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"

37120 results found.

  1. GRB 260310A: Fermi GBM Observation
  2. GRB 260310A: potential optical counterpart
  3. Fermi GRB 260312B: Global MASTER-Net observations report
  4. Fermi GRB 260311B: Global MASTER-Net observations report
  5. Swift BAT trigger 1500148: A solar flare
  6. GRB 260312B: BALROG localization (Fermi Trigger 795001611 / GRB 260312407)
  7. GRB 260312B: Fermi GBM Final Real-time Localization
  8. GRB 260310B: GECAM-B observation of a burst
  9. Retraction of GCN 43965: GRB is actually solar flare
  10. GRB 260312A: Swift detection of a burst
  11. GRB 260311B: Fermi GBM Final Real-time Localization
  12. GRB 260131A/B: radio detection with the VLA
  13. GRB260307A: GECAM-B observation of a burst
  14. GRB 260308A: SVOM/GRM observation of a short GRB
  15. EP260306a: Mondy optical upper limit
  16. GRB 260310A: AstroSat CZTI detection of a long burst
  17. GRB 260311A: Fermi GBM Final Real-time Localization
  18. Fermi GRB 260310B: Global MASTER-Net observations report
  19. GRB 260310B: Fermi GBM Final Real-time Localization
  20. Fermi GRB 260310A: Global MASTER-Net observations report
  21. GRB 260307B: SVOM/ECLAIRs refined analysis
  22. GRB 260208A: radio detection with the VLA
  23. GRB 260310A: Fermi GBM Final Real-time Localization
  24. GRB 260307A: Glowbug gamma-ray detection
  25. GRB 260308A: Fermi GBM Final Real-time Localization
  26. Fermi GBM Sub-Threshold Detection of GRB 260307B
  27. GRB 260307B: Mephisto optical upper limits
  28. GRB 260307B: possible NOT optical counterpart
  29. GRB 260307B: SVOM/VT upper limit with X band data analysis
  30. Fermi GRB 260307A: Global MASTER-Net observations report
  31. GRB 260307B: SVOM/VT optical candidate
  32. GRB 260307B: SVOM/C-GFT upper limit
  33. GRB 260307B: SVOM detection of a burst
  34. GRB 260307A: Fermi GBM Final Localization
  35. GRB 260211A: late-time NOT i-band observations consistent with archival flux
  36. GRB 260207A: TESS Detection and Possible VLA Counterpart
  37. EP260302a: Optical afterglow rebrightening
  38. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  39. GRB 260303A: 1.3m DFOT optical upper limit (duplicate submission)
  40. GRB 260303A: 1.3m DFOT optical upper limit
  41. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  42. GRB 260303A: SVOM/ECLAIRs refined analysis
  43. Fermi GRB 260305A: Global MASTER-Net observations report
  44. GRB 260305A: Fermi GBM Final Real-time Localization
  45. GRB 260303B: AstroSat CZTI detection
  46. GRB 260304A: AstroSat CZTI detection of a long burst
  47. GRB 260303A: SVOM/VT optical observations
  48. GRB 260303A: J-band observations with WINTER
  49. GRB 260303B: NuSTAR detection of prompt emission
  50. Fermi GRB 260303B: Global MASTER-Net observations report
  51. GRB 260228A: SVOM/ECLAIRs refined analysis
  52. GRB 260225A: SVOM/ECLAIRs refined analysis
  53. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  54. GRB 260303B: Fermi GBM Final Real-time Localization
  55. EP260302a: analysis of the follow-up EP-FXT observation
  56. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  57. GRB 260303A: SVOM detection of a burst
  58. GRB 260228A: EP-FXT follow-up observation
  59. GRB 251130B: TERI Gamma-ray detection
  60. GRB 260208A: TERI Gamma-ray detection
  61. GRB 260302A: Fermi GBM Final Real-time Localization
  62. EP260227a: Mondy optical observations
  63. GRB 260228A: CAHA 2.2m telescope optical upper limit
  64. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  65. EP260227a: Mephisto optical detection
  66. GRID detection of GRB 260225D
  67. GRB 260228A: SVOM/VT optical upper limits
  68. GRB 260225D: SVOM/GRM observation
  69. GRB 260225B: SVOM/GRM observation
  70. GRB 260228A: SVOM detection of a burst
  71. EP260227a: Liverpool Telescope optical observations
  72. GRB 260226A: Asiago r-band upper limit
  73. GRB 260225A: SVOM/VT optical continued observations and upper limit
  74. GRID detection of GRB 260223A
  75. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  76. Konus-Wind detection of GRB 260226A
  77. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  78. GRB 260225A: WINTER J-band upper limit
  79. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  80. GRB 260226A: COLIBRÍ optical upper limits
  81. GRB 260226A: LCOGT Optical Upper Limit
  82. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  83. GRB 260226A: Glowbug gamma-ray detection
  84. GRB 260226A: NuSTAR detection of bright prompt emission
  85. GRB 260226A : GROWTH-India Telescope optical observations
  86. GRB 260226A: LAST optical upper limit
  87. GRB 260226A: Fermi GBM observation
  88. GRB 260226A: Fermi-LAT refined analysis
  89. Fermi GRB 260226A: Global MASTER-Net observations report
  90. GRB 260226A: AstroSat CZTI detection of bright long burst
  91. GRB 260226A: Fermi-LAT detection of a bright burst
  92. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  93. GRB260225A: SVOM/ECLAIRs refined position
  94. GRB 260226A: Fermi GBM Final Real-time Localization
  95. GRB 260225A: EP-FXT follow-up observation
  96. GRB 260225A: SVOM/VT optical observation
  97. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  98. GRB 260225C: Fermi GBM Final Real-time Localization
  99. GRB 260223A: Fermi GBM Observation
  100. GRB 260225A: SVOM/VT optical upper limits

Advanced

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