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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"

11748 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 detection of a possible magnetar burst
  13. GRB 260731A: AstroSat CZTI detection of a long burst
  14. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  15. GRB 260730B: AstroSat CZTI detection
  16. EP260731a: Einstein Probe detection of an X-ray transient
  17. EP260729a: Einstein Probe detection of an X-ray transient
  18. EP260727a: SAO RAS optical observations
  19. EP260728a: Einstein Probe detection of a fast X-ray transient
  20. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  21. Konus-Wind detection of GRB 260727A
  22. EP260727a: Einstein Probe detection of an X-ray transient
  23. GRB 260727A: AstroSat CZTI detection
  24. EP260723a: further EP-FXT follow-up observation
  25. EP260725a: EP-WXT detection of an X-ray transient
  26. EP260723a: EP-WXT detection of a fast X-ray transient
  27. Konus-Wind detection of GRB 260721A
  28. Konus-Wind detection of GRB 260714B
  29. GRB 260705A: Retraction of optical counterpart
  30. Fermi trigger No 806104130: Global MASTER-Net observations report
  31. Fermi GRB 260718A: Global MASTER-Net observations report
  32. GRB 260718A: SVOM detection of a burst
  33. sb26071506: SVOM detection of a X-ray transient
  34. GRB 260710A: AstroSat CZTI detection
  35. GRB 260709A: AstroSat CZTI detection
  36. GRB 260714B: AstroSat CZTI detection
  37. GRB 260714B: Fermi-LAT detection
  38. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  39. EP260713a: Einstein Probe detection of an X-ray transient
  40. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  41. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  42. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  43. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  44. GRB 260705C: AstroSat CZTI detection
  45. GRB 260706A : GRANDMA Upper limits
  46. IceCube-260708A: One candidate from the Zwicky Transient Facility
  47. GRB260708B: MAXI/GSC detection
  48. GRB 260708A: Fermi-LAT detection
  49. EP260707a: LCOGT Optical Upper Limit
  50. EP260707a: Einstein Probe detection of an X-ray transient
  51. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  52. The EP-WXT trigger 01709274141 is likely a flaring star
  53. IPN triangulation of GRB 260627A
  54. GRB 260706A: SVOM detection of a burst
  55. GRB 260629A: AstroSat CZTI detection
  56. GRB 260704A: SVOM detection of a possible GRB
  57. EP260703a: EP-WXT detection of a fast X-ray transient
  58. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  59. Fermi GRB 260703A: Global MASTER-Net observations report
  60. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  61. Fermi trigger No 804552016: Global MASTER-Net observations report
  62. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  63. EP260628a: EP-WXT detection of a fast X-ray transient
  64. Konus-Wind detection of GRB 260623B / EP260623a
  65. EP260623a: FTW optical and NIR observations
  66. Konus-Wind detection of GRB 260618B
  67. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  68. EP260623a: Optical follow-up observations with Kinder
  69. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  70. EP260623a: Einstein Probe detection of an X-ray transient
  71. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  72. GRB 260618B: LCO optical observations
  73. GRB 260618B: Fermi GBM Observation
  74. GRB 260604B: 239Alferov CubeSat detection
  75. GRB 260604A: 239Alferov CubeSat detection
  76. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  77. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  78. Konus-Wind detection of GRB 260617A
  79. GRB 260616B: AstroSat CZTI detection
  80. GRB 260616A: AstroSat CZTI detection
  81. GRB 260614B: NuSTAR detection of prompt emission
  82. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  83. GRB 260618B: Fermi-LAT detection
  84. GRB 260610B: AbAO optical observations
  85. Konus-Wind detection of GRB 260616B/EP260616a
  86. Konus-Wind detection of GRB 260616A
  87. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  88. GRB260616C: MAXI/GSC detection
  89. GRB 260616A: Fermi-LAT detection
  90. GRB 260614A: AstroSat CZTI detection
  91. GRB 260614B: SVOM/VT optical afterglow confirmation
  92. GRB 260614A: GECAM-B observation
  93. GRB 260603C: AstroSat CZTI detection
  94. GRB 260610B: IAC-80 Optical observations
  95. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  96. EP260610b: MAO/AZT-22 optical observations
  97. EP260610b: NOT optical observation
  98. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  99. EP260610b: Einstein Probe detection of an X-ray transient
  100. Konus-Wind detection of GRB 260601A

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