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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').
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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"

36404 results found.

  1. EP 250427A: Optical counterpart detection by LCO.
  2. GRB 250430A: Swift detection of a burst with optical counterpart
  3. EP250427a / GRB 250427A: OHP/T193 continued photometric observations
  4. EP250428b: SAO RAS optical upper limit
  5. GRB 250427A: Swift/UVOT Detection
  6. EP250427a / GRB 250427A: OHP/T193 photometric observations
  7. EP250427a: EP-FXT follow-up observations
  8. EP250427a/GRB 250427A: FTW optical and NIR observations of the counterpart
  9. GRB250427A/EP250427a GIT optical afterglow detection:
  10. GRB 250427A: Swift-XRT refined Analysis
  11. EP250427a / GRB 250427A: LCO optical counterpart detection
  12. EP250427a / GRB 250427A: VLT/X-shooter redshift confirmation z = 1.520
  13. EP250427A/GRB250427A: Keck/LRIS redshift
  14. GRB 250424A: LCO optical observation
  15. GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
  16. GRB 250424A: Swift-BAT refined analysis
  17. GRB 250424A: SVOM/GRM observation of a long burst
  18. GRB 250424A: PRIME near-infrared detection
  19. GRB 250424A: WINTER J-band detection
  20. GRB 250424A: EIRSAT-1 GMOD Detection
  21. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 250424A: SVOM/VT optical observation
  24. GRB 250419A: Mondy Optical Observations
  25. GRB 250424A: Swift/UVOT Detection
  26. Konus-Wind detection of GRB 250424A
  27. GRB 250424A: Skynet Optical Observations
  28. GRB 250424A: Kilonova-Catcher optical afterglow detection
  29. GRB 250419a: Continued Liverpool Telescope observations
  30. GRB 250419A: Liverpool Telescope optical upper limit
  31. GRB 250407A: GRBAlpha detection
  32. GRB 250404A / EP250404a: GRBAlpha detection
  33. GRB 250330B: GRBAlpha detection
  34. GRB 250419A: SVOM/ECLAIRs refined analysis
  35. GRB 250424A: Swift-XRT refined Analysis
  36. GRB 250424A: Enhanced Swift-XRT position
  37. GRB 250424A: AstroSat CZTI detection of a bright long burst
  38. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  39. GRB 250424A: BlackGEM optical afterglow detection
  40. GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
  41. GRB 250424A: likely host galaxy
  42. GRB 250424A: DDOTI Afterglow Detection
  43. GRB 250424A: REM optical/NIR afterglow detection
  44. GRB 250424A: Swift detection of a burst with an optical counterpart
  45. Swift GRB 250424A: Global MASTER-Net observations report
  46. Swift GRB 250424A: Global MASTER-Net OT detection
  47. EP250421a: Nickel optical upper limit
  48. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  49. EP250421a: Upper limits from Fermi-GBM Observations
  50. SVOM/sb25042207: BOOTES-2 early optical upper limit
  51. SVOM/sb25042207: GOTO optical upper limits
  52. GRB 250421A: AstroSat CZTI detection
  53. GRB250419A: VLA radio detection
  54. GRB 250419A: Mephisto Multi-band Optical Detection
  55. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  56. GRB 250419A: Optical Observations via Virtual Telescope Project
  57. GRB 250419A: Mondy Continued Optical Observations
  58. Fermi GRB 250421A: Global MASTER-Net observations report
  59. GRB 250421B: AstroSat CZTI detection of a bright long burst
  60. GRB 250421A: Fermi GBM Final Real-time Localization
  61. GRB 250419A: Liverpool Telescope observations
  62. GRB 250419A: LCO optical observation
  63. GRB 250419A: JinShan optical observations
  64. GRB 250419A: SVOM/VT optical continuous observations
  65. GRB 250419A: SVOM/C-GFT optical observations
  66. GRB 250419A: Swift/UVOT Follow up
  67. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  68. GRB 250419A: LCO optical afterglow multi-band observations
  69. GRB 250419A: Mondy and AbAO Optical Observations
  70. GRB 250419A: Liverpool Telescope observations
  71. GRB 250419A: AKO Optical Afterglow Detection
  72. GRB 250419A: MASTER optical afterglow observation
  73. GRB 250407A: rest-frame energetics from Konus-Wind observation
  74. GRB 250419A: Swift-XRT localisation
  75. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  76. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  77. GRB 250419A: Swift-XRT refined Analysis
  78. GRB 250419A: GOTO optical counterpart detection
  79. GRB 250419A: KAIT optical afterglow observations
  80. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  81. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  82. GRB 250419A: SVOM detection of a soft burst
  83. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  84. Konus-Wind detection of GRB 250403A
  85. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  86. SVOM/sb25041603 is not a GRB
  87. Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
  88. Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
  89. GRB 250416B: Fermi GBM Final Real-time Localization
  90. GRB 250416A: Fermi GBM Final Real-time Localization
  91. Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
  92. GRB 250413A: AstroSat CZTI detection
  93. EP250304a: ATCA radio observations
  94. GRB 250412A: AstroSat CZTI detection
  95. GRB 250411A: DDOTI Optical Observations
  96. Fermi GRB 250411A: Global MASTER-Net observations report
  97. GRB 250411A: Fermi GBM Final Real-time Localization
  98. GRB 250407A: Continued KAIT/Nickel optical observations
  99. GRB 250314A: e-MERLIN observations
  100. GRB 250407A: Mondy and AbAO Optical Observations

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