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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"

20539 results found.

  1. GRB 250430A: AKO Optical Afterglow Detection
  2. GRB 250430A: Kanata optical upper limit
  3. EP 250427A: Optical counterpart detection by LCO.
  4. GRB 250430A: Swift detection of a burst with optical counterpart
  5. EP250427a/GRB250427A: HCT optical follow-up
  6. SVOM/sb25043004: SVOM detection of a X-ray transient
  7. EP250428b: GROWTH-India telescope optical upper limit
  8. EP250428b: SAO RAS optical upper limit
  9. EP250428b: LAST optical upper limit
  10. GRB 250427A: Swift/UVOT Detection
  11. EP250428b: Einstein Probe detection of a fast X-ray transient
  12. EP250427A: COLIBRÍ Continuing Optical Observations
  13. GRB250427A/EP250427a GIT optical afterglow detection:
  14. EP250427a: LT optical counterpart detection
  15. EP250427a / GRB 250427A: LCO optical counterpart detection
  16. EP250427a: REM optical/NIR afterglow detection
  17. GRB 250424A: LCO optical observation
  18. EP250427A: COLIBRÍ Optical Detection
  19. EP250427a: TRT optical counterpart detection
  20. EP 250427a: BOOTES-7 optical afterglow candidate
  21. EP250427a: Einstein Probe detection of a fast X-ray transient
  22. GRB 250424A: SVOM/GRM observation of a long burst
  23. GRB 250424A: PRIME near-infrared detection
  24. GRB 250424A: WINTER J-band detection
  25. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  26. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  27. GRB 250419A: Mondy Optical Observations
  28. GRB 250424A: Swift/UVOT Detection
  29. Konus-Wind detection of GRB 250424A
  30. Fermi-LAT gamma-ray observations of IceCube-250421A
  31. GRB 250424A: Skynet Optical Observations
  32. GRB 250424A: Kilonova-Catcher optical afterglow detection
  33. GRB 250419A: SVOM/ECLAIRs refined analysis
  34. GRB 250424A: Swift-XRT refined Analysis
  35. GRB 250424A: Enhanced Swift-XRT position
  36. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  37. GRB 250424A: BlackGEM optical afterglow detection
  38. GRB 250424A: DDOTI Afterglow Detection
  39. GRB 250424A: REM optical/NIR afterglow detection
  40. GRB 250424A: Swift detection of a burst with an optical counterpart
  41. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  42. EP250421a: Nickel optical upper limit
  43. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  44. SVOM/sb25042207: XRT observations
  45. GRB250419A: VLA radio detection
  46. IceCube-250421A: DDOTI Detection of the LAST Candidate
  47. GRB 250419A: Mephisto Multi-band Optical Detection
  48. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  49. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  50. EP250421a: NOT optical observations
  51. GRB 250419A: Optical Observations via Virtual Telescope Project
  52. EP250421a: REM optical upper limit
  53. EP250421A: COLIBRÍ Optical Upper Limit
  54. GRB 250419A: Mondy Continued Optical Observations
  55. GRB 250421B: AstroSat CZTI detection of a bright long burst
  56. EP250421a: Einstein Probe detection of an X-ray transient
  57. EP250421a: Mephisto optical counterpart confirmation
  58. IceCube-Cascade 250414A: Upper limits from a search for additional neutrino events in IceCube
  59. EP250421a: JinShan likely optical counterpart
  60. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  61. GRB 250419A: LCO optical observation
  62. GRB 250419A: JinShan optical observations
  63. GRB 250419A: SVOM/C-GFT optical observations
  64. GRB 250419A: Swift/UVOT Follow up
  65. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  66. GRB 250419A: LCO optical afterglow multi-band observations
  67. GRB 250419A: Mondy and AbAO Optical Observations
  68. GRB 250419A: AKO Optical Afterglow Detection
  69. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  70. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  71. GRB 250419A: KAIT optical afterglow observations
  72. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  73. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  74. GRB 250419A: SVOM detection of a soft burst
  75. EP250416a: refined EP-WXT and EP-FXT analysis
  76. EP20250416a: Swift/XRT counterpart detection
  77. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  78. IceCube-250416A: DDOTI Optical Observations
  79. EP250416a: Gemini South-GMOS optical counterpart
  80. SVOM/sb25041603 is not a GRB
  81. EP250416a: Einstein Probe detection of an X-ray transient
  82. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  83. IceCube 250414.324: DDOTI Optical Observations
  84. GRB 250413A: AstroSat CZTI detection
  85. GRB 250412A: AstroSat CZTI detection
  86. EP250404a: Nanshan 0.43m Telescope optical observatios
  87. GRB 250411A: DDOTI Optical Observations
  88. GRB 250314A: e-MERLIN observations
  89. GRB 250407A: Mondy and AbAO Optical Observations
  90. EP250227a: Further NOT optical observations
  91. IceCube-250406A: Swift-XRT observations
  92. GRB 250407A: LCO detection of a fading optical counterpart
  93. Fermi-LAT gamma-ray observations of IceCube-250406A
  94. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  95. Konus-Wind detection of GRB 250407A
  96. GRB 250407A: SVOM/GRM observation of a bright long burst
  97. GRB 250407A: EP-WXT afterglow detection
  98. EP250407a: EP-WXT detection of a fast X-ray transient
  99. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  100. GRB 250407A: KAIT Optical Afterglow Candidate

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