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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"

28054 results found.

  1. GRB 260519C: NuSTAR detection of prompt emission
  2. Konus-Wind detection of GRB 260518A
  3. GRB 260516D: SVOM/ECLAIRs refined analysis
  4. GRB 260421B: radio detection with the VLA
  5. GRB 260509A: CrAO ZTSh optical upper limit
  6. GRB 260516D: GOTO optical counterpart detection
  7. GRB 260516D: LCO optical observations
  8. GRB 260515A: further Liverpool Telescope observations
  9. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  10. GRB 260516D: GROWTH-India Telescope optical detection
  11. GRB 260516D: SVOM/VT optical bright candidate
  12. GRB 260515A: CrAO ZTSh BVRI optical observations
  13. Fermi GRB 260516C: Global MASTER-Net observations report
  14. SVOM GRB260516D: Global MASTER-Net observations report
  15. GRB 260516D: SVOM possible detection of a burst
  16. GRB 260515A: LCO optical counterpart detection
  17. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  18. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  19. EP260514a: NOT optical counterpart confirmation
  20. EP260514a: TRT optical counterpart candidate
  21. EP260514a: SVOM/VT optical candidate
  22. Fermi GRB 260516B: Global MASTER-Net observations report
  23. GRB 260515A: OHP/T193 optical observations
  24. EP260514a: COLIBRÍ optical upper limits
  25. GRB 260515A: LCO optical observations
  26. SVOM GRB 260515A: Global MASTER-Net observations report
  27. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  28. GRB 260515A: SVOM/VT optical candidate from VHF data
  29. GRB 260515A: JinShan optical counterpart candidate
  30. GRB 260515A: SVOM detection of a burst
  31. GRB 260510C: Glowbug gamma-ray detection
  32. EP260514a: GROWTH-India Telescope optical upper limit
  33. GRB 260511B: GMG Optical Upper Limit
  34. EP260514a: Global MASTER-Net observations report
  35. EP260514a: Einstein Probe detection of a fast X-ray transient
  36. EP260512a: LCO optical upper limits
  37. GRB 260511B: Mephisto multi-band optical followup
  38. Fermi GRB 260514A: Global MASTER-Net observations report
  39. GRB 260512A: AstroSat CZTI detection
  40. EP260512a: EP-FXT follow-up observation
  41. EP260507a: Xinglong Schmidt optical counterpart detection
  42. EP260512a: Global MASTER-Net observations report
  43. Fermi GRB 260513A: Global MASTER-Net observations report
  44. Fermi GRB 260512A: Global MASTER-Net observations report
  45. GRB 260511B: further SAO RAS optical observations
  46. GRB 260509A: SVOM/VT optical observations
  47. The EP-WXT trigger 01709262036 is likely a flaring star
  48. EP260512a: COLIBRÍ optical upper limits
  49. EP260512a: Einstein Probe detection of an X-ray transient
  50. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  51. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  52. GRB 260512A: NuSTAR detection of prompt emission
  53. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  54. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  55. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  56. GRB 260511A: Glowbug gamma-ray detection
  57. GRB 260511B: SAO RAS optical observations
  58. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  59. GRB 260511B: FRAM-ORM optical detection
  60. GRB 260511A: EP-FXT follow-up observation
  61. GRB 260511B: EP-FXT follow-up observation
  62. GRB 260511B: LCO optical counterpart detection
  63. GRB260511B: MAO/AZT-22 optical observations
  64. GRB 260511B: LCO optical observations
  65. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  66. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  67. GRB 260510B: EP-FXT follow-up observation
  68. GRB 260510C: Fermi GBM Observation
  69. GRB 260509A: SAO RAS optical observations
  70. GRB 260511A: REM near-infrared detection
  71. GRB 260511B: GROWTH-India Telescope optical observations
  72. GRB 260506B: Glowbug gamma-ray detection
  73. GRB 260506A: Glowbug gamma-ray detection of a short burst
  74. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  75. GRB 260511B: NuSTAR detection of prompt emission
  76. GRB 260511A: NuSTAR detection of prompt emission
  77. GRB 260511B: Fermi GBM Detection
  78. GRB 260511B: SVOM/VT optical observation with VHF data
  79. GRB 260511B: TRT optical observation
  80. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  81. GRB 260511A: Fermi GBM Detection
  82. GRB 260511B SVOM/C-GFT optical counterpart detection
  83. EP260509a: LCO optical upper limits
  84. GRB 260511A: UTGO H50 optical afterglow observation
  85. GRB 260511B: SVOM detection of a burst
  86. GRB 260510C: EP-FXT follow-up observation
  87. EP260509a: EP-FXT non-detection and upper limit
  88. GRB 260511A: SVOM/VT optical observation with VHF data
  89. Fermi GRB 260511A: Global MASTER-Net observations report
  90. GRB 260511A: KAIT optical afterglow observations
  91. GRB 260511A: LCO optical afterglow detection
  92. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  93. GRB 260511A: TRT optical counterpart detection
  94. GRB 260511A: SVOM detection of a bright burst
  95. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  96. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  97. GRB 260510C: MAXI/GSC detection
  98. EP260509a: Global MASTER-Net observations report
  99. Fermi GBM Sub-Threshold Detection of GRB 260510B
  100. GRB 260510C: SVOM detection of a burst

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