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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"

12283 results found.

  1. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 260714B: Fermi GBM Final Real-time Localization
  3. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  4. GRB 260706A: ATCA detection of possible radio counterpart
  5. GRB 260705A: ATCA radio observations
  6. GRB 260714A: Fermi GBM Final Real-time Localization
  7. GRB 260619A: SVOM/VT continuous optical observations
  8. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  9. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  10. GRB 260708A: GRANDMA Optical Observations
  11. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  12. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  13. GRB 260710A: Insight-HXMT/HE detection
  14. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  15. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  16. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  17. GRB 260708A: LCO optical observations
  18. GRB 260710A: Fermi GBM Detection
  19. GRB 260709A: SVOM/GRM detection
  20. GRB 260709A: GECAM-B observation
  21. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  22. GRB 260705C: AstroSat CZTI detection
  23. GRB 260710A: Fermi GBM Final Real-time Localization
  24. GRB 260708A: Glowbug gamma-ray detection
  25. GRB 260706A : GRANDMA Upper limits
  26. GRB 260708A: Kilonova-Catcher optical afterglow detection
  27. GRB 260708A: GECAM-B observation of a burst
  28. IceCube-260708A: One candidate from the Zwicky Transient Facility
  29. GRB 260708A: Fermi-GBM observation
  30. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  31. GRB 260709A: Fermi GBM Final Real-time Localization
  32. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  33. GRB 260708A: Fermi-LAT detection
  34. GRB 260705B: SVOM/GRM observation
  35. GRB 260708A: Fermi-GBM detection
  36. GRB 260706A: Further EP-FXT follow-up observation
  37. GRB 260706A: SVOM/VT optical upper limits
  38. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  39. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  40. GRB 260705C: Glowbug gamma-ray detection of a short burst
  41. GRB 260706A: SVOM/ECLAIRs refined analysis
  42. GRB 260706A: SVOM/GRM observation
  43. GRB 260706A: REM optical/NIR observations
  44. IceCube-260704A: No candidates from the Zwicky Transient Facility
  45. GRB 260706A: LCO optical upper limit
  46. GRB 260706A: EP-FXT follow-up observation
  47. GRB 260707A: Fermi GBM Final Real-time Localization
  48. GRB 260706A: Fermi GBM Observation
  49. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  50. GRB 260706A: SVOM detection of a burst
  51. GRB 260706A: Fermi GBM Final Real-time Localization
  52. GRB 260705C: Fermi GBM Final Localization
  53. GRB 260705B: Fermi GBM Final Real-time Localization
  54. Fermi GBM Sub-Threshold Detection of GRB 260705A
  55. GRB 260629A: SVOM/GRM observation of a short burst
  56. GRB 260629A: GECAM-A observation of a short burst
  57. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 260629A: AstroSat CZTI detection
  59. GRB 260703B: Fermi GBM Final Localization
  60. Fermi trigger No 804738310: Global MASTER-Net observations report
  61. Fermi GRB 260703A: Global MASTER-Net observations report
  62. GRB 260703A: Fermi GBM Final Localization
  63. GRB 260610B: VLA detection
  64. GRB 260623A: Glowbug gamma-ray detection
  65. GRB 260614B: ATCA Radio Upper Limits
  66. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  67. Fermi trigger No 804552016: Global MASTER-Net observations report
  68. GRB 260701A: Fermi GBM Final Real-time Localization
  69. Fermi GBM trigger 804552016/260630945 is not a GRB
  70. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  71. GRB 260629A: Fermi GBM Final Real-time Localization
  72. Fermi GRB 260628A: Global MASTER-Net observations report
  73. GRB 260628A: Fermi GBM Final Real-time Localization
  74. GRB 260618A: Fermi GBM Observation
  75. MASS-Cube (GRID 2.0) detection of GRB 260616B
  76. Fermi GBM trigger 804010507/260624677 is not a GRB
  77. Konus-Wind detection of GRB 260618B
  78. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  79. GRB 260624A: Fermi GBM Final Real-time Localization
  80. GRB 260617A: Glowbug gamma-ray detection of a short burst
  81. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  82. GRB 260623A: Fermi GBM Final Real-time Localization
  83. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  84. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 260618B: LCO optical observations
  86. EP260618a: JinShan optical observations
  87. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  88. GRB 260618B: Fermi GBM Observation
  89. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  91. GRB 260604B: 239Alferov CubeSat detection
  92. GRB 260604A: 239Alferov CubeSat detection
  93. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  94. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  95. GRB 260618B: SVOM/VT optical candidate
  96. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  97. Konus-Wind detection of GRB 260617A
  98. GRB 260616B: AstroSat CZTI detection
  99. GRB 260616A: AstroSat CZTI detection
  100. GRB 260616A: SVOM/GRM observation

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