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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"

45947 results found.

  1. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  2. GRB 250419A: SVOM detection of a soft burst
  3. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  4. EP250416a: Swift/XRT counterpart fading
  5. EP250416a: refined EP-WXT and EP-FXT analysis
  6. Konus-Wind detection of GRB 250403A
  7. EP20250416a: Swift/XRT counterpart detection
  8. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  9. IceCube-250416A: DDOTI Optical Observations
  10. EP250416a: Gemini South-GMOS optical counterpart
  11. EP250225a: SVOM/VT optical brightening
  12. SVOM/sb25041603 is not a GRB
  13. EP250416a: GSP optical upper limit
  14. EP250416a: Global MASTER-Net observations report
  15. Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
  16. EP250416a: Einstein Probe detection of an X-ray transient
  17. IceCube-250416A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube-250416A: Global MASTER-Net observations report
  19. Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
  20. GRB 250416B: Fermi GBM Final Real-time Localization
  21. GRB 250416A: Fermi GBM Final Real-time Localization
  22. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  23. SVOM/sb25041603: SVOM detection of an X-ray transient
  24. Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
  25. IceCube 250414.324: DDOTI Optical Observations
  26. GRB 250413A: AstroSat CZTI detection
  27. EP250304a: ATCA radio observations
  28. GRB 250412A: AstroSat CZTI detection
  29. EP250404a: Nanshan 0.43m Telescope optical observatios
  30. Fermi trigger No 766148493: Global MASTER-Net observations report
  31. Fermi trigger No 766173972: Global MASTER-Net observations report
  32. GRB 250411A: DDOTI Optical Observations
  33. Fermi GRB 250411A: Global MASTER-Net observations report
  34. GRB 250411A: Fermi GBM Final Real-time Localization
  35. GRB 250407A: Continued KAIT/Nickel optical observations
  36. GRB 250314A: e-MERLIN observations
  37. GRB 250407A: Mondy and AbAO Optical Observations
  38. EP250227a: Further NOT optical observations
  39. GRB 250320B: cubesat Avion detection
  40. IceCube-250406A: Swift-XRT observations
  41. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  42. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-250409A
  43. IPN triangulation of GRB 250407A
  44. EP250407a: Global MASTER-Net observations report
  45. GRB 250407A: LCO detection of a fading optical counterpart
  46. Fermi-LAT gamma-ray observations of IceCube-250406A
  47. EP250407a: Swift-XRT observations
  48. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  49. Konus-Wind detection of GRB 250407A
  50. GRB 250407A: SVOM/GRM observation of a bright long burst
  51. GRB 250407A: EP-WXT afterglow detection
  52. EP250407a: EP-WXT detection of a fast X-ray transient
  53. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  54. GRB 250407A: KAIT Optical Afterglow Candidate
  55. IceCube-250406A: No candidates from the Zwicky Transient Facility
  56. GRB 250407A: Fermi GBM Detection
  57. GRB 250407A: Swift-XRT afterglow detection
  58. Fermi GRB 250407A: Global MASTER-Net observations report
  59. GRB 250407A: Swift ToO observations
  60. GRB 250407A: SRG/ART-XC afterglow detection
  61. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  62. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  63. Konus-Wind detection of GRB 250406B (short/hard)
  64. IPN triangulation of GRB 250406B (short/hard)
  65. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  66. GRB 250407A: Fermi GBM Final Real-time Localization
  67. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  69. IceCube 250406.951: DDOTI Optical Observations
  70. GRB 250406A: AstroSat CZTI detection
  71. IceCube Alert 250406.95: Global MASTER-Net observations report
  72. Fermi trigger No 765663719: Global MASTER-Net observations report
  73. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  74. Fermi GRB 250406A: Global MASTER-Net observations report
  75. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  76. GRB 250406A: Fermi GBM Final Real-time Localization
  77. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  78. Fermi trigger No 765619921: Global MASTER-Net observations report
  79. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  80. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit
  81. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  82. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  83. Konus-Wind detection of GRB 250404A / EP250404a
  84. GRB 250404A / EP250404a: Mondy optical observations
  85. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  86. GRB 250404A / EP250404a: GMG spectroscopic redshift at z ~ 2.627
  87. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  88. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  89. EP250402a: Optical upper limit with PD 1.3m observations
  90. GRB 250404A / EP250404a: NOT optical observations
  91. GRB 250331D: Swift-XRT afterglow detection
  92. GRB 250404B: AstroSat CZTI detection of a short burst
  93. GRB 250403A: AstroSat CZTI detection
  94. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  95. EP250404a: REM optical/NIR observations
  96. EP250404a: Seimei/TriCCS optical counterpart detection
  97. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  98. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  99. EP250404a: LCO optical counterpart detection
  100. Fermi GRB 250404A: Global MASTER-Net observations report

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