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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"

28255 results found.

  1. GRB 260212A: Glowbug gamma-ray detection
  2. Fermi GRB 260212A: Global MASTER-Net observations report
  3. GRB 260211A: LAST optical upper limit
  4. GRB 260210A: SVOM/GRM observation
  5. Fermi GBM Sub-Threshold Detection of GRB 260211A
  6. GRID detection of GRB 260207B
  7. GRB 260211A: LCO optical upper limits
  8. GRB260131A/B: 3.6m DOT Optical Observations
  9. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  10. Fermi trigger No 792537871: Global MASTER-Net observations report
  11. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  12. EP260209a: COLIBRÍ optical upper limit
  13. Fermi GRB 260210C: Global MASTER-Net observations report
  14. EP260209a: LCO optical upper limits
  15. EP260210a: Global MASTER-Net observations report
  16. EP260210a: refined analysis of the EP-FXT observation
  17. EP260209a: Global MASTER-Net observations report
  18. GRB 260208A: LCO detection of the optical counterpart
  19. EP260209a: Einstein Probe detection of a fast X-ray transient
  20. EP260210a: Optical upper limits with Kinder observations
  21. GRB 260210A: Glowbug gamma-ray detection
  22. GRB 260208C: AstroSat CZTI detection
  23. EP260210a: COLIBRÍ optical upper limit
  24. EP260210a: SVOM/C-GFT upper limit
  25. EP260210a: Einstein Probe detection of an X-ray transient
  26. GRB 260207B: AstroSat CZTI detection
  27. GRB 260208C: SVOM/GRM observation
  28. GRB 260204A: Swift-XRT afterglow detection
  29. GRB 260208B: AstroSat CZTI detection of a bright long burst
  30. GRB260208A: Liverpool Telescope optical follow-up observations
  31. GRB 260208A: Glowbug gamma-ray detection
  32. GRB 260208A: NuSTAR detection of prompt emission
  33. GRB 260208A: Fermi GBM Observation
  34. Fermi GRB 260209A: Global MASTER-Net observations report
  35. GRB 260208B: Swift-XRT observations
  36. GRB 260131A/B: continued Mondy optical observations
  37. GRB 260204A: Swift/UVOT Upper Limits
  38. GRB 260208B: COLIBRÍ optical observations
  39. GRB 260208A: Mondy optical observations
  40. GRB 260208A: 1.3m DFOT optical detection
  41. GRB 260208A: COLIBRÍ optical observations
  42. GRB 260208B: EP-FXT observation
  43. Fermi GRB 260208C: Global MASTER-Net observations report
  44. GRB 260208B: SVOM/VT optical candidate
  45. GRB 260208A: GECAM-B observation of a bright burst
  46. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  47. GRB 260208A: SVOM/VT optical observation
  48. Fermi GRB 260208D: Global MASTER-Net observations report
  49. GRB 260208A: Swift-XRT observations
  50. GRB 260208B: SVOM/GRM observation of a bright burst
  51. GRB 260208B: Fermi GBM Detection
  52. LAT GRB 260208B: Global MASTER-Net observations report
  53. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  54. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  55. Fermi GRB 260208A: Global MASTER-Net observations report
  56. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  57. GRB 260131A/B: Mondy and Terskol optical observations
  58. Fermi GRB 260207B: Global MASTER-Net observations report
  59. GRB 260206A: Swift-XRT observations
  60. Fermi trigger No 792135758: Global MASTER-Net observations report
  61. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  62. GRB 260204A: Swift-XRT observations
  63. GRB 260204A: SVOM/VT optical candidate
  64. GRB 260204A : MASTER Global robotic net optical observations
  65. Fermi GBM Sub-Threshold Detection of GRB 260204A
  66. GRB 260204A: LCO optical upper limits
  67. EP260110a: Late GTC/EMIR near-infrared observations
  68. GRB 260121A: 239Alferov CubeSat detection
  69. GRB 260131A: KAIT optical observations
  70. GRB 251230A: MeerLICHT afterglow detection
  71. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  72. GRB 260130A: Insight-HXMT/HE detection
  73. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  74. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  75. GRB 260127A: GECAM-B observation
  76. EP260131a: Liverpool Telescope optical upper limits
  77. EP260131a: COLIBRÍ further observations
  78. EP260131a: SVOM/VT optical observation
  79. EP260131a: Xinglong optical upper limit
  80. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  81. GRB 260131A/B: Fermi GBM Observation
  82. EP260131a: COLIBRÍ observations of slow optical fading
  83. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  84. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  85. GRB 260131B: MAXI/GSC detection
  86. EP260131a: COLIBRÍ optical observations of the counterpart
  87. EP260131a: Las Cumbres detection of an optical counterpart
  88. GRB 260127B: AstroSat CZTI detection
  89. GRB 260130A: Fermi GBM Detection
  90. EP260131a: Einstein Probe detection of an X-ray transient
  91. GRB 260127B: Fermi GBM Detection
  92. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  93. Fermi GRB 260130A: Global MASTER-Net observations report
  94. Fermi GRB 260129A: Global MASTER-Net observations report
  95. GRB 260128B: LCO optical upper limits
  96. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  97. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  98. GRB 260127A: Swift-BAT refined analysis
  99. GRB 260127B: Swift-XRT observations
  100. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations

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