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"

3775 results found.

  1. EP Alert 260820.31: Global MASTER-Net observations report
  2. GRB 260809A: SVOM/ECLAIRs refined analysis
  3. IceCube Alert 260825A: Global MASTER-Net observations report
  4. SVOM trigger sb26081806 is not a GRB
  5. EP260806a: SAO RAS multicolor optical observations
  6. EP260806a: SVOM/ECLAIRs detection through targeted search
  7. Fermi GBM Sub-Threshold Detection of GRB 260809A
  8. GRB 260808B: J-band upper limit with WINTER
  9. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  10. GRB 260809A: SVOM detection of a faint burst
  11. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  12. Fermi GRB 260805A: Global MASTER-Net observations report
  13. Fermi GRB 260802B: Global MASTER-Net observations report
  14. GRB 260726A: SVOM/ECLAIRs refined analysis
  15. EP260727a: Einstein Probe detection of an X-ray transient
  16. Fermi GRB 260726A: Global MASTER-Net observations report
  17. EP260723a: Liverpool Telescope likely optical counterpart
  18. Fermi GRB 260718A: Global MASTER-Net observations report
  19. EP260703a: SVOM/ECLAIRs Upper Limit
  20. GRB 260714B: Fermi-LAT detection
  21. EP260713a: Einstein Probe detection of an X-ray transient
  22. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  23. IceCube Alert 260709A: Global MASTER-Net observations report
  24. GRB260708B: MAXI/GSC detection
  25. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  26. EP260703a: EP-WXT detection of a fast X-ray transient
  27. Fermi trigger No 804552016: Global MASTER-Net observations report
  28. EP260628a: EP-FXT follow-up observation
  29. EP260623a: Liverpool Telescope optical observations
  30. EP260623a: REM optical/NIR afterglow detection
  31. GRB 260616C: GECAM-B observation of a burst
  32. Konus-Wind detection of GRB 260616A
  33. GRB260616C: MAXI/GSC detection
  34. GRB 260614A: AstroSat CZTI detection
  35. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  36. GRB 260531B: Glowbug gamma-ray detection
  37. Fermi GRB 260601A: Global MASTER-Net observations report
  38. Fermi trigger No 801900520: Global MASTER-Net observations report
  39. GRB 260531B: Fermi GBM Final Real-time Localization
  40. GRB 260531A: MAXI/GSC detection
  41. GRB 260529A: Fermi GBM Final Real-time Localization
  42. EP260526a: SVOM/VT optical upper limits
  43. EP260527a: SVOM/VT optical observation
  44. Fermi trigger No 801580882: Global MASTER-Net observations report
  45. Fermi trigger No 801135305: Global MASTER-Net observations report
  46. GRB 260516D: GROWTH-India Telescope optical detection
  47. GRB 260515A: CrAO ZTSh BVRI optical observations
  48. SVOM GRB 260515A: Global MASTER-Net observations report
  49. GRB 260510C: Glowbug gamma-ray detection
  50. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  51. EP260514a: Global MASTER-Net observations report
  52. GRB 260511B: further SAO RAS optical observations
  53. GRB 260510C: Fermi GBM Observation
  54. GRB 260511A: NuSTAR detection of prompt emission
  55. GRB 260510C: AstroSat CZTI detection
  56. GRB 260510C: EP-FXT follow-up observation
  57. GRB 260511A: KAIT optical afterglow observations
  58. GRB 260510C: SVOM/VT optical upper limits
  59. GRB 260510C: MAXI/GSC detection
  60. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  61. EP260507a: GOTO optical counterpart detection
  62. EP260507a: Einstein Probe detection of an X-ray transient
  63. Fermi GRB 260506A: Global MASTER-Net observations report
  64. SVOM GRB 260504B: MASTER-OAFA optical observations
  65. EP260502a: BOOTES-7 observations of a fading catalogued source close to the X-ray position
  66. EP260430a: Global MASTER-Net observations report
  67. Fermi GRB 260421C: Global MASTER-Net observations report
  68. Fermi GRB 260421B: Global MASTER-Net observations report
  69. Fermi GRB 260417B: Global MASTER-Net observations report
  70. EP260417a: Global MASTER-Net observations report
  71. Fermi GRB 260417A: Global MASTER-Net observations report
  72. EP260416a: Global MASTER-Net observations report
  73. Fermi trigger No 797912738: Global MASTER-Net observations report
  74. GRB 260411B: GOTO optical counterpart candidate
  75. EP260409a: Global MASTER-Net observations report
  76. GRB 260404A: Fermi GBM Final Localization
  77. EP260403a: Mephisto optical upper limits
  78. GRID detection of GRB 260401A
  79. EP260405a: Global MASTER-Net observations report
  80. Fermi trigger No 797039833: Global MASTER-Net observations report
  81. Fermi Gamma-ray Burst Monitor trigger 796931884/260403749 is not a GRB
  82. GRB 260330B: SVOM/ECLAIRs refined analysis
  83. GRB 260330B: SVOM/VT optical candidate
  84. GRB 260402B: GECAM-B observation
  85. GRB 260402B: Fermi GBM Final Real-time Localization
  86. GRB 260401A: SVOM/GRM observation
  87. GRB 260401A: GECAM-B observation
  88. GRB 260401A: Fermi GBM Observation
  89. GRB 260401A: NuSTAR detection of prompt emission
  90. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  91. GRB 260401A: MAXI/GSC detection
  92. EP260329b: Mondy and Assy-Turgen optical upper limits
  93. GRB 260310A / AT2026fgk: Luminance-band optical follow-up with a 28cm telescope in Daocheng
  94. EP260321a :Xinglong optical observations
  95. GRB 260321A: SVOM/ECLAIRs refined analysis
  96. Fermi GBM Sub-Threshold Detection of GRB 260330B
  97. GRB 260330B: SVOM detection of a burst
  98. EP260327a: Global MASTER-Net observations report
  99. GRB 260310A / AT2026fgk: R- and I-band observations with the PKU 60 cm optical telescope
  100. IPN triangulation of GRB 260316B

Advanced

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