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"

45450 results found.

  1. IceCube Alert 260217A: Global MASTER-Net observations report
  2. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  3. GRB 260217A: Fermi GBM Final Localization
  4. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  5. sb26021801: SVOM detection of a long faint X-ray transient
  6. The EP-WXT trigger 01709258455 is likely a flaring star
  7. EP-WXT 01709258455: NOT optical upper limits
  8. EP260214b: Mondy optical observations
  9. EP260214b: 1.3m DFOT optical upper limit
  10. EP260210a: Mondy optical upper limits
  11. Konus-Wind detection of GRB 260212A
  12. GRB 260208A: AbAO and Terskol optical upper limits
  13. GRB 260208A: continued Mondy optical observations
  14. IPN triangulation of GRB 260212A
  15. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  16. GRB 260213A: GECAM-B observation of a short burst
  17. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  18. GRB 260216A: Fermi GBM Final Real-time Localization
  19. EP260214b: Liverpool Telescope optical observations
  20. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  21. EP260214b: Optical upper limit with Kinder observations
  22. EP260214a: Optical upper limits with Kinder observations
  23. EP260214b: EP-FXT follow-up observation
  24. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  25. EP260214b: DDOTI Optical Detection
  26. EP260214b: GROWTH-India Telescope optical upper limit
  27. EP260214a: VLT near-infrared observation
  28. EP260214b: SVOM/VT optical observation
  29. EP260214a: NOT optical upper limits
  30. EP260214a: COLIBRÍ optical upper limits
  31. EP260214b: OHP/T120 optical observations
  32. EP260214a: refined analysis of the EP-FXT observation
  33. EP260214b: LCO optical counterpart detection
  34. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  35. GRB 260211A: SVOM/VT optical counterpart
  36. EP260214b: COLIBRÍ optical observations
  37. EP260214a: SVOM/VT optical upper limits
  38. EP260214b: NOT optical counterpart detection
  39. EP260214b: Einstein Probe detection of a fast X-ray transient
  40. EP260214a: Global MASTER-Net observations report
  41. EP260214a: Einstein Probe detection of an X-ray transient
  42. GRB 260212A: AstroSat CZTI detection
  43. GRB 260212A: Fermi GBM Observation
  44. EP260213a: Liverpool Telescope optical upper limits
  45. EP260213a: Global MASTER-Net observations report
  46. EP260213a: COLIBRÍ optical upper limits
  47. GRB 260212A: GECAM-B observation
  48. EP260213a: Optical upper limits with Kinder observations
  49. EP260213a: SVOM/VT optical upper limit
  50. EP260213a: Mondy R-band optical upper limit
  51. EP260213a: NUTTelA-TAO Early Optical Limits
  52. EP260213a: SVOM/C-GFT upper limit
  53. EP260213a: refined analysis of the EP-FXT observation
  54. EP260213a: Einstein Probe detection of a fast X-ray transient
  55. EP/WXT 01709258378: NOT optical upper limits
  56. GRB 260212A: SVOM/GRM observation of a long burst
  57. GRB 260213B: Fermi GBM Final Localization
  58. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  59. GRB 260211A - SVOM/ECLAIRs refined analysis
  60. GRB 260204A: SVOM/ECLAIRs refined analysis
  61. GRB 260213A: Fermi GBM Final Localization
  62. GRB 260211A: EP-FXT follow-up observation
  63. GRB 260211A: SVOM/VT optical observation
  64. GRB 260212A: Glowbug gamma-ray detection
  65. GRB 260211A: GOTO optical upper limit
  66. Fermi GRB 260212A: Global MASTER-Net observations report
  67. GRB 260212A: Fermi GBM Final Real-time Localization
  68. GRB 260211A: LAST optical upper limit
  69. GRB 260210A: SVOM/GRM observation
  70. Fermi GBM Sub-Threshold Detection of GRB 260211A
  71. Konus-Wind detection of GRB 260207B
  72. GRB 260128B: SVOM/ECLAIRs refined analysis
  73. GRID detection of GRB 260207B
  74. GRB 260211A: LCO optical upper limits
  75. GRB260131A/B: 3.6m DOT Optical Observations
  76. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  77. Fermi trigger No 792537871: Global MASTER-Net observations report
  78. GRB 260211A: SVOM detection of a burst
  79. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  80. Konus-Wind detection of GRB 260209B
  81. GRB 260208A: Swift UVOT detection
  82. Konus-Wind detection of GRB 260127B
  83. EP260209a: COLIBRÍ optical upper limit
  84. Fermi GRB 260210C: Global MASTER-Net observations report
  85. EP260209a: LCO optical upper limits
  86. EP260210a: Global MASTER-Net observations report
  87. EP260210a: refined analysis of the EP-FXT observation
  88. EP260209a: Global MASTER-Net observations report
  89. GRB 260208A: LCO detection of the optical counterpart
  90. EP260209a: Einstein Probe detection of a fast X-ray transient
  91. EP260210a: Optical upper limits with Kinder observations
  92. IPN triangulation of GRB 260207B (short/hard with EE)
  93. GRB 260210C: Fermi GBM Final Real-time Localization
  94. GRB 260210A: Glowbug gamma-ray detection
  95. GRB 260210B: Fermi GBM Final Real-time Localization
  96. EP260210a: SVOM/VT optical upper limit
  97. GRB 260210A: AstroSat CZTI detection
  98. GRB 260208C: AstroSat CZTI detection
  99. EP260210a: COLIBRÍ optical upper limit
  100. EP260210a: SVOM/C-GFT upper limit

Advanced

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