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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"

12082 results found.

  1. EP260809a: COLIBRÍ optical observations
  2. EP260809a: Einstein Probe detection of an X-ray transient
  3. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  4. GRB 260808B: SVOM/VT optical candidate from VHF data
  5. GRB 260808B: SVOM detection of a faint burst
  6. GRB 260807A: SVOM possible detection of a faint burst
  7. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  8. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  9. EP260806a: Einstein Probe detection of an X-ray transient
  10. SN 2026stf / GRB 260708A: ATLAS forced photometry
  11. Fermi GRB 260802B: Global MASTER-Net observations report
  12. GRB 260802A / EP J223759.5+531421: SVOM/VT optical upper limit
  13. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  14. GRB 260731A: AstroSat CZTI detection of a long burst
  15. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  16. GRB 260730B: AstroSat CZTI detection
  17. EP260731a: Einstein Probe detection of an X-ray transient
  18. EP260729a: Einstein Probe detection of an X-ray transient
  19. EP260727a: SAO RAS optical observations
  20. EP260728a: Einstein Probe detection of a fast X-ray transient
  21. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  22. Konus-Wind detection of GRB 260727A
  23. EP260727a: Einstein Probe detection of an X-ray transient
  24. GRB 260727A: AstroSat CZTI detection
  25. EP260723a: further EP-FXT follow-up observation
  26. EP260725a: EP-WXT detection of an X-ray transient
  27. EP260723a: EP-WXT detection of a fast X-ray transient
  28. Konus-Wind detection of GRB 260721A
  29. Konus-Wind detection of GRB 260714B
  30. GRB 260705A: Retraction of optical counterpart
  31. Fermi trigger No 806104130: Global MASTER-Net observations report
  32. Fermi GRB 260718A: Global MASTER-Net observations report
  33. GRB 260718A: SVOM detection of a burst
  34. sb26071506: SVOM detection of a X-ray transient
  35. GRB 260710A: AstroSat CZTI detection
  36. GRB 260709A: AstroSat CZTI detection
  37. GRB 260714B: AstroSat CZTI detection
  38. GRB 260714B: Fermi-LAT detection
  39. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  40. EP260713a: Einstein Probe detection of an X-ray transient
  41. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  42. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  43. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  44. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  45. GRB 260705C: AstroSat CZTI detection
  46. GRB 260706A : GRANDMA Upper limits
  47. IceCube-260708A: One candidate from the Zwicky Transient Facility
  48. GRB260708B: MAXI/GSC detection
  49. GRB 260708A: Fermi-LAT detection
  50. EP260707a: LCOGT Optical Upper Limit
  51. EP260707a: Einstein Probe detection of an X-ray transient
  52. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  53. The EP-WXT trigger 01709274141 is likely a flaring star
  54. IPN triangulation of GRB 260627A
  55. GRB 260706A: SVOM detection of a burst
  56. GRB 260629A: AstroSat CZTI detection
  57. GRB 260704A: SVOM detection of a possible GRB
  58. EP260703a: EP-WXT detection of a fast X-ray transient
  59. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  60. Fermi GRB 260703A: Global MASTER-Net observations report
  61. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  62. Fermi trigger No 804552016: Global MASTER-Net observations report
  63. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  64. EP260628a: EP-WXT detection of a fast X-ray transient
  65. Konus-Wind detection of GRB 260623B / EP260623a
  66. EP260623a: FTW optical and NIR observations
  67. Konus-Wind detection of GRB 260618B
  68. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  69. EP260623a: Optical follow-up observations with Kinder
  70. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  71. EP260623a: Einstein Probe detection of an X-ray transient
  72. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  73. GRB 260618B: LCO optical observations
  74. GRB 260618B: Fermi GBM Observation
  75. GRB 260604B: 239Alferov CubeSat detection
  76. GRB 260604A: 239Alferov CubeSat detection
  77. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  78. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  79. Konus-Wind detection of GRB 260617A
  80. GRB 260616B: AstroSat CZTI detection
  81. GRB 260616A: AstroSat CZTI detection
  82. GRB 260614B: NuSTAR detection of prompt emission
  83. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 260618B: Fermi-LAT detection
  85. GRB 260610B: AbAO optical observations
  86. Konus-Wind detection of GRB 260616B/EP260616a
  87. Konus-Wind detection of GRB 260616A
  88. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  89. GRB260616C: MAXI/GSC detection
  90. GRB 260616A: Fermi-LAT detection
  91. GRB 260614A: AstroSat CZTI detection
  92. GRB 260614B: SVOM/VT optical afterglow confirmation
  93. GRB 260614A: GECAM-B observation
  94. GRB 260603C: AstroSat CZTI detection
  95. GRB 260610B: IAC-80 Optical observations
  96. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  97. EP260610b: MAO/AZT-22 optical observations
  98. EP260610b: NOT optical observation
  99. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  100. EP260610b: Einstein Probe detection of an X-ray transient

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