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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. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  2. EP260514a: GROWTH-India Telescope optical upper limit
  3. GRB 260511B: NOT optical observations
  4. Konus-Wind detection of GRB 260512A
  5. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  6. GRB 260511B: GMG Optical Upper Limit
  7. EP260514a: Global MASTER-Net observations report
  8. EP260514a: Einstein Probe detection of a fast X-ray transient
  9. EP260512a: LCO optical upper limits
  10. IPN triangulation of GRB 260512A
  11. GRB 260511B: Mephisto multi-band optical followup
  12. Fermi GRB 260514A: Global MASTER-Net observations report
  13. GRB 260512A: AstroSat CZTI detection
  14. The EP-WXT trigger 01709262077 is likely a flaring star
  15. EP260512a: EP-FXT follow-up observation
  16. EP260507a: Xinglong Schmidt optical counterpart detection
  17. GRB 260514A: Fermi GBM Final Real-time Localization
  18. EP260512a: Global MASTER-Net observations report
  19. Fermi GRB 260513A: Global MASTER-Net observations report
  20. Fermi GRB 260512A: Global MASTER-Net observations report
  21. GRB 260511B: further SAO RAS optical observations
  22. GRB 260513A: Fermi GBM Final Real-time Localization
  23. GRB 260509A: SVOM/VT optical observations
  24. Konus-Wind detection of GRB 260511B
  25. The EP-WXT trigger 01709262036 is likely a flaring star
  26. EP260512a: COLIBRÍ optical upper limits
  27. EP260512a: Einstein Probe detection of an X-ray transient
  28. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  29. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  30. GRB 260512A: NuSTAR detection of prompt emission
  31. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  32. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  33. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  34. GRB 260512A: Fermi GBM Final Real-time Localization
  35. GRB 260511A: Glowbug gamma-ray detection
  36. Konus-Wind detection of GRB 260511A
  37. MASS-Cube (GRID 2.0) detection of GRB 260511A
  38. MASS-Cube (GRID 2.0) detection of GRB 260507A
  39. GRB 260511B: SAO RAS optical observations
  40. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  41. GRB 260511B: FRAM-ORM optical detection
  42. GRB 260511A: EP-FXT follow-up observation
  43. GRB 260511B: EP-FXT follow-up observation
  44. GRB 260511B: LCO optical counterpart detection
  45. GRB260511B: MAO/AZT-22 optical observations
  46. GRB 260511A: SVOM/VT optical observations
  47. GRB 260511B: LCO optical observations
  48. GRB 260511B: OHP/T193 spectroscopic observations
  49. GRB 260511B: GOTO optical counterpart detection
  50. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  51. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  52. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  53. GRB 260511B: SVOM/VT optical observations
  54. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  55. GRB 260510B: EP-FXT follow-up observation
  56. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  57. GRB 260510C: Fermi GBM Observation
  58. GRB 260509A: SAO RAS optical observations
  59. GRB 260511A: REM near-infrared detection
  60. GRB 260511B: GROWTH-India Telescope optical observations
  61. GRB 260511B: AstroSat CZTI detection
  62. GRB 260506B: Glowbug gamma-ray detection
  63. GRB 260506A: Glowbug gamma-ray detection of a short burst
  64. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  65. GRB 260511B: NuSTAR detection of prompt emission
  66. GRB 260511A: NuSTAR detection of prompt emission
  67. GRB 260511B: Fermi GBM Detection
  68. GRB 260511C: Fermi GBM Final Real-time Localization
  69. GRB 260511B: SVOM/VT optical observation with VHF data
  70. GRB 260511B: TRT optical observation
  71. GRB 260510B: SVOM/ECLAIRs refined analysis
  72. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  73. GRB 260511A: Fermi GBM Detection
  74. GRB 260511B SVOM/C-GFT optical counterpart detection
  75. EP260509a: LCO optical upper limits
  76. GRB 260511A: UTGO H50 optical afterglow observation
  77. GRB 260510C: AstroSat CZTI detection
  78. GRB 260511B: SVOM detection of a burst
  79. GRB 260511B: Fermi GBM Final Real-time Localization
  80. GRB 260510C: EP-FXT follow-up observation
  81. GRB 260510C: SVOM/VT optical counterpart confirmation
  82. EP260509a: EP-FXT non-detection and upper limit
  83. GRB 260511A: SVOM/VT optical observation with VHF data
  84. Fermi GRB 260511A: Global MASTER-Net observations report
  85. GRB 260511A: KAIT optical afterglow observations
  86. GRB 260511A: LCO optical afterglow detection
  87. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  88. GRB 260511A: TRT optical counterpart detection
  89. GRB 260511A: SVOM detection of a bright burst
  90. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  91. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  92. GRB 260511A: Fermi GBM Final Real-time Localization
  93. GRB 260510B: SVOM/VT optical upper limits
  94. GRB 260510C: SVOM/VT optical upper limits
  95. GRB 260510C: MAXI/GSC detection
  96. EP260509a: Global MASTER-Net observations report
  97. Fermi GBM Sub-Threshold Detection of GRB 260510B
  98. GRB 260510D: Fermi GBM Final Real-time Localization
  99. GRB 260510B: GOTO early upper limit
  100. GRB 260510C: SVOM detection of a burst

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