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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"

26678 results found.

  1. GRB 260511B: GMG Optical Upper Limit
  2. EP260514a: Global MASTER-Net observations report
  3. IPN triangulation of GRB 260512A
  4. GRB 260511B: Mephisto multi-band optical followup
  5. Fermi GRB 260514A: Global MASTER-Net observations report
  6. The EP-WXT trigger 01709262077 is likely a flaring star
  7. EP260507a: Xinglong Schmidt optical counterpart detection
  8. GRB 260514A: Fermi GBM Final Real-time Localization
  9. EP260512a: Global MASTER-Net observations report
  10. Fermi GRB 260513A: Global MASTER-Net observations report
  11. Fermi GRB 260512A: Global MASTER-Net observations report
  12. GRB 260513A: Fermi GBM Final Real-time Localization
  13. GRB 260509A: SVOM/VT optical observations
  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 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 260512A: Fermi GBM Final Real-time Localization
  21. GRB 260511B: SAO RAS optical observations
  22. GRB 260511A: EP-FXT follow-up observation
  23. GRB 260511B: EP-FXT follow-up observation
  24. GRB 260511B: LCO optical counterpart detection
  25. GRB260511B: MAO/AZT-22 optical observations
  26. GRB 260511A: SVOM/VT optical observations
  27. GRB 260511B: LCO optical observations
  28. GRB 260511B: GOTO optical counterpart detection
  29. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  30. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  31. GRB 260511B: SVOM/VT optical observations
  32. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  33. GRB 260510B: EP-FXT follow-up observation
  34. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  35. GRB 260510C: Fermi GBM Observation
  36. GRB 260509A: SAO RAS optical observations
  37. GRB 260511A: REM near-infrared detection
  38. GRB 260511B: GROWTH-India Telescope optical observations
  39. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  40. GRB 260511B: Fermi GBM Detection
  41. GRB 260511C: Fermi GBM Final Real-time Localization
  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. GRB 260511A: UTGO H50 optical afterglow observation
  48. GRB 260511B: SVOM detection of a burst
  49. GRB 260511B: Fermi GBM Final Real-time Localization
  50. GRB 260510C: EP-FXT follow-up observation
  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: SVOM detection of a bright burst
  57. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  58. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  59. GRB 260511A: Fermi GBM Final Real-time Localization
  60. GRB 260510B: SVOM/VT optical upper limits
  61. GRB 260510C: SVOM/VT optical upper limits
  62. GRB 260510C: MAXI/GSC detection
  63. EP260509a: Global MASTER-Net observations report
  64. Fermi GBM Sub-Threshold Detection of GRB 260510B
  65. GRB 260510D: Fermi GBM Final Real-time Localization
  66. GRB 260510C: SVOM detection of a burst
  67. GRB 260510C: Fermi GBM Final Real-time Localization
  68. GRB 260510B: LCO optical upper limits
  69. GRB 260509A: Liverpool Telescope optical observations
  70. GRB 260510B: SVOM detection of a burst
  71. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  72. SVOM GRB 260509A: MASTER-OAFA optical observation
  73. Fermi GRB 260510A: Global MASTER-Net observations report
  74. GRB 260510A: Fermi GBM Final Real-time Localization
  75. GRB 260509A: SVOM/VT optical candidate with VHF data
  76. GRB 260509A: LCO optical counterpart detection
  77. GRB 260509A: GOTO optical counterpart candidate
  78. GRB 260509A: SVOM detection of a burst
  79. EP260507a: REM optical/NIR observations
  80. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  81. EP260507a: COLIBRÍ optical observations
  82. EP260507a: SVOM/VT optical observations
  83. EP260507a: Liverpool Telescope optical upper limits
  84. GRB 260507A: Fermi GBM Final Real-time Localization
  85. EP260507a: GOTO optical counterpart detection
  86. EP260507a: TRT optical counterpart detection
  87. EP260507a: Kinder optical counterpart candidate
  88. EP260507a: LCO optical counterpart
  89. GRB 260504B: SVOM/ECLAIRs refined analysis
  90. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  91. GRB 260506B: Fermi GBM Final Real-time Localization
  92. EP260502a is likely a flaring star
  93. Fermi GRB 260506A: Global MASTER-Net observations report
  94. GRB 260506A: Fermi GBM Final Real-time Localization
  95. IceCube Alert 260505A: Global MASTER-Net observations report
  96. GRB 260504B: SVOM/VT optical upper limits
  97. GRB 260504C: SVOM/GRM observation of short GRB
  98. GRB 260504B: SVOM/MXT refined analysis and potential detection
  99. GRB 260503A: SVOM/GRM observation of a GRB
  100. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN

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