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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"

27317 results found.

  1. GRB 260511B: Mephisto multi-band optical followup
  2. Fermi GRB 260514A: Global MASTER-Net observations report
  3. GRB 260512A: AstroSat CZTI detection
  4. EP260512a: EP-FXT follow-up observation
  5. EP260507a: Xinglong Schmidt optical counterpart detection
  6. EP260512a: Global MASTER-Net observations report
  7. Fermi GRB 260513A: Global MASTER-Net observations report
  8. Fermi GRB 260512A: Global MASTER-Net observations report
  9. GRB 260511B: further SAO RAS optical observations
  10. GRB 260509A: SVOM/VT optical observations
  11. The EP-WXT trigger 01709262036 is likely a flaring star
  12. EP260512a: COLIBRÍ optical upper limits
  13. EP260512a: Einstein Probe detection of an X-ray transient
  14. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  15. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  16. GRB 260512A: NuSTAR detection of prompt emission
  17. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  18. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  19. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  20. GRB 260511A: Glowbug gamma-ray detection
  21. GRB 260511B: SAO RAS optical observations
  22. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  23. GRB 260511B: FRAM-ORM optical detection
  24. GRB 260511A: EP-FXT follow-up observation
  25. GRB 260511B: EP-FXT follow-up observation
  26. GRB 260511B: LCO optical counterpart detection
  27. GRB260511B: MAO/AZT-22 optical observations
  28. GRB 260511B: LCO optical observations
  29. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  30. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  31. GRB 260510B: EP-FXT follow-up observation
  32. GRB 260510C: Fermi GBM Observation
  33. GRB 260509A: SAO RAS optical observations
  34. GRB 260511A: REM near-infrared detection
  35. GRB 260511B: GROWTH-India Telescope optical observations
  36. GRB 260506B: Glowbug gamma-ray detection
  37. GRB 260506A: Glowbug gamma-ray detection of a short burst
  38. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  39. GRB 260511B: NuSTAR detection of prompt emission
  40. GRB 260511A: NuSTAR detection of prompt emission
  41. GRB 260511B: Fermi GBM Detection
  42. GRB 260511B: SVOM/VT optical observation with VHF data
  43. GRB 260511B: TRT optical observation
  44. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  45. GRB 260511A: Fermi GBM Detection
  46. GRB 260511B SVOM/C-GFT optical counterpart detection
  47. EP260509a: LCO optical upper limits
  48. GRB 260511A: UTGO H50 optical afterglow observation
  49. GRB 260511B: SVOM detection of a burst
  50. GRB 260510C: EP-FXT follow-up observation
  51. EP260509a: EP-FXT non-detection and upper limit
  52. GRB 260511A: SVOM/VT optical observation with VHF data
  53. Fermi GRB 260511A: Global MASTER-Net observations report
  54. GRB 260511A: KAIT optical afterglow observations
  55. GRB 260511A: LCO optical afterglow detection
  56. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  57. GRB 260511A: TRT optical counterpart detection
  58. GRB 260511A: SVOM detection of a bright burst
  59. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  60. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  61. GRB 260510C: MAXI/GSC detection
  62. EP260509a: Global MASTER-Net observations report
  63. Fermi GBM Sub-Threshold Detection of GRB 260510B
  64. GRB 260510C: SVOM detection of a burst
  65. GRB 260510B: LCO optical upper limits
  66. EP260509a: Einstein Probe detection of an X-ray transient
  67. GRB 260509A: Liverpool Telescope optical observations
  68. GRB 260510B: SVOM detection of a burst
  69. GRB 260509A: LCO optical observations
  70. SVOM GRB 260509A: MASTER-OAFA optical observation
  71. Fermi GRB 260510A: Global MASTER-Net observations report
  72. GRB 260509A: KAIT optical observations
  73. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  74. GRB 260509A: SVOM/VT optical candidate with VHF data
  75. GRB 260509A: LCO optical counterpart detection
  76. GRB 260509A: SVOM detection of a burst
  77. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  78. EP260507a: REM optical/NIR observations
  79. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  80. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  81. EP260507a: COLIBRÍ optical observations
  82. EP260507a: NOT optical observations
  83. EP260507a: further Liverpool Telescope observations
  84. EP260507a: Liverpool Telescope optical upper limits
  85. EP260507a: TRT optical counterpart detection
  86. EP260507a: Kinder optical counterpart candidate
  87. EP260507a: LCO optical counterpart
  88. EP260507a: Einstein Probe detection of an X-ray transient
  89. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  90. Fermi GRB 260506A: Global MASTER-Net observations report
  91. IceCube Alert 260505A: Global MASTER-Net observations report
  92. GRB 260430B: Glowbug gamma-ray detection
  93. GRB 260421B: radio observation with the VLA
  94. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  95. GRB 260430B: AstroSat CZTI detection of a long burst
  96. GRB 260502A: SVOM/GRM observation of a short GRB
  97. GRB 260503A: SVOM/GRM observation of a GRB
  98. Konus-Wind detection of GRB 260411C
  99. GRB 260504B: REM optical/NIR observations
  100. GRB 260504B: LCO z-band upper limit

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