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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"

36341 results found.

  1. GRB 250515A: GOTO candidate optical counterpart
  2. GRB 250515A: Fermi GBM Final Localization
  3. GRB 250424A: COLIBRÍ detection of the associated supernova
  4. Konus-Wind detection of GRB 250512B / EP250512a
  5. GRB 250502A: TESS observations
  6. GRB 250511A: GECAM-A detection of a short burst
  7. GRB 250509A: Swift-BAT refined analysis
  8. Fermi GRB 250512A: Global MASTER-Net observations report
  9. Konus-Wind detection of GRB 250506A
  10. EP250512a/GRB 250512B: REM optical/NIR observations
  11. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  12. GRB 250507B: AstroSat CZTI detection
  13. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  14. EP250512a/GRB 250512B: FTW optical and NIR observations of the counterpart
  15. GRB 250512B/EP250512a: SVOM/VT optical fading
  16. GRB 250512B/EP250512a：SVOM/VT bright optical counterpart
  17. GRB 250507B: GRBAlpha detection
  18. GRB 250506A: GRBAlpha detection
  19. GRB 250512B: SVOM detection of a burst
  20. GRB 250507B: SVOM/GRM observation of a burst
  21. GRB 250512A: Fermi GBM Final Real-time Localization
  22. EP250511a: REM optical/NIR observations
  23. EP250511a: BOOTES-5 optical upper limit
  24. GRB 250510B: Fermi GBM Observation
  25. Fermi GRB 250510C: Global MASTER-Net observations report
  26. Fermi GRB 250510B: Global MASTER-Net observations report
  27. GRB 250510C: Fermi GBM Final Real-time Localization
  28. GRB 250510A: Swift-XRT observations
  29. GRB 250509A: Fermi GBM Observation
  30. GRB 250510A: follow-up observation with EP-FXT
  31. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  32. GRB 250510B: Fermi GBM Final Localization
  33. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  34. GRB 250509A: Swift-XRT refined Analysis
  35. GRB 250510A: SVOM possible detection of a burst
  36. GRB 250507A: J-band observations with WINTER (duplicate submission)
  37. GRB 250507A: J-band observations with WINTER
  38. GRB 250509A: Enhanced Swift-XRT position
  39. GRB 250509A: Prompt enhanced Swift-XRT position
  40. Fermi GRB 250509A: Global MASTER-Net observations report
  41. Swift GRB 250509A: Global MASTER-Net observations report
  42. GRB 250509A: Swift detection of a burst
  43. GRB 250509A: Fermi GBM Final Real-time Localization
  44. GRB 250506A: NOT optical upper limits
  45. EP250508a: KAIT optical upper limit
  46. GRB 250507A: KAIT optical upper limit
  47. GRB 250505B: SVOM/GRM observation of a short burst
  48. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  49. GRB 250506A: GECAM detection
  50. EP250508a: REM optical/NIR observations
  51. GRB 250506A: Swift-XRT afterglow detection
  52. GRB 250506A: SVOM/VT optical upper limit
  53. GRB 250507A: Swift-XRT refined Analysis
  54. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 250506A: Swift/UVOT Upper Limits
  56. GRB 250427B : SVOM detection of a burst through offline search
  57. GRB 250507A: follow-up observation with EP-FXT
  58. GRB 250430A / EP250430a: AstroSat CZTI detection
  59. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  60. GRB 250507A: refined SVOM/MXT data analysis
  61. GRB 250507A: REM optical/NIR observations
  62. GRB 250507A: SVOM/VT optical upper limit
  63. GRB 250506A: Swift-XRT observations
  64. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  65. GRB 250507A: SVOM detection of a long burst
  66. GRB 250506A: Mephisto optical upper limits
  67. GRB 250504A: EIRSAT-1 GMOD Detection
  68. GRB 250506A: Swift ToO observations
  69. GRB 250502A: Bassano Bresciano Observatory upper limit
  70. GRB 250430A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  71. GRB 250506A: Xinglong 2.16m optical upper limit
  72. GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
  73. GRB 250506A: REM optical/NIR upper limits
  74. GRB 250506A: Fermi GBM Observation
  75. GRB 250506A: Swift XRT observations and possible counterpart detection
  76. GRB 250506A: TRT optical observations
  77. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  78. GRB 250506A: SVOM detection of a burst
  79. GRB 250504A: Swift-BAT refined analysis
  80. GRB 250430A: Swift-BAT refined analysis
  81. GRB 250506A: Fermi GBM Final Real-time Localization
  82. GRB 250504A: Swift-XRT refined Analysis
  83. GRB 250504A: VLT/X-shooter upper limits
  84. Fermi GRB 250505A: Global MASTER-Net observations report
  85. GRB 250504A: SVOM/VT upper limit
  86. GRB 250504A: REM optical/NIR observations
  87. GRB 250502A: REM optical/NIR observations
  88. GRB 250505A: Fermi GBM Final Real-time Localization
  89. GRB 250504A: MeerLICHT optical afterglow detection
  90. GRB 250504A: Fermi GBM Observation
  91. GRB 250504A: Enhanced Swift-XRT position
  92. Fermi GRB 250504A: Global MASTER-Net observations report
  93. GRB 250504A: Swift detection of a burst
  94. GRB 250504A: Fermi GBM Final Real-time Localization
  95. GRB 250502A: Swift/UVOT Follow up
  96. GRB 250502A: Mondy and Tien-Shan Optical Observations
  97. GRB 250502A: KAIT optical observations
  98. GRB 250502A: Montarrenti Observatory optical detection
  99. GRB 250502A: Swift-XRT afterglow detection
  100. GRB 250502A: NOT optical observations

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