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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"

21791 results found.

  1. GRB 260515A: SVOM/ECLAIRs refined analysis
  2. GRB 260421B: radio detection with the VLA
  3. GRB 260516D: GOTO optical counterpart detection
  4. GRB 260516D: LCO optical observations
  5. GRB 260515A: further Liverpool Telescope observations
  6. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  7. GRB 260516D: GROWTH-India Telescope optical detection
  8. GRB 260515A: CrAO ZTSh BVRI optical observations
  9. Fermi GRB 260516C: Global MASTER-Net observations report
  10. SVOM GRB260516D: Global MASTER-Net observations report
  11. GRB 260515A: Liverpool Telescope optical detection
  12. GRB 260515A: LCO optical counterpart detection
  13. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  15. EP260514a: SVOM/VT optical candidate
  16. Fermi GRB 260516B: Global MASTER-Net observations report
  17. GRB 260515A: SVOM/VT optical observations
  18. GRB 260515A: OHP/T193 optical observations
  19. GRB 260515A: LCO optical observations
  20. SVOM GRB 260515A: Global MASTER-Net observations report
  21. GRB 260515A: NOT optical observations.
  22. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  23. GRB 260515A: JinShan optical counterpart candidate
  24. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  25. GRB 260511B: NOT optical observations
  26. EP260514a: Global MASTER-Net observations report
  27. GRB 260511B: Mephisto multi-band optical followup
  28. Fermi GRB 260514A: Global MASTER-Net observations report
  29. EP260512a: EP-FXT follow-up observation
  30. EP260507a: Xinglong Schmidt optical counterpart detection
  31. EP260512a: Global MASTER-Net observations report
  32. Fermi GRB 260513A: Global MASTER-Net observations report
  33. Fermi GRB 260512A: Global MASTER-Net observations report
  34. GRB 260511B: further SAO RAS optical observations
  35. GRB 260509A: SVOM/VT optical observations
  36. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  37. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  38. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  39. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  40. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  41. GRB 260511B: SAO RAS optical observations
  42. GRB 260511B: FRAM-ORM optical detection
  43. GRB 260511B: LCO optical counterpart detection
  44. GRB260511B: MAO/AZT-22 optical observations
  45. GRB 260511A: SVOM/VT optical observations
  46. GRB 260511B: LCO optical observations
  47. GRB 260511B: OHP/T193 spectroscopic observations
  48. GRB 260511B: GOTO optical counterpart detection
  49. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  50. GRB 260511B: SVOM/VT optical observations
  51. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  52. GRB 260509A: SAO RAS optical observations
  53. GRB 260511A: REM near-infrared detection
  54. GRB 260511B: GROWTH-India Telescope optical observations
  55. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  56. GRB 260510B: SVOM/ECLAIRs refined analysis
  57. GRB 260511B SVOM/C-GFT optical counterpart detection
  58. GRB 260511A: UTGO H50 optical afterglow observation
  59. GRB 260510C: SVOM/VT optical counterpart confirmation
  60. EP260509a: EP-FXT non-detection and upper limit
  61. GRB 260511A: SVOM/VT optical observation with VHF data
  62. Fermi GRB 260511A: Global MASTER-Net observations report
  63. GRB 260511A: KAIT optical afterglow observations
  64. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  65. GRB 260510B: SVOM/VT optical upper limits
  66. GRB 260510C: SVOM/VT optical upper limits
  67. EP260509a: Global MASTER-Net observations report
  68. Fermi GBM Sub-Threshold Detection of GRB 260510B
  69. GRB 260510B: GOTO early upper limit
  70. GRB 260509A: Liverpool Telescope optical observations
  71. GRB 260509A: LCO optical observations
  72. SVOM GRB 260509A: MASTER-OAFA optical observation
  73. Fermi GRB 260510A: Global MASTER-Net observations report
  74. GRB 260509A: KAIT optical observations
  75. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  76. GRB 260509A: SVOM/VT optical candidate with VHF data
  77. GRB 260509A: GOTO optical counterpart candidate
  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: SVOM/VT optical observations
  83. EP260507a: NOT optical observations
  84. EP260507a: further Liverpool Telescope observations
  85. EP260507a: Liverpool Telescope optical upper limits
  86. EP260507a: GOTO optical counterpart detection
  87. EP260507a: Kinder optical counterpart candidate
  88. GRB 260504B: SVOM/ECLAIRs refined analysis
  89. EP260502a is likely a flaring star
  90. Fermi GRB 260506A: Global MASTER-Net observations report
  91. IceCube Alert 260505A: Global MASTER-Net observations report
  92. GRB 260504B: SVOM/VT optical upper limits
  93. GRB 260421B: radio observation with the VLA
  94. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  95. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  96. GRB 260504B: REM optical/NIR observations
  97. GRB 260504B: AST3-2 i-band upper limit
  98. SVOM GRB 260504B: MASTER-OAFA optical observations
  99. Fermi GRB 260504A: Global MASTER-Net observations report
  100. GRB 260429B / EP260429a: EP-FXT follow-up observation

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