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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.

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

28282 results found.

  1. Fermi GBM Sub-Threshold Detection of GRB 250610B
  2. GRB 250610B: Swift/UVOT Detection
  3. EP250610A: Swift/UVOT Upper limits
  4. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  5. EP250610a: TNG NIR upper limit
  6. GRB 250610B: REM optical/NIR observations
  7. EP250610a: Liverpool Telescope optical upper limits
  8. GRB 250610B: additional Liverpool Telescope optical observations
  9. GRB 250610B: SVOM/GRM analysis
  10. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  11. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  12. GRB 250610B: Swift-XRT counterpart detection
  13. GRB 250610B: SVOM/VT optical counterpart
  14. GRB 250610B: OHP/T120 optical counterpart candidate
  15. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  16. EP250610a: refined analysis of the EP-WXT and EP-FXT observations
  17. GRB 250605A: Swift-BAT refined analysis
  18. EP250610a: SVOM/VT optical upper limit
  19. EP250610a: REM optical/NIR observations
  20. GRB 250609A: Fermi GBM Observation
  21. EP250610a: Swift-XRT counterpart detection
  22. EP250610a: COLIBRÍ optical upper limit
  23. EP250610a: Einstein Probe detection of an X-ray transient
  24. Fermi trigger No 771072240: Global MASTER-Net observations report
  25. GRB 250609A: Swift/BAT-GUANO localization skymap of a likely short burst
  26. GRB 250605A: Swift/UVOT Upper Limits
  27. GRB 250527C: CrAO Optical Upper Limit
  28. GRB 250607A: SVOM/GRM observation of a long burst
  29. EP-WXT trigger 01709178244: confirmation of a stellar flare by BOOTES-5 & BOOTES-7
  30. GRB 250605A: Swift-XRT refined Analysis
  31. GRB 250605A: Enhanced Swift-XRT position
  32. GRB 250605A: Swift detection of a burst
  33. IPN triangulation of GRB 250404B
  34. IPN triangulation of GRB 250529A
  35. GRB 250601A: PRIME H band upper limit.
  36. GRB 250601A: PRIME J band upper limit.
  37. GRB 250601A: VLT/FORS2 Optical Observation
  38. GRB 250601A: Fermi GBM Observation
  39. GRB 250602A: DDOTI Optical Follow-Up of the Fermi/LAT Localization
  40. GRB 250603A: Swift/UVOT Upper Limits
  41. GRB 250603A: Swift-XRT refined Analysis
  42. GRB 250603A: Enhanced Swift-XRT position
  43. GRB 250603A: Swift-XRT position and confirmation of GRB nature
  44. GRB 250603A: Swift detection of a burst or new Galactic transient Swift J0839.7-3916
  45. GRB 250602A: Fermi GBM Observation
  46. GRB 250602A: DDOTI Optical Upper Limit
  47. GRB 250530C: Swift-BAT refined analysis
  48. GRB 250601A: Swift/XRT candidate afterglow
  49. GRB 250601A: Swift-XRT observations
  50. GRB 250601A: Swift/BAT-GUANO arcminute localization of a likely short burst
  51. GRB 250601A: Fermi GBM Final Real-time Localization
  52. EP#01709177494: SVOM/VT optical observations
  53. EP#01709177494: Swift-XRT counterpart detection of known source
  54. GRB 250521C/ZTF25aarhkyn/AT2025mgj: COLIBRÍ optical observations
  55. GRB 250530C: Swift-XRT refined Analysis
  56. GRB 250530A: TNG detection of a NIR source inside the Swift/XRT error circle
  57. GRB 250530C: Enhanced Swift-XRT position
  58. GRB 250530C: Swift detection of a burst
  59. GRB 250530A: EP-FXT counterpart detection
  60. GRB 250530A: SVOM/VT optical upper limit
  61. GRB 250530A: Swift-XRT counterpart detection
  62. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate retraction and detection limit
  63. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  64. GRB 250530A: SVOM detection of a burst
  65. GRB 250527C: Swift/UVOT Upper Limits
  66. GRB 250527D: Swift/BAT-GUANO localization skymap of a burst
  67. GRB 250527B: Swift-XRT observations
  68. GRB 250520A: Swift-BAT refined analysis
  69. GRB 250527C: Swift/BAT-GUANO arcminute localization of a burst
  70. GRB 250521D: SVOM/GRM analysis suggests a possible “long” duration type I burst
  71. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  72. EP250526a: refined analysis of the EP-WXT and EP-FXT observations
  73. GRB 250314A: CIDER NB1008 upper limit
  74. EP250526a: COLIBRÍ optical upper limits
  75. EP250526a: Einstein Probe detection of a fast X-ray transient
  76. EP J1350.0-8622: Einstein Probe detection of an X-ray transient candidate
  77. EP-WXT trigger 01709176712: SVOM/C-GFT observations of blue-to-red color variation
  78. GRB 250523A: BALROG localization (Fermi Trigger 769703188 / GRB 250523602)
  79. The EP-WXT trigger 01709176612: SVOM/VT optical observations
  80. EP#01709176612: Swift-XRT counterpart detection of flaring star
  81. GRB 250521D: DDOTI Optical Upper Limit
  82. GRB 250521B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 250521D: LAST tentative optical counterpart candidate
  84. GRB 250521A: DDOTI Optical Upper Limit
  85. GRB 250520A: VLT/FORS2 Optical Observation
  86. GRB 250502A: Tautenburg observations
  87. GRB 250520A: Swift/UVOT Upper Limits
  88. IPN triangulation of GRB 250516B
  89. GRB 250520A: J-band observations with WINTER
  90. GRB 250520A: Gemini-South optical observations
  91. GRB 250520A: Swift-XRT refined Analysis
  92. GRB 250520A: REM optical/NIR early observations
  93. GRB 250520A：SVOM/VT optical candidate
  94. GRB 250520A: COLIBRÍ optical upper limit
  95. GRB 250520A: DDOTI Optical Upper Limit
  96. GRB 250520A: AstroSat CZTI detection of a short burst
  97. GRB 250520A: Enhanced Swift-XRT position
  98. GRB 250520A: Swift detection of a burst
  99. GRB 250516A: Swift-BAT refined analysis
  100. GRB 250516A: COLIBRÍ optical upper limit

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