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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"

28037 results found.

  1. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  2. EP260514a: NOT optical counterpart confirmation
  3. EP260514a: TRT optical counterpart candidate
  4. EP260514a: SVOM/VT optical candidate
  5. Fermi GRB 260516B: Global MASTER-Net observations report
  6. GRB 260515A: OHP/T193 optical observations
  7. EP260514a: COLIBRÍ optical upper limits
  8. GRB 260515A: LCO optical observations
  9. SVOM GRB 260515A: Global MASTER-Net observations report
  10. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  11. GRB 260515A: SVOM/VT optical candidate from VHF data
  12. GRB 260515A: JinShan optical counterpart candidate
  13. GRB 260515A: SVOM detection of a burst
  14. GRB 260510C: Glowbug gamma-ray detection
  15. EP260514a: GROWTH-India Telescope optical upper limit
  16. GRB 260511B: GMG Optical Upper Limit
  17. EP260514a: Global MASTER-Net observations report
  18. EP260514a: Einstein Probe detection of a fast X-ray transient
  19. EP260512a: LCO optical upper limits
  20. GRB 260511B: Mephisto multi-band optical followup
  21. Fermi GRB 260514A: Global MASTER-Net observations report
  22. GRB 260512A: AstroSat CZTI detection
  23. EP260512a: EP-FXT follow-up observation
  24. EP260507a: Xinglong Schmidt optical counterpart detection
  25. EP260512a: Global MASTER-Net observations report
  26. Fermi GRB 260513A: Global MASTER-Net observations report
  27. Fermi GRB 260512A: Global MASTER-Net observations report
  28. GRB 260511B: further SAO RAS optical observations
  29. GRB 260509A: SVOM/VT optical observations
  30. The EP-WXT trigger 01709262036 is likely a flaring star
  31. EP260512a: COLIBRÍ optical upper limits
  32. EP260512a: Einstein Probe detection of an X-ray transient
  33. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  34. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  35. GRB 260512A: NuSTAR detection of prompt emission
  36. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  37. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  38. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  39. GRB 260511A: Glowbug gamma-ray detection
  40. GRB 260511B: SAO RAS optical observations
  41. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  42. GRB 260511B: FRAM-ORM optical detection
  43. GRB 260511A: EP-FXT follow-up observation
  44. GRB 260511B: EP-FXT follow-up observation
  45. GRB 260511B: LCO optical counterpart detection
  46. GRB260511B: MAO/AZT-22 optical observations
  47. GRB 260511B: LCO optical observations
  48. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  49. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  50. GRB 260510B: EP-FXT follow-up observation
  51. GRB 260510C: Fermi GBM Observation
  52. GRB 260509A: SAO RAS optical observations
  53. GRB 260511A: REM near-infrared detection
  54. GRB 260511B: GROWTH-India Telescope optical observations
  55. GRB 260506B: Glowbug gamma-ray detection
  56. GRB 260506A: Glowbug gamma-ray detection of a short burst
  57. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  58. GRB 260511B: NuSTAR detection of prompt emission
  59. GRB 260511A: NuSTAR detection of prompt emission
  60. GRB 260511B: Fermi GBM Detection
  61. GRB 260511B: SVOM/VT optical observation with VHF data
  62. GRB 260511B: TRT optical observation
  63. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  64. GRB 260511A: Fermi GBM Detection
  65. GRB 260511B SVOM/C-GFT optical counterpart detection
  66. EP260509a: LCO optical upper limits
  67. GRB 260511A: UTGO H50 optical afterglow observation
  68. GRB 260511B: SVOM detection of a burst
  69. GRB 260510C: EP-FXT follow-up observation
  70. EP260509a: EP-FXT non-detection and upper limit
  71. GRB 260511A: SVOM/VT optical observation with VHF data
  72. Fermi GRB 260511A: Global MASTER-Net observations report
  73. GRB 260511A: KAIT optical afterglow observations
  74. GRB 260511A: LCO optical afterglow detection
  75. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  76. GRB 260511A: TRT optical counterpart detection
  77. GRB 260511A: SVOM detection of a bright burst
  78. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  79. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  80. GRB 260510C: MAXI/GSC detection
  81. EP260509a: Global MASTER-Net observations report
  82. Fermi GBM Sub-Threshold Detection of GRB 260510B
  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. SVOM GRB 260509A: MASTER-OAFA optical observation
  90. Fermi GRB 260510A: Global MASTER-Net observations report
  91. GRB 260509A: KAIT optical observations
  92. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  93. GRB 260509A: SVOM/VT optical candidate with VHF data
  94. GRB 260509A: LCO optical counterpart detection
  95. GRB 260509A: SVOM detection of a burst
  96. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  97. EP260507a: REM optical/NIR observations
  98. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  99. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  100. EP260507a: COLIBRÍ optical observations

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