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"

12090 results found.

  1. GRB 260614A: GECAM-B observation
  2. GRB 260603C: AstroSat CZTI detection
  3. GRB 260610B: IAC-80 Optical observations
  4. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  5. EP260610b: MAO/AZT-22 optical observations
  6. EP260610b: NOT optical observation
  7. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  8. EP260610b: Einstein Probe detection of an X-ray transient
  9. Konus-Wind detection of GRB 260601A
  10. EP260610a: Einstein Probe detection of a fast X-ray transient
  11. GRB 260609A: Fermi GBM Final Localization
  12. Konus-Wind detection of GRB 260604C
  13. GRB 260604C: AstroSat CZTI detection
  14. GRB 260604C: SVOM/ECLAIRs refined analysis
  15. Konus-Wind detection of GRB 260607B
  16. GRB 260604C: further SAO RAS optical observations
  17. GRB 260607B: AstroSat CZTI detection
  18. GRB 260607B: Fermi-LAT detection
  19. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  20. GRB 260604C: LCO optical upper limit
  21. EP260602d: EP-FXT follow-up observation
  22. EP260602c: EP-FXT follow-up observation
  23. GRB 260601B / EP260601a: AstroSat CZTI detection
  24. GRB 260604C: Fermi GBM Observation
  25. GRB 260604C: LAST detection of optical counterpart candidate
  26. Fermi GRB 260604C: Global MASTER-Net observations report
  27. Fermi GRB 260604C: Global MASTER-Net observations report
  28. SVOM GRB260604.85: Global MASTER-Net observations report
  29. GRB 260604C: SVOM detection of a long burst
  30. GRB 260604C: Fermi GBM Final Real-time Localization
  31. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  32. EP260602a: EP-FXT follow-up observation
  33. EP260602d: Optical Upper limits with kinder observations
  34. Konus-Wind detection of GRB 260601B/EP260601a
  35. EP260601a/GRB 260601B: EP-FXT follow-up observation
  36. GRB 260601B / EP260601a: Mondy optical upper limit
  37. EP260602d: Einstein Probe detection of a fast X-ray transient
  38. EP260602c: Einstein Probe detection of a fast X-ray transient
  39. EP260602a: COLIBRÍ optical observations
  40. SVOM GRB260603.23: Global MASTER-Net observations report
  41. GRB 260603A: SVOM detection of a burst
  42. Fermi GRB 260602B: Global MASTER-Net observations report
  43. Fermi GRB 260602B: Global MASTER-Net observations report
  44. GRB 260601B/EP260601a: J-band upper limit with WINTER
  45. EP260602a: Optical upper limits with Kinder observations
  46. EP260602a: Einstein Probe detection of a fast X-ray transient
  47. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  48. GRB 260601A: Fermi GBM Observation
  49. EP260530a/AT 2026nwl: COLIBRÍ optical observations
  50. Fermi GRB 260601A: Global MASTER-Net observations report
  51. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  52. Fermi trigger No 801900520: Global MASTER-Net observations report
  53. GRB 260531A: MAXI/GSC detection
  54. EP260527a/GRB 260527A: further FTW optical and NIR observations
  55. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  56. EP260527a/GRB 260527A: EP-FXT follow-up observation
  57. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  58. EP260527a: Einstein Probe detection of a fast X-ray transient
  59. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  60. GRB 260525A: AstroSat CZTI detection
  61. Fermi GRB 260526A: Global MASTER-Net observations report
  62. GRB 260523B: AstroSat CZTI detection
  63. Fermi trigger No 801135305: Global MASTER-Net observations report
  64. Fermi GRB 260522A: Global MASTER-Net observations report
  65. GRB 260522A: Fermi-LAT detection
  66. GRB 260511A: iTelescope T-75 optical detection
  67. GRB 260428A: TERI Gamma-ray detection
  68. Konus-Wind detection of GRB 260519C
  69. GRB 260520B: Fermi GBM Final Localization
  70. GRB 260509A: SVOM/ECLAIRs refined analysis
  71. GRB 260520A: Fermi GBM Final Localization
  72. Konus-Wind detection of GRB 260518A
  73. GRB 260518A: AstroSat CZTI detection of a long burst
  74. GRB 260516D: SVOM/ECLAIRs refined analysis
  75. GRB 260516D: EP-FXT follow-up observation
  76. GRB 260516D: SVOM/VT optical bright candidate
  77. GRB 260516D: FRAM-ORM optical limit
  78. GRB 260515A: CrAO ZTSh BVRI optical observations
  79. Fermi GRB 260516C: Global MASTER-Net observations report
  80. GRB 260516D: SVOM possible detection of a burst
  81. Konus-Wind detection of GRB 260515A
  82. GRB 260515A: EP-FXT follow-up observation
  83. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  84. Fermi GRB 260516B: Global MASTER-Net observations report
  85. GRID detection of GRB 260507A
  86. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  87. SVOM GRB 260515A: Global MASTER-Net observations report
  88. GRB 260515A: SVOM detection of a burst
  89. Konus-Wind detection of GRB 260512A
  90. GRB 260512A: AstroSat CZTI detection
  91. GRB 260511B: further SAO RAS optical observations
  92. Konus-Wind detection of GRB 260511B
  93. Konus-Wind detection of GRB 260511A
  94. MASS-Cube (GRID 2.0) detection of GRB 260507A
  95. GRB 260511B: SAO RAS optical observations
  96. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  97. GRB 260511A: EP-FXT follow-up observation
  98. GRB 260511B: AstroSat CZTI detection
  99. GRB 260511B: NuSTAR detection of prompt emission
  100. GRB 260510C: AstroSat CZTI detection

Advanced

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