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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"

26486 results found.

  1. EP260618a: COLIBRÍ optical counterpart candidate
  2. GRB 260619A: SVOM possible detection of a faint burst
  3. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  4. EP260618a: EP-WXT detection of an X-ray transient
  5. GRB 260610B: AbAO optical observations
  6. EP260616a/GRB 260616B: EP-FXT follow-up observation
  7. GRB 260506B: cubesat Avion detection
  8. GRB 260616C: GECAM-B observation of a burst
  9. GRB 260617A: Fermi GBM Detection
  10. GRB 260616A: Fermi GBM Observation
  11. Konus-Wind detection of GRB 260616B/EP260616a
  12. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  13. GRB 260616A: GECAM-B observation
  14. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  15. GRB 260429A: cubesat Avion detection
  16. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  17. EP260616a: EP-WXT detection of a fast X-ray transient
  18. The EP-WXT trigger 01709270148 is likely a flaring star
  19. GRB 260616B: Fermi GBM Detection
  20. The EP-WXT trigger 01709269893 is likely a flaring star
  21. GRB 260614B: SVOM/ECLAIRs refined analysis
  22. GRB 260610B: Terskol optical observations
  23. GRB 260614B: GECAM-B observation
  24. GRB 260610B: SVOM/GRM observation
  25. GRB 260614B: Fermi GBM Observation
  26. GRB 260614B: SVOM/VT optical candidate from VHF data
  27. GRB 260614B: SVOM detection of a burst
  28. GRB 260611B: SVOM/GRM detection
  29. The EP-WXT trigger 01709269488 is likely a flaring star
  30. GRB 260603C: AstroSat CZTI detection
  31. GRB 260610B: further Liverpool Telescope optical observations
  32. GRB 260610B: Fermi GBM Observation
  33. GRB 260610B / AT2026owq: GRANDMA optical observations
  34. GRB 260610B / AT2026owq: further SAO RAS optical observations
  35. EP260605a: COLIBRÍ optical upper limits
  36. GRB 260610b: Liverpool Telescope optical observations
  37. EP260610b: Liverpool Telescope optical upper limits
  38. IceCube-260610A: EP-FXT follow-up observation
  39. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  40. GRB 260610B / AT2026owq: SAO RAS optical observations
  41. The EP-WXT trigger 01709269176 is likely a flaring star
  42. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  43. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  44. GRB 260610B: TRT optical observation
  45. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  46. EP260610b: COLIBRÍ optical observations
  47. GRB 260610B: DDOTI optical observations
  48. EP260610b: MAO/AZT-22 optical observations
  49. EP260610b: NOT optical observation
  50. EP260610b: SVOM/VT optical confirmation with blue color
  51. GRB 260515A: SOAR optical observations
  52. EP260610a: SVOM/VT optical upper limits
  53. EP260610b: Einstein Probe detection of an X-ray transient
  54. Konus-Wind detection of GRB 260601A
  55. EP260610a: COLIBRÍ optical upper limits
  56. EP260610a: Einstein Probe detection of a fast X-ray transient
  57. GRB 260608A: Fermi GRB Observation
  58. GRB 260604C: SVOM/ECLAIRs refined analysis
  59. GRB 260608A: SVOM/ECLAIRs refined analysis
  60. GRB 260607B: GECAM-B observation
  61. GRB 260604C: further SAO RAS optical observations
  62. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  63. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  64. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  65. GRB 260604C: SVOM/C-GFT upper limit
  66. GRB 260607B: AstroSat CZTI detection
  67. GRB 260608A: SVOM detection of a burst
  68. EP260605a: EP-FXT follow-up observation
  69. GRB 260607A: TRT optical observations
  70. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  71. GRB 260604A: SVOM/GRM detection
  72. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  73. GRB 260607B: Fermi GBM Observation
  74. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  75. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  76. GRB 260604C: GECAM-B observation
  77. GRB 260604C: 6 GHz VLA observations
  78. GRB 260604C: SAO RAS optical observations
  79. GRB 260604B: SVOM/GRM detection
  80. GRB260603A: SVOM/ECLAIRs refined analysis
  81. EP260605a: Einstein Probe detection of a fast X-ray transient
  82. EP260603a: COLIBRÍ optical upper limit
  83. GRB 260604A: Glowbug gamma-ray detection
  84. GRB 260604C: LCO optical upper limit
  85. The EP-WXT trigger 01709267001 is likely a flaring star
  86. EP260602d: EP-FXT follow-up observation
  87. EP260602c: EP-FXT follow-up observation
  88. GRB 260601B / EP260601a: AstroSat CZTI detection
  89. GRB 260527A/EP260527a: 6 GHz VLA observations
  90. GRB 260604C: Kilonova-Catcher optical afterglow detection
  91. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  92. The EP-WXT trigger 01709266798 is likely a flaring star
  93. GRB 260604C: Jinshan optical observations
  94. GRB 260604C: Fermi GBM Observation
  95. EP260602d: J-band upper limit with WINTER
  96. EP260602b: J-band upper limit with WINTER
  97. GRB 260604C: LAST detection of optical counterpart candidate
  98. GRB 260604C: SVOM detection of a long burst
  99. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  100. EP260602a: EP-FXT follow-up observation

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