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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"

18334 results found.

  1. The EP-WXT trigger 01709266106 is not a real source
  2. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  3. EP-WXT 01709266106: NOT optical upper limits
  4. Fermi trigger No 801135305: Global MASTER-Net observations report
  5. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  6. GRB 260511A: iTelescope T-75 optical detection
  7. GRB 260520B: SVOM/GRM observation
  8. Konus-Wind detection of GRB 260518A
  9. GRB 260518A: AstroSat CZTI detection of a long burst
  10. GRB 260421B: radio detection with the VLA
  11. GRB 260509A: CrAO ZTSh optical upper limit
  12. GRB 260516D: EP-FXT follow-up observation
  13. GRB 260516D: GOTO optical counterpart detection
  14. GRB 260516D: LCO optical observations
  15. GRB 260515A: further Liverpool Telescope observations
  16. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  17. GRB 260516D: GROWTH-India Telescope optical detection
  18. GRB 260516D: SVOM/VT optical bright candidate
  19. GRB 260515A: CrAO ZTSh BVRI optical observations
  20. Konus-Wind detection of GRB 260515A
  21. GRB 260515A: LCO optical counterpart detection
  22. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 260515A: EP-FXT follow-up observation
  24. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  25. EP260514a: NOT optical counterpart confirmation
  26. EP260514a: TRT optical counterpart candidate
  27. EP260514a: SVOM/VT optical candidate
  28. GRB 260515A: OHP/T193 optical observations
  29. EP260514a: COLIBRÍ optical upper limits
  30. GRB 260515A: LCO optical observations
  31. GRB 260515A: SVOM/VT optical candidate from VHF data
  32. GRB 260515A: JinShan optical counterpart candidate
  33. GRB 260515A: SVOM detection of a burst
  34. EP260514a: GROWTH-India Telescope optical upper limit
  35. GRB 260511B: GMG Optical Upper Limit
  36. EP260514a: Einstein Probe detection of a fast X-ray transient
  37. EP260512a: LCO optical upper limits
  38. GRB 260511B: Mephisto multi-band optical followup
  39. The EP-WXT trigger 01709262077 is likely a flaring star
  40. EP260512a: EP-FXT follow-up observation
  41. EP260507a: Xinglong Schmidt optical counterpart detection
  42. GRB 260511B: further SAO RAS optical observations
  43. The EP-WXT trigger 01709262036 is likely a flaring star
  44. EP260512a: COLIBRÍ optical upper limits
  45. EP260512a: Einstein Probe detection of an X-ray transient
  46. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  47. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  48. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  49. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  50. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  51. GRB 260511B: SAO RAS optical observations
  52. GRB 260511B: FRAM-ORM optical detection
  53. GRB 260511A: EP-FXT follow-up observation
  54. GRB 260511B: EP-FXT follow-up observation
  55. GRB 260511B: LCO optical counterpart detection
  56. GRB260511B: MAO/AZT-22 optical observations
  57. GRB 260511B: LCO optical observations
  58. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  59. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  60. GRB 260510B: EP-FXT follow-up observation
  61. GRB 260509A: SAO RAS optical observations
  62. GRB 260511A: REM near-infrared detection
  63. GRB 260511B: GROWTH-India Telescope optical observations
  64. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  65. GRB 260511B: SVOM/VT optical observation with VHF data
  66. GRB 260511B: TRT optical observation
  67. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  68. GRB 260511A: Fermi GBM Detection
  69. GRB 260511B SVOM/C-GFT optical counterpart detection
  70. EP260509a: LCO optical upper limits
  71. GRB 260511A: UTGO H50 optical afterglow observation
  72. GRB 260511B: SVOM detection of a burst
  73. GRB 260510C: EP-FXT follow-up observation
  74. GRB 260510C: SVOM/VT optical counterpart confirmation
  75. EP260509a: EP-FXT non-detection and upper limit
  76. GRB 260511A: SVOM/VT optical observation with VHF data
  77. GRB 260511A: KAIT optical afterglow observations
  78. GRB 260511A: LCO optical afterglow detection
  79. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  80. GRB 260511A: TRT optical counterpart detection
  81. GRB 260511A: SVOM detection of a bright burst
  82. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  83. GRB 260510C: SVOM detection of a burst
  84. GRB 260510B: LCO optical upper limits
  85. EP260509a: Einstein Probe detection of an X-ray transient
  86. GRB 260509A: Liverpool Telescope optical observations
  87. GRB 260510B: SVOM detection of a burst
  88. GRB 260509A: LCO optical observations
  89. GRB 260509A: KAIT optical observations
  90. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  91. GRB 260509A: SVOM/VT optical candidate with VHF data
  92. GRB 260509A: LCO optical counterpart detection
  93. GRB 260509A: SVOM detection of a burst
  94. EP260507a: REM optical/NIR observations
  95. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  96. EP260507a: COLIBRÍ optical observations
  97. EP260507a: NOT optical observations
  98. EP260507a: further Liverpool Telescope observations
  99. EP260507a: Liverpool Telescope optical upper limits
  100. EP260507a: TRT optical counterpart detection

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