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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"

18512 results found.

  1. EP250421A: COLIBRÍ Optical Upper Limit
  2. GRB 250419A: Mondy Continued Optical Observations
  3. Fermi GRB 250421A: Global MASTER-Net observations report
  4. EP250421a: Einstein Probe detection of an X-ray transient
  5. EP250421a: Mephisto optical counterpart confirmation
  6. EP250421a: JinShan likely optical counterpart
  7. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  8. GRB 250419A: LCO optical observation
  9. GRB 250419A: JinShan optical observations
  10. GRB 250419A: SVOM/C-GFT optical observations
  11. GRB 250419A: Swift/UVOT Follow up
  12. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  13. GRB 250419A: LCO optical afterglow multi-band observations
  14. GRB 250419A: Mondy and AbAO Optical Observations
  15. GRB 250419A: AKO Optical Afterglow Detection
  16. GRB 250419A: KAIT optical afterglow observations
  17. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  18. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  19. GRB 250419A: SVOM detection of a soft burst
  20. EP250416a: refined EP-WXT and EP-FXT analysis
  21. EP20250416a: Swift/XRT counterpart detection
  22. IceCube-250416A: DDOTI Optical Observations
  23. EP250416a: Gemini South-GMOS optical counterpart
  24. SVOM/sb25041603 is not a GRB
  25. EP250416a: Einstein Probe detection of an X-ray transient
  26. IceCube-250416A: Global MASTER-Net observations report
  27. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  28. IceCube 250414.324: DDOTI Optical Observations
  29. EP250304a: ATCA radio observations
  30. EP250404a: Nanshan 0.43m Telescope optical observatios
  31. GRB 250411A: DDOTI Optical Observations
  32. GRB 250314A: e-MERLIN observations
  33. GRB 250407A: Mondy and AbAO Optical Observations
  34. EP250227a: Further NOT optical observations
  35. IceCube-250406A: Swift-XRT observations
  36. GRB 250407A: LCO detection of a fading optical counterpart
  37. GRB 250407A: SVOM/GRM observation of a bright long burst
  38. GRB 250407A: EP-WXT afterglow detection
  39. EP250407a: EP-WXT detection of a fast X-ray transient
  40. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  41. GRB 250407A: KAIT Optical Afterglow Candidate
  42. IceCube-250406A: No candidates from the Zwicky Transient Facility
  43. GRB 250407A: Swift-XRT afterglow detection
  44. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  45. IPN triangulation of GRB 250406B (short/hard)
  46. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  47. IceCube 250406.951: DDOTI Optical Observations
  48. IceCube Alert 250406.95: Global MASTER-Net observations report
  49. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  50. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  51. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  52. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  53. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  54. Konus-Wind detection of GRB 250404A / EP250404a
  55. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  56. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  57. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  58. EP250402a: Optical upper limit with PD 1.3m observations
  59. GRB 250404A / EP250404a: NOT optical observations
  60. GRB 250331D: Swift-XRT afterglow detection
  61. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  62. EP250404a: REM optical/NIR observations
  63. EP250404a: Seimei/TriCCS optical counterpart detection
  64. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  65. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  66. EP250404a: LCO optical counterpart detection
  67. EP250404a: Xinglong decaying optical counterpart
  68. GRB 250403A: Montarrenti Observatory optical detection
  69. GRB 250403A: KAIT optical observations
  70. EP250404a: AKO Optical Afterglow Detection
  71. EP250404a: LAST detection of optical counterpart
  72. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  73. GRB 250327B: VIRT Optical Upper Limit
  74. EP250404a: Mephisto multi-band optical detection
  75. EP250321A: J band upper limit by SYSU 80cm telescope
  76. EP250404a: Nanshan/HMT optical counterpart detection
  77. EP250404a: Einstein Probe detection of an X-ray transient
  78. GRB 250403A: Swift/UVOT Detection
  79. GRB 250402A: Swift/UVOT Upper Limits
  80. EP250402a: Optical upper limit with Kinder observations
  81. GRB 250403A: REM NIR afterglow detection
  82. GRB 250403A: LCO optical counterpart detection
  83. GRB 250403A: JinShan optical observations
  84. GRB 250402A: EP-FXT afterglow detection
  85. GRB 250403A: Optical counterpart detection by LCO.
  86. EP250402a: EP-FXT follow-up observations
  87. GRB 250403A: GMG Optical Observation
  88. GRB 250403A: 1.6m Mephisto multi-band optical detection
  89. GRB 250403A: SVOM/C-GFT optical observations
  90. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  91. GRB 250402A: REM optical/NIR upper limits
  92. GRB 250402A: LCO optical counterpart detection
  93. The EP-WXT trigger 01709133862 is a flaring star
  94. EP250402a: Einstein Probe detection of a fast X-ray transient
  95. GRB 250402A: SVOM/VT optical counterpart
  96. GRB 250402A: SVOM detection of a burst
  97. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  98. GRB 250329B: Swift/UVOT Upper Limit
  99. GRB 250329A: Swift/UVOT Upper Limit
  100. GRB 250327B: Swift/UVOT Detection

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