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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"

36227 results found.

  1. GRB 250419a: Continued Liverpool Telescope observations
  2. GRB 250419A: Liverpool Telescope optical upper limit
  3. GRB 250407A: GRBAlpha detection
  4. GRB 250404A / EP250404a: GRBAlpha detection
  5. GRB 250330B: GRBAlpha detection
  6. GRB 250419A: SVOM/ECLAIRs refined analysis
  7. GRB 250424A: Swift-XRT refined Analysis
  8. GRB 250424A: Enhanced Swift-XRT position
  9. GRB 250424A: AstroSat CZTI detection of a bright long burst
  10. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  11. GRB 250424A: BlackGEM optical afterglow detection
  12. GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
  13. GRB 250424A: likely host galaxy
  14. GRB 250424A: DDOTI Afterglow Detection
  15. GRB 250424A: REM optical/NIR afterglow detection
  16. GRB 250424A: Swift detection of a burst with an optical counterpart
  17. Swift GRB 250424A: Global MASTER-Net observations report
  18. Swift GRB 250424A: Global MASTER-Net OT detection
  19. EP250421a: Nickel optical upper limit
  20. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  21. EP250421a: Upper limits from Fermi-GBM Observations
  22. SVOM/sb25042207: XRT observations
  23. SVOM/sb25042207: GOTO optical upper limits
  24. GRB 250421A: AstroSat CZTI detection
  25. GRB250419A: VLA radio detection
  26. GRB 250419A: Mephisto Multi-band Optical Detection
  27. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  28. GRB 250419A: Optical Observations via Virtual Telescope Project
  29. GRB 250419A: Mondy Continued Optical Observations
  30. Fermi GRB 250421A: Global MASTER-Net observations report
  31. GRB 250421B: AstroSat CZTI detection of a bright long burst
  32. GRB 250421A: Fermi GBM Final Real-time Localization
  33. GRB 250419A: Liverpool Telescope observations
  34. GRB 250419A: LCO optical observation
  35. GRB 250419A: JinShan optical observations
  36. GRB 250419A: SVOM/VT optical continuous observations
  37. GRB 250419A: SVOM/C-GFT optical observations
  38. GRB 250419A: Swift/UVOT Follow up
  39. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  40. GRB 250419A: LCO optical afterglow multi-band observations
  41. GRB 250419A: Mondy and AbAO Optical Observations
  42. GRB 250419A: Liverpool Telescope observations
  43. GRB 250419A: AKO Optical Afterglow Detection
  44. GRB 250419A: MASTER optical afterglow observation
  45. GRB 250407A: rest-frame energetics from Konus-Wind observation
  46. GRB 250419A: Swift-XRT localisation
  47. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  48. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  49. GRB 250419A: Swift-XRT refined Analysis
  50. GRB 250419A: GOTO optical counterpart detection
  51. GRB 250419A: KAIT optical afterglow observations
  52. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  53. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  54. GRB 250419A: SVOM detection of a soft burst
  55. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  56. Konus-Wind detection of GRB 250403A
  57. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  58. SVOM/sb25041603 is not a GRB
  59. Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
  60. Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
  61. GRB 250416B: Fermi GBM Final Real-time Localization
  62. GRB 250416A: Fermi GBM Final Real-time Localization
  63. Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
  64. GRB 250413A: AstroSat CZTI detection
  65. EP250304a: ATCA radio observations
  66. GRB 250412A: AstroSat CZTI detection
  67. GRB 250411A: DDOTI Optical Observations
  68. Fermi GRB 250411A: Global MASTER-Net observations report
  69. GRB 250411A: Fermi GBM Final Real-time Localization
  70. GRB 250407A: Continued KAIT/Nickel optical observations
  71. GRB 250314A: e-MERLIN observations
  72. GRB 250407A: Mondy and AbAO Optical Observations
  73. GRB 250320B: cubesat Avion detection
  74. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  75. IPN triangulation of GRB 250407A
  76. GRB 250407A: LCO detection of a fading optical counterpart
  77. EP250407a: Swift-XRT observations
  78. Konus-Wind detection of GRB 250407A
  79. GRB 250407A: SVOM/GRM observation of a bright long burst
  80. GRB 250407A: EP-WXT afterglow detection
  81. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  82. GRB 250407A: KAIT Optical Afterglow Candidate
  83. GRB 250407A: Fermi GBM Detection
  84. GRB 250407A: Swift-XRT afterglow detection
  85. Fermi GRB 250407A: Global MASTER-Net observations report
  86. GRB 250407A: Swift ToO observations
  87. GRB 250407A: SRG/ART-XC afterglow detection
  88. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  89. Konus-Wind detection of GRB 250406B (short/hard)
  90. IPN triangulation of GRB 250406B (short/hard)
  91. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  92. GRB 250407A: Fermi GBM Final Real-time Localization
  93. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  94. GRB 250406A: AstroSat CZTI detection
  95. Fermi GRB 250406A: Global MASTER-Net observations report
  96. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  97. GRB 250406A: Fermi GBM Final Real-time Localization
  98. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  99. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  100. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit

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