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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"

24364 results found.

  1. GRB 260708A: GRANDMA Optical Observations
  2. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  3. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  4. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  5. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  6. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  7. GRB 260708A: LCO optical observations
  8. GRB 260710A: Fermi GBM Detection
  9. GRB 260709A: SVOM/GRM detection
  10. GRB 260709A: GECAM-B observation
  11. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  12. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  13. GRB 260710A: Fermi GBM Final Real-time Localization
  14. GRB 260704A: SVOM/ECLAIRs refined analysis
  15. IceCube-260708A: One candidate from the Zwicky Transient Facility
  16. GRB 260708A: Fermi-GBM observation
  17. IceCube Alert 260709A: Global MASTER-Net observations report
  18. GRB 260709A: Fermi GBM Final Real-time Localization
  19. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  20. LAT GRB260708.42: Global MASTER-Net observations report
  21. GRB 260708A: Fermi-LAT detection
  22. GRB 260705B: SVOM/GRM observation
  23. GRB 260708A: Fermi-GBM detection
  24. GRB 260706A: Further EP-FXT follow-up observation
  25. EP260707a is not a real source
  26. EP260707a: LCOGT Optical Upper Limit
  27. EP260707a: TRT optical upper limit
  28. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  29. GRB 260706A: SVOM/ECLAIRs refined analysis
  30. GRB 260706A: SVOM/GRM observation
  31. GRB 260706A: REM optical/NIR observations
  32. IceCube-260704A: No candidates from the Zwicky Transient Facility
  33. GRB 260706A: LCO optical upper limit
  34. GRB 260706A: EP-FXT follow-up observation
  35. GRB 260707A: Fermi GBM Final Real-time Localization
  36. The EP-WXT trigger 01709274141 is likely a flaring star
  37. GRB 260706A: Fermi GBM Observation
  38. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  39. IPN triangulation of GRB 260627A
  40. GRB 260705A: SVOM/ECLAIRs refined analysis
  41. GRB 260706A: SVOM detection of a burst
  42. GRB 260706A: Fermi GBM Final Real-time Localization
  43. The EP-WXT trigger 01709274014 is likely a flaring star
  44. GRB 260705A: LCO optical upper limits
  45. GRB 260704A: NOT optical upper limits
  46. GRB 260705C: Fermi GBM Final Localization
  47. GRB 260705B: Fermi GBM Final Real-time Localization
  48. Fermi GBM Sub-Threshold Detection of GRB 260705A
  49. GRB 260705A: SVOM detection of a burst
  50. GRB 260704A: EP-FXT follow-up observation
  51. GRB 260629A: SVOM/GRM observation of a short burst
  52. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  53. EP260703a: EP-FXT follow-up observation
  54. GRB 260704A: SVOM detection of a possible GRB
  55. GRB 260703B: Fermi GBM Final Localization
  56. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  57. Fermi trigger No 804738310: Global MASTER-Net observations report
  58. Fermi GRB 260703A: Global MASTER-Net observations report
  59. GRB 260703A: Fermi GBM Final Localization
  60. GRB 260614B: ATCA Radio Upper Limits
  61. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  62. Fermi trigger No 804552016: Global MASTER-Net observations report
  63. GRB 260701A: Fermi GBM Final Real-time Localization
  64. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  65. EP260628a: EP-FXT follow-up observation
  66. GRB 260629A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 260628A: Global MASTER-Net observations report
  68. GRB 260628A: Fermi GBM Final Real-time Localization
  69. The EP-WXT trigger 01709272671 is likely a flaring star
  70. EP260626a: EP-FXT follow-up observation
  71. Konus-Wind detection of GRB 260623B / EP260623a
  72. EP260623a: TNG NIR afterglow detection
  73. GRB 260618A: Fermi GBM Observation
  74. GRB 260619A: SVOM/ECLAIRs refined analysis
  75. Konus-Wind detection of GRB 260618B
  76. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  77. GRB 260624A: Fermi GBM Final Real-time Localization
  78. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  79. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  80. IPN triangulation of GRB 260605A
  81. GRB 260623A: Fermi GBM Final Real-time Localization
  82. EP260623a: SVOM/VT optical observations
  83. EP260623a: REM optical/NIR afterglow detection
  84. GRB 260614B: EP-FXT follow-up observation
  85. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  87. GRB 260618B: LCO optical observations
  88. The EP-WXT trigger 01709271197 is likely a flaring star
  89. EP260618a: JinShan optical observations
  90. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  91. GRB 260618B: Fermi GBM Observation
  92. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  93. GRB 260619A: TRT optical counterpart confirmation
  94. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  95. GRB 260619A: SVOM/VT optical counterpart confirmation
  96. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  97. GRB 260618B: SVOM/VT optical candidate
  98. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  99. Konus-Wind detection of GRB 260617A
  100. GRB 260616A: SVOM/GRM observation

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