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"

28114 results found.

  1. GRB 250202A: Fermi GBM Final Real-time Localization
  2. GRB 250201A: INTEGRAL SPI/ACS detection
  3. Konus-Wind detection of GRB 250129A
  4. GRB 250129A: 1.3m DFOT Optical observations
  5. GRB 250201A: Fermi GBM Final Real-time Localization
  6. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  7. GRB 250129A: optical photometry from Konkoly
  8. GRB 250129A: COLIBRÍ Optical Observations
  9. GRB 250128B: VLA possible radio detection
  10. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  11. GRB 250129A: iTelescope optical observation
  12. GRB 250129A: NOT optical observations of continuining activity
  13. GRB 250129a: Liverpool Telescope optical follow-up
  14. GRB 250129A: TNG NIR afterglow detection
  15. GRB 250129A: AKO Optical Afterglow Detection
  16. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  17. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  18. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  19. GRB 250128B: VLA radio upper limit
  20. Ep250125A: 1.3m DFOT optical upper limit
  21. GRB 250129A: Skynet optical observations
  22. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  23. GRB 250129A: Swift-XRT refined Analysis
  24. GRB 250128B: Gemini-North optical extended source detection
  25. GRB 250128B: TNG optical upper limit
  26. GRB 250129A: Swift/UVOT Detection
  27. GRB 250128B: VLT/HAWKI near-infrared observations
  28. GRB 250127A: CrAO and Terskol optical upper limits
  29. GRB 250129A: Enhanced Swift-XRT position
  30. GRB 250128B: NOT optical upper limit
  31. GRB 250128B: VLT/FORS2 optical observations
  32. GRB 250129A: REM optical/NIR afterglow detection
  33. GRB 250129A: OHP/T193 optical and spectroscopy observations
  34. GRB 250129A: Early afterglow detection by LCO.
  35. GRB 250128B: OHP/T193 optical upper limit
  36. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  37. GRB 250129A: LCO optical observations
  38. GRB 250129A: GOTO optical observations show brightening afterglow
  39. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  40. GRB 250128B: Enhanced Swift-XRT position
  41. GRB 250129A: Swift detection of a burst with an optical counterpart
  42. Swift GRB 250129A: Global MASTER-Net OT detection
  43. GRB 250128B: Swift-XRT refined Analysis
  44. GRB 250128B: GOTO optical upper limit
  45. GRB 250128B: LCO optical observations
  46. GRB 250128B: Swift detection of a short burst
  47. GRB 250128B: Fermi GBM Final Real-time Localization
  48. GRB 250127A: Swift-XRT observations
  49. GRB 250127B: DDOTI Upper Limit on the Afterglow
  50. GRB 250127A: EP-FXT afterglow detection
  51. GRB 250128A: Fermi GBM Final Real-time Localization
  52. GRB 250127A: SVOM/VT upper limit
  53. GRB 250127B: Fermi GBM Final Real-time Localization
  54. IPN triangulation of GRB 250119C
  55. GRB 250127A: Swift ToO observations
  56. GRB 241223A: cubesat Avion detection
  57. GRB 250127A: SVOM detection of a long burst
  58. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  59. EP250125A: Non-detection from Fermi-GBM Observations
  60. GRB 250126A: MAXI/GSC detection
  61. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  62. GRB 250126A: Fermi GBM Final Real-time Localization
  63. GECAM-A detection of a bright burst from SGR 1E1841-045
  64. EP250125a: Optical upper limit with Kinder observations
  65. EP250125a: REM optical counterpart detection
  66. EP250125a: Swift/XRT detection of a fading counterpart
  67. EP250125a: a new X-ray transient detected by Einstein Probe
  68. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  69. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  70. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  71. Konus-Wind detection of GRB 250118B
  72. Konus-Wind detection of GRB 250119B
  73. IPN triangulation of GRB 250119B
  74. GRB 250122A: Fermi GBM Final Real-time Localization
  75. Improved IPN triangulation of GRB 250107C
  76. GRB 250121A: INTEGRAL/SPI-ACS detection
  77. GRB 250121A: Fermi-LAT detection
  78. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  79. GRB 250121A: Fermi GBM Final Real-time Localization
  80. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  81. Konus-Wind detection of GRB 250117A
  82. IPN triangulation of GRB 250117A (short)
  83. ATCA detection of possible radio counterpart to GRB 250114A
  84. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  85. GRB 250119B: INTEGRAL/SPI-ACS detection
  86. GRB 250119C: Fermi GBM Final Real-time Localization
  87. GRB 250119B: Fermi GBM Final Real-time Localization
  88. GRB 250119A: Fermi GBM Final Real-time Localization
  89. GRB 250118A: Fermi GBM Final Real-time Localization
  90. EP250108a / AT2025kg: VLA radio upper limit
  91. Konus-Wind detection of GRB 250116A
  92. GRB 250116A: GECAM-B detection of a long burst
  93. GRB 241217A / EP241217B: radio detection with the VLA
  94. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  95. GRB 250116A: Fermi-LAT detection
  96. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  97. GRB 250114B: Swift-XRT afterglow detection
  98. GRB 250114B: SVOM/VT upper limit
  99. Konus-Wind detection of GRB 250113A
  100. IPN triangulation of GRB 250113A

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