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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"

32570 results found.

  1. GRB 250424A: REM optical/NIR afterglow detection
  2. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  3. EP250421a: Nickel optical upper limit
  4. EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
  5. EP250421a: Upper limits from Fermi-GBM Observations
  6. SVOM/sb25042207: XRT observations
  7. SVOM/sb25042207: BOOTES-2 early optical upper limit
  8. SVOM/sb25042207: GOTO optical upper limits
  9. GRB 250421A: AstroSat CZTI detection
  10. GRB250419A: VLA radio detection
  11. IceCube-250421A: DDOTI Detection of the LAST Candidate
  12. GRB 250419A: Mephisto Multi-band Optical Detection
  13. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  14. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  15. EP250421a: NOT optical observations
  16. GRB 250419A: Optical Observations via Virtual Telescope Project
  17. EP250421a: REM optical upper limit
  18. EP250421a: Swift/XRT counterpart detection
  19. EP250421A: COLIBRÍ Optical Upper Limit
  20. GRB 250419A: Mondy Continued Optical Observations
  21. Fermi GRB 250421A: Global MASTER-Net observations report
  22. EP250421a: Global MASTER-Net observations report
  23. EP250421a: Mephisto optical counterpart confirmation
  24. GRB 250419A: Liverpool Telescope observations
  25. GRB 250419A: LCO optical observation
  26. GRB 250419A: JinShan optical observations
  27. GRB 250419A: SVOM/VT optical continuous observations
  28. GRB 250419A: SVOM/C-GFT optical observations
  29. GRB 250419A: Swift/UVOT Follow up
  30. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  31. GRB 250419A: LCO optical afterglow multi-band observations
  32. GRB 250419A: Mondy and AbAO Optical Observations
  33. GRB 250419A: Liverpool Telescope observations
  34. GRB 250419A: AKO Optical Afterglow Detection
  35. GRB 250419A: MASTER optical afterglow observation
  36. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  37. GRB 250407A: rest-frame energetics from Konus-Wind observation
  38. GRB 250419A: Swift-XRT localisation
  39. GRB 250407A: GTC/OSIRIS+ spectroscopic redshift z = 1.36
  40. GRB 250419A: VLT/X-shooter spectroscopic redshift z = 0.845
  41. GRB 250419A: Swift-XRT refined Analysis
  42. GRB 250419A: GOTO optical counterpart detection
  43. GRB 250419A: KAIT optical afterglow observations
  44. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  45. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  46. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  47. EP250416a: Swift/XRT counterpart fading
  48. EP250416a: refined EP-WXT and EP-FXT analysis
  49. Konus-Wind detection of GRB 250403A
  50. EP20250416a: Swift/XRT counterpart detection
  51. GRB 250403A: VLT/FORS2 spectroscopic redshift z = 1.847
  52. IceCube-250416A: DDOTI Optical Observations
  53. EP250416a: Gemini South-GMOS optical counterpart
  54. EP250225a: SVOM/VT optical brightening
  55. SVOM/sb25041603 is not a GRB
  56. EP250416a: GSP optical upper limit
  57. EP250416a: Global MASTER-Net observations report
  58. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  59. GRB 250413A: AstroSat CZTI detection
  60. EP250304a: ATCA radio observations
  61. EP250404a: Nanshan 0.43m Telescope optical observatios
  62. GRB 250411A: DDOTI Optical Observations
  63. Fermi GRB 250411A: Global MASTER-Net observations report
  64. GRB 250407A: Continued KAIT/Nickel optical observations
  65. GRB 250314A: e-MERLIN observations
  66. GRB 250407A: Mondy and AbAO Optical Observations
  67. EP250227a: Further NOT optical observations
  68. GRB 250320B: cubesat Avion detection
  69. IceCube-250406A: Swift-XRT observations
  70. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  71. IPN triangulation of GRB 250407A
  72. EP250407a: Global MASTER-Net observations report
  73. GRB 250407A: LCO detection of a fading optical counterpart
  74. Fermi-LAT gamma-ray observations of IceCube-250406A
  75. EP250407a: Swift-XRT observations
  76. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  77. Konus-Wind detection of GRB 250407A
  78. GRB 250407A: SVOM/GRM observation of a bright long burst
  79. GRB 250407A: EP-WXT afterglow detection
  80. EP250407a: EP-WXT detection of a fast X-ray transient
  81. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  82. GRB 250407A: KAIT Optical Afterglow Candidate
  83. IceCube-250406A: No candidates from the Zwicky Transient Facility
  84. GRB 250407A: Fermi GBM Detection
  85. GRB 250407A: Swift-XRT afterglow detection
  86. Fermi GRB 250407A: Global MASTER-Net observations report
  87. GRB 250407A: Swift ToO observations
  88. GRB 250407A: SRG/ART-XC afterglow detection
  89. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  90. Konus-Wind detection of GRB 250406B (short/hard)
  91. IPN triangulation of GRB 250406B (short/hard)
  92. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  93. GRB 250406A: AstroSat CZTI detection
  94. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  95. Fermi GRB 250406A: Global MASTER-Net observations report
  96. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  97. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  98. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit
  99. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  100. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope

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