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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"

19551 results found.

  1. GRB 260307B: SVOM/VT upper limit with X band data analysis
  2. GRB260307B: GROWTH-India Telescope optical upper limit
  3. GRB 260307B: SVOM/VT optical candidate
  4. GRB 260307B: SVOM/C-GFT upper limit
  5. GRB 260307B: SVOM detection of a burst
  6. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  7. GRB 260207A: TESS Detection and Possible VLA Counterpart
  8. EP260302a: SVOM/VT optical observation
  9. EP260306a: SVOM/VT optical observation
  10. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  11. EP260306a: Einstein Probe detection of an X-ray transient
  12. GRB 260303A: 1.3m DFOT optical upper limit
  13. GRB 260303A: SVOM/VT optical observations
  14. GRB 260303A: J-band observations with WINTER
  15. EP260302a: analysis of the follow-up EP-FXT observation
  16. EP260302a: LCO observations
  17. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  18. GRB 260303A: SVOM detection of a burst
  19. EP260302a: Einstein Probe detection of an X-ray transient
  20. EP260227a: Mondy optical observations
  21. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  22. EP260227a: Mephisto optical detection
  23. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  24. EP260227a: SVOM/VT optical observation
  25. GRB 260228A: SVOM/VT optical upper limits
  26. GRB 260225D: SVOM/GRM observation
  27. EP260227A: 3.6m DOT optical afterglow detection
  28. GRB 260225B: SVOM/GRM observation
  29. GRB 260228A: SVOM detection of a burst
  30. EP260227a: Liverpool Telescope optical observations
  31. EP260227a: LCOGT Optical Observations
  32. GRB 260226A: Asiago r-band upper limit
  33. EP260227a: Liverpool Telescope observations
  34. EP260227a: COLIBRÍ optical observations
  35. EP260227a: NOT optical observations
  36. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  37. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  38. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  39. EP260214a: VLT/FORS2 optical observations
  40. GRB 260225A: WINTER J-band upper limit
  41. GRB 260226A: COLIBRÍ optical upper limits
  42. GRB 260226A: LCOGT Optical Upper Limit
  43. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  44. GRB 260226A : GROWTH-India Telescope optical observations
  45. GRB 260226A: LAST optical upper limit
  46. GRB 260226A: Fermi GBM observation
  47. EP260224a: LCO optical upper limits
  48. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  49. GRB 260225A: SVOM/VT optical upper limits
  50. EP260223a: Liverpool Telescope upper limits
  51. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  52. GRB 260225A: SVOM detection of a burst
  53. EP260224a: Einstein Probe detection of an X-ray transient
  54. EP 260225.148: COLIBRÍ Confirmation of flaring star
  55. EP260223a: Xinglong optical upper limit
  56. EP260213a: Mephisto optical upper limits
  57. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  58. sb26021801: SVOM/C-GFT upper limit
  59. EP260223a: COLIBRÍ optical upper limits
  60. EP260223a: Einstein Probe detection of an X-ray transient
  61. GRB 260223A: SVOM/GRM observation
  62. GRB 260223A: COLIBRÍ further optical observations and a brightening
  63. EP260221a: Optical upper limit with Kinder observations
  64. GRB 260223A: COLIBRÍ optical observations
  65. GRB 260223A: DDOTI Optical Candidate
  66. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  67. EP260221a: COLIBRÍ optical counterpart candidate
  68. EP260221a: Gemini South z-band upper limit
  69. EP260221a: EP-FXT follow-up observation
  70. EP-WXT01709258519: Xinglong optical upper limit
  71. EP260221a: Xinglong optical upper limit
  72. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  73. EP260221a: GOTO optical upper limit
  74. EP260221a: COLIBRÍ optical upper limit
  75. SVOM alert sb26021801: LCO optical upper limit
  76. EP260221a: Einstein Probe detection of an X-ray transient
  77. SVOM alert sb26021801: LAST optical upper limit
  78. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  79. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  80. EP-WXT 01709258455: NOT optical upper limits
  81. EP260214b: Mondy optical observations
  82. EP260214b: 1.3m DFOT optical upper limit
  83. EP260210a: Mondy optical upper limits
  84. Konus-Wind detection of GRB 260212A
  85. GRB 260208A: AbAO and Terskol optical upper limits
  86. GRB 260208A: continued Mondy optical observations
  87. IPN triangulation of GRB 260212A
  88. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  89. EP260214b: Liverpool Telescope optical observations
  90. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  91. EP260214b: Optical upper limit with Kinder observations
  92. EP260214a: Optical upper limits with Kinder observations
  93. EP260214b: EP-FXT follow-up observation
  94. EP260214b: DDOTI Optical Detection
  95. EP260214b: GROWTH-India Telescope optical upper limit
  96. EP260214a: VLT near-infrared observation
  97. EP260214a: NOT optical upper limits
  98. EP260214a: COLIBRÍ optical upper limits
  99. EP260214b: OHP/T120 optical observations
  100. EP260214a: refined analysis of the EP-FXT observation

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