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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"

3379 results found.

  1. EP250903a: Global MASTER-Net observations report
  2. EP250903a: TRT optical observations
  3. EP250903a: Einstein Probe detection of an X-ray transient
  4. EP 250827B: Detection of supernova counterpart by LCO.
  5. EP/WXT01709201159: GOTO optical follow-up
  6. EP250827b / AT 2025wkm: TRT optical observations
  7. EP250827b: NOT spectroscopic observations and AT 2025wkm classification as a broad-lined type-Ic supernova
  8. GRB 250830B: Swift-XRT afterglow detection
  9. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  10. GRB 250901A: EP-FXT follow-up observation
  11. EP250901a: Swift-XRT observations
  12. EP250831a: NOT optical observations and tentative afterglow candidate
  13. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  14. EP250901a: Mephisto optical upper limits
  15. EP250901a: Global MASTER-Net observations report
  16. EP250901a: Einstein Probe detection of an X-ray transient
  17. EP250831a: EP-FXT follow-up observation
  18. EP250831a: Swift-XRT observations
  19. EP250831a: Global MASTER-Net observations report
  20. EP250831a: EP-WXT detection of a fast X-ray transient
  21. GRB 250830B: Swift-XRT observations
  22. EP250830a: Global MASTER-Net observations report
  23. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  24. EP-WXT trigger 01709200994: Liverpool Telescope upper limits
  25. EP-WXT trigger 01709200994: confirmation of a stellar flare by BOOTES-6
  26. The EP-WXT trigger 01709200994 is likely a flaring star
  27. EP250827a: very early ATLAS detections, starting 43 sec after the EP trigger
  28. EP250828a: refined analysis of the EP-WXT and EP-FXT observations
  29. EP250828a: Optical counterpart detection with Kinder observations
  30. EP250828a: Liverpool Telescope upper limits
  31. EP250828a: Global MASTER-Net observations report
  32. EP-WXT trigger 01709200800 : KAIT optical observations
  33. EP250827a: Swift/UVOT Detection
  34. EP250828a: NOT optical counterpart confirmation
  35. EP250828a: SVOM/VT optical candidate
  36. EP250828a: Seimei/TriCCS optical counterpart detection
  37. EP250827a: STEP/T80S Confirmation of fading optical counterpart
  38. EP250828a: Optical upper limit with Kinder observations
  39. EP250827a: LCO observations show fading optical counterpart
  40. EP250828a: Einstein Probe detection of an X-ray transient
  41. EP250827a: Preliminary analysis of the EP-WXT and EP-FXT observations
  42. EP250827a: confirmation of optical rebrightening with LCO
  43. EP250827A: An optical rebrightening was detected by LCO.
  44. EP250827a: Swift-XRT counterpart detection
  45. The EP-WXT trigger 01709200800 is likely a flaring star
  46. EP250827a: TRT optical observations
  47. EP250827a / GRB 250827A: MASTER-OAFA OT observation
  48. EP250827a: Gemini-South redshift z = 1.613
  49. EP250827a: Global MASTER-Net observations report
  50. EP250827a: Gemini-South optical counterpart detection
  51. EP250827a: Einstein Probe detection of an X-ray transient
  52. EP triggers 01709200706 and 01709200707: GOTO confirmation of flaring stars
  53. The EP-WXT trigger 01709200707 is likely a flaring star
  54. The EP-WXT trigger 01709200706 is likely a flaring star
  55. Konus-Wind detection of GRB 250821B
  56. EP250821a: Swift/XRT counterpart fading
  57. EP250821a: VLT X-shooter spectroscopic redshift z = 0.577
  58. EP250821a: SVOM/VT optical observation
  59. EP250821a: Rapidly fading optical source detected in Las Cumbres followup
  60. EP250821a: Swift XRT and UVOT counterpart detection
  61. EP250821a: Preliminary analysis of the EP-WXT and EP-FXT observations
  62. LIGO/Virgo/KAGRA S250818k: EP/FXT observation of AT 2025ulz
  63. EP250821a: Einstein Probe detection of an X-ray transient
  64. GRB 250818B: Kilonova-Catcher optical afterglow detection
  65. GRB 250818B: SAO RAS optical observations
  66. GRB 250818B: EP-FXT counterpart detection
  67. GRB 250813B: Liverpool Telescope optical upper limits
  68. GRB 250813B: SVOM/GRM observation
  69. GRB 250813B: SVOM/VT optical observations
  70. GRB 250813B: EP-FXT counterpart detection
  71. EP250812a: NOT, NTT, and GS observations
  72. EP250812a: Liverpool Telescope upper limits
  73. EP250812a: SVOM/VT optical counterpart
  74. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  75. GRB 250812A: EP-FXT counterpart detection
  76. EP 250812a: GOTO optical upper limit
  77. EP250812a: Swift-XRT counterpart detection
  78. EP250812a: Einstein Probe detection of an X-ray transient
  79. EP250807a: EP-FXT follow-up observation upper limit
  80. EP250807a: Global MASTER-Net observations report
  81. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  82. Konus-Wind detection of GRB 250807A
  83. GRB 250806A: SVOM/MXT refined analysis
  84. EP250807a: NTT z-band optical upper limit
  85. EP250807a: EP-WXT detection of a fast X-ray transient
  86. EP 250807.979: GOTO optical upper limit
  87. EP250807a: COLIBRÍ optical upper limit
  88. EP250806a: Upper limit from Fermi-GBM Observations
  89. EP250806a:SVOM/VT refined analysis
  90. EP250806a: Liverpool telescope optical upper limit
  91. GRB 250806A: EP-FXT observation
  92. EP#01709198415/EP250806a: Swift-XRT observations
  93. EP250806a: Global MASTER-Net observations report
  94. EP250802a: EP-FXT follow-up observation
  95. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  96. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  97. EP250806a: SVOM /VT optical candidate
  98. EP250806a: COLIBRÍ optical upper limit
  99. EP250806a: Einstein Probe detection of an X-ray transient
  100. EP250730a: SVOM/VT optical upper limit

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