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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

15243 results found.

  1. IceCube cascade alert 142200_1517143 retraction
  2. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  3. Konus-Wind detection of GRB 260226A
  4. EP260214a: VLT/FORS2 optical observations
  5. GRB 260225A: WINTER J-band upper limit
  6. GRB 260226A: COLIBRÍ optical upper limits
  7. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  8. GRB 260226A: LAST optical upper limit
  9. GRB 260226A: Fermi-LAT refined analysis
  10. GRB 260226A: AstroSat CZTI detection of bright long burst
  11. GRB 260226A: Fermi-LAT detection of a bright burst
  12. GRB 260225A: EP-FXT follow-up observation
  13. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  14. GRB 260225A: SVOM detection of a burst
  15. EP260213a: Mephisto optical upper limits
  16. sb26021801: SVOM/VT optical upper limits
  17. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  18. GRB 260223A: SVOM/GRM observation
  19. GRB 260223A: COLIBRÍ further optical observations and a brightening
  20. GRB 260223A: COLIBRÍ optical observations
  21. EP260221a: COLIBRÍ optical counterpart candidate
  22. EP260221a: EP-FXT follow-up observation
  23. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  24. GRB 260219A: AstroSat CZTI detection
  25. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 260219A: GECAM-B observation of a long burst
  27. SVOM alert sb26021801: LAST optical upper limit
  28. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  29. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  30. sb26021801: SVOM detection of a long faint X-ray transient
  31. EP260214b: 1.3m DFOT optical upper limit
  32. Konus-Wind detection of GRB 260212A
  33. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  34. GRB 260213A: GECAM-B observation of a short burst
  35. EP260214b: Liverpool Telescope optical observations
  36. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  37. EP260214b: Optical upper limit with Kinder observations
  38. EP260214a: Optical upper limits with Kinder observations
  39. EP260214b: DDOTI Optical Detection
  40. EP260214a: NOT optical upper limits
  41. EP260214a: COLIBRÍ optical upper limits
  42. GRB 260211A: SVOM/VT optical counterpart
  43. EP260214b: COLIBRÍ optical observations
  44. GRB 260212A: AstroSat CZTI detection
  45. GRB 260212A: Fermi GBM Observation
  46. EP260213a: COLIBRÍ optical upper limits
  47. GRB 260212A: GECAM-B observation
  48. EP260213a: Optical upper limits with Kinder observations
  49. GRB 260212A: SVOM/GRM observation of a long burst
  50. GRB 260211A - SVOM/ECLAIRs refined analysis
  51. GRB 260204A: SVOM/ECLAIRs refined analysis
  52. GRB 260211A: LAST optical upper limit
  53. GRB 260210A: SVOM/GRM observation
  54. Konus-Wind detection of GRB 260207B
  55. GRB 260128B: SVOM/ECLAIRs refined analysis
  56. GRID detection of GRB 260207B
  57. GRB260131A/B: 3.6m DOT Optical Observations
  58. GRB 260211A: SVOM detection of a burst
  59. Konus-Wind detection of GRB 260209B
  60. Konus-Wind detection of GRB 260127B
  61. GRB 260208A: LCO detection of the optical counterpart
  62. EP260210a: Optical upper limits with Kinder observations
  63. GRB 260210A: AstroSat CZTI detection
  64. GRB 260208C: AstroSat CZTI detection
  65. GRB 260208B: refined analysis of the EP-FXT observation
  66. GRB 260207B: AstroSat CZTI detection
  67. GRB 260208C: SVOM/GRM observation
  68. GRB 260208B: AstroSat CZTI detection of a bright long burst
  69. GRB260208A: Liverpool Telescope optical follow-up observations
  70. GRB 260208A: Fermi GBM Observation
  71. GRB 260208B: Swift-XRT observations
  72. GRB 260131A/B: continued Mondy optical observations
  73. GRB 260204A: Swift/UVOT Upper Limits
  74. GRB 260208A: 1.3m DFOT optical detection
  75. GRB 260208A: GECAM-B observation of a bright burst
  76. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  77. GRB 260208B: Swift ToO observations
  78. GRB 260208B: SVOM/GRM observation of a bright burst
  79. GRB 260208B: Fermi-LAT detection
  80. GRB 260208A: Fermi-LAT detection
  81. GRB 260207B: GECAM-B observation
  82. GRB 260208A: Swift ToO observations
  83. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)
  84. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  85. GRB 260131A/B: Mondy and Terskol optical observations
  86. GRB 260206A: Tiled Swift observations
  87. GRB 260204A: Swift-XRT observations
  88. GRB 260204A: LCO optical afterglow detection
  89. EP260110a: Late GTC/EMIR near-infrared observations
  90. GRB 260204A: SVOM detection of a burst
  91. GRB 260121A: 239Alferov CubeSat detection
  92. Konus-Wind detection of GRB 260121A
  93. GRB 260131A/B: OHP/T193 optical observations
  94. GRID detection of GRB 260131A/B
  95. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  96. GRB 260130A: Insight-HXMT/HE detection
  97. GRB 260130A: GECAM-B observation of a short burst
  98. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  99. GRB 260127B: Insight-HXMT/HE detection
  100. GRB 260127B: GECAM-B observation of a short burst

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