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"

21769 results found.

  1. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  2. EP260227a: Mephisto optical detection
  3. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  4. EP260227a: SVOM/VT optical observation
  5. GRB 260228A: SVOM/VT optical upper limits
  6. GRB 260225D: SVOM/GRM observation
  7. EP260227A: 3.6m DOT optical afterglow detection
  8. GRB 260225B: SVOM/GRM observation
  9. GRB 260228A: SVOM detection of a burst
  10. EP260227a: Liverpool Telescope optical observations
  11. EP260227a: LCOGT Optical Observations
  12. GRB 260226A: Asiago r-band upper limit
  13. EP260227a: Liverpool Telescope observations
  14. EP260227a: COLIBRÍ optical observations
  15. EP260227a: NOT optical observations
  16. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  17. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  18. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  19. EP260214a: VLT/FORS2 optical observations
  20. GRB 260225A: WINTER J-band upper limit
  21. GRB 260226A: COLIBRÍ optical upper limits
  22. GRB 260226A: LCOGT Optical Upper Limit
  23. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  24. GRB 260226A : GROWTH-India Telescope optical observations
  25. GRB 260226A: LAST optical upper limit
  26. GRB 260226A: AstroSat CZTI detection of bright long burst
  27. EP260224a: LCO optical upper limits
  28. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  29. GRB 260225A: SVOM/VT optical upper limits
  30. EP260223a: Liverpool Telescope upper limits
  31. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  32. EP260224a: Einstein Probe detection of an X-ray transient
  33. EP 260225.148: COLIBRÍ Confirmation of flaring star
  34. EP260223a: Xinglong optical upper limit
  35. EP260213a: Mephisto optical upper limits
  36. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  37. sb26021801: SVOM/C-GFT upper limit
  38. EP260223a: COLIBRÍ optical upper limits
  39. EP260223a: Einstein Probe detection of an X-ray transient
  40. GRB 260223A: SVOM/GRM observation
  41. GRB 260223A: COLIBRÍ further optical observations and a brightening
  42. EP260221a: Optical upper limit with Kinder observations
  43. GRB 260223A: COLIBRÍ optical observations
  44. GRB 260223A: DDOTI Optical Candidate
  45. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  46. EP260221a: COLIBRÍ optical counterpart candidate
  47. EP260221a: Gemini South z-band upper limit
  48. EP260221a: EP-FXT follow-up observation
  49. EP-WXT01709258519: Xinglong optical upper limit
  50. EP260221a: Xinglong optical upper limit
  51. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  52. EP260221a: GOTO optical upper limit
  53. EP260221a: COLIBRÍ optical upper limit
  54. SVOM alert sb26021801: LCO optical upper limit
  55. EP260221a: Einstein Probe detection of an X-ray transient
  56. SVOM alert sb26021801: LAST optical upper limit
  57. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  58. sb26021801: SVOM detection of a long faint X-ray transient
  59. EP-WXT 01709258455: NOT optical upper limits
  60. EP260214b: Mondy optical observations
  61. EP260214b: 1.3m DFOT optical upper limit
  62. EP260210a: Mondy optical upper limits
  63. GRB 260208A: AbAO and Terskol optical upper limits
  64. GRB 260208A: continued Mondy optical observations
  65. IPN triangulation of GRB 260212A
  66. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  67. EP260214b: Liverpool Telescope optical observations
  68. EP260214b: Optical upper limit with Kinder observations
  69. EP260214a: Optical upper limits with Kinder observations
  70. EP260214b: EP-FXT follow-up observation
  71. EP260214b: DDOTI Optical Detection
  72. EP260214b: GROWTH-India Telescope optical upper limit
  73. EP260214a: VLT near-infrared observation
  74. EP260214a: NOT optical upper limits
  75. EP260214a: COLIBRÍ optical upper limits
  76. EP260214b: OHP/T120 optical observations
  77. EP260214a: refined analysis of the EP-FXT observation
  78. EP260214b: LCO optical counterpart detection
  79. EP260214b: COLIBRÍ optical observations
  80. EP260214b: NOT optical counterpart detection
  81. EP260214b: Einstein Probe detection of a fast X-ray transient
  82. EP260214a: Einstein Probe detection of an X-ray transient
  83. GRB 260212A: AstroSat CZTI detection
  84. EP260213a: Liverpool Telescope optical upper limits
  85. EP260213a: COLIBRÍ optical upper limits
  86. EP260213a: Optical upper limits with Kinder observations
  87. EP260213a: Mondy R-band optical upper limit
  88. EP260213a: NUTTelA-TAO Early Optical Limits
  89. EP260213a: SVOM/C-GFT upper limit
  90. EP260213a: refined analysis of the EP-FXT observation
  91. EP260213a: Einstein Probe detection of a fast X-ray transient
  92. EP/WXT 01709258378: NOT optical upper limits
  93. GRB 260212A: SVOM/GRM observation of a long burst
  94. GRB 260211A - SVOM/ECLAIRs refined analysis
  95. GRB 260211A: GOTO optical upper limit
  96. GRB 260211A: LAST optical upper limit
  97. GRB 260210A: SVOM/GRM observation
  98. Konus-Wind detection of GRB 260207B
  99. GRB 260211A: LCO optical upper limits
  100. GRB260131A/B: 3.6m DOT Optical Observations

Advanced

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