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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"

32572 results found.

  1. GRB 250516B: NuSTAR Detection of the Prompt Emission
  2. Fermi GRB 250516A: Global MASTER-Net observations report
  3. GRB 250515A: Swift-XRT observations
  4. GRB 250515A: NOT classification of GOTO25cqo as a type-Ia SN
  5. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  6. Swift GRB 250516A: Global MASTER-Net observations report
  7. GRB 250515A: 1.6m Mephisto optical detection
  8. GRB 250516A: AstroSat CZTI detection
  9. GRB 250515A/GOTO25cqo: SVOM/VT optical blue color
  10. GRB 250516A: Fermi GBM Observation
  11. GRB 250516A: Swift/UVOT Detection
  12. GRB 250515A: Swift ToO observations
  13. GRB 250512B / EP250512a: SVOM/GRM analysis
  14. GRB 250515A: GOTO candidate optical counterpart
  15. GRB 250424A: COLIBRÍ detection of the associated supernova
  16. Konus-Wind detection of GRB 250512B / EP250512a
  17. GRB 250502A: TESS observations
  18. GRB 250509A: Swift-BAT refined analysis
  19. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Final Epochs)
  20. Fermi GRB 250512A: Global MASTER-Net observations report
  21. Konus-Wind detection of GRB 250506A
  22. EP250512a/GRB 250512B: REM optical/NIR observations
  23. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  24. GRB 250507B: AstroSat CZTI detection
  25. EP250511a: Gemini optical counterpart observation
  26. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  27. EP250512a/GRB 250512B: FTW optical and NIR observations of the counterpart
  28. EP250512a: Global MASTER-Net observations report
  29. EP250511a: FTW optical and NIR observations
  30. GRB 250512B/EP250512a: SVOM/VT optical fading
  31. GRB 250512B/EP250512a:SVOM/VT bright optical counterpart
  32. EP250511a: Mephisto optical upper limits
  33. GRB 250506A: GRBAlpha detection
  34. GRB 250512B: SVOM detection of a burst
  35. EP250511a: REM optical/NIR observations
  36. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  37. EP250511a: SVOM/VT optical candidate comfirmation
  38. EP250511a: Global MASTER-Net observations report
  39. EP250511a: COLIBRÍ optical counterpart candidate
  40. EP250511a: BOOTES-5 optical upper limit
  41. EP250508a: Gemini NIR upper limits
  42. GRB 250510B: Fermi GBM Observation
  43. Fermi GRB 250510C: Global MASTER-Net observations report
  44. Fermi GRB 250510B: Global MASTER-Net observations report
  45. GRB 250510A: Swift-XRT observations
  46. GRB 250509A: Fermi GBM Observation
  47. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  48. GRB 250510A: follow-up observation with EP-FXT
  49. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  50. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  51. GRB 250507A: J-band observations with WINTER (duplicate submission)
  52. GRB 250507A: J-band observations with WINTER
  53. EP250508a: SVOM/VT optical candidate fading
  54. Fermi GRB 250509A: Global MASTER-Net observations report
  55. Swift GRB 250509A: Global MASTER-Net observations report
  56. GRB 250506A: NOT optical upper limits
  57. EP250508a: Liverpool Telescope optical upper limits
  58. EP250508a: follow-up observation with EP-FXT
  59. EP250508a: SVOM/VT optical candidate
  60. EP250508a: KAIT optical upper limit
  61. GRB 250507A: KAIT optical upper limit
  62. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  63. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  64. GRB 250506A: GECAM detection
  65. EP250508a: REM optical/NIR observations
  66. EP250508a: Global MASTER-Net observations report
  67. GRB 250506A: SVOM/VT optical upper limit
  68. EP250508a: COLIBRÍ Optical Limit
  69. GRB 250507A: Swift-XRT refined Analysis
  70. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 250506A: Swift/UVOT Upper Limits
  72. GRB 250507A: follow-up observation with EP-FXT
  73. GRB 250430A / EP250430a: AstroSat CZTI detection
  74. EP#01709175213/IGR J19566+0326: Swift-XRT detection
  75. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  76. GRB 250507A: refined SVOM/MXT data analysis
  77. GRB 250507A: REM optical/NIR observations
  78. GRB 250507A: SVOM/VT optical upper limit
  79. GRB 250506A: Swift-XRT observations
  80. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  81. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  82. GRB 250506A: Mephisto optical upper limits
  83. GRB 250504A: EIRSAT-1 GMOD Detection
  84. GRB 250506A: Swift ToO observations
  85. GRB 250502A: Bassano Bresciano Observatory upper limit
  86. GRB 250430A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  87. GRB 250506A: Xinglong 2.16m optical upper limit
  88. SVOM/sb25050601: EP-FXT observations
  89. GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
  90. GRB 250506A: REM optical/NIR upper limits
  91. GRB 250506A: Fermi GBM Observation
  92. GRB 250506A: Swift XRT observations and possible counterpart detection
  93. GRB 250506A: TRT optical observations
  94. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  95. GRB 250504A: Swift-BAT refined analysis
  96. GRB 250430A: Swift-BAT refined analysis
  97. GRB 250504A: VLT/X-shooter upper limits
  98. Fermi GRB 250505A: Global MASTER-Net observations report
  99. GRB 250504A: SVOM/VT upper limit
  100. GRB 250504A: REM optical/NIR observations

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