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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"

28273 results found.

  1. GRB 250430A: NUTTelA-TAO Early Measurements
  2. GRB 250430A: DDOTI Optical Observations
  3. GRB 250430A: Leavitt Observatory optical upper limit
  4. GRB 250430A: Bassano Bresciano Observatory upper limit
  5. GRB 250430A : MITSuME Akeno optical upper limits
  6. SVOM/sb25043004: EP-FXT observations
  7. EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
  8. GRB 250424A: CALET Gamma-Ray Burst Monitor detection
  9. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 250430A: AKO Optical Afterglow Detection
  12. GRB 250430A: Kanata optical upper limit
  13. EP 250427A: Optical counterpart detection by LCO.
  14. GRB 250430A: Swift detection of a burst with optical counterpart
  15. EP250427a/GRB250427A: HCT optical follow-up
  16. SVOM/sb25043004: SVOM detection of a X-ray transient
  17. EP250428b: GROWTH-India telescope optical upper limit
  18. EP250428b: SAO RAS optical upper limit
  19. EP250428b: LAST optical upper limit
  20. GRB 250427A: Swift/UVOT Detection
  21. EP250428b: Global MASTER-Net observations report
  22. EP250428b: Einstein Probe detection of a fast X-ray transient
  23. Fermi-LAT Gamma-ray Observations of IceCube-250426A
  24. EP250427a: Lesedi optical counterpart detection
  25. EP250427A: COLIBRÍ Continuing Optical Observations
  26. GRB250427A/EP250427a GIT optical afterglow detection:
  27. EP250427a: LT optical counterpart detection
  28. GRB 250427A: Swift-XRT refined Analysis
  29. EP250427a / GRB 250427A: LCO optical counterpart detection
  30. EP250427a: REM optical/NIR afterglow detection
  31. GRB 250424A: LCO optical observation
  32. GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
  33. EP250427A: COLIBRÍ Optical Detection
  34. EP250427a: TRT optical counterpart detection
  35. EP250427a: Einstein Probe detection of a fast X-ray transient
  36. GRB 250424A: Swift-BAT refined analysis
  37. GRB 250424A: SVOM/GRM observation of a long burst
  38. GRB 250424A: PRIME near-infrared detection
  39. GRB 250424A: WINTER J-band detection
  40. GRB 250424A: EIRSAT-1 GMOD Detection
  41. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 250419A: Mondy Optical Observations
  44. GRB 250424A: Swift/UVOT Detection
  45. Fermi-LAT gamma-ray observations of IceCube-250421A
  46. GRB 250424A: Skynet Optical Observations
  47. GRB 250424A: Kilonova-Catcher optical afterglow detection
  48. GRB 250330B: GRBAlpha detection
  49. GRB 250424A: Swift-XRT refined Analysis
  50. GRB 250424A: Enhanced Swift-XRT position
  51. GRB 250424A: AstroSat CZTI detection of a bright long burst
  52. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  53. GRB 250424A: BlackGEM optical afterglow detection
  54. GRB 250424A: DDOTI Afterglow Detection
  55. GRB 250424A: REM optical/NIR afterglow detection
  56. GRB 250424A: Swift detection of a burst with an optical counterpart
  57. Swift GRB 250424A: Global MASTER-Net OT detection
  58. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  59. EP250421a: Nickel optical upper limit
  60. EP250421a: Upper limits from Fermi-GBM Observations
  61. SVOM/sb25042207: SVOM detection of an X-ray transient
  62. IceCube-250421A: DDOTI Detection of the LAST Candidate
  63. GRB 250419A: Mephisto Multi-band Optical Detection
  64. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  65. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  66. EP250421a: NOT optical observations
  67. GRB 250419A: Optical Observations via Virtual Telescope Project
  68. EP250421a: REM optical upper limit
  69. EP250421A: COLIBRÍ Optical Upper Limit
  70. GRB 250419A: Mondy Continued Optical Observations
  71. GRB 250421B: AstroSat CZTI detection of a bright long burst
  72. EP250421a: Einstein Probe detection of an X-ray transient
  73. EP250421a: Mephisto optical counterpart confirmation
  74. IceCube-Cascade 250414A: Upper limits from a search for additional neutrino events in IceCube
  75. EP250421a: JinShan likely optical counterpart
  76. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  77. GRB 250419A: LCO optical observation
  78. GRB 250419A: JinShan optical observations
  79. GRB 250419A: SVOM/C-GFT optical observations
  80. GRB 250419A: Swift/UVOT Follow up
  81. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  82. GRB 250419A: LCO optical afterglow multi-band observations
  83. GRB 250419A: Mondy and AbAO Optical Observations
  84. GRB 250419A: AKO Optical Afterglow Detection
  85. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  86. GRB 250419A: Swift-XRT refined Analysis
  87. GRB 250419A: KAIT optical afterglow observations
  88. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  89. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  90. GRB 250419A: SVOM detection of a soft burst
  91. EP250416a: Swift/XRT counterpart fading
  92. EP20250416a: Swift/XRT counterpart detection
  93. IceCube-250416A: DDOTI Optical Observations
  94. EP250416a: Gemini South-GMOS optical counterpart
  95. SVOM/sb25041603 is not a GRB
  96. EP250416a: GSP optical upper limit
  97. EP250416a: Einstein Probe detection of an X-ray transient
  98. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  99. SVOM/sb25041603: SVOM detection of an X-ray transient
  100. IceCube 250414.324: DDOTI Optical Observations

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