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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"

27924 results found.

  1. GRB 250520B: Fermi GBM Final Real-time Localization
  2. GRB 250520A:SVOM/VT optical candidate
  3. GRB 250520A: COLIBRÍ optical upper limit
  4. GRB 250520A: DDOTI Optical Upper Limit
  5. GRB 250520A: AstroSat CZTI detection of a short burst
  6. GRB 250516B: GRBAlpha detection
  7. GRB 250520A: SVOM/GRM observation
  8. GRB 250520A: Enhanced Swift-XRT position
  9. GRB 250520A: GOTO optical upper limit
  10. GRB 250520A: Prompt enhanced Swift-XRT position
  11. GRB 250520A: Swift detection of a burst
  12. Swift GRB 250520A: Global MASTER-Net observations report
  13. GRB 250516B: Insight-HXMT detection
  14. EP250427a/GRB250427A: VLA Detection of Radio Counterpart
  15. GRB 250516A: Swift-BAT refined analysis
  16. Konus-Wind detection of GRB 250516A
  17. GRB 250516B: NuSTAR Detection of the Prompt Emission
  18. EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
  19. GRB 250515A: Swift-XRT observations
  20. Swift GRB 250516A: Global MASTER-Net observations report
  21. GRB 250515A: 1.6m Mephisto optical detection
  22. GRB 250516A: AstroSat CZTI detection
  23. GRB 250516A: Fermi GBM Observation
  24. GRB 250516A: Swift-XRT refined Analysis
  25. GRB 250516A: Swift/UVOT Detection
  26. GRB 250515A: Swift ToO observations
  27. GRB 250516B: GECAM-B detection of a bright long burst
  28. GRB 250516A: Enhanced Swift-XRT position
  29. GRB 250516A: Swift detection of a burst
  30. GRB 250516A: Fermi GBM Final Real-time Localization
  31. GRB 250515A: Fermi GBM Final Localization
  32. GRB 250424A: COLIBRÍ detection of the associated supernova
  33. Konus-Wind detection of GRB 250512B / EP250512a
  34. GRB 250502A: TESS observations
  35. GRB 250511A: GECAM-A detection of a short burst
  36. GRB 250509A: Swift-BAT refined analysis
  37. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Final Epochs)
  38. Konus-Wind detection of GRB 250506A
  39. GRB 250507B: AstroSat CZTI detection
  40. GRB 250507B: GRBAlpha detection
  41. GRB 250506A: GRBAlpha detection
  42. GRB 250512B: SVOM detection of a burst
  43. EP250512a: Einstein Probe detection of an X-ray transient
  44. GRB 250512A: Fermi GBM Final Real-time Localization
  45. EP250511a: BOOTES-5 optical upper limit
  46. EP250511a: Einstein Probe detection of an X-ray transient
  47. GRB 250510B: Fermi GBM Observation
  48. GRB 250510C: Fermi GBM Final Real-time Localization
  49. GRB 250510A: Swift-XRT observations
  50. GRB 250509A: Fermi GBM Observation
  51. GRB 250510A: follow-up observation with EP-FXT
  52. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  53. GRB 250510B: Fermi GBM Final Localization
  54. GRB 250509A: Swift-XRT refined Analysis
  55. GRB 250510A: SVOM possible detection of a burst
  56. GRB 250507A: J-band observations with WINTER
  57. GRB 250509A: Enhanced Swift-XRT position
  58. GRB 250509A: Prompt enhanced Swift-XRT position
  59. Swift GRB 250509A: Global MASTER-Net observations report
  60. GRB 250509A: Swift detection of a burst
  61. GRB 250509A: Fermi GBM Final Real-time Localization
  62. GRB 250506A: NOT optical upper limits
  63. EP250508a: Liverpool Telescope optical upper limits
  64. EP250508a: follow-up observation with EP-FXT
  65. GRB 250506A: GECAM detection
  66. GRB 250506A: Swift-XRT afterglow detection
  67. EP250508a: Einstein Probe detection of an X-ray transient
  68. GRB 250507A: Swift-XRT refined Analysis
  69. GRB 250506A: Swift/UVOT Upper Limits
  70. GRB 250427B : SVOM detection of a burst through offline search
  71. GRB 250430A / EP250430a: AstroSat CZTI detection
  72. EP#01709175213/IGR J19566+0326: Swift-XRT detection
  73. GRB 250506A: Swift-XRT observations
  74. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  75. GRB 250507A: SVOM detection of a long burst
  76. GRB 250504A: EIRSAT-1 GMOD Detection
  77. GRB 250506A: Swift ToO observations
  78. IceCube-250506A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 250430A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  80. GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
  81. GRB 250506A: Swift XRT observations and possible counterpart detection
  82. GRB 250506A: TRT optical observations
  83. GRB 250506A: SVOM detection of a burst
  84. GRB 250504A: Swift-BAT refined analysis
  85. GRB 250430A: Swift-BAT refined analysis
  86. GRB 250506A: Fermi GBM Final Real-time Localization
  87. GRB 250504A: Swift-XRT refined Analysis
  88. GRB 250504A: VLT/X-shooter upper limits
  89. GRB 250504A: SVOM/VT upper limit
  90. GRB 250504A: REM optical/NIR observations
  91. GRB 250505A: Fermi GBM Final Real-time Localization
  92. GRB 250504A: MeerLICHT optical afterglow detection
  93. GRB 250504A: Fermi GBM Observation
  94. GRB 250504A: Enhanced Swift-XRT position
  95. GRB 250504A: Swift detection of a burst
  96. GRB 250504A: Fermi GBM Final Real-time Localization
  97. Swift GRB250504.98: Global MASTER-Net observations report
  98. GRB 250502A: Swift/UVOT Follow up
  99. GRB 250502A: Montarrenti Observatory optical detection
  100. GRB 250502A: Swift-XRT afterglow detection

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