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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').
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"

32493 results found.

  1. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  2. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  3. NuSTAR Transient 260828: LCO Optical Upper Limits
  4. SVOM trigger sb26083106 is not a GRB
  5. GRB 260829A: AstroSat CZTI detection
  6. GRB 260831B: EP-FXT follow-up observation
  7. GRB 260830A: NuSTAR detection of prompt emission
  8. GRB 260831B: LCO optical upper limits
  9. EP260830a: Global MASTER-Net observations report
  10. GRB 260827A: SVOM/GRM observation
  11. IPN triangulation of GRB 260829A
  12. GRB 260827A: Glowbug gamma-ray detection
  13. EP260727a: ATCA 10 GHz detection
  14. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  15. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  16. GRB 260829A: GECAM-B observation of a long burst
  17. GRB 260825A: SVOM/GRM observation of a long burst
  18. GRB 260825A: GECAM-B observation
  19. GRB 260829A: Fermi GBM Detection
  20. GRB 260825A: AstroSat CZTI detection
  21. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  23. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 260818B: Further EP-FXT observation
  25. GRB 260818B: VLT optical and nIR observations
  26. GRB 260818B: TNG NIR observations
  27. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  28. GRB 260818B: 6 GHz VLA observations
  29. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  30. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  31. GRB 260808B: SAO RAS observations of the optical rebrightening
  32. EP260822a: Global MASTER-Net observations report
  33. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  34. GRB 260807A: EP-FXT follow-up observations
  35. GRB 260822A: SVOM/ECLAIRs refined analysis
  36. GRB 260809A: SVOM/ECLAIRs refined analysis
  37. GRB 260822A: SVOM/VT optical upper limits
  38. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  39. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  40. GRB 260822A: EP/FXT follow-up observations
  41. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  42. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  43. EP260822a: EP-FXT non-detection and upper limit
  44. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  45. GRB 260822A: GOTO optical counterpart detection
  46. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  47. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  48. GRB 260822A: LCO optical upper limits
  49. GRB 260822A: GROWTH-India Telescope Upper Limits
  50. GRB 260822A: GOTO optical upper limit
  51. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  52. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  53. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  54. GRB 260818B: VLA radio observations
  55. GRB 260818B: SVOM/C-GFT optical upper limit
  56. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  57. GRB 260820A: Insight-HXMT/HE detection
  58. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  59. GRB 260818B: SVOM/GRM observation
  60. GRB 260818B: Insight-HXMT detection
  61. GRB 260818B: EP-FXT follow-up observation
  62. GRB 260818A: J-band observations with WINTER
  63. GRB 260818B: SVOM/ECLAIRs refined analysis
  64. GRB 260818A: SVOM/ECLAIRs refined analysis
  65. GRB 260818B: NOT optical upper limits
  66. GRB 260810A: SVOM/GRM observation
  67. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  68. GRB260818A: EP-FXT follow-up observation
  69. GRB 260818B: LCO optical upper limits
  70. EP260806a: SAO RAS multicolor optical observations
  71. GRB 260818A: LCO optical upper limits
  72. EP260812a: AbAO optical upper limit
  73. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. GRB 260810A: Insight-HXMT/HE detection
  75. EP260806a: SVOM/ECLAIRs detection through targeted search
  76. EP260806a: NUTTELA-TAO optical observations
  77. EP260812a: AZT-22 optical upper limit
  78. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  79. EP260806a: WFST optical observations
  80. EP260812b: Optical upper limit with Kinder
  81. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  82. GRB 260808B: Liverpool Telescope further optical observations
  83. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  84. EP260812a: NOT and Liverpool Telescope upper limits:
  85. EP260812b: Liverpool Telescope observations
  86. EP260812b: GOTO detection of the optical counterpart
  87. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  88. EP260812a: SVOM/C-GFT optical upper limit
  89. EP260812b: COLIBRÍ optical observations
  90. EP260812b: SVOM/VT optical observation
  91. GRB 260808A: SVOM/GRM observation
  92. EP260812b: Einstein Probe detection of an X-ray transient
  93. Fermi GBM Sub-Threshold Detection of GRB 260809A
  94. GRB 260810A: Glowbug gamma-ray detection
  95. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  96. GRB 260809A: SAO RAS optical observations
  97. GRB 260808B: SAO RAS optical observations
  98. GRB 260808B: SVOM/VT optical re-brightening at day 3
  99. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  100. GRB 260806A: CALET Gamma-Ray Burst Monitor detection

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