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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"

20515 results found.

  1. GRB 251205A: COLIBRÍ optical observations
  2. GRB 251205A: NOT optical observations
  3. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  4. GRB 251205A: Enhanced Swift-XRT position
  5. Swift GRB 251205A : MASTER OT detection with host galaxy
  6. GRB 251205A: Swift detection of a burst with an optical afterglow
  7. GRB 251203C: SVOM/ECLAIRs refined analysis
  8. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  9. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  10. GRB 251202A: SVOM/GRM observation
  11. GRB 251203A: SVOM/GRM observation
  12. GRB 251203C: J-band observations with WINTER
  13. GRB 251203C: SVOM/VT optical counterpart
  14. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  15. GRB 251203B: Swift-XRT observations
  16. GRB 251203C: LCO optical upper limits
  17. GRB 251203B: LCO optical upper limits
  18. GRB 251203B: SVOM/VT optical observation
  19. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  20. GRB 251203B: SVOM detection of a burst
  21. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  22. EP251130a: MAO/AZT-22 optical observations
  23. EP251202a / GRB251202A: AstroSat CZTI detection
  24. GRB 251201B: Fermi GBM Observation
  25. EP251202a/GRB 251202A: KAIT optical observations
  26. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  27. IPN triangulation of GRB 251129B (short/hard)
  28. GRB251129A/EP251129a: Swift UVOT detection
  29. GRB 251202A: Swift/UVOT Detection
  30. GRB 251201B: Kilonova-Catcher optical afterglow detection
  31. GRB 251201B: Swift/UVOT Detection
  32. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  33. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  34. GRB 251126A: SAO RAS optical marginal detection
  35. GRB 251202A: Swift-XRT afterglow detection
  36. EP251129a/GRB 251129A: NOWT Detection
  37. GRB 251126A: SVOM/VT optical observation
  38. EP251130a: SVOM/VT optical observation
  39. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  40. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  41. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 251201A: SVOM/GRM observation of a burst
  43. GRB 251201B: SVOM/VT optical fading
  44. Swift GRB 251201B : MASTER optical counterpart detection
  45. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  46. GRB 251201B: Enhanced Swift-XRT position
  47. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  48. GRB 251130B: AstroSat CZTI detection
  49. GRB 251201B: Swift detection of a burst with an optical counterpart
  50. EP251130a: Mondy optical observations
  51. EP251130a: Optical detections with Kinder observations
  52. EP251130a: SAO RAS optical observations
  53. EP251130A: Optical observation from 1.3m DFOT
  54. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  55. EP251130a: JinShan optical observations
  56. GRB 251127A: SVOM/GRM observation
  57. EP251130a: COLIBRÍ optical counterpart candidate
  58. EP251130a: Einstein Probe detection of an X-ray transient
  59. GRB 251129A / EP251129a: SAO RAS optical observations
  60. GRB 251126A: SAO RAS optical observations
  61. GRB 251128A: GECAM-B detection
  62. GRB 251128A: SVOM/GRM observation of a long burst
  63. SVOM GRB 251129A : MASTER optical counterpart detection
  64. GRB 251129A: Swift-XRT afterglow detection
  65. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  66. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  67. GRB 251129A: SVOM detection of a burst
  68. GRB 251129A: SVOM detection of a burst
  69. GRB 251126A: Swift-BAT refined analysis
  70. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  71. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 251126A: further SAO RAS optical observations
  73. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  74. GRB251126A: MAO/AZT-22 optical observations
  75. GRB251126A: Continued optical observation from 1.3m DFOT
  76. GRB 251126A: Swift/UVOT Detection
  77. EP251124a: Pan-STARRS ri-band imaging and photometry
  78. GRB 251126A: Mondy and SAO RAS optical observations
  79. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  80. GRB 251126A: 1.3m DFOT optical afterglow detection
  81. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  82. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  83. GRB 251126A: Enhanced Swift-XRT position
  84. GRB 251126A: Kilonova-Catcher optical afterglow detection
  85. GRB 251126A: Nanshan/HMT optical afterglow detection
  86. GRB 251126A: GIT discovery of the likely optical afterglow
  87. GRB 251126A: Swift detection of a burst
  88. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  89. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  90. EP251124b: NOT r- and z-band optical upper limits
  91. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  92. EP251124b: EP-WXT detection of a fast X-ray transient
  93. EP251124a: Xinglong GWAC-F60A optical observation
  94. EP251124a: NOT r- and z-band optical upper limits
  95. EP251124a: Swift-XRT observations
  96. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  97. EP251124a: Optical upper limit with Kinder observations
  98. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  99. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  100. EP251124a: GROWTH-India Telescope optical upper limits

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