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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"

21950 results found.

  1. EP250416a: Global MASTER-Net observations report
  2. IceCube-250416A: Global MASTER-Net observations report
  3. IceCube 250414.324: DDOTI Optical Observations
  4. EP250304a: ATCA radio observations
  5. EP250404a: Nanshan 0.43m Telescope optical observatios
  6. Fermi trigger No 766148493: Global MASTER-Net observations report
  7. Fermi trigger No 766173972: Global MASTER-Net observations report
  8. GRB 250411A: DDOTI Optical Observations
  9. Fermi GRB 250411A: Global MASTER-Net observations report
  10. GRB 250407A: Continued KAIT/Nickel optical observations
  11. GRB 250314A: e-MERLIN observations
  12. GRB 250407A: Mondy and AbAO Optical Observations
  13. EP250227a: Further NOT optical observations
  14. IceCube-250406A: Swift-XRT observations
  15. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-250409A
  16. EP250407a: Global MASTER-Net observations report
  17. GRB 250407A: LCO detection of a fading optical counterpart
  18. Fermi-LAT gamma-ray observations of IceCube-250406A
  19. EP250407a: Swift-XRT observations
  20. EP250407a: EP-WXT detection of a fast X-ray transient
  21. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  22. GRB 250407A: KAIT Optical Afterglow Candidate
  23. IceCube-250406A: No candidates from the Zwicky Transient Facility
  24. GRB 250407A: Swift-XRT afterglow detection
  25. Fermi GRB 250407A: Global MASTER-Net observations report
  26. GRB 250407A: Swift ToO observations
  27. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  28. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  29. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  30. IceCube 250406.951: DDOTI Optical Observations
  31. IceCube Alert 250406.95: Global MASTER-Net observations report
  32. Fermi trigger No 765663719: Global MASTER-Net observations report
  33. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  34. Fermi GRB 250406A: Global MASTER-Net observations report
  35. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  36. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  37. Fermi trigger No 765619921: Global MASTER-Net observations report
  38. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  39. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  40. GRB 250404A / EP250404a: Mondy optical observations
  41. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  42. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  43. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  44. EP250402a: Optical upper limit with PD 1.3m observations
  45. GRB 250404A / EP250404a: NOT optical observations
  46. GRB 250331D: Swift-XRT afterglow detection
  47. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  48. EP250404a: REM optical/NIR observations
  49. EP250404a: Seimei/TriCCS optical counterpart detection
  50. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  51. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  52. EP250404a: LCO optical counterpart detection
  53. Fermi GRB 250404A: Global MASTER-Net observations report
  54. EP250404a: Xinglong decaying optical counterpart
  55. GRB 250403A: Montarrenti Observatory optical detection
  56. EP250404a: Global MASTER-Net observations report
  57. GRB 250403A: KAIT optical observations
  58. EP250404a: LAST detection of optical counterpart
  59. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  60. GRB 250403A: Fermi GBM observations
  61. EP250404a: Mephisto multi-band optical detection
  62. EP250321A: J band upper limit by SYSU 80cm telescope
  63. EP250404a: Nanshan/HMT optical counterpart detection
  64. GRB 250402A: Mondy optical observations
  65. EP250402a: Optical upper limit with Kinder observations
  66. GRB 250403A: REM NIR afterglow detection
  67. GRB 250403A: LCO optical counterpart detection
  68. GRB 250403A: JinShan optical observations
  69. GRB 250403A: Optical counterpart detection by LCO.
  70. EP250402a: EP-FXT follow-up observations
  71. GRB 250403A: Swift-XRT observations
  72. GRB 250322A: 10 GHz VLA radio upper limits
  73. Fermi GRB 250403A: Global MASTER-Net observations report
  74. GRB 250403A: GOTO optical counterpart follow-up observations
  75. GRB 250402A: NUTTelA-TAO Early Optical Limits
  76. GRB 250403A: 1.6m Mephisto multi-band optical detection
  77. GRB 250403A: SVOM/C-GFT optical observations
  78. GRB 250403A: GOTO detection of the optical afterglow
  79. GRB 250402A: Swift-XRT observations
  80. GRB 250225B: VLT host galaxy redshift z = 0.950
  81. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  82. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  83. GRB 250402A: REM optical/NIR upper limits
  84. GRB 250402A: LCO optical counterpart detection
  85. GRB 250402A: refined SVOM/MXT data analysis
  86. EP250402a: Einstein Probe detection of a fast X-ray transient
  87. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  88. GRB 250314A: ALMA detection
  89. GRB 250329B: Swift/UVOT Upper Limit
  90. GRB 250329A: Swift/UVOT Upper Limit
  91. GRB 250327B: Swift/UVOT Detection
  92. GRB 250327A: Swift/UVOT Upper Limits
  93. GRB 250327B: Kilonova-Catcher Observations
  94. GRB250331D: AbAO optical observations
  95. GRB 250331C: Swift/UVOT Upper Limits
  96. GRB 250331B: Swift/UVOT Upper Limits
  97. GRB 250328A: AbAO AS-32 Optical Observations
  98. GRB 250219A: NOT candidate host galaxy detection
  99. GRB 250331D: Swift-XRT observations
  100. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)

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