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"

26922 results found.

  1. GRB 260217A: Fermi GBM Final Localization
  2. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  3. sb26021801: SVOM detection of a long faint X-ray transient
  4. The EP-WXT trigger 01709258455 is likely a flaring star
  5. EP-WXT 01709258455: NOT optical upper limits
  6. EP260214b: 1.3m DFOT optical upper limit
  7. IPN triangulation of GRB 260212A
  8. GRB 260213A: GECAM-B observation of a short burst
  9. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  10. GRB 260216A: Fermi GBM Final Real-time Localization
  11. EP260214b: Liverpool Telescope optical observations
  12. EP260214b: Optical upper limit with Kinder observations
  13. EP260214a: Optical upper limits with Kinder observations
  14. EP260214b: EP-FXT follow-up observation
  15. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  16. EP260214b: DDOTI Optical Detection
  17. EP260214b: GROWTH-India Telescope optical upper limit
  18. EP260214a: VLT near-infrared observation
  19. EP260214b: SVOM/VT optical observation
  20. EP260214a: NOT optical upper limits
  21. EP260214a: COLIBRÍ optical upper limits
  22. EP260214b: OHP/T120 optical observations
  23. EP260214a: refined analysis of the EP-FXT observation
  24. EP260214b: LCO optical counterpart detection
  25. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  26. GRB 260211A: SVOM/VT optical counterpart
  27. EP260214b: COLIBRÍ optical observations
  28. EP260214a: SVOM/VT optical upper limits
  29. EP260214b: NOT optical counterpart detection
  30. EP260214b: Einstein Probe detection of a fast X-ray transient
  31. EP260214a: Global MASTER-Net observations report
  32. EP260214a: Einstein Probe detection of an X-ray transient
  33. GRB 260212A: Fermi GBM Observation
  34. EP260213a: Global MASTER-Net observations report
  35. EP260213a: COLIBRÍ optical upper limits
  36. GRB 260212A: GECAM-B observation
  37. EP260213a: Optical upper limits with Kinder observations
  38. EP260213a: SVOM/VT optical upper limit
  39. EP260213a: NUTTelA-TAO Early Optical Limits
  40. EP260213a: SVOM/C-GFT upper limit
  41. EP260213a: refined analysis of the EP-FXT observation
  42. EP260213a: Einstein Probe detection of a fast X-ray transient
  43. EP/WXT 01709258378: NOT optical upper limits
  44. GRB 260212A: SVOM/GRM observation of a long burst
  45. GRB 260213B: Fermi GBM Final Localization
  46. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  47. GRB 260211A - SVOM/ECLAIRs refined analysis
  48. GRB 260204A: SVOM/ECLAIRs refined analysis
  49. GRB 260213A: Fermi GBM Final Localization
  50. GRB 260211A: EP-FXT follow-up observation
  51. GRB 260211A: SVOM/VT optical observation
  52. GRB 260211A: GOTO optical upper limit
  53. Fermi GRB 260212A: Global MASTER-Net observations report
  54. GRB 260212A: Fermi GBM Final Real-time Localization
  55. GRB 260210A: SVOM/GRM observation
  56. Fermi GBM Sub-Threshold Detection of GRB 260211A
  57. GRB 260128B: SVOM/ECLAIRs refined analysis
  58. GRID detection of GRB 260207B
  59. GRB 260211A: LCO optical upper limits
  60. GRB260131A/B: 3.6m DOT Optical Observations
  61. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  62. Fermi trigger No 792537871: Global MASTER-Net observations report
  63. GRB 260211A: SVOM detection of a burst
  64. GRB 260208A: Swift UVOT detection
  65. EP260209a: COLIBRÍ optical upper limit
  66. Fermi GRB 260210C: Global MASTER-Net observations report
  67. EP260209a: LCO optical upper limits
  68. EP260210a: Global MASTER-Net observations report
  69. EP260210a: refined analysis of the EP-FXT observation
  70. EP260209a: Global MASTER-Net observations report
  71. GRB 260208A: LCO detection of the optical counterpart
  72. EP260209a: Einstein Probe detection of a fast X-ray transient
  73. EP260210a: Optical upper limits with Kinder observations
  74. IPN triangulation of GRB 260207B (short/hard with EE)
  75. GRB 260210C: Fermi GBM Final Real-time Localization
  76. GRB 260210B: Fermi GBM Final Real-time Localization
  77. EP260210a: SVOM/VT optical upper limit
  78. EP260210a: COLIBRÍ optical upper limit
  79. EP260210a: SVOM/C-GFT upper limit
  80. GRB 260208B: refined analysis of the EP-FXT observation
  81. EP260210a: Einstein Probe detection of an X-ray transient
  82. GRB 260208C: SVOM/GRM observation
  83. GRB260208A: Liverpool Telescope optical follow-up observations
  84. GRB 260208A: Fermi GBM Observation
  85. Fermi GRB 260209A: Global MASTER-Net observations report
  86. GRB 260208B: Swift-XRT observations
  87. GRB 260204A: Swift/UVOT Upper Limits
  88. GRB 260208B: COLIBRÍ optical observations
  89. GRB 260208A: 1.3m DFOT optical detection
  90. GRB 260208A: COLIBRÍ optical observations
  91. GRB 260208B: EP-FXT observation
  92. GRB 260208A: Liverpool Telescope optical detection
  93. Fermi GRB 260208C: Global MASTER-Net observations report
  94. GRB 260208B: SVOM/VT optical candidate
  95. GRB 260208A: GECAM-B observation of a bright burst
  96. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  97. GRB 260209A: Fermi GBM Final Real-time Localization
  98. GRB 260208A: SVOM/VT optical observation
  99. Fermi GRB 260208D: Global MASTER-Net observations report
  100. GRB 260208D: Fermi GBM Final Real-time Localization

Advanced

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