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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"

37680 results found.

  1. EP250427a / GRB 250427A: LCO optical counterpart detection
  2. EP250427a / GRB 250427A: VLT/X-shooter redshift confirmation z = 1.520
  3. EP250427A/GRB250427A: Keck/LRIS redshift
  4. EP250427a: REM optical/NIR afterglow detection
  5. GRB 250424A: LCO optical observation
  6. GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
  7. GRB 250424A: Swift-BAT refined analysis
  8. IceCube-250426A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 250424A: SVOM/GRM observation of a long burst
  10. GRB 250424A: PRIME near-infrared detection
  11. GRB 250424A: WINTER J-band detection
  12. GRB 250424A: EIRSAT-1 GMOD Detection
  13. GRB 250424A: SVOM/VT optical observation
  14. GRB 250419A: Mondy Optical Observations
  15. GRB 250424A: Swift/UVOT Detection
  16. Konus-Wind detection of GRB 250424A
  17. Fermi-LAT gamma-ray observations of IceCube-250421A
  18. GRB 250424A: Skynet Optical Observations
  19. GRB 250424A: Kilonova-Catcher optical afterglow detection
  20. GRB 250419a: Continued Liverpool Telescope observations
  21. GRB 250419A: Liverpool Telescope optical upper limit
  22. GRB 250407A: GRBAlpha detection
  23. GRB 250404A / EP250404a: GRBAlpha detection
  24. GRB 250330B: GRBAlpha detection
  25. GRB 250419A: SVOM/ECLAIRs refined analysis
  26. GRB 250424A: Swift-XRT refined Analysis
  27. GRB 250424A: Enhanced Swift-XRT position
  28. GRB 250424A: AstroSat CZTI detection of a bright long burst
  29. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  30. GRB 250424A: BlackGEM optical afterglow detection
  31. GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
  32. GRB 250424A: likely host galaxy
  33. GRB 250424A: DDOTI Afterglow Detection
  34. GRB 250424A: REM optical/NIR afterglow detection
  35. GRB 250424A: Swift detection of a burst with an optical counterpart
  36. Swift GRB 250424A: Global MASTER-Net observations report
  37. Swift GRB 250424A: Global MASTER-Net OT detection
  38. EP250421a: Nickel optical upper limit
  39. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  40. EP250421a: Upper limits from Fermi-GBM Observations
  41. SVOM/sb25042207: GOTO optical upper limits
  42. GRB 250421A: AstroSat CZTI detection
  43. GRB250419A: VLA radio detection
  44. GRB 250419A: Mephisto Multi-band Optical Detection
  45. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  46. GRB 250419A: Optical Observations via Virtual Telescope Project
  47. GRB 250419A: Mondy Continued Optical Observations
  48. Fermi GRB 250421A: Global MASTER-Net observations report
  49. GRB 250421B: AstroSat CZTI detection of a bright long burst
  50. IceCube-250421A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 250421A: Fermi GBM Final Real-time Localization
  52. GRB 250419A: Liverpool Telescope observations
  53. GRB 250419A: LCO optical observation
  54. GRB 250419A: JinShan optical observations
  55. GRB 250419A: SVOM/VT optical continuous observations
  56. GRB 250419A: SVOM/C-GFT optical observations
  57. GRB 250419A: Swift/UVOT Follow up
  58. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  59. GRB 250419A: LCO optical afterglow multi-band observations
  60. GRB 250419A: Mondy and AbAO Optical Observations
  61. GRB 250419A: Liverpool Telescope observations
  62. GRB 250419A: AKO Optical Afterglow Detection
  63. GRB 250419A: MASTER optical afterglow observation
  64. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  65. GRB 250407A: rest-frame energetics from Konus-Wind observation
  66. GRB 250419A: Swift-XRT localisation
  67. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  68. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  69. GRB 250419A: Swift-XRT refined Analysis
  70. GRB 250419A: GOTO optical counterpart detection
  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. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  76. Konus-Wind detection of GRB 250403A
  77. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  78. SVOM/sb25041603 is not a GRB
  79. Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
  80. IceCube-250416A - IceCube observation of a high-energy neutrino candidate track-like event
  81. Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
  82. GRB 250416B: Fermi GBM Final Real-time Localization
  83. GRB 250416A: Fermi GBM Final Real-time Localization
  84. Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
  85. GRB 250413A: AstroSat CZTI detection
  86. EP250304a: ATCA radio observations
  87. GRB 250412A: AstroSat CZTI detection
  88. Fermi trigger No 766148493: Global MASTER-Net observations report
  89. Fermi trigger No 766173972: Global MASTER-Net observations report
  90. GRB 250411A: DDOTI Optical Observations
  91. Fermi GRB 250411A: Global MASTER-Net observations report
  92. GRB 250411A: Fermi GBM Final Real-time Localization
  93. GRB 250407A: Continued KAIT/Nickel optical observations
  94. GRB 250314A: e-MERLIN observations
  95. GRB 250407A: Mondy and AbAO Optical Observations
  96. GRB 250320B: cubesat Avion detection
  97. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  98. IPN triangulation of GRB 250407A
  99. GRB 250407A: LCO detection of a fading optical counterpart
  100. Fermi-LAT gamma-ray observations of IceCube-250406A

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