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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"

45757 results found.

  1. GRB 250419A: MASTER optical afterglow observation
  2. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  3. GRB 250407A: rest-frame energetics from Konus-Wind observation
  4. GRB 250419A: Swift-XRT localisation
  5. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  6. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  7. GRB 250419A: Swift-XRT refined Analysis
  8. GRB 250419A: GOTO optical counterpart detection
  9. GRB 250419A: KAIT optical afterglow observations
  10. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  11. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  12. GRB 250419A: SVOM detection of a soft burst
  13. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  14. EP250416a: Swift/XRT counterpart fading
  15. EP250416a: refined EP-WXT and EP-FXT analysis
  16. Konus-Wind detection of GRB 250403A
  17. EP20250416a: Swift/XRT counterpart detection
  18. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  19. IceCube-250416A: DDOTI Optical Observations
  20. EP250416a: Gemini South-GMOS optical counterpart
  21. EP250225a: SVOM/VT optical brightening
  22. SVOM/sb25041603 is not a GRB
  23. EP250416a: GSP optical upper limit
  24. EP250416a: Global MASTER-Net observations report
  25. Fermi Gamma-ray Burst Monitor trigger 766505186/250416588 (GRB 250416A) is not a GRB
  26. EP250416a: Einstein Probe detection of an X-ray transient
  27. IceCube-250416A - IceCube observation of a high-energy neutrino candidate track-like event
  28. IceCube-250416A: Global MASTER-Net observations report
  29. Fermi Gamma-ray Burst Monitor trigger 766511207/250416657 is not a GRB
  30. GRB 250416B: Fermi GBM Final Real-time Localization
  31. GRB 250416A: Fermi GBM Final Real-time Localization
  32. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  33. SVOM/sb25041603: SVOM detection of an X-ray transient
  34. Fermi Gamma-ray Burst Monitor trigger 766474855/250416237 is not a GRB
  35. IceCube 250414.324: DDOTI Optical Observations
  36. GRB 250413A: AstroSat CZTI detection
  37. EP250304a: ATCA radio observations
  38. GRB 250412A: AstroSat CZTI detection
  39. EP250404a: Nanshan 0.43m Telescope optical observatios
  40. Fermi trigger No 766148493: Global MASTER-Net observations report
  41. Fermi trigger No 766173972: Global MASTER-Net observations report
  42. GRB 250411A: DDOTI Optical Observations
  43. Fermi GRB 250411A: Global MASTER-Net observations report
  44. GRB 250411A: Fermi GBM Final Real-time Localization
  45. GRB 250407A: Continued KAIT/Nickel optical observations
  46. GRB 250314A: e-MERLIN observations
  47. GRB 250407A: Mondy and AbAO Optical Observations
  48. EP250227a: Further NOT optical observations
  49. GRB 250320B: cubesat Avion detection
  50. IceCube-250406A: Swift-XRT observations
  51. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  52. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-250409A
  53. IPN triangulation of GRB 250407A
  54. EP250407a: Global MASTER-Net observations report
  55. GRB 250407A: LCO detection of a fading optical counterpart
  56. Fermi-LAT gamma-ray observations of IceCube-250406A
  57. EP250407a: Swift-XRT observations
  58. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  59. Konus-Wind detection of GRB 250407A
  60. GRB 250407A: SVOM/GRM observation of a bright long burst
  61. GRB 250407A: EP-WXT afterglow detection
  62. EP250407a: EP-WXT detection of a fast X-ray transient
  63. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  64. GRB 250407A: KAIT Optical Afterglow Candidate
  65. IceCube-250406A: No candidates from the Zwicky Transient Facility
  66. GRB 250407A: Fermi GBM Detection
  67. GRB 250407A: Swift-XRT afterglow detection
  68. Fermi GRB 250407A: Global MASTER-Net observations report
  69. GRB 250407A: Swift ToO observations
  70. GRB 250407A: SRG/ART-XC afterglow detection
  71. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  72. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  73. Konus-Wind detection of GRB 250406B (short/hard)
  74. IPN triangulation of GRB 250406B (short/hard)
  75. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  76. GRB 250407A: Fermi GBM Final Real-time Localization
  77. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  78. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  79. IceCube 250406.951: DDOTI Optical Observations
  80. GRB 250406A: AstroSat CZTI detection
  81. IceCube Alert 250406.95: Global MASTER-Net observations report
  82. Fermi trigger No 765663719: Global MASTER-Net observations report
  83. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  84. Fermi GRB 250406A: Global MASTER-Net observations report
  85. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  86. GRB 250406A: Fermi GBM Final Real-time Localization
  87. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  88. Fermi trigger No 765619921: Global MASTER-Net observations report
  89. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  90. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit
  91. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  92. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  93. Konus-Wind detection of GRB 250404A / EP250404a
  94. GRB 250404A / EP250404a: Mondy optical observations
  95. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  96. GRB 250404A / EP250404a: GMG spectroscopic redshift at z ~ 2.627
  97. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  98. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  99. EP250402a: Optical upper limit with PD 1.3m observations
  100. GRB 250404A / EP250404a: NOT optical observations

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