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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"

45642 results found.

  1. GRB 260829A: Fermi GBM Final Real-time Localization
  2. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  5. Fermi GBM trigger 809666623/260829141 is not a GRB
  6. GRB 260818B: Further EP-FXT observation
  7. GRB 260818B: VLT optical and nIR observations
  8. GRB 260818B: TNG NIR observations
  9. MAXI GRB260827.40: Global MASTER-Net observations report
  10. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  11. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  12. GRB 260827A: Fermi GBM Final Real-time Localization
  13. GRB 260818B: 6 GHz VLA observations
  14. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  15. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  16. GRB 260808B: SAO RAS observations of the optical rebrightening
  17. EP260822a: Global MASTER-Net observations report
  18. EP Alert 260820.31: Global MASTER-Net observations report
  19. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  20. GRB 260807A: EP-FXT follow-up observations
  21. GRB 260822A: SVOM/ECLAIRs refined analysis
  22. GRB 260809A: SVOM/ECLAIRs refined analysis
  23. GRB 260822A: SVOM/VT optical upper limits
  24. IceCube Alert 260825A: Global MASTER-Net observations report
  25. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 260825A: Fermi GBM Final Real-time Localization
  27. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  28. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  29. GRB 260822A: EP/FXT follow-up observations
  30. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  31. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  32. EP260822a: EP-FXT non-detection and upper limit
  33. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  34. GRB 260822A: GOTO optical counterpart detection
  35. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  36. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  37. EP260822a: Einstein Probe detection of a fast X-ray transient
  38. GRB 260822A: LCO optical upper limits
  39. The EP-WXT trigger 01709287395 is likely a flaring star
  40. GRB260822B: Fermi GBM Final Localization
  41. GRB 260822A: GROWTH-India Telescope Upper Limits
  42. GRB 260822A: GOTO optical upper limit
  43. GRB 260822A: SVOM detection of a short burst
  44. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  45. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  46. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 260818B: VLA radio observations
  48. GRB 260818B: SVOM/C-GFT optical upper limit
  49. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  50. IceCube Alert 260821A: Global MASTER-Net observations report
  51. The EP-WXT trigger 01709286204 is likely a flaring star
  52. GRB 260820A: Insight-HXMT/HE detection
  53. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  54. GRB 260818B: SVOM/GRM observation
  55. EP detected a brightening of LMXB 1ES 1735-26.9
  56. GRB260820A: Fermi GBM Final Real-Time Localization
  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. GRB 260818B: SVOM detection of a short burst
  68. SVOM trigger sb26081806 is not a GRB
  69. EP260806a: SAO RAS multicolor optical observations
  70. GRB 260818A: LCO optical upper limits
  71. EP260812a: AbAO optical upper limit
  72. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  73. GRB 260810A: Insight-HXMT/HE detection
  74. GRB 260818A: SVOM possible detection of a long and faint GRB
  75. EP260806a: SVOM/ECLAIRs detection through targeted search
  76. EP260806a: NUTTELA-TAO optical observations
  77. The EP-WXT trigger 01709281429 is likely a flaring star
  78. EP260812a: AZT-22 optical upper limit
  79. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  80. EP260806a: WFST optical observations
  81. The EP-WXT trigger 01709280562 is likely a flaring star
  82. EP260812b: Optical upper limit with Kinder
  83. The EP-WXT trigger 01709279838 is likely a flaring star
  84. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  85. GRB 260808B: Liverpool Telescope further optical observations
  86. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  87. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  88. GRB 260813A: Fermi GBM Final Real-time Localization
  89. EP260812a: NOT and Liverpool Telescope upper limits:
  90. EP260812b: Liverpool Telescope observations
  91. EP260812b: GOTO detection of the optical counterpart
  92. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  93. EP260812a: SVOM/C-GFT optical upper limit
  94. EP260812b: COLIBRÍ optical observations
  95. EP260812b: SVOM/VT optical observation
  96. GRB 260808A: SVOM/GRM observation
  97. EP260812b: Einstein Probe detection of an X-ray transient
  98. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  99. Fermi GBM Sub-Threshold Detection of GRB 260809A
  100. GRB 260810A: Glowbug gamma-ray detection

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