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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"

20542 results found.

  1. EP250407a: EP-WXT detection of a fast X-ray transient
  2. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  3. GRB 250407A: KAIT Optical Afterglow Candidate
  4. IceCube-250406A: No candidates from the Zwicky Transient Facility
  5. GRB 250407A: Swift-XRT afterglow detection
  6. GRB 250407A: SRG/ART-XC afterglow detection
  7. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  8. IPN triangulation of GRB 250406B (short/hard)
  9. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  10. IceCube 250406.951: DDOTI Optical Observations
  11. GRB 250406A: AstroSat CZTI detection
  12. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  13. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  14. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  15. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  16. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  17. Konus-Wind detection of GRB 250404A / EP250404a
  18. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  19. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  20. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  21. EP250402a: Optical upper limit with PD 1.3m observations
  22. GRB 250404A / EP250404a: NOT optical observations
  23. GRB 250331D: Swift-XRT afterglow detection
  24. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  25. EP250404a: REM optical/NIR observations
  26. EP250404a: Seimei/TriCCS optical counterpart detection
  27. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  28. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  29. EP250404a: LCO optical counterpart detection
  30. EP250404a: Xinglong decaying optical counterpart
  31. GRB 250403A: Montarrenti Observatory optical detection
  32. GRB 250403A: KAIT optical observations
  33. EP250404a: AKO Optical Afterglow Detection
  34. EP250404a: LAST detection of optical counterpart
  35. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  36. GRB 250327B: VIRT Optical Upper Limit
  37. EP250404a: Mephisto multi-band optical detection
  38. EP250321A: J band upper limit by SYSU 80cm telescope
  39. EP250404a: BOOTES-4/JGT optical afterglow detection
  40. EP250404a: Nanshan/HMT optical counterpart detection
  41. EP250404a: Einstein Probe detection of an X-ray transient
  42. GRB 250404A: Fermi GBM Final Real-time Localization
  43. GRB 250403A: Swift/UVOT Detection
  44. GRB 250402A: Swift/UVOT Upper Limits
  45. EP250402a: Optical upper limit with Kinder observations
  46. GRB 250403A: REM NIR afterglow detection
  47. GRB 250403A: LCO optical counterpart detection
  48. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  49. GRB 250403A: JinShan optical observations
  50. GRB 250403A: Optical counterpart detection by LCO.
  51. GRB 250322A: 10 GHz VLA radio upper limits
  52. GRB 250402A: NUTTelA-TAO Early Optical Limits
  53. GRB 250403A: GMG Optical Observation
  54. GRB 250403A: 1.6m Mephisto multi-band optical detection
  55. GRB 250403A: SVOM/C-GFT optical observations
  56. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  57. GRB 250402A: REM optical/NIR upper limits
  58. GRB 250402A: LCO optical counterpart detection
  59. EP250402a: Einstein Probe detection of a fast X-ray transient
  60. GRB 250402A: SVOM/VT optical counterpart
  61. GRB 250402A: SVOM detection of a burst
  62. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  63. GRB 250329B: Swift/UVOT Upper Limit
  64. GRB 250329A: Swift/UVOT Upper Limit
  65. GRB 250327B: Swift/UVOT Detection
  66. GRB 250327A: Swift/UVOT Upper Limits
  67. GRB 250331E: SVOM/GRM observation
  68. GRB 250327B: Kilonova-Catcher Observations
  69. GRB250331D: AbAO optical observations
  70. GRB 250331C: Swift/UVOT Upper Limits
  71. GRB 250331B: Swift/UVOT Upper Limits
  72. GRB 250328A: AbAO AS-32 Optical Observations
  73. GRB 250219A: NOT candidate host galaxy detection
  74. GRB 250331D: Swift-XRT observations
  75. GRB 250331B: Swift-XRT refined Analysis
  76. GRB 250331B: Swift-XRT refined Analysis
  77. GRB 250330B: SVOM/GRM observation of a short burst
  78. Fermi GRB 250331E: Global MASTER-Net observations report
  79. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  80. GRB 250331C: Enhanced Swift-XRT position
  81. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  82. GRB 250331B: Enhanced Swift-XRT position
  83. GRB 250320C : SVOM detection of a burst through offline search
  84. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  85. GRB 250330A: VLT/FORS2 Afterglow Detection
  86. GRB20250327B: 45th Parallel Observatory upper limit
  87. GRB 250328A: Swift/UVOT Detection
  88. GRB 250328A: Swift-XRT refined Analysis
  89. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  90. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  91. GRB 250331C: Swift detection of a burst
  92. GRB 250331B: Swift detection of a burst
  93. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  94. GRB 250330A: Swift/UVOT Upper Limits
  95. GRB 250330A: Swift-XRT afterglow detection
  96. GRB 250328A: 1.6m Mephisto optical observations
  97. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  98. GRB 250330A: VLT/FORS2 Optical Observations
  99. GRB 250330A: Prompt Swift-XRT position
  100. GRB 250329B: Swift-XRT afterglow detection

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