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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"
  1. Fermi GRB 260514A: Global MASTER-Net observations report
  2. GRB 260512A: AstroSat CZTI detection
  3. The EP-WXT trigger 01709262077 is likely a flaring star
  4. EP260512a: EP-FXT follow-up observation
  5. EP260507a: Xinglong Schmidt optical counterpart detection
  6. GRB 260514A: Fermi GBM Final Real-time Localization
  7. EP260512a: Global MASTER-Net observations report
  8. Fermi GRB 260513A: Global MASTER-Net observations report
  9. Fermi GRB 260512A: Global MASTER-Net observations report
  10. GRB 260511B: further SAO RAS optical observations
  11. GRB 260513A: Fermi GBM Final Real-time Localization
  12. GRB 260509A: SVOM/VT optical observations
  13. Konus-Wind detection of GRB 260511B
  14. The EP-WXT trigger 01709262036 is likely a flaring star
  15. EP260512a: COLIBRÍ optical upper limits
  16. EP260512a: Einstein Probe detection of an X-ray transient
  17. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  18. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  19. GRB 260512A: NuSTAR detection of prompt emission
  20. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  21. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  22. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  23. GRB 260512A: Fermi GBM Final Real-time Localization
  24. GRB 260511A: Glowbug gamma-ray detection
  25. Konus-Wind detection of GRB 260511A
  26. MASS-Cube (GRID 2.0) detection of GRB 260511A
  27. MASS-Cube (GRID 2.0) detection of GRB 260507A
  28. GRB 260511B: SAO RAS optical observations
  29. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  30. GRB 260511B: FRAM-ORM optical detection
  31. GRB 260511A: EP-FXT follow-up observation
  32. GRB 260511B: EP-FXT follow-up observation
  33. GRB 260511B: LCO optical counterpart detection
  34. GRB260511B: MAO/AZT-22 optical observations
  35. GRB 260511A: SVOM/VT optical observations
  36. GRB 260511B: LCO optical observations
  37. GRB 260511B: OHP/T193 spectroscopic observations
  38. GRB 260511B: GOTO optical counterpart detection
  39. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  40. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  41. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  42. GRB 260511B: SVOM/VT optical observations
  43. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  44. GRB 260510B: EP-FXT follow-up observation
  45. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  46. GRB 260510C: Fermi GBM Observation
  47. GRB 260509A: SAO RAS optical observations
  48. GRB 260511A: REM near-infrared detection
  49. GRB 260511B: GROWTH-India Telescope optical observations
  50. GRB 260511B: AstroSat CZTI detection
  51. GRB 260506B: Glowbug gamma-ray detection
  52. GRB 260506A: Glowbug gamma-ray detection of a short burst
  53. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  54. GRB 260511B: NuSTAR detection of prompt emission
  55. GRB 260511A: NuSTAR detection of prompt emission
  56. GRB 260511B: Fermi GBM Detection
  57. GRB 260511C: Fermi GBM Final Real-time Localization
  58. GRB 260511B: SVOM/VT optical observation with VHF data
  59. GRB 260511B: TRT optical observation
  60. GRB 260510B: SVOM/ECLAIRs refined analysis
  61. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  62. GRB 260511A: Fermi GBM Detection
  63. GRB 260511B SVOM/C-GFT optical counterpart detection
  64. EP260509a: LCO optical upper limits
  65. GRB 260511A: UTGO H50 optical afterglow observation
  66. GRB 260510C: AstroSat CZTI detection
  67. GRB 260511B: SVOM detection of a burst
  68. GRB 260511B: Fermi GBM Final Real-time Localization
  69. GRB 260510C: EP-FXT follow-up observation
  70. GRB 260510C: SVOM/VT optical counterpart confirmation
  71. EP260509a: EP-FXT non-detection and upper limit
  72. GRB 260511A: SVOM/VT optical observation with VHF data
  73. Fermi GRB 260511A: Global MASTER-Net observations report
  74. GRB 260511A: KAIT optical afterglow observations
  75. GRB 260511A: LCO optical afterglow detection
  76. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  77. GRB 260511A: TRT optical counterpart detection
  78. GRB 260511A: SVOM detection of a bright burst
  79. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  80. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  81. GRB 260511A: Fermi GBM Final Real-time Localization
  82. GRB 260510B: SVOM/VT optical upper limits
  83. GRB 260510C: SVOM/VT optical upper limits
  84. GRB 260510C: MAXI/GSC detection
  85. EP260509a: Global MASTER-Net observations report
  86. Fermi GBM Sub-Threshold Detection of GRB 260510B
  87. GRB 260510D: Fermi GBM Final Real-time Localization
  88. GRB 260510B: GOTO early upper limit
  89. GRB 260510C: SVOM detection of a burst
  90. GRB 260510C: Fermi GBM Final Real-time Localization
  91. GRB 260510A: GECAM-B observation
  92. GRB 260510B: LCO optical upper limits
  93. EP260509a: Einstein Probe detection of an X-ray transient
  94. GRB 260509A: Liverpool Telescope optical observations
  95. GRB 260510B: SVOM detection of a burst
  96. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  97. GRB 260509A: LCO optical observations
  98. SVOM GRB 260509A: MASTER-OAFA optical observation
  99. Fermi GRB 260510A: Global MASTER-Net observations report
  100. GRB 260509A: KAIT optical observations

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