: SVOM/VT optical afterglow detection
  84. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  85. GRB 250205A: SVOM detection of a burst
  86. Konus-Wind detection of GRB 250201A
  87. IPN triangulation of GRB 250201A
  88. Konus-Wind detection of GRB 250202B
  89. GRB 250129A: Swift-BAT refined analysis
  90. IPN triangulation of GRB 250204B (short/hard)
  91. IPN triangulation of GRB 250202B
  92. GRB 250204B: AstroSat CZTI detection of a short burst
  93. GRB 250204B: Fermi GBM Final Localization
  94. GRB 250129A: LCO late afterglow detection
  95. GRB 250204A: Fermi GBM Final Real-time Localization
  96. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  97. GRB 250202B: NuSTAR detection of the prompt emission
  98. GRB 250202C: GRBAlpha detection
  99. GRB 250202B: Fermi GBM Detection
  100. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event

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