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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"

6838 results found.

  1. GRB 261030A: Fermi GBM Detection
  2. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  3. GRB 261029A: Fermi GBM Observation
  4. EP261010a: Xinglong optical follow-up
  5. GRB 261029A: Fermi-LAT detection
  6. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  7. EP261025a: EP-FXT follow-up observations
  8. GRB 261026A: SVOM/VT optical blue bump
  9. GRB 261026A: SAO RAS optical observations
  10. EP261015a: VST optical observations
  11. EP261015a: GSP multiband optical follow-up observations
  12. EP261015a: Further optical observations with the 1.3m DFOT
  13. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  14. GRB 261020A: Fermi GBM Observation
  15. EP261015a: Wendelstein 43 cm optical observations
  16. EP261015a: Follow-up with the 1.3m DFOT
  17. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  18. GRB 261017A: Swift-XRT refined Analysis
  19. GRB 261017A: Fermi GBM Observation
  20. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  21. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  22. GRB 261011A: 1.3m DFOT optical upper limit
  23. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  24. GRB 261011A: SAO RAS and AbAO optical observations
  25. GRB 261010A: initial pulse rest-frame energetics from Konus-Wind detection
  26. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  27. GRB 261010A: Swift-XRT refined Analysis
  28. GRB 261011A: Swift-XRT refined Analysis
  29. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  30. Konus-Wind detection of GRB 261007A/EP261007a
  31. GRB 261011A: GMG Optical Observation
  32. GRB 261010A: Fermi GBM Observation
  33. GRB 261011A: Optical follow-up observations with Kinder
  34. EP261010a: NOT optical upper limits
  35. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  36. EP261007b: NOT optical observations, variable source outside the FXT region
  37. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  38. GRB 261007A/EP261007a: Optical follow-up observations with Kinder
  39. EP261006a: Optical follow-up observations with Kinder
  40. GRB 261007A: Swift-XRT afterglow detection
  41. GRB 261007A: Fermi GBM observation
  42. GRB 261005B: Swift-XRT refined Analysis
  43. GRB 261005B: Fermi GBM Observation
  44. EP#01709320865: Swift-XRT observations
  45. Konus-Wind detection of GRB 260919A / EP 260920a
  46. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  47. EP260927a: Einstein Probe detection of a fast X-ray transient
  48. GRB 260925A: Swift-XRT refined Analysis
  49. EP260924a: EP-FXT follow-up observation
  50. Konus-Wind detection of GRB 260924A
  51. GRB 260924A: Optical follow-up observations with Kinder
  52. GRB 260924A: Swift-XRT refined Analysis
  53. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  54. GRB 260924A: Fermi GRB Observation
  55. Konus-Wind detection of GRB 260921A (possible merger-origin)
  56. GRB 260924A: Fermi-LAT detection of a bright burst
  57. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  58. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  59. GRB 260922A: Swift-XRT refined Analysis
  60. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  61. GRB 260921A: Fermi GBM Observation
  62. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  63. EP260917a: refined analysis of the EP-FXT observations
  64. GRB 260915A: Swift-XRT afterglow detection
  65. GRB 260916B: Fermi GBM Detection
  66. GRB 260909A: Swift-XRT observations
  67. GRB 260914A: EP-FXT follow-up observation
  68. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  69. GRB 260903A: Swift-XRT observations
  70. GRB 260903A: SAO RAS optical upper limit
  71. EP260903a: EP-FXT follow-up observation
  72. GRB 260903A: SAO RAS optical observations
  73. NuSTAR Transient 260828: SOAR Optical Upper Limits
  74. EP260901a: EP-FXT follow-up observation
  75. EP260830a: EP-FXT follow-up observation
  76. NuSTAR Transient 260828: LCO Optical Upper Limits
  77. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  78. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  79. GRB 260829A: Fermi GBM Detection
  80. GRB 260818B: Further EP-FXT observation
  81. GRB 260808B: SAO RAS observations of the optical rebrightening
  82. GRB 260807A: EP-FXT follow-up observations
  83. GRB 260822A: EP/FXT follow-up observations
  84. GRB 260822A: GROWTH-India Telescope Upper Limits
  85. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  86. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  87. GRB 260818B: EP-FXT follow-up observation
  88. GRB260818A: EP-FXT follow-up observation
  89. EP260806a: SAO RAS multicolor optical observations
  90. EP260812b: Optical upper limit with Kinder
  91. EP260812a: NOT and Liverpool Telescope upper limits:
  92. GRB 260809A: SAO RAS optical observations
  93. GRB 260808B: SAO RAS optical observations
  94. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  95. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  96. AT 2026wki: EP/FXT follow-up observations
  97. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  98. GRB 260727A: EP-FXT further follow-up observations and candidate afterglow
  99. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  100. EP260727a: SAO RAS optical observations

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