Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

11524 results found.

  1. GRB 250226A: Fermi GBM Final Real-time Localization
  2. Fermi GRB 250225A: Global MASTER-Net observations report
  3. GRB 250223C: SVOM/GRM observation of a long burst
  4. EP250215A: J band upper limit by SYSU 80cm telescope
  5. GRB 250225A: Fermi GBM Final Real-time Localization
  6. GRB 250207a: ATCA Radio Upper Limits
  7. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  8. GRB 250119B: VZLUSAT-2 detection
  9. GRB 250223C: Fermi GBM Final Real-time Localization
  10. GRB 250202B: VZLUSAT-2 detection
  11. GRB 250210A: VZLUSAT-2 detection
  12. GRB 250206A: VZLUSAT-2 detection
  13. GRB 250223B: Fermi GBM Final Localization
  14. Fermi GRB 250223A: Global MASTER-Net observations report
  15. Fermi trigger No 762020305: Global MASTER-Net observations report
  16. GRB 250223A: Fermi GBM Final Real-time Localization
  17. Fermi trigger No 761805304: Global MASTER-Net observations report
  18. Fermi Gamma-ray Burst Monitor trigger 761867337/250221909 is not a GRB
  19. Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB
  20. GRB 250220B: Fermi GBM Final Real-time Localization
  21. Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB
  22. GRB 250220A: Fermi GBM Final Real-time Localization
  23. Konus-Wind detection of GRB 250217C (short)
  24. Konus-Wind detection of GRB 250215A / EP250215a
  25. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  26. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  27. GRB 250217C: SVOM/GRM observation
  28. GRB 250217C: Fermi GBM Observation
  29. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  30. IPN triangulation of GRB 250217C (short)
  31. GRB 250216A: AstroSat CZTI detection
  32. GRB 250217C: AstroSat CZTI detection of a short burst
  33. Fermi GRB 250217C: Global MASTER-Net observations report
  34. GRB 250217C: Fermi GBM Final Real-time Localization
  35. Fermi GRB 250217A: Global MASTER-Net observations report
  36. GRANDMA/OPD observations of GRB250215A
  37. GRB 250217B: Fermi GBM Final Real-time Localization
  38. GRB 250217A: Fermi GBM Final Real-time Localization
  39. Fermi GRB 250216A: Global MASTER-Net observations report
  40. GRB 250215A / EP250215a: LCO detection of the afterglow
  41. GRB 250216A: Fermi GBM Final Real-time Localization
  42. GRB 250215A: Swift/UVOT Upper Limits
  43. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  44. EP250215a / GRB 250215A : GTC redshift z = 4.61
  45. GRB 250215A: Fermi GBM Observation
  46. EP250215a / GRB 250215A : NOT optical observations
  47. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  48. GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
  49. GRB 250215A: Swift-XRT refined Analysis
  50. GRB 250215A: SVOM/GRM observation
  51. EP250215a / GRB 250215A: AstroSat CZTI detection
  52. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  53. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  54. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  55. Fermi GRB 250215A: Global MASTER-Net observations report
  56. GRB 250215A: Fermi GBM Final Real-time Localization
  57. Fermi trigger No 761206993: Global MASTER-Net observations report
  58. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  59. Fermi GRB 250214A: Global MASTER-Net observations report
  60. GRB 250214A: Fermi GBM Final Real-time Localization
  61. GRB 250210A: GRBAlpha detection
  62. Fermi GRB 250212A: Global MASTER-Net observations report
  63. Fermi trigger No 760945500: Global MASTER-Net observations report
  64. GRB 250212A: Fermi GBM Final Real-time Localization
  65. GRB 250207A: Fermi GBM Observation
  66. GRB 250206A: Fermi GBM Observation
  67. GRB 250205A / EP250205A: radio detection with the VLA
  68. Konus-Wind detection of GRB 250207A
  69. Konus-Wind detection of GRB 250206A
  70. GRB 250210A: SVOM/GRM observation of a long burst
  71. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  72. GRB 250207A: Skynet optical afterglow observations
  73. EP250207A: Upper limits from Fermi-GBM Observations
  74. GRB 250210A: INTEGRAL SPI-ACS detection
  75. GRB 250210A: AstroSat CZTI detection
  76. Fermi GRB 250210A: Global MASTER-Net observations report
  77. GRB 250210A: Fermi GBM Final Real-time Localization
  78. GRB 250204B: GRBAlpha detection
  79. GRB 250204A: GRBAlpha detection
  80. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  81. GRB 250206A: Swift-XRT observations
  82. GRB 250206A: Tiled Swift observations
  83. GRB 250206A: EIRSAT-1 GMOD Detection
  84. GRB 250206A: Fermi-LAT detection
  85. GRB 250208A: Fermi GBM Final Real-time Localization
  86. GRB 250207A: REM IR afterglow detection
  87. GRB 250207A: FRAM-Auger optical detection
  88. Konus-Wind detection of GRB 250204B
  89. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 250207A: REM optical afterglow detection
  91. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  92. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  93. GRB 250207A: Fermi GBM Final Real-time Localization
  94. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  95. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  96. GRB 250206A: Fermi GBM Final Real-time Localization
  97. GRB 250205A: Fermi GBM Observation
  98. GRB 250204B: SVOM/GRM observation of a likely short burst
  99. Konus-Wind detection of GRB 250201A
  100. IPN triangulation of GRB 250201A

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