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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"

28125 results found.

  1. GRB 250530A: SVOM/VT optical upper limit
  2. GRB 250530A: Swift-XRT counterpart detection
  3. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate retraction and detection limit
  4. GRB 250530A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  5. GRB 250530A: SVOM detection of a burst
  6. GRB 250527C: Swift/UVOT Upper Limits
  7. GRB 250527D: Swift/BAT-GUANO localization skymap of a burst
  8. GRB 250527B: Swift-XRT observations
  9. GRB 250520A: Swift-BAT refined analysis
  10. GRB 250527C: Swift/BAT-GUANO arcminute localization of a burst
  11. GRB 250521D: SVOM/GRM analysis suggests a possible “long” duration type I burst
  12. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  13. EP250526a: refined analysis of the EP-WXT and EP-FXT observations
  14. GRB 250314A: CIDER NB1008 upper limit
  15. EP250526a: COLIBRÍ optical upper limits
  16. EP250526a: Einstein Probe detection of a fast X-ray transient
  17. EP J1350.0-8622: Einstein Probe detection of an X-ray transient candidate
  18. EP-WXT trigger 01709176712: SVOM/C-GFT observations of blue-to-red color variation
  19. GRB 250523A: BALROG localization (Fermi Trigger 769703188 / GRB 250523602)
  20. The EP-WXT trigger 01709176612: SVOM/VT optical observations
  21. EP#01709176612: Swift-XRT counterpart detection of flaring star
  22. GRB 250521D: DDOTI Optical Upper Limit
  23. GRB 250521B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  24. GRB 250521D: LAST tentative optical counterpart candidate
  25. GRB 250521A: DDOTI Optical Upper Limit
  26. GRB 250520A: VLT/FORS2 Optical Observation
  27. GRB 250502A: Tautenburg observations
  28. GRB 250520A: Swift/UVOT Upper Limits
  29. IPN triangulation of GRB 250516B
  30. GRB 250520A: J-band observations with WINTER
  31. GRB 250520A: Gemini-South optical observations
  32. GRB 250520A: Swift-XRT refined Analysis
  33. GRB 250520A: REM optical/NIR early observations
  34. GRB 250520A：SVOM/VT optical candidate
  35. GRB 250520A: COLIBRÍ optical upper limit
  36. GRB 250520A: DDOTI Optical Upper Limit
  37. GRB 250520A: AstroSat CZTI detection of a short burst
  38. GRB 250520A: Enhanced Swift-XRT position
  39. GRB 250520A: Swift detection of a burst
  40. GRB 250516A: Swift-BAT refined analysis
  41. GRB 250516A: COLIBRÍ optical upper limit
  42. EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
  43. GRB 250515A: Swift-XRT observations
  44. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  45. GRB 250515A: 1.6m Mephisto optical detection
  46. GRB 250516A: Fermi GBM Observation
  47. GRB 250516A: Swift-XRT refined Analysis
  48. GRB 250516A: Swift/UVOT Detection
  49. GRB 250516B: GECAM-B detection of a bright long burst
  50. GRB 250516A: Enhanced Swift-XRT position
  51. GRB 250516A: Swift detection of a burst
  52. MAXI GRB250515.65: Global MASTER-Net observations report
  53. GRB 250424A: COLIBRÍ detection of the associated supernova
  54. GRB 250502A: TESS observations
  55. GRB 250509A: Swift-BAT refined analysis
  56. Fermi GRB 250512A: Global MASTER-Net observations report
  57. EP250512a/GRB 250512B: REM optical/NIR observations
  58. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  59. GRB 250507B: AstroSat CZTI detection
  60. EP250511a: Gemini optical counterpart observation
  61. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  62. EP250511a: Mephisto optical upper limits
  63. GRB 250512B: SVOM detection of a burst
  64. EP250512a: Einstein Probe detection of an X-ray transient
  65. EP250511a: REM optical/NIR observations
  66. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  67. EP250511a: COLIBRÍ optical counterpart candidate
  68. EP250511a: BOOTES-5 optical upper limit
  69. EP250511a: Einstein Probe detection of an X-ray transient
  70. EP250508a: Gemini NIR upper limits
  71. GRB 250510B: Fermi GBM Observation
  72. GRB 250510A: Swift-XRT observations
  73. GRB 250509A: Fermi GBM Observation
  74. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  75. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  77. GRB 250509A: Swift-XRT refined Analysis
  78. GRB 250510A: SVOM possible detection of a burst
  79. GRB 250507A: J-band observations with WINTER
  80. GRB 250509A: Enhanced Swift-XRT position
  81. GRB 250509A: Swift detection of a burst
  82. GRB 250506A: NOT optical upper limits
  83. EP250508a: Liverpool Telescope optical upper limits
  84. EP250508a: KAIT optical upper limit
  85. GRB 250507A: KAIT optical upper limit
  86. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  87. GRB 250505B: SVOM/GRM observation of a short burst
  88. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  89. EP250508a: REM optical/NIR observations
  90. GRB 250506A: Swift-XRT afterglow detection
  91. EP250508a: COLIBRÍ Optical Limit
  92. EP250508a: Einstein Probe detection of an X-ray transient
  93. GRB 250507A: Swift-XRT refined Analysis
  94. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 250506A: Swift/UVOT Upper Limits
  96. GRB 250507A: follow-up observation with EP-FXT
  97. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  98. GRB 250507A: REM optical/NIR observations
  99. GRB 250507A: SVOM/VT optical upper limit
  100. GRB 250506A: Swift-XRT observations

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