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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"
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submitter:"Judith Racusin"

43899 results found.

  1. EP250807a: Global MASTER-Net observations report
  2. Fermi GRB 250808A: Global MASTER-Net observations report
  3. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  4. GRB 250808A: VLT X-shooter candidate counterpart
  5. GRB 250809A: Prompt enhanced Swift-XRT position
  6. GRB 250809A: Swift detection of a gamma ray burst
  7. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  8. GRB 250808A: Fermi GBM Observation
  9. GRB 250808A: Swift-XRT candidate counterpart detection
  10. GRB 250807A: SVOM/VT optical continued observation
  11. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  12. GRB 250808A: SVOM detection of a long burst
  13. GRB 250808A: Fermi GBM Final Real-time Localization
  14. Konus-Wind detection of GRB 250807A
  15. GRB 250807B: Swift/UVOT Detection
  16. GRB 250807B: Kilonova-Catcher optical afterglow detection
  17. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 250807A: Swift/UVOT Detection
  19. GRB 250807A: Swift-XRT refined Analysis
  20. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  21. GRB 250806A: SVOM/MXT refined analysis
  22. GRB 250806A: SVOM/ECLAIRs refined analysis
  23. EP250807a: NTT z-band optical upper limit
  24. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  25. GRB 250804B: Insight-HXMT detection
  26. GRB 250807A: SVOM/GRM observation
  27. Swift GRB250807.45: Global MASTER-Net observations report
  28. GRB 250807A: AstroSat CZTI detection of bright long burst
  29. GRB 250807B: Swift-XRT refined Analysis
  30. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  31. GRB 250807B: NTT optical observations
  32. EP250807a: EP-WXT detection of a fast X-ray transient
  33. EP 250807.979: GOTO optical upper limit
  34. EP250807a: COLIBRÍ optical upper limit
  35. GRB 250807A: SVOM/VT optical observation
  36. EP250806a: Upper limit from Fermi-GBM Observations
  37. GRB 250807B: Enhanced Swift-XRT position
  38. Swift GRB250807.65: Global MASTER-Net observations report
  39. GRB 250807A: Enhanced Swift-XRT position
  40. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  41. GRB 250807B: Swift detection of a burst with an optical counterpart.
  42. GRB 250805A: Kilonova-Catcher optical upper limits
  43. EP250806a:SVOM/VT refined analysis
  44. EP250806a: Liverpool telescope optical upper limit
  45. GRB 250807A: Swift detection of a burst with an optical counterpart
  46. IceCube Alert 250804.84: Global MASTER-Net observations report
  47. GRB 250806A: EP-FXT observation
  48. EP#01709198415/EP250806a: Swift-XRT observations
  49. EP250806a: Global MASTER-Net observations report
  50. EP250802a: EP-FXT follow-up observation
  51. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  52. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  53. EP250806a: SVOM /VT optical candidate
  54. GRB 250806A: J-band upper limit from WINTER
  55. GRB 250805A: Swift-BAT refined analysis
  56. GRB 250806A: KAIT optical upper limit
  57. GRB 250806A: SVOM/VT refined analysis
  58. GRB 250806A: Swift-XRT counterpart detection
  59. EP250806a: COLIBRÍ optical upper limit
  60. GRB 250806A: Kilonova-Catcher optical upper limits
  61. EP250806a: Einstein Probe detection of an X-ray transient
  62. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  63. GRB 250806A: SVOM/VT optical upper limit
  64. GRB 250806A: SVOM detection of a soft burst
  65. GRB 250805A: SVOM/VT optical counterpart
  66. GRB 250805A: ESO/VLT observations
  67. GRB 250805A: Swift-XRT refined Analysis
  68. GRB 250804B: Swift-XRT observations
  69. GRB 250805A: Enhanced Swift-XRT position
  70. GRB 250804C: AstroSat CZTI detection of a long burst
  71. GRB 250805A: TRT optical upper limits
  72. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 250805A: Swift-XRT observations
  74. GRB 250805A: Swift detection of a burst
  75. Swift GRB250805.26: Global MASTER-Net observations report
  76. GRB 250804B: Tiled Swift observations
  77. Fermi trigger No 776041355: Global MASTER-Net observations report
  78. GRB 250804B: SVOM/GRM observation of a short burst
  79. GRB 250804A: Fermi GBM Final Localization
  80. EP250802a: additional Liverpool Telescope upper limits
  81. EP250730a: SVOM/VT optical upper limit
  82. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  83. EP250802a: Liverpool Telescope optical upper limits
  84. EP250802a: Global MASTER-Net observations report
  85. EP250802a: GROWTH-India Telescope optical upper limit
  86. EP250802a: Einstein Probe detection of an X-ray transient
  87. LIGO/Virgo/KAGRA S250802dn: Updated Sky localization
  88. The EP-WXT trigger 01709198251 is likely a flaring star
  89. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  90. The EP-WXT trigger 01709198202 is likely a flaring star
  91. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  92. GRB 250702B: SMA observations
  93. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  94. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  95. EP250711a: CrAO and Assy optical observations
  96. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  97. EP250730a: Global MASTER-Net observations report
  98. EP250730a: COLIBRÍ optical upper limit
  99. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  100. EP250730a: Einstein Probe detection of an X-ray transient

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