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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"

28228 results found.

  1. Fermi trigger No 796485221: Global MASTER-Net observations report
  2. GRB 260327A: Insight-HXMT/HE detection
  3. EP260329b: Optical follow-up with Kinder observations
  4. EP 260329b: COLIBRÍ optical observations
  5. EP260329a: Optical upper limit with Kinder observations
  6. EP260329b: LCO optical observations of the counterpart
  7. GRB 260326A: Insight-HXMT/HE detection
  8. EP260329b: Einstein Probe detection of an X-ray transient
  9. EP260329a: Einstein Probe detection of an X-ray transient
  10. EP-WXT trigger 01709259209: TRT optical counterpart detection
  11. The EP-WXT trigger 01709259209 (EP260329b?): Las Cumbres discovery of the optical counterpart
  12. EP260327a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  13. EP260327a: SVOM/VT optical upper limits
  14. EP260327a: WINTER J-band upper limit
  15. EP260327a: COLIBRÍ optical upper limits
  16. EP260327a: Gemini-North optical upper limits
  17. EP260324a: GROWTH-India Telescope optical observation
  18. EP260327a: Global MASTER-Net observations report
  19. EP260327a: Einstein Probe detection of an X-ray transient
  20. GRB 260310A / AT 2026fgk: COLIBRÍ photometric evidence of the emerging supernova
  21. GRB 260310A / AT2026fgk: Late-time infrared detection with MIRAGE on the MDM 1.3m telescope
  22. EP260324a: ZTF discovery of the optical counterpart ZTF26aapviim/AT2026hir
  23. GRB 260310A / AT2026fgk: R- and I-band observations with the PKU 60 cm optical telescope
  24. GRB 260326A: Fermi GBM Detection
  25. EP260321a: JinShan near-infrared observations
  26. EP260321a: Upper limits from a neutrino search with IceCube
  27. GRB 260310A/AT2026fgk: Kilonova-Catcher late optical afterglow detection at about 15 days post trigger time
  28. EP260321a: J-band observations by the SYSU 80 cm infrared telescope
  29. GRB 260321A: SVOM/COLIBRÍ (FM-GFT) optical upper limits at the FXT positions
  30. EP-WXT trigger 01709259112: confirmation of a stellar flare by BOOTES-5 & BOOTES-7
  31. Fermi GRB 260323A: Global MASTER-Net observations report
  32. GRB260310A: Palomar 60-inch photometry of an extremely bright late-time afterglow with a temporal break at 8 days
  33. GRB 260320A: Glowbug gamma-ray detection
  34. EP260321a: COLIBRÍ further optical observations and brightening
  35. EP260321a: Continued brightening from Kinder follow-up of the emerging supernova candidate
  36. EP260321a: Early TRT rising followed by JinShan decaying and then re-rising
  37. GRB 260321A: EP-FXT follow-up observation
  38. EP260321a: GOTO detection of blue variable source
  39. EP260321a: VLT imaging and spectroscopy show the variable source to be at z = 0.0343
  40. EP260321a: further Kinder optical observations
  41. GRB 260321A: SVOM/VT optical upper limits
  42. EP260321a: Las Cumbres upper limit
  43. GRB 260321A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  44. EP260321a: COLIBRÍ optical upper limit on any supernova shock breakout emission
  45. EP260321a: refined analysis of the EP-WXT and EP-FXT observations, implying a possible supernova shock breakout candidate
  46. EP260321a: SVOM/VT optical upper limit
  47. Fermi GBM Sub-Threshold Detection of GRB 260321A
  48. EP260321a: Kinder observations detect a blue variable star and set limits on a source from the z =0.034 galaxy within the error circle
  49. EP260321a: Global MASTER-Net observations report
  50. EP260321a: Einstein Probe detection of an X-ray transient
  51. GRB 260318A: Glowbug gamma-ray detection
  52. GRB 260310A / AT 2026fgk: KAIT optical observations
  53. GRB 260320A: NuSTAR detection of prompt emission
  54. EP-WXT trigger 01709258989: KAIT confirmation of a stellar flare
  55. GRB 260310A: no evidence of re-brightening up to 9.6 days in optical observation at Mondy
  56. GRB 260310A / AT 2026fgk: COLIBRÍ evidence of a late rebrightening
  57. EP-WXT trigger 01709258989: confirmation of a stellar flare by BOOTES-7
  58. GRB 260318A: SVOM/GRM observation
  59. GRB 260310A: classification as long GRB based on Eiso, Ep, and T_90
  60. GRB260310A/AT2026fgk: Further optical observation from 1.3m DFOT
  61. Fermi GRB 260318A: Global MASTER-Net observations report
  62. GRB 260316A / EP260316a: COLIBRÍ optical followup of counterpart candidate
  63. GRB 260310A / AT 2026fgk: radio detection with the VLA
  64. GRB 260310A / AT2026fgk: SVOM/VT optical observations
  65. GRB 260310A / AT2026fgk: LCO optical observations
  66. GRB 260316B: SVOM/GRM observation
  67. EP260316a / GRB 260316A: SVOM/VT optical upper limits
  68. EP260316a: COLIBRÍ faint optical counterpart candidate
  69. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  70. EP260316a: refined analysis of the EP-WXT and EP-FXT observations
  71. IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
  72. EP260316a: Xinglong optical upper limit
  73. EP260316a: optical upper limit with Kinder observations
  74. EP260316a / GRB 260316A : Fermi-GBM Sub-Threshold Detection
  75. GRB 260314A: Glowbug gamma-ray detection
  76. The EP-WXT trigger 00199258890 (EP260316a): a correction to the trigger time and FXT automatic follow-up
  77. IceCube-260315A: COLIBRÍ optical observations
  78. EP260314a: Xinglong optical upper limit
  79. EP260314a: optical upper limit with Kinder observations
  80. IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
  81. GRB 260310A / AT2026fgk: 1.3m DFOT optical observations
  82. GRB 260310A / AT 2026fgk: iTelescope optical observations
  83. EP260314a: COLIBRÍ optical upper limit
  84. EP260314a: refined analysis of the EP-WXT and EP-FXT observations
  85. EP260314a: Global MASTER-Net observations report
  86. EP260314a: SVOM/VT optical candidate
  87. Fermi trigger No 795185313: Global MASTER-Net observations report
  88. IceCube Alert 260315A: Global MASTER-Net observations report
  89. EP260314a: Einstein Probe detection of an X-ray transient
  90. GRB 260310A / AT2026fgk: SAO RAS optical observations
  91. GRB 260310A / AT2026fgk: Multiband optical follow-up with Kinder observations
  92. GRB 260310A / AT 2026fgk: COLIBRÍ continuing optical observations
  93. Fermi GRB 260314A: Global MASTER-Net observations report
  94. Fermi GRB 260313A: Global MASTER-Net observations report
  95. GRB 260310A/AT 2026fgk: WINTER NIR Detections
  96. GRB 260310A/AT 2026fgk: J-band observations by the SYSU 80 cm infrared telescope
  97. GRB 260310A/AT 2026fgk: DDOTI Optical Detection
  98. GRB 260312B: AstroSat CZTI detection
  99. GRB 260310A / AT2026fgk: OSIRIS+/GTC spectroscopy confirms redshift z = 0.153
  100. GRB 260310A / AT 2026fgk: COLIBRÍ optical observations

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