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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

24705 results found.

  1. EP250421a: REM optical upper limit
  2. EP250421A: COLIBRÍ Optical Upper Limit
  3. GRB 250419A: Mondy Continued Optical Observations
  4. GRB 250421B: AstroSat CZTI detection of a bright long burst
  5. EP250421a: Einstein Probe detection of an X-ray transient
  6. EP250421a: Mephisto optical counterpart confirmation
  7. IceCube-Cascade 250414A: Upper limits from a search for additional neutrino events in IceCube
  8. EP250421a: JinShan likely optical counterpart
  9. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  10. GRB 250419A: LCO optical observation
  11. GRB 250419A: JinShan optical observations
  12. GRB 250419A: SVOM/C-GFT optical observations
  13. GRB 250419A: Swift/UVOT Follow up
  14. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  15. GRB 250419A: LCO optical afterglow multi-band observations
  16. GRB 250419A: Mondy and AbAO Optical Observations
  17. GRB 250419A: AKO Optical Afterglow Detection
  18. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  19. GRB 250419A: Swift-XRT refined Analysis
  20. GRB 250419A: KAIT optical afterglow observations
  21. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  22. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  23. GRB 250419A: SVOM detection of a soft burst
  24. EP250416a: Swift/XRT counterpart fading
  25. EP20250416a: Swift/XRT counterpart detection
  26. IceCube-250416A: DDOTI Optical Observations
  27. EP250416a: Gemini South-GMOS optical counterpart
  28. SVOM/sb25041603 is not a GRB
  29. EP250416a: GSP optical upper limit
  30. EP250416a: Einstein Probe detection of an X-ray transient
  31. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  32. SVOM/sb25041603: SVOM detection of an X-ray transient
  33. IceCube 250414.324: DDOTI Optical Observations
  34. GRB 250413A: AstroSat CZTI detection
  35. EP250304a: ATCA radio observations
  36. EP250404a: Nanshan 0.43m Telescope optical observatios
  37. GRB 250411A: DDOTI Optical Observations
  38. Fermi GRB 250411A: Global MASTER-Net observations report
  39. GRB 250407A: Continued KAIT/Nickel optical observations
  40. GRB 250314A: e-MERLIN observations
  41. GRB 250407A: Mondy and AbAO Optical Observations
  42. EP250227a: Further NOT optical observations
  43. GRB 250320B: cubesat Avion detection
  44. IceCube-250406A: Swift-XRT observations
  45. GRB 250407A: LCO detection of a fading optical counterpart
  46. Fermi-LAT gamma-ray observations of IceCube-250406A
  47. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  48. GRB 250407A: SVOM/GRM observation of a bright long burst
  49. GRB 250407A: EP-WXT afterglow detection
  50. EP250407a: EP-WXT detection of a fast X-ray transient
  51. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  52. GRB 250407A: KAIT Optical Afterglow Candidate
  53. IceCube-250406A: No candidates from the Zwicky Transient Facility
  54. GRB 250407A: Fermi GBM Detection
  55. GRB 250407A: Swift-XRT afterglow detection
  56. GRB 250407A: SRG/ART-XC afterglow detection
  57. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  58. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  59. IPN triangulation of GRB 250406B (short/hard)
  60. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  61. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  62. IceCube 250406.951: DDOTI Optical Observations
  63. GRB 250406A: AstroSat CZTI detection
  64. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  65. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  66. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  67. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  68. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  69. Konus-Wind detection of GRB 250404A / EP250404a
  70. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  71. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  72. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  73. EP250402a: Optical upper limit with PD 1.3m observations
  74. GRB 250404A / EP250404a: NOT optical observations
  75. GRB 250331D: Swift-XRT afterglow detection
  76. GRB 250404B: AstroSat CZTI detection of a short burst
  77. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  78. EP250404a: REM optical/NIR observations
  79. EP250404a: Seimei/TriCCS optical counterpart detection
  80. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  81. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  82. EP250404a: LCO optical counterpart detection
  83. EP250404a: Xinglong decaying optical counterpart
  84. GRB 250403A: Montarrenti Observatory optical detection
  85. GRB 250404A: Fermi GBM Detection
  86. GRB 250403A: KAIT optical observations
  87. EP250404a: AKO Optical Afterglow Detection
  88. EP250404a: LAST detection of optical counterpart
  89. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  90. GRB 250403A: Fermi GBM observations
  91. GRB 250327B: VIRT Optical Upper Limit
  92. EP250404a: Mephisto multi-band optical detection
  93. GRB 250331C Swift-BAT refined analysis
  94. GRB 250331B Swift-BAT refined analysis
  95. GRB 250330A Swift-BAT refined analysis
  96. EP250321A: J band upper limit by SYSU 80cm telescope
  97. EP250404a: Nanshan/HMT optical counterpart detection
  98. EP250404a: Einstein Probe detection of an X-ray transient
  99. GRB 250403A: Swift/UVOT Detection
  100. GRB 250402A: Swift/UVOT Upper Limits

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