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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. GRB 260830A: NuSTAR detection of prompt emission
  2. GRB 260831B: LCO optical upper limits
  3. EP260830a: Global MASTER-Net observations report
  4. EP260830a: EP-WXT detection of a fast X-ray transient
  5. GRB 260827A: SVOM/GRM observation
  6. NuSTAR 260828: a 1100s hard X-ray transient
  7. GRB 260831B: SVOM detection of a possible burst
  8. IPN triangulation of GRB 260829A
  9. GRB 260827A: Glowbug gamma-ray detection
  10. EP260727a: ATCA 10 GHz detection
  11. GRB 260831A: Fermi GBM Final Real-time Localization
  12. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  13. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  14. GRB 260829A: GECAM-B observation of a long burst
  15. GRB 260825A: SVOM/GRM observation of a long burst
  16. GRB 260825A: GECAM-B observation
  17. GRB 260829A: Fermi GBM Detection
  18. GRB 260825A: AstroSat CZTI detection
  19. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  20. GRB 260829A: Fermi GBM Final Real-time Localization
  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. Fermi GBM trigger 809666623/260829141 is not a GRB
  25. GRB 260818B: Further EP-FXT observation
  26. GRB 260818B: VLT optical and nIR observations
  27. GRB 260818B: TNG NIR observations
  28. MAXI GRB260827.40: Global MASTER-Net observations report
  29. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  30. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  31. GRB 260827A: Fermi GBM Final Real-time Localization
  32. GRB 260818B: 6 GHz VLA observations
  33. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  34. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  35. GRB 260808B: SAO RAS observations of the optical rebrightening
  36. EP260822a: Global MASTER-Net observations report
  37. EP Alert 260820.31: Global MASTER-Net observations report
  38. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  39. GRB 260807A: EP-FXT follow-up observations
  40. GRB 260822A: SVOM/ECLAIRs refined analysis
  41. GRB 260809A: SVOM/ECLAIRs refined analysis
  42. GRB 260822A: SVOM/VT optical upper limits
  43. IceCube Alert 260825A: Global MASTER-Net observations report
  44. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 260825A: Fermi GBM Final Real-time Localization
  46. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  48. GRB 260822A: EP/FXT follow-up observations
  49. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  50. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  51. EP260822a: EP-FXT non-detection and upper limit
  52. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  53. GRB 260822A: GOTO optical counterpart detection
  54. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  55. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  56. EP260822a: Einstein Probe detection of a fast X-ray transient
  57. GRB 260822A: LCO optical upper limits
  58. The EP-WXT trigger 01709287395 is likely a flaring star
  59. GRB260822B: Fermi GBM Final Localization
  60. GRB 260822A: GROWTH-India Telescope Upper Limits
  61. GRB 260822A: GOTO optical upper limit
  62. GRB 260822A: SVOM detection of a short burst
  63. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  64. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  65. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  66. GRB 260818B: VLA radio observations
  67. GRB 260818B: SVOM/C-GFT optical upper limit
  68. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  69. IceCube Alert 260821A: Global MASTER-Net observations report
  70. The EP-WXT trigger 01709286204 is likely a flaring star
  71. GRB 260820A: Insight-HXMT/HE detection
  72. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 260818B: SVOM/GRM observation
  74. EP detected a brightening of LMXB 1ES 1735-26.9
  75. GRB260820A: Fermi GBM Final Real-Time Localization
  76. GRB 260818B: Insight-HXMT detection
  77. GRB 260818B: EP-FXT follow-up observation
  78. GRB 260818A: J-band observations with WINTER
  79. GRB 260818B: SVOM/ECLAIRs refined analysis
  80. GRB 260818A: SVOM/ECLAIRs refined analysis
  81. GRB 260818B: NOT optical upper limits
  82. GRB 260810A: SVOM/GRM observation
  83. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  84. GRB260818A: EP-FXT follow-up observation
  85. GRB 260818B: LCO optical upper limits
  86. GRB 260818B: SVOM detection of a short burst
  87. SVOM trigger sb26081806 is not a GRB
  88. EP260806a: SAO RAS multicolor optical observations
  89. GRB 260818A: LCO optical upper limits
  90. EP260812a: AbAO optical upper limit
  91. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  92. GRB 260810A: Insight-HXMT/HE detection
  93. GRB 260818A: SVOM possible detection of a long and faint GRB
  94. EP260806a: SVOM/ECLAIRs detection through targeted search
  95. EP260806a: NUTTELA-TAO optical observations
  96. The EP-WXT trigger 01709281429 is likely a flaring star
  97. EP260812a: AZT-22 optical upper limit
  98. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  99. EP260806a: WFST optical observations
  100. The EP-WXT trigger 01709280562 is likely a flaring star

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