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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"

32692 results found.

  1. GRB 250424A: EIRSAT-1 GMOD Detection
  2. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  4. GRB 250424A: SVOM/VT optical observation
  5. GRB 250419A: Mondy Optical Observations
  6. GRB 250424A: Swift/UVOT Detection
  7. Konus-Wind detection of GRB 250424A
  8. Fermi-LAT gamma-ray observations of IceCube-250421A
  9. GRB 250424A: Skynet Optical Observations
  10. GRB 250424A: Kilonova-Catcher optical afterglow detection
  11. GRB 250419a: Continued Liverpool Telescope observations
  12. GRB 250419A: Liverpool Telescope optical upper limit
  13. GRB 250407A: GRBAlpha detection
  14. GRB 250404A / EP250404a: GRBAlpha detection
  15. GRB 250330B: GRBAlpha detection
  16. GRB 250419A: SVOM/ECLAIRs refined analysis
  17. GRB 250424A: AstroSat CZTI detection of a bright long burst
  18. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  19. GRB 250424A: BlackGEM optical afterglow detection
  20. GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
  21. GRB 250424A: likely host galaxy
  22. GRB 250424A: DDOTI Afterglow Detection
  23. GRB 250424A: REM optical/NIR afterglow detection
  24. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  25. EP250421a: Nickel optical upper limit
  26. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  27. EP250421a: Upper limits from Fermi-GBM Observations
  28. SVOM/sb25042207: XRT observations
  29. SVOM/sb25042207: BOOTES-2 early optical upper limit
  30. SVOM/sb25042207: GOTO optical upper limits
  31. GRB 250421A: AstroSat CZTI detection
  32. GRB250419A: VLA radio detection
  33. IceCube-250421A: DDOTI Detection of the LAST Candidate
  34. GRB 250419A: Mephisto Multi-band Optical Detection
  35. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  36. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  37. EP250421a: NOT optical observations
  38. GRB 250419A: Optical Observations via Virtual Telescope Project
  39. EP250421a: REM optical upper limit
  40. EP250421a: Swift/XRT counterpart detection
  41. EP250421A: COLIBRÍ Optical Upper Limit
  42. GRB 250419A: Mondy Continued Optical Observations
  43. Fermi GRB 250421A: Global MASTER-Net observations report
  44. EP250421a: Global MASTER-Net observations report
  45. EP250421a: Mephisto optical counterpart confirmation
  46. GRB 250419A: Liverpool Telescope observations
  47. GRB 250419A: LCO optical observation
  48. GRB 250419A: JinShan optical observations
  49. GRB 250419A: SVOM/VT optical continuous observations
  50. GRB 250419A: SVOM/C-GFT optical observations
  51. GRB 250419A: Swift/UVOT Follow up
  52. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  53. GRB 250419A: LCO optical afterglow multi-band observations
  54. GRB 250419A: Mondy and AbAO Optical Observations
  55. GRB 250419A: Liverpool Telescope observations
  56. GRB 250419A: AKO Optical Afterglow Detection
  57. GRB 250419A: MASTER optical afterglow observation
  58. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  59. GRB 250407A: rest-frame energetics from Konus-Wind observation
  60. GRB 250419A: Swift-XRT localisation
  61. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  62. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  63. GRB 250419A: Swift-XRT refined Analysis
  64. GRB 250419A: GOTO optical counterpart detection
  65. GRB 250419A: KAIT optical afterglow observations
  66. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  67. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  68. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  69. EP250416a: Swift/XRT counterpart fading
  70. EP250416a: refined EP-WXT and EP-FXT analysis
  71. Konus-Wind detection of GRB 250403A
  72. EP20250416a: Swift/XRT counterpart detection
  73. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  74. IceCube-250416A: DDOTI Optical Observations
  75. EP250416a: Gemini South-GMOS optical counterpart
  76. EP250225a: SVOM/VT optical brightening
  77. SVOM/sb25041603 is not a GRB
  78. EP250416a: GSP optical upper limit
  79. EP250416a: Global MASTER-Net observations report
  80. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  81. GRB 250413A: AstroSat CZTI detection
  82. EP250304a: ATCA radio observations
  83. EP250404a: Nanshan 0.43m Telescope optical observatios
  84. GRB 250411A: DDOTI Optical Observations
  85. Fermi GRB 250411A: Global MASTER-Net observations report
  86. GRB 250407A: Continued KAIT/Nickel optical observations
  87. GRB 250314A: e-MERLIN observations
  88. GRB 250407A: Mondy and AbAO Optical Observations
  89. EP250227a: Further NOT optical observations
  90. GRB 250320B: cubesat Avion detection
  91. IceCube-250406A: Swift-XRT observations
  92. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  93. IPN triangulation of GRB 250407A
  94. EP250407a: Global MASTER-Net observations report
  95. GRB 250407A: LCO detection of a fading optical counterpart
  96. Fermi-LAT gamma-ray observations of IceCube-250406A
  97. EP250407a: Swift-XRT observations
  98. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  99. Konus-Wind detection of GRB 250407A
  100. GRB 250407A: SVOM/GRM observation of a bright long burst

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