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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

42548 results found.

  1. GRB 250521D: LAST tentative optical counterpart candidate
  2. GRB 250520A: 10 GHz VLA radio source
  3. GRB 250521B: Swift ToO observations
  4. GRB 250521D: Fermi GBM Final Real-time Localization
  5. GRB 250521C: Fermi GBM Final Localization
  6. GRB 250521A: DDOTI Optical Upper Limit
  7. GRB 250521B: SVOM detection of a burst through offline search
  8. Konus-Wind detection of GRB 250520A (short/hard)
  9. GRB 250520A: VLT/FORS2 Optical Observation
  10. GRB 250502A: Tautenburg observations
  11. GRB 250520A: Swift/UVOT Upper Limits
  12. GRB 250521A: Fermi GBM Final Real-time Localization
  13. Konus-Wind detection of GRB 250516B
  14. GRB 250520A: J-band observations with WINTER
  15. GRB 250520A: Gemini-South optical observations
  16. GRB 250520A: Swift-XRT refined Analysis
  17. GRB 250520A: REM optical/NIR early observations
  18. GRB 250520B: Fermi GBM Final Real-time Localization
  19. GRB 250520A：SVOM/VT optical candidate
  20. GRB 250520A: COLIBRÍ optical upper limit
  21. GRB 250520A: DDOTI Optical Upper Limit
  22. GRB 250520A: AstroSat CZTI detection of a short burst
  23. GRB 250520A: SVOM/GRM observation
  24. GRB 250520A: Enhanced Swift-XRT position
  25. GRB 250520A: GOTO optical upper limit
  26. GRB 250520A: Prompt enhanced Swift-XRT position
  27. GRB 250520A: Swift detection of a burst
  28. Swift GRB 250520A: Global MASTER-Net observations report
  29. GRB 250516B: Insight-HXMT detection
  30. EP250427a/GRB250427A: VLA Detection of Radio Counterpart
  31. GRB 250516A: Swift-BAT refined analysis
  32. GRB 250516A: COLIBRÍ optical upper limit
  33. Konus-Wind detection of GRB 250516A
  34. GRB 250516B: NuSTAR Detection of the Prompt Emission
  35. EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
  36. Fermi GRB 250516A: Global MASTER-Net observations report
  37. GRB 250515A: Swift-XRT observations
  38. GRB 250515A: NOT classification of GOTO25cqo as a type-Ia SN
  39. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  40. Swift GRB 250516A: Global MASTER-Net observations report
  41. GRB 250515A: 1.6m Mephisto optical detection
  42. GRB 250516A: AstroSat CZTI detection
  43. GRB 250515A/GOTO25cqo: SVOM/VT optical blue color
  44. GRB 250516A: Fermi GBM Observation
  45. GRB 250516A: Swift-XRT refined Analysis
  46. GRB 250516A: Swift/UVOT Detection
  47. GRB 250515A: Swift ToO observations
  48. GRB 250516B: GECAM-B detection of a bright long burst
  49. GRB 250516A: Enhanced Swift-XRT position
  50. GRB 250516A: Swift detection of a burst
  51. GRB 250516A: Fermi GBM Final Real-time Localization
  52. GRB 250512B / EP250512a: SVOM/GRM analysis
  53. GRB 250515A: GOTO candidate optical counterpart
  54. MAXI GRB250515.65: Global MASTER-Net observations report
  55. GRB 250515A: Fermi GBM Final Localization
  56. GRB 250424A: COLIBRÍ detection of the associated supernova
  57. Konus-Wind detection of GRB 250512B / EP250512a
  58. GRB 250502A: TESS observations
  59. Fermi trigger No 768922089: Global MASTER-Net observations report
  60. GRB 250511A: GECAM-A detection of a short burst
  61. GRB 250509A: Swift-BAT refined analysis
  62. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Final Epochs)
  63. Fermi GRB 250512A: Global MASTER-Net observations report
  64. Konus-Wind detection of GRB 250506A
  65. EP250512a/GRB 250512B: REM optical/NIR observations
  66. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  67. GRB 250507B: AstroSat CZTI detection
  68. EP250511a: Gemini optical counterpart observation
  69. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  70. EP250512a/GRB 250512B: FTW optical and NIR observations of the counterpart
  71. EP250512a: Global MASTER-Net observations report
  72. EP250511a: FTW optical and NIR observations
  73. GRB 250512B/EP250512a: SVOM/VT optical fading
  74. GRB 250512B/EP250512a：SVOM/VT bright optical counterpart
  75. EP250511a: Mephisto optical upper limits
  76. GRB 250512B: SVOM detection of a burst
  77. GRB 250507B: SVOM/GRM observation of a burst
  78. EP250512a: Einstein Probe detection of an X-ray transient
  79. GRB 250512A: Fermi GBM Final Real-time Localization
  80. EP250511a: REM optical/NIR observations
  81. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  82. EP250511a: SVOM/VT optical candidate comfirmation
  83. EP250511a: Global MASTER-Net observations report
  84. EP250511a: COLIBRÍ optical counterpart candidate
  85. EP250511a: BOOTES-5 optical upper limit
  86. EP250511a: Einstein Probe detection of an X-ray transient
  87. EP250508a: Gemini NIR upper limits
  88. GRB 250510B: Fermi GBM Observation
  89. Fermi GRB 250510C: Global MASTER-Net observations report
  90. Fermi GRB 250510B: Global MASTER-Net observations report
  91. GRB 250510C: Fermi GBM Final Real-time Localization
  92. GRB 250510A: Swift-XRT observations
  93. GRB 250509A: Fermi GBM Observation
  94. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  95. GRB 250510A: follow-up observation with EP-FXT
  96. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  97. GRB 250510B: Fermi GBM Final Localization
  98. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  99. GRB 250509A: Swift-XRT refined Analysis
  100. GRB 250510A: SVOM possible detection of a burst

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