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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"

19549 results found.

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

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