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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"

28302 results found.

  1. sb25061207: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  2. sb25061218: Swift-XRT observations
  3. EP250612a: refined analysis of the EP-WXT and EP-FXT observations
  4. GRB 250610B: J band upper limit by SYSU 80cm infrared telescope
  5. sb25061207: EP-FXT follow-up observation and afterglow candidate
  6. GRB 250612B: Fermi GBM Observation
  7. EP250612a / GRB 250612B: SVOM/VT optical candidate
  8. GRB 250612C: Fermi GBM Observation
  9. sb25061218: SVOM detection of a X-ray transient
  10. sb25061207: Swift-XRT observations
  11. EP250612a/GRB 250612B: JinShan optical upper limit
  12. sb25061207: SVOM/VT optical counterpart
  13. GRB 250612C: BALROG localization (Fermi Trigger 771432801 / GRB 250612620)
  14. GRB 250610B: Swift-XRT refined Analysis
  15. EP250610a: Upper limit from Fermi-GBM Observations
  16. GRB 250612B: BALROG localization (Fermi Trigger 771424081 / GRB 250612519)
  17. EP250612a: Einstein Probe detection of an X-ray transient
  18. GRB 250610B: MISTRAL/T193 and T120 OHP further observations
  19. sb25061207: SVOM detection of a X-ray transient
  20. GRB 250612A: Swift detection of a burst or new Galactic transient Swift J1643.6-3854
  21. Fermi GBM Sub-Threshold Detection of GRB 250610B
  22. GRB 250610B: Swift/UVOT Detection
  23. EP250610A: Swift/UVOT Upper limits
  24. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  25. EP250610a: TNG NIR upper limit
  26. GRB 250610B: REM optical/NIR observations
  27. EP250610a: Liverpool Telescope optical upper limits
  28. GRB 250610B: additional Liverpool Telescope optical observations
  29. GRB 250610B: SVOM/GRM analysis
  30. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  31. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  32. GRB 250610B: Swift-XRT counterpart detection
  33. GRB 250610B: SVOM/VT optical counterpart
  34. GRB 250610B: OHP/T120 optical counterpart candidate
  35. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  36. EP250610a: refined analysis of the EP-WXT and EP-FXT observations
  37. GRB 250605A: Swift-BAT refined analysis
  38. EP250610a: SVOM/VT optical upper limit
  39. EP250610a: REM optical/NIR observations
  40. GRB 250609A: Fermi GBM Observation
  41. EP250610a: Swift-XRT counterpart detection
  42. EP250610a: COLIBRÍ optical upper limit
  43. EP250610a: Einstein Probe detection of an X-ray transient
  44. Fermi trigger No 771072240: Global MASTER-Net observations report
  45. GRB 250609A: Swift/BAT-GUANO localization skymap of a likely short burst
  46. GRB 250605A: Swift/UVOT Upper Limits
  47. GRB 250527C: CrAO Optical Upper Limit
  48. GRB 250607A: SVOM/GRM observation of a long burst
  49. EP-WXT trigger 01709178244: confirmation of a stellar flare by BOOTES-5 & BOOTES-7
  50. GRB 250605A: Swift-XRT refined Analysis
  51. GRB 250605A: Enhanced Swift-XRT position
  52. GRB 250605A: Swift detection of a burst
  53. IPN triangulation of GRB 250404B
  54. IPN triangulation of GRB 250529A
  55. GRB 250601A: PRIME H band upper limit.
  56. GRB 250601A: PRIME J band upper limit.
  57. GRB 250601A: VLT/FORS2 Optical Observation
  58. GRB 250601A: Fermi GBM Observation
  59. GRB 250602A: DDOTI Optical Follow-Up of the Fermi/LAT Localization
  60. GRB 250603A: Swift/UVOT Upper Limits
  61. GRB 250603A: Swift-XRT refined Analysis
  62. GRB 250603A: Enhanced Swift-XRT position
  63. GRB 250603A: Swift-XRT position and confirmation of GRB nature
  64. GRB 250603A: Swift detection of a burst or new Galactic transient Swift J0839.7-3916
  65. GRB 250602A: Fermi GBM Observation
  66. GRB 250602A: DDOTI Optical Upper Limit
  67. GRB 250530C: Swift-BAT refined analysis
  68. GRB 250601A: Swift/XRT candidate afterglow
  69. GRB 250601A: Swift-XRT observations
  70. GRB 250601A: Swift/BAT-GUANO arcminute localization of a likely short burst
  71. GRB 250601A: Fermi GBM Final Real-time Localization
  72. EP#01709177494: SVOM/VT optical observations
  73. EP#01709177494: Swift-XRT counterpart detection of known source
  74. GRB 250521C/ZTF25aarhkyn/AT2025mgj: COLIBRÍ optical observations
  75. GRB 250530C: Swift-XRT refined Analysis
  76. GRB 250530A: TNG detection of a NIR source inside the Swift/XRT error circle
  77. GRB 250530C: Enhanced Swift-XRT position
  78. GRB 250530C: Swift detection of a burst
  79. GRB 250530A: EP-FXT counterpart detection
  80. GRB 250530A: SVOM/VT optical upper limit
  81. GRB 250530A: Swift-XRT counterpart detection
  82. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate retraction and detection limit
  83. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  84. GRB 250530A: SVOM detection of a burst
  85. GRB 250527C: Swift/UVOT Upper Limits
  86. GRB 250527D: Swift/BAT-GUANO localization skymap of a burst
  87. GRB 250527B: Swift-XRT observations
  88. GRB 250520A: Swift-BAT refined analysis
  89. GRB 250527C: Swift/BAT-GUANO arcminute localization of a burst
  90. GRB 250521D: SVOM/GRM analysis suggests a possible “long” duration type I burst
  91. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  92. EP250526a: refined analysis of the EP-WXT and EP-FXT observations
  93. GRB 250314A: CIDER NB1008 upper limit
  94. EP250526a: COLIBRÍ optical upper limits
  95. EP250526a: Einstein Probe detection of a fast X-ray transient
  96. EP J1350.0-8622: Einstein Probe detection of an X-ray transient candidate
  97. EP-WXT trigger 01709176712: SVOM/C-GFT observations of blue-to-red color variation
  98. GRB 250523A: BALROG localization (Fermi Trigger 769703188 / GRB 250523602)
  99. The EP-WXT trigger 01709176612: SVOM/VT optical observations
  100. EP#01709176612: Swift-XRT counterpart detection of flaring star

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