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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. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  2. GRB 260512A: Fermi GBM Final Real-time Localization
  3. GRB 260511A: Glowbug gamma-ray detection
  4. Konus-Wind detection of GRB 260511A
  5. MASS-Cube (GRID 2.0) detection of GRB 260511A
  6. MASS-Cube (GRID 2.0) detection of GRB 260507A
  7. GRB 260511B: SAO RAS optical observations
  8. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  9. GRB 260511B: FRAM-ORM optical detection
  10. GRB 260511A: EP-FXT follow-up observation
  11. GRB 260511B: EP-FXT follow-up observation
  12. GRB 260511B: LCO optical counterpart detection
  13. GRB260511B: MAO/AZT-22 optical observations
  14. GRB 260511A: SVOM/VT optical observations
  15. GRB 260511B: LCO optical observations
  16. GRB 260511B: OHP/T193 spectroscopic observations
  17. GRB 260511B: GOTO optical counterpart detection
  18. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  19. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  20. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  21. GRB 260511B: SVOM/VT optical observations
  22. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 260510B: EP-FXT follow-up observation
  24. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  25. GRB 260510C: Fermi GBM Observation
  26. GRB 260509A: SAO RAS optical observations
  27. GRB 260511A: REM near-infrared detection
  28. GRB 260511B: GROWTH-India Telescope optical observations
  29. GRB 260511B: AstroSat CZTI detection
  30. GRB 260506B: Glowbug gamma-ray detection
  31. GRB 260506A: Glowbug gamma-ray detection of a short burst
  32. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  33. GRB 260511B: NuSTAR detection of prompt emission
  34. GRB 260511A: NuSTAR detection of prompt emission
  35. GRB 260511B: Fermi GBM Detection
  36. GRB 260511C: Fermi GBM Final Real-time Localization
  37. GRB 260511B: SVOM/VT optical observation with VHF data
  38. GRB 260511B: TRT optical observation
  39. GRB 260510B: SVOM/ECLAIRs refined analysis
  40. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  41. GRB 260511A: Fermi GBM Detection
  42. GRB 260511B SVOM/C-GFT optical counterpart detection
  43. EP260509a: LCO optical upper limits
  44. GRB 260511A: UTGO H50 optical afterglow observation
  45. GRB 260510C: AstroSat CZTI detection
  46. GRB 260511B: SVOM detection of a burst
  47. GRB 260511B: Fermi GBM Final Real-time Localization
  48. GRB 260510C: EP-FXT follow-up observation
  49. GRB 260510C: SVOM/VT optical counterpart confirmation
  50. EP260509a: EP-FXT non-detection and upper limit
  51. GRB 260511A: SVOM/VT optical observation with VHF data
  52. Fermi GRB 260511A: Global MASTER-Net observations report
  53. GRB 260511A: KAIT optical afterglow observations
  54. GRB 260511A: LCO optical afterglow detection
  55. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  56. GRB 260511A: TRT optical counterpart detection
  57. GRB 260511A: SVOM detection of a bright burst
  58. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  59. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  60. GRB 260511A: Fermi GBM Final Real-time Localization
  61. GRB 260510B: SVOM/VT optical upper limits
  62. GRB 260510C: SVOM/VT optical upper limits
  63. GRB 260510C: MAXI/GSC detection
  64. EP260509a: Global MASTER-Net observations report
  65. Fermi GBM Sub-Threshold Detection of GRB 260510B
  66. GRB 260510D: Fermi GBM Final Real-time Localization
  67. GRB 260510B: GOTO early upper limit
  68. GRB 260510C: SVOM detection of a burst
  69. GRB 260510C: Fermi GBM Final Real-time Localization
  70. GRB 260510A: GECAM-B observation
  71. GRB 260510B: LCO optical upper limits
  72. EP260509a: Einstein Probe detection of an X-ray transient
  73. GRB 260509A: Liverpool Telescope optical observations
  74. GRB 260510B: SVOM detection of a burst
  75. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  76. GRB 260509A: LCO optical observations
  77. SVOM GRB 260509A: MASTER-OAFA optical observation
  78. Fermi GRB 260510A: Global MASTER-Net observations report
  79. GRB 260509A: KAIT optical observations
  80. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  81. GRB 260510A: Fermi GBM Final Real-time Localization
  82. GRB 260509A: SVOM/VT optical candidate with VHF data
  83. GRB 260509A: LCO optical counterpart detection
  84. GRB 260509A: GOTO optical counterpart candidate
  85. GRB 260509A: SVOM detection of a burst
  86. GRB 260506B: AstroSat CZTI detection
  87. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  88. EP260507a: REM optical/NIR observations
  89. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  90. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  91. EP260507a: COLIBRÍ optical observations
  92. EP260507a: SVOM/VT optical observations
  93. EP260507a: NOT optical observations
  94. EP260507a: further Liverpool Telescope observations
  95. EP260507a: Liverpool Telescope optical upper limits
  96. GRB 260507A: Fermi GBM Final Real-time Localization
  97. EP260507a: GOTO optical counterpart detection
  98. EP260507a: TRT optical counterpart detection
  99. EP260507a: Kinder optical counterpart candidate
  100. EP260507a: LCO optical counterpart

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