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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

18506 results found.

  1. IPN triangulation of GRB 250404B
  2. IPN triangulation of GRB 250529A
  3. The EP-WXT trigger 01709177837 is likely a flaring star
  4. GRB 250601A: PRIME H band upper limit.
  5. GRB 250601A: PRIME J band upper limit.
  6. GRB 250601A: VLT/FORS2 Optical Observation
  7. GRB 250602A: DDOTI Optical Follow-Up of the Fermi/LAT Localization
  8. GRB 250603A: Swift/UVOT Upper Limits
  9. GRB 250603A: Enhanced Swift-XRT position
  10. GRB 250603A: Swift-XRT position and confirmation of GRB nature
  11. GRB 250603A: Swift detection of a burst or new Galactic transient Swift J0839.7-3916
  12. GRB 250602A: DDOTI Optical Upper Limit
  13. GRB 250601A: EP-FXT follow-up observation and afterglow candidates
  14. EP#01709177494: SVOM/VT optical observations
  15. GRB 250521C/ZTF25aarhkyn/AT2025mgj: COLIBRÍ optical observations
  16. GRB 250530C: Swift-XRT refined Analysis
  17. GRB 250530A: TNG detection of a NIR source inside the Swift/XRT error circle
  18. GRB 250530C: Enhanced Swift-XRT position
  19. GRB 250530C: Swift detection of a burst
  20. GRB 250530A: EP-FXT counterpart detection
  21. GRB 250530A: SVOM/VT optical upper limit
  22. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate retraction and detection limit
  23. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  24. GRB 250530A: SVOM detection of a burst
  25. GRB 250527C: Swift/UVOT Upper Limits
  26. GRB 250527D: Swift/BAT-GUANO localization skymap of a burst
  27. EP J1350.0-8622: EP-FXT follow-up observation
  28. GRB 250527B: Swift-XRT observations
  29. The EP-WXT trigger 01709177124 is likely a flaring star
  30. EP250526a: refined analysis of the EP-WXT and EP-FXT observations
  31. EP250526a: COLIBRÍ optical upper limits
  32. EP250526a: Einstein Probe detection of a fast X-ray transient
  33. EP J1350.0-8622: Einstein Probe detection of an X-ray transient candidate
  34. EP-WXT trigger 01709176712: SVOM/C-GFT observations of blue-to-red color variation
  35. The EP-WXT trigger 01709176712 is likely a flaring star
  36. The EP-WXT trigger 01709176612: SVOM/VT optical observations
  37. GRB 250521B: EP-FXT follow-up observation and afterglow candidates
  38. GRB 250521D: DDOTI Optical Upper Limit
  39. The EP-WXT trigger 01709176612 is likely a flaring star
  40. GRB 250521B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  41. GRB 250521D: LAST tentative optical counterpart candidate
  42. GRB 250521A: DDOTI Optical Upper Limit
  43. GRB 250520A: VLT/FORS2 Optical Observation
  44. GRB 250502A: Tautenburg observations
  45. GRB 250520A: Swift/UVOT Upper Limits
  46. IPN triangulation of GRB 250516B
  47. GRB 250520A: J-band observations with WINTER
  48. GRB 250520A: Gemini-South optical observations
  49. GRB 250520A: Swift-XRT refined Analysis
  50. GRB 250520A: REM optical/NIR early observations
  51. GRB 250520A：SVOM/VT optical candidate
  52. GRB 250520A: COLIBRÍ optical upper limit
  53. GRB 250520A: DDOTI Optical Upper Limit
  54. GRB 250520A: AstroSat CZTI detection of a short burst
  55. GRB 250520A: Enhanced Swift-XRT position
  56. GRB 250520A: Swift detection of a burst
  57. GRB 250516A: COLIBRÍ optical upper limit
  58. Konus-Wind detection of GRB 250516A
  59. EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
  60. GRB 250515A: Swift-XRT observations
  61. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  62. GRB 250515A: 1.6m Mephisto optical detection
  63. GRB 250516A: AstroSat CZTI detection
  64. GRB 250516A: Swift/UVOT Detection
  65. GRB 250516A: Enhanced Swift-XRT position
  66. GRB 250516A: Swift detection of a burst
  67. GRB 250512B / EP250512a: SVOM/GRM analysis
  68. GRB 250424A: COLIBRÍ detection of the associated supernova
  69. EP250512a/GRB 250512B: REM optical/NIR observations
  70. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  71. EP250511a: Gemini optical counterpart observation
  72. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  73. EP250511a: Mephisto optical upper limits
  74. GRB 250512B: SVOM detection of a burst
  75. EP250512a: Einstein Probe detection of an X-ray transient
  76. EP250511a: REM optical/NIR observations
  77. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  78. EP250511a: COLIBRÍ optical counterpart candidate
  79. EP250511a: Einstein Probe detection of an X-ray transient
  80. EP250508a: Gemini NIR upper limits
  81. Fermi GRB 250510B: Global MASTER-Net observations report
  82. GRB 250510A: Swift-XRT observations
  83. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  84. GRB 250510A: follow-up observation with EP-FXT
  85. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  86. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  87. GRB 250507A: J-band observations with WINTER
  88. GRB 250509A: Enhanced Swift-XRT position
  89. GRB 250509A: Swift detection of a burst
  90. GRB 250509A: Fermi GBM Final Real-time Localization
  91. GRB 250506A: NOT optical upper limits
  92. EP250508a: Liverpool Telescope optical upper limits
  93. EP250508a: follow-up observation with EP-FXT
  94. EP250508a: KAIT optical upper limit
  95. GRB 250507A: KAIT optical upper limit
  96. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  97. GRB 250505B: SVOM/GRM observation of a short burst
  98. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  99. EP250508a: REM optical/NIR observations
  100. GRB 250506A: Swift-XRT afterglow detection

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