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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32489 results found.

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

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