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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"

11751 results found.

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

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