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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"

28100 results found.

  1. GRB 250521B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  2. GRB 250521D: LAST tentative optical counterpart candidate
  3. GRB 250521A: DDOTI Optical Upper Limit
  4. GRB 250520A: VLT/FORS2 Optical Observation
  5. GRB 250502A: Tautenburg observations
  6. GRB 250520A: Swift/UVOT Upper Limits
  7. IPN triangulation of GRB 250516B
  8. GRB 250520A: J-band observations with WINTER
  9. GRB 250520A: Gemini-South optical observations
  10. GRB 250520A: Swift-XRT refined Analysis
  11. GRB 250520A: REM optical/NIR early observations
  12. GRB 250520A:SVOM/VT optical candidate
  13. GRB 250520A: COLIBRÍ optical upper limit
  14. GRB 250520A: DDOTI Optical Upper Limit
  15. GRB 250520A: AstroSat CZTI detection of a short burst
  16. GRB 250520A: Enhanced Swift-XRT position
  17. GRB 250520A: Swift detection of a burst
  18. GRB 250516A: Swift-BAT refined analysis
  19. GRB 250516A: COLIBRÍ optical upper limit
  20. EP-WXT trigger (ID: 01709176312): a new X-ray outburst of HMXB RX J0111.2-7317
  21. GRB 250515A: Swift-XRT observations
  22. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  23. GRB 250515A: 1.6m Mephisto optical detection
  24. GRB 250516A: Fermi GBM Observation
  25. GRB 250516A: Swift-XRT refined Analysis
  26. GRB 250516A: Swift/UVOT Detection
  27. GRB 250516B: GECAM-B detection of a bright long burst
  28. GRB 250516A: Enhanced Swift-XRT position
  29. GRB 250516A: Swift detection of a burst
  30. MAXI GRB250515.65: Global MASTER-Net observations report
  31. GRB 250424A: COLIBRÍ detection of the associated supernova
  32. GRB 250502A: TESS observations
  33. GRB 250509A: Swift-BAT refined analysis
  34. Fermi GRB 250512A: Global MASTER-Net observations report
  35. EP250512a/GRB 250512B: REM optical/NIR observations
  36. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  37. GRB 250507B: AstroSat CZTI detection
  38. EP250511a: Gemini optical counterpart observation
  39. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  40. EP250511a: Mephisto optical upper limits
  41. GRB 250512B: SVOM detection of a burst
  42. EP250512a: Einstein Probe detection of an X-ray transient
  43. EP250511a: REM optical/NIR observations
  44. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  45. EP250511a: COLIBRÍ optical counterpart candidate
  46. EP250511a: BOOTES-5 optical upper limit
  47. EP250511a: Einstein Probe detection of an X-ray transient
  48. EP250508a: Gemini NIR upper limits
  49. GRB 250510B: Fermi GBM Observation
  50. GRB 250510A: Swift-XRT observations
  51. GRB 250509A: Fermi GBM Observation
  52. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  53. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  54. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  55. GRB 250509A: Swift-XRT refined Analysis
  56. GRB 250510A: SVOM possible detection of a burst
  57. GRB 250507A: J-band observations with WINTER
  58. GRB 250509A: Enhanced Swift-XRT position
  59. GRB 250509A: Swift detection of a burst
  60. GRB 250506A: NOT optical upper limits
  61. EP250508a: Liverpool Telescope optical upper limits
  62. EP250508a: KAIT optical upper limit
  63. GRB 250507A: KAIT optical upper limit
  64. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  65. GRB 250505B: SVOM/GRM observation of a short burst
  66. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  67. EP250508a: REM optical/NIR observations
  68. GRB 250506A: Swift-XRT afterglow detection
  69. EP250508a: COLIBRÍ Optical Limit
  70. EP250508a: Einstein Probe detection of an X-ray transient
  71. GRB 250507A: Swift-XRT refined Analysis
  72. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  73. GRB 250506A: Swift/UVOT Upper Limits
  74. GRB 250507A: follow-up observation with EP-FXT
  75. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  76. GRB 250507A: REM optical/NIR observations
  77. GRB 250507A: SVOM/VT optical upper limit
  78. GRB 250506A: Swift-XRT observations
  79. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  80. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  81. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  82. GRB 250507A: SVOM detection of a long burst
  83. GRB 250506A: Mephisto optical upper limits
  84. GRB 250504A: EIRSAT-1 GMOD Detection
  85. GRB 250502A: Bassano Bresciano Observatory upper limit
  86. GRB 250506A: Xinglong 2.16m optical upper limit
  87. SVOM/sb25050601: EP-FXT observations
  88. GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
  89. GRB 250506A: REM optical/NIR upper limits
  90. GRB 250506A: Fermi GBM Observation
  91. GRB 250506A: Swift XRT observations and possible counterpart detection
  92. GRB 250506A: TRT optical observations
  93. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  94. GRB 250506A: SVOM detection of a burst
  95. GRB 250504A: Swift-BAT refined analysis
  96. GRB 250430A: Swift-BAT refined analysis
  97. GRB 250504A: Swift-XRT refined Analysis
  98. GRB 250504A: VLT/X-shooter upper limits
  99. GRB 250504A: REM optical/NIR observations
  100. GRB 250502A: REM optical/NIR observations

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