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"

35997 results found.

  1. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  2. GRB 250129A: Swift-XRT refined Analysis
  3. GRB 250128B: Gemini-North optical extended source detection
  4. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  5. GRB 250128B: TNG optical upper limit
  6. GRB 250129A: Swift/UVOT Detection
  7. GRB 250128B: VLT/HAWKI near-infrared observations
  8. GRB 250127A: CrAO and Terskol optical upper limits
  9. GRB 250129A: Enhanced Swift-XRT position
  10. GRB 250128B: NOT optical upper limit
  11. GRB 250128B: VLT/FORS2 optical observations
  12. GRB 250129A: REM optical/NIR afterglow detection
  13. GRB 250129A: OHP/T193 optical and spectroscopy observations
  14. GRB 250129A: Early afterglow detection by LCO.
  15. GRB 250128B: OHP/T193 optical upper limit
  16. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  17. GRB 250129A: LCO optical observations
  18. GRB 250129A: NOT optical observations and redshift confirmation
  19. GRB 250129A: GOTO optical observations show brightening afterglow
  20. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  21. Swift GRB 250129A: Global MASTER-Net observations report
  22. GRB 250128B: Enhanced Swift-XRT position
  23. Fermi GRB 250128B: Global MASTER-Net observations report
  24. GRB 250129A: Swift detection of a burst with an optical counterpart
  25. Swift GRB 250129A: Global MASTER-Net OT detection
  26. GRB 250128B: Swift-XRT refined Analysis
  27. GRB 250128B: Fermi GBM Observation
  28. GRB 250128B: GOTO optical upper limit
  29. Swift GRB 250128B: Global MASTER-Net observations report
  30. EP250125a: Upper limits from Swift/BAT-GUANO
  31. GRB 250128B: LCO optical observations
  32. GRB 250128B: Swift detection of a short burst
  33. GRB 250128B: Fermi GBM Final Real-time Localization
  34. GRB 250127A: Swift-XRT observations
  35. GRB 250127B: DDOTI Upper Limit on the Afterglow
  36. GRB 250127A: EP-FXT afterglow detection
  37. Fermi GRB 250128A: Global MASTER-Net observations report
  38. GRB 250128A: Fermi GBM Final Real-time Localization
  39. GRB 250117A: Fermi GBM Observation
  40. Fermi GRB 250127B: Global MASTER-Net observations report
  41. GRB 250127A: SVOM/VT upper limit
  42. GRB 250127B: Fermi GBM Final Real-time Localization
  43. IPN triangulation of GRB 250119C
  44. GRB 250127A: Swift ToO observations
  45. GRB 250127A: LCO optical upper limit
  46. GRB 241223A: cubesat Avion detection
  47. GRB 250127A: SVOM detection of a long burst
  48. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  49. EP250125A: Non-detection from Fermi-GBM Observations
  50. GRB 250126A: MAXI/GSC detection
  51. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  52. GRB 250126A: Fermi GBM Final Real-time Localization
  53. GRB 250118A: Fermi GBM Observation
  54. GRB 250119C: Fermi GBM Observation
  55. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  56. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  57. EP250108a: AbAO, CMO and Terskol optical upper limits
  58. Konus-Wind detection of GRB 250118B
  59. GRB 250121A: Fermi GBM Observation
  60. IPN triangulation of GRB 250118B
  61. Konus-Wind detection of GRB 250119B
  62. IPN triangulation of GRB 250119B
  63. GRB 250122A: Fermi GBM Final Real-time Localization
  64. Improved IPN triangulation of GRB 250107C
  65. GRB 250114A: Swift-BAT refined analysis
  66. GRB 250121A: INTEGRAL/SPI-ACS detection
  67. GRB 250121A: Fermi-LAT detection
  68. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  69. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  70. GRB 250121A: Fermi GBM Final Real-time Localization
  71. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  72. GRB 250119B: Fermi GBM Observation
  73. Konus-Wind detection of GRB 250117A
  74. IPN triangulation of GRB 250117A (short)
  75. ATCA detection of possible radio counterpart to GRB 250114A
  76. GRB 250119B: INTEGRAL/SPI-ACS detection
  77. EP 250108A: Late-time optical observation by LCO
  78. GRB 250117A: SVOM/GRM observation of a short burst
  79. GRB 250119C: Fermi GBM Final Real-time Localization
  80. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  81. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  82. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  83. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  84. GRB 250117A: GECAM observation of a short burst
  85. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  86. GRB 250119B: Fermi GBM Final Real-time Localization
  87. GRB 250119A: Fermi GBM Final Real-time Localization
  88. GRB 250118A: Fermi GBM Final Real-time Localization
  89. EP250108a / AT2025kg: VLA radio upper limit
  90. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  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. Swift Trigger 1282245 is not a GRB
  96. GRB 250116A: Fermi-LAT detection
  97. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  98. GRB 250114B: Swift-XRT afterglow detection
  99. GRB 250114B: SVOM/VT upper limit
  100. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB

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