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"

36351 results found.

  1. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  2. GRB 250215A: Swift-XRT refined Analysis
  3. GRB 250215A: SVOM/GRM observation
  4. EP250215a / GRB 250215A: AstroSat CZTI detection
  5. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  6. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  7. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  8. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  9. Fermi GRB 250215A: Global MASTER-Net observations report
  10. GRB 250215A: Fermi GBM Final Real-time Localization
  11. GRB 250213A：SVOM/VT optical candidate
  12. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  13. Fermi GRB 250214A: Global MASTER-Net observations report
  14. GRB 250213A: Swift ToO observations
  15. GRB 250214A: Fermi GBM Final Real-time Localization
  16. GRB 250213A: SVOM detection of a burst
  17. GRB 250205A: VIRT Optical Upper Limit
  18. GRB 250205A: Leavitt Observatory optical upper limit
  19. GRB 250210A: GRBAlpha detection
  20. Fermi GRB 250212A: Global MASTER-Net observations report
  21. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  22. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  23. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  24. GRB 250211B: A long GRB detected by INTEGRAL
  25. GRB 250211A: Swift ToO observations
  26. GRB 250212A: Fermi GBM Final Real-time Localization
  27. GRB 250207A: Fermi GBM Observation
  28. GRB 250206A: Fermi GBM Observation
  29. GRB 250205A / EP250205A: radio detection with the VLA
  30. Konus-Wind detection of GRB 250207A
  31. Konus-Wind detection of GRB 250206A
  32. GRB 250210A: SVOM/GRM observation of a long burst
  33. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  34. GRB 250207A: Skynet optical afterglow observations
  35. GRB 241128A: VIRT Optical Upper Limit
  36. EP250207A: Upper limits from Fermi-GBM Observations
  37. GRB 250210A: INTEGRAL SPI-ACS detection
  38. GRB 250210A: AstroSat CZTI detection
  39. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  40. Fermi GRB 250210A: Global MASTER-Net observations report
  41. GRB 250210A: Fermi GBM Final Real-time Localization
  42. LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
  43. IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 250204B: GRBAlpha detection
  45. GRB 250204A: GRBAlpha detection
  46. GRB 250207A: 1.3m DFOT Optical observations
  47. GRB 250206A: Swift-XRT observations
  48. GRB 250129A: GRANDMA Continued Afterglow Detection
  49. GRB 250207A: Swift-BAT refined analysis
  50. GRB 250205A: 1.3m DFOT optical upper limit
  51. GRB 250206A: Tiled Swift observations
  52. GRB 250206A: EIRSAT-1 GMOD Detection
  53. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  54. GRB 250206A: Fermi-LAT detection
  55. GRB 250207B: Swift-XRT observations
  56. GRB 250208A: Fermi GBM Final Real-time Localization
  57. GRB 250207A: Swift-XRT refined Analysis
  58. GRB 250207A: Enhanced Swift-XRT position
  59. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  60. GRB 250207A: REM IR afterglow detection
  61. GRB 250207A: FRAM-Auger optical detection
  62. GRB 250207B: Tiled Swift observations
  63. Konus-Wind detection of GRB 250204B
  64. GRB 250207A: REM optical afterglow detection
  65. GRB 250207A: Swift/UVOT Detection
  66. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  67. GRB 250129A: Continued AbAO and Mondy optical observations
  68. GRB 250207B: MAXI/GSC detection
  69. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  70. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  71. GRB 250207A: Swift detection of a burst with optical counterpart
  72. GRB 250207A: Fermi GBM Final Real-time Localization
  73. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  74. GRB 250206A: Fermi GBM Final Real-time Localization
  75. GRB 250205A: Fermi GBM Observation
  76. GRB 250205A: REM NIR upper limit
  77. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  78. GRB 250205A: Swift/UVOT Upper Limits
  79. EP250205a/GRB 250205A: correction to the source localization
  80. EP250205a/GRB 250205A: Einstein Probe observation
  81. GRB 250127C: SVOM/GRM observation of a burst
  82. GRB 250204B: SVOM/GRM observation of a likely short burst
  83. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  84. GRB 250205A: Swift/XRT detection
  85. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  86. GRB250205A: SVOM/VT optical afterglow detection
  87. GRB 250205A: GOTO optical upper limits
  88. GRB 250205A: OHP/T193 optical counterpart candidate
  89. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  90. GRB 250205A: SVOM detection of a burst
  91. Konus-Wind detection of GRB 250201A
  92. IPN triangulation of GRB 250201A
  93. Konus-Wind detection of GRB 250202B
  94. GRB 250129A: Swift-BAT refined analysis
  95. EP 250108A: Upper limits from Fermi-GBM Observations
  96. IPN triangulation of GRB 250204B (short/hard)
  97. IPN triangulation of GRB 250202B
  98. GRB 250204B: AstroSat CZTI detection of a short burst
  99. GRB 250204B: Fermi GBM Final Localization
  100. GRB 250129A: LCO late afterglow detection

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