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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"

3298 results found.

  1. EP260214b: EP-FXT follow-up observation
  2. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  3. EP260214b: GROWTH-India Telescope optical upper limit
  4. EP260214a: VLT near-infrared observation
  5. EP260214a: NOT optical upper limits
  6. EP260214a: COLIBRÍ optical upper limits
  7. EP260214a: refined analysis of the EP-FXT observation
  8. EP260214b: LCO optical counterpart detection
  9. GRB 260211A: SVOM/VT optical counterpart
  10. EP260214a: SVOM/VT optical upper limits
  11. EP260214b: NOT optical counterpart detection
  12. EP260214b: Einstein Probe detection of a fast X-ray transient
  13. EP260214a: Global MASTER-Net observations report
  14. EP260214a: Einstein Probe detection of an X-ray transient
  15. EP260213a: Liverpool Telescope optical upper limits
  16. EP260213a: Global MASTER-Net observations report
  17. EP260213a: COLIBRÍ optical upper limits
  18. EP260213a: Optical upper limits with Kinder observations
  19. EP260213a: SVOM/VT optical upper limit
  20. EP260213a: NUTTelA-TAO Early Optical Limits
  21. EP260213a: SVOM/C-GFT upper limit
  22. EP260213a: refined analysis of the EP-FXT observation
  23. EP260213a: Einstein Probe detection of a fast X-ray transient
  24. EP/WXT 01709258378: NOT optical upper limits
  25. GRB 260211A: EP-FXT follow-up observation
  26. GRB 260211A: SVOM/VT optical observation
  27. Konus-Wind detection of GRB 260207B
  28. Konus-Wind detection of GRB 260209B
  29. Konus-Wind detection of GRB 260127B
  30. EP260209a: COLIBRÍ optical upper limit
  31. EP260209a: LCO optical upper limits
  32. EP260210a: Global MASTER-Net observations report
  33. EP260210a: refined analysis of the EP-FXT observation
  34. EP260209a: Global MASTER-Net observations report
  35. EP260209a: Einstein Probe detection of a fast X-ray transient
  36. EP260210a: Optical upper limits with Kinder observations
  37. EP260210a: SVOM/VT optical upper limit
  38. EP260210a: COLIBRÍ optical upper limit
  39. EP260210a: SVOM/C-GFT upper limit
  40. GRB 260208B: refined analysis of the EP-FXT observation
  41. EP260210a: Einstein Probe detection of an X-ray transient
  42. GRB 260208B: Swift-XRT observations
  43. GRB 260208B: EP-FXT observation
  44. EP260110a: Late GTC/EMIR near-infrared observations
  45. Konus-Wind detection of GRB 260121A
  46. GRB 260131A/B: EP/FXT X-ray afterglow detection
  47. EP260131a: Liverpool Telescope optical upper limits
  48. Konus-Wind detection of GRB 260128A / EP260128a
  49. Konus-Wind detection of GRB 260131A/B
  50. EP260131a: SVOM/VT optical observation
  51. EP260131a: Xinglong optical upper limit
  52. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  53. EP260131a: Las Cumbres detection of an optical counterpart
  54. EP260131a: Einstein Probe detection of an X-ray transient
  55. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  56. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  57. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  58. EP260128a: NOT optical counterpart candidate
  59. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  60. EP260128a: Liverpool Telescope optical observations and possible counterpart
  61. EP260128a: LCO optical upper limits
  62. EP260126a: SVOM/VT optical upperlimit
  63. EP260128a: Global MASTER-Net observations report
  64. EP260128a: Einstein Probe detection of an X-ray transient
  65. EP260126a: Seimei/TriCCS optical upper limit
  66. The EP-WXT trigger 01709253145 is likely a flaring star
  67. EP260126a: EP-FXT follow-up observation
  68. EP260126a: Optical upper limit with Kinder observations
  69. EP260126a: Liverpool Telescope optical upper limits
  70. EP260126a: Further NOT optical upper limits
  71. EP260126a: COLIBRÍ optical upper limits
  72. EP260126a: NOT optical observations
  73. EP260126a: Einstein Probe detection of a fast X-ray transient
  74. Konus-Wind detection of GRB 260120B
  75. EP260119a: Xinglong optical upper limit
  76. The EP-WXT trigger 01709251871 is likely a flaring star
  77. EP260116a: COLIBRÍ further observations
  78. EP260105a: GTC/HiPERCAM optical observations
  79. EP260119a: Liverpool Telescope optical follow-up observations
  80. EP260119a: SVOM/VT optical observation
  81. EP260119a: update of EP-FXT follow-up observation
  82. EP260119a: NOT optical observations
  83. EP260116a: COLIBRÍ detection of a fading optical source
  84. EP260119a: Global MASTER-Net observations report
  85. EP260119a: COLIBRÍ optical counterpart candidate
  86. EP260119a: preliminary result from the EP-FXT observation
  87. EP260119a: EP-WXT detection of a fast X-ray transient
  88. GRB 260117A: SVOM/VT optical candidate
  89. GRB 260117A: SVOM/C-GFT upper limit
  90. EP 260116a: COLIBRÍ optical upper limit
  91. EP260116a: Liverpool Telescope upper limits
  92. EP260116A: 1.3m DFOT optical upper limit
  93. EP260116a: Global MASTER-Net observations report
  94. EP260116a: Xinglong optical upper limit
  95. EP260116a: Einstein Probe detection of an X-ray transient
  96. Konus-Wind detection of GRB 260114A
  97. Konus-Wind detection of GRB 251230A / EP251230a
  98. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  99. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  100. EP260110a: TRT optical upper limits

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