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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"

28115 results found.

  1. GRB 260610B: Terskol optical observations
  2. GRB 260610B: SVOM/GRM observation
  3. GRB 260614B: Fermi GBM Observation
  4. GRB 260614B: SVOM/VT optical candidate from VHF data
  5. GRB 260614B: SVOM detection of a burst
  6. GRB 260611B: SVOM/GRM detection
  7. The EP-WXT trigger 01709269488 is likely a flaring star
  8. GRB 260610B: further Liverpool Telescope optical observations
  9. GRB 260610B: Fermi GBM Observation
  10. GRB 260610B / AT2026owq: GRANDMA optical observations
  11. GRB 260610B / AT2026owq: further SAO RAS optical observations
  12. EP260605a: COLIBRÍ optical upper limits
  13. GRB 260610b: Liverpool Telescope optical observations
  14. EP260610b: Liverpool Telescope optical upper limits
  15. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  16. GRB 260610B / AT2026owq: SAO RAS optical observations
  17. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  18. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  19. GRB 260610B / AT2026owq: Early ATLAS observations
  20. GRB 260610B: TRT optical observation
  21. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  22. EP260610b: COLIBRÍ optical observations
  23. GRB 260610B: DDOTI optical observations
  24. EP260610b: MAO/AZT-22 optical observations
  25. EP260610b: NOT optical observation
  26. EP260610b: SVOM/VT optical confirmation with blue color
  27. GRB 260515A: SOAR optical observations
  28. EP260610a: SVOM/VT optical upper limits
  29. EP260610b: Einstein Probe detection of an X-ray transient
  30. EP260610a: COLIBRÍ optical upper limits
  31. EP260610a: Einstein Probe detection of a fast X-ray transient
  32. GRB 260608A: Fermi GRB Observation
  33. GRB 260604C: further SAO RAS optical observations
  34. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  35. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  36. GRB 260604C: SVOM/C-GFT upper limit
  37. EP260605a: EP-FXT follow-up observation
  38. GRB 260607A: TRT optical observations
  39. GRB 260604A: SVOM/GRM detection
  40. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  41. GRB 260607B: Fermi GBM Observation
  42. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  43. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  44. GRB 260604C: 6 GHz VLA observations
  45. GRB 260604C: SAO RAS optical observations
  46. GRB 260604B: SVOM/GRM detection
  47. EP260605a: Einstein Probe detection of a fast X-ray transient
  48. EP260603a: COLIBRÍ optical upper limit
  49. GRB 260604A: Glowbug gamma-ray detection
  50. GRB 260604C: LCO optical upper limit
  51. EP260602d: EP-FXT follow-up observation
  52. EP260602c: EP-FXT follow-up observation
  53. GRB 260601B / EP260601a: AstroSat CZTI detection
  54. GRB 260527A/EP260527a: 6 GHz VLA observations
  55. GRB 260604C: Kilonova-Catcher optical afterglow detection
  56. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  57. GRB 260604C: Jinshan optical observations
  58. GRB 260604C: Fermi GBM Observation
  59. EP260602d: J-band upper limit with WINTER
  60. EP260602b: J-band upper limit with WINTER
  61. GRB 260604C: LAST detection of optical counterpart candidate
  62. Fermi GRB 260604C: Global MASTER-Net observations report
  63. Fermi GRB 260604C: Global MASTER-Net observations report
  64. SVOM GRB260604.85: Global MASTER-Net observations report
  65. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  66. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  67. EP260602a: EP-FXT follow-up observation
  68. EP260603a: Global MASTER-Net observations report
  69. EP260603a: Einstein Probe detection of a fast X-ray transient
  70. EP260602d: Optical Upper limits with kinder observations
  71. EP260602b: Liverpool Telescope observations
  72. EP260602a: Liverpool Telescope optical upper limits
  73. EP260602b: Liverpool Telescope and LCO observations
  74. EP260602a: GTC and Liverpool Telescope optical observations
  75. EP260601a/GRB 260601B: EP-FXT follow-up observation
  76. GRB 260601B / EP260601a: Mondy optical upper limit
  77. EP260602b: EP-FXT follow-up observation
  78. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  79. GRB 260603A: Kilonova-Catcher optical upper limit
  80. GRB 260603A: SVOM/VT optical observations
  81. EP260602a: NOT NIR J-band observations
  82. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  83. EP260602d: Einstein Probe detection of a fast X-ray transient
  84. Fermi trigger No 802141998: Global MASTER-Net observations report
  85. GRB 260601A: SVOM/GRM observation of a short burst
  86. EP260602c: Einstein Probe detection of a fast X-ray transient
  87. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  88. EP260602a: COLIBRÍ optical observations
  89. GRB260601B/EP260601a: NOT near-infrared observations
  90. SVOM GRB260603.23: Global MASTER-Net observations report
  91. GRB 260603A: SVOM detection of a burst
  92. EP260602b: Einstein Probe detection of a fast X-ray transient
  93. Fermi GRB 260602B: Global MASTER-Net observations report
  94. Fermi GRB 260602B: Global MASTER-Net observations report
  95. EP260530a: Xinglong optical spectroscopy of EP260530a / AT 2026nwl
  96. EP260602a: SVOM/VT optical candidate
  97. EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
  98. GRB 260601B/EP260601a: J-band upper limit with WINTER
  99. EP260530a/AT 2026nwl: COLIBRÍ optical follow up
  100. EP260530a/AT 2026nwl: KAIT optical observations

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