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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"

27348 results found.

  1. GRB 260516D: GOTO optical counterpart detection
  2. GRB 260516D: LCO optical observations
  3. GRB 260515A: further Liverpool Telescope observations
  4. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  5. GRB 260516D: GROWTH-India Telescope optical counterpart discovery
  6. GRB 260516D: SVOM/VT optical bright candidate
  7. GRB 260515A: CrAO ZTSh BVRI optical observations
  8. Fermi GRB 260516C: Global MASTER-Net observations report
  9. SVOM GRB260516.86: Global MASTER-Net observations report
  10. GRB 260516D: SVOM possible detection of a short faint burst
  11. GRB 260515A: LCO optical counterpart detection
  12. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) further optical observations
  13. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  14. EP260514a: NOT optical counterpart confirmation
  15. EP260514a: TRT optical counterpart candidate
  16. EP260514a: SVOM/VT optical candidate
  17. Fermi GRB 260516B: Global MASTER-Net observations report
  18. GRB 260515A: OHP/T193 optical observations
  19. EP260514a: COLIBRÍ optical upper limits
  20. GRB 260515A: LCO optical observations
  21. SVOM GRB 260515A: Global MASTER-Net observations report
  22. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  23. GRB 260515A: SVOM/VT optical candidate from VHF data
  24. GRB 260515A: JinShan optical counterpart candidate
  25. GRB 260515A: SVOM detection of a burst
  26. GRB 260510C: Glowbug gamma-ray detection
  27. EP260514a: GROWTH-India Telescope optical upper limit
  28. GRB 260511B: GMG Optical Upper Limit
  29. EP260514a: Global MASTER-Net observations report
  30. EP260514a: Einstein Probe detection of a fast X-ray transient
  31. EP260512a: LCO optical upper limits
  32. GRB 260511B: Mephisto multi-band optical followup
  33. Fermi GRB 260514A: Global MASTER-Net observations report
  34. GRB 260512A: AstroSat CZTI detection
  35. EP260512a: EP-FXT follow-up observation
  36. EP260507a: Xinglong Schmidt optical counterpart detection
  37. EP260512a: Global MASTER-Net observations report
  38. Fermi GRB 260513A: Global MASTER-Net observations report
  39. Fermi GRB 260512A: Global MASTER-Net observations report
  40. GRB 260511B: further SAO RAS optical observations
  41. GRB 260509A: SVOM/VT optical observations
  42. The EP-WXT trigger 01709262036 is likely a flaring star
  43. EP260512a: COLIBRÍ optical upper limits
  44. EP260512a: Einstein Probe detection of an X-ray transient
  45. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  46. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  47. GRB 260512A: NuSTAR detection of prompt emission
  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 260511A: Glowbug gamma-ray detection
  52. GRB 260511B: SAO RAS optical observations
  53. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  54. GRB 260511B: FRAM-ORM optical detection
  55. GRB 260511A: EP-FXT follow-up observation
  56. GRB 260511B: EP-FXT follow-up observation
  57. GRB 260511B: LCO optical counterpart detection
  58. GRB260511B: MAO/AZT-22 optical observations
  59. GRB 260511B: LCO optical observations
  60. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  61. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  62. GRB 260510B: EP-FXT follow-up observation
  63. GRB 260510C: Fermi GBM Observation
  64. GRB 260509A: SAO RAS optical observations
  65. GRB 260511A: REM near-infrared detection
  66. GRB 260511B: GROWTH-India Telescope optical observations
  67. GRB 260506B: Glowbug gamma-ray detection
  68. GRB 260506A: Glowbug gamma-ray detection of a short burst
  69. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  70. GRB 260511B: NuSTAR detection of prompt emission
  71. GRB 260511A: NuSTAR detection of prompt emission
  72. GRB 260511B: Fermi GBM Detection
  73. GRB 260511B: SVOM/VT optical observation with VHF data
  74. GRB 260511B: TRT optical observation
  75. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  76. GRB 260511A: Fermi GBM Detection
  77. GRB 260511B SVOM/C-GFT optical counterpart detection
  78. EP260509a: LCO optical upper limits
  79. GRB 260511A: UTGO H50 optical afterglow observation
  80. GRB 260511B: SVOM detection of a burst
  81. GRB 260510C: EP-FXT follow-up observation
  82. EP260509a: EP-FXT non-detection and upper limit
  83. GRB 260511A: SVOM/VT optical observation with VHF data
  84. Fermi GRB 260511A: Global MASTER-Net observations report
  85. GRB 260511A: KAIT optical afterglow observations
  86. GRB 260511A: LCO optical afterglow detection
  87. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  88. GRB 260511A: TRT optical counterpart detection
  89. GRB 260511A: SVOM detection of a bright burst
  90. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  91. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  92. GRB 260510C: MAXI/GSC detection
  93. EP260509a: Global MASTER-Net observations report
  94. Fermi GBM Sub-Threshold Detection of GRB 260510B
  95. GRB 260510C: SVOM detection of a burst
  96. GRB 260510B: LCO optical upper limits
  97. EP260509a: Einstein Probe detection of an X-ray transient
  98. GRB 260509A: Liverpool Telescope optical observations
  99. GRB 260510B: SVOM detection of a burst
  100. GRB 260509A: LCO optical observations

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