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"

36133 results found.

  1. GRB 251024A: Enhanced Swift-XRT position
  2. GRB 251023C: Glowbug gamma-ray detection
  3. GRB 251024A: LCOGT Optical Afterglow Detection
  4. GRB 251022A: KAIT optical observations
  5. GRB 251024A: Swift detection of a burst
  6. Swift GRB 251024A: Global MASTER-Net observations report
  7. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  8. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  9. GRB 251023B: OHP/T193 optical observations
  10. EP251023a: OHP/T193 optical observations
  11. GRB 251023C: AstroSat CZTI detection
  12. EP251023b/GRB 251023B: JinShan optical observation
  13. GRB 251022A: Swift-XRT detection of GOTO25iym
  14. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  15. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  16. GRB 251022A: GROWTH-India Telescope optical observations
  17. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  18. GRB 251022A: Fermi GBM Observation
  19. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  20. GRB 251023A: Glowbug gamma-ray detection
  21. GRB 251023B: Glowbug gamma-ray detection
  22. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  23. IPN triangulation of GRB 251016B
  24. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  25. EP#01709247298: Swift-XRT counterpart detection
  26. GRB 251013C: further SAO RAS optical observations
  27. GRB 251022A: COLIBRÍ optical observations
  28. GRB 251013C: ISON-Castelgrande observatory optical observations
  29. GRB 251022A: MASTER OT detection
  30. GRB 251022A: DDOTI Optical Detection
  31. EP251021b/GRB 251021A: SVOM/VT optical candidate
  32. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  33. Fermi GRB 251023A: Global MASTER-Net observations report
  34. GRB 251022A: GOTO optical counterpart detection
  35. GRB 251023A: Fermi GBM Final Localization Correction
  36. GRB 251022A: Fermi-LAT detection
  37. GRB 251016B: Fermi GBM Detection
  38. GRB 251022A: Tiled Swift observations
  39. GRB 251022A: Fermi GBM Final Real-time Localization
  40. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  41. GRB 250911A: MAXI/GSC detection
  42. GRB 251016A: SVOM/ECLAIRs refined analysis
  43. GRB 251017A : RAPAS follow-up observations
  44. GRB 251017A: COLIBRÍ optical observations of a late plateau
  45. GRB 251017A: Swift-BAT refined analysis
  46. GRB 251016A: Fermi GBM Observation
  47. GRB 251018A: Fermi GBM Observation
  48. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  49. GRB 251018A: Swift-XRT refined Analysis
  50. GRB 251018A: Enhanced Swift-XRT position
  51. GRB 251016A: HXMT/HE detection
  52. GRB 251016A: Swift-XRT afterglow detection
  53. GRB 251017A: Swift/UVOT Detection
  54. GRB 251016A: Swift/UVOT Detection
  55. GRB 251018A: Swift/UVOT Detection
  56. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  57. GRB 251016A: VLT/FORS2 Optical Observation
  58. GRB 251017A: COLIBRÍ photometric redshift
  59. GRB 251017A: Swift-XRT refined Analysis
  60. GRB 251018A: MASTER OT detection
  61. GRB 251018A: TRT optical afterglow detection
  62. Swift GRB 251018A: Global MASTER-Net observations report
  63. GRB 251018A: Swift detection of a burst with an optical counterpart
  64. GRB 251018A: Fermi GBM Final Real-time Localization
  65. GRB 251017A: SVOM/VT optical observation
  66. GRB 251011A: Fermi GBM Observation
  67. GRB 251017A: OHP/T193 i-band observations
  68. GRB 251013C: OHP/T193 third epoch optical observations and detected rebrightening
  69. GRB 251017A: J-band detection with WINTER
  70. GRB 251017A: Glowbug gamma-ray detection
  71. GRB 251013C: Liverpool Telescope observations
  72. GRB 251013C: Leavitt Observatory optical photometry
  73. Fermi GRB 251016B: Global MASTER-Net observations report
  74. GRB 251017A: JinShan observations of the optical afterglow
  75. Swift GRB 251017A: Global MASTER-Net observations report
  76. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  77. Swift Trigger 1404295 is not a GRB
  78. GRB 251016A: AstroSat CZTI detection of a short burst
  79. GRB 251017A: Enhanced Swift-XRT position
  80. GRB 251017A: COLIBRÍ Early Afterglow Detection
  81. GRB 251016B: AstroSat CZTI detection
  82. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  83. GRB 251017A: Swift detection of a burst with an optical counterpart
  84. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  85. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  86. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  87. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) observations of a strong and late rebrightening of the optical counterpart
  88. GRB 251007B: Swift-BAT refined analysis
  89. GRB 251016B: Fermi GBM Final Real-time Localization
  90. GRB 251014D: Swift-BAT refined analysis
  91. GRB 251016A: BOOTES-6/DPRT optical upper limit
  92. GRB 251016A: Glowbug gamma-ray detection of a short burst
  93. GRB 251013C: VLA detection
  94. Fermi GRB 251016A: Global MASTER-Net observations report
  95. GRB 251016A: Fermi GBM Final Localization
  96. GRB 251016A: SVOM detection of a short burst
  97. GRB 251014A: Swift-XRT observations
  98. GRB 251014B: PRIME J-band upper limit
  99. GRB 251013C: Kilonova-Catcher optical afterglow detection
  100. GRB 251013D: Swift/UVOT Observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov