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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"

41698 results found.

  1. GRB 260709A: SVOM/GRM detection
  2. GRB 260709A: GECAM-B observation
  3. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  4. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  5. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  6. GRB 260705C: AstroSat CZTI detection
  7. GRB 260708A: Glowbug gamma-ray detection
  8. GRB 260704A: SVOM/ECLAIRs refined analysis
  9. GRB 260706A : GRANDMA Upper limits
  10. GRB 260708A: Kilonova-Catcher optical afterglow detection
  11. GRB 260708A: GECAM-B observation of a burst
  12. IceCube-260708A: One candidate from the Zwicky Transient Facility
  13. GRB 260708A: Fermi-GBM observation
  14. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  15. IceCube Alert 260709A: Global MASTER-Net observations report
  16. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  17. LAT GRB260708.42: Global MASTER-Net observations report
  18. GRB260708B: MAXI/GSC detection
  19. GRB 260708A: Fermi-LAT detection
  20. GRB 260705B: SVOM/GRM observation
  21. GRB 260706A: Further EP-FXT follow-up observation
  22. GRB 260706A: SVOM/VT optical upper limits
  23. EP260707a (by EP-FXT): NOT optical upper limit
  24. EP260707a is not a real source
  25. EP260707a: LCOGT Optical Upper Limit
  26. EP260707a: TRT optical upper limit
  27. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  28. EP260707a: Einstein Probe detection of an X-ray transient
  29. Nova AT2026oyp (ASASSN-26dt): Pre-outburst Swift UVOT observation
  30. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  31. GRB 260705C: Glowbug gamma-ray detection of a short burst
  32. GRB 260706A: SVOM/ECLAIRs refined analysis
  33. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  34. GRB 260706A: SVOM/GRM observation
  35. GRB 260706A: REM optical/NIR observations
  36. IceCube-260704A: No candidates from the Zwicky Transient Facility
  37. GRB 260706A: LCO optical upper limit
  38. GRB 260706A: EP-FXT follow-up observation
  39. The EP-WXT trigger 01709274141 is likely a flaring star
  40. GRB 260706A: Fermi GBM Observation
  41. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  42. IPN triangulation of GRB 260627A
  43. GRB 260705A: SVOM/ECLAIRs refined analysis
  44. GRB 260706A: SVOM detection of a burst
  45. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  46. The EP-WXT trigger 01709274014 is likely a flaring star
  47. IceCube260704A: OHP/T193 optical observations
  48. GRB 260705A: LCO optical upper limits
  49. GRB 260704A: NOT optical upper limits
  50. Fermi GBM Sub-Threshold Detection of GRB 260705A
  51. GRB 260705A: SVOM detection of a burst
  52. GRB 260704A: EP-FXT follow-up observation
  53. GRB 260629A: SVOM/GRM observation of a short burst
  54. GRB 260629A: GECAM-A observation of a short burst
  55. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  56. GRB 260629A: AstroSat CZTI detection
  57. EP260703a: EP-FXT follow-up observation
  58. GRB 260704A: SVOM detection of a possible GRB
  59. EP260703a: EP-WXT detection of a fast X-ray transient
  60. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  61. Fermi trigger No 804738310: Global MASTER-Net observations report
  62. Fermi GRB 260703A: Global MASTER-Net observations report
  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. Fermi GBM trigger 804552016/260630945 is not a GRB
  69. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  70. EP260628a: EP-FXT follow-up observation
  71. Fermi GRB 260628A: Global MASTER-Net observations report
  72. EP260628a: EP-WXT detection of a fast X-ray transient
  73. The EP-WXT trigger 01709272671 is likely a flaring star
  74. EP260626a: further Liverpool Telescope optical upper limits
  75. EP260626a: EP-FXT follow-up observation
  76. EP260626a: COLIBRÍ optical upper limit
  77. EP260626a: Liverpool Telescope upper limits
  78. EP260626a: EP-WXT detection of a fast X-ray transient
  79. Konus-Wind detection of GRB 260623B / EP260623a
  80. EP260623a: TNG NIR afterglow detection
  81. GRB 260618A: Fermi GBM Observation
  82. MASS-Cube (GRID 2.0) detection of GRB 260616B
  83. EP260623a: FTW optical and NIR observations
  84. GRB 260619A: SVOM/ECLAIRs refined analysis
  85. EP260623a: Liverpool Telescope optical observations
  86. Fermi GBM trigger 804010507/260624677 is not a GRB
  87. Konus-Wind detection of GRB 260618B
  88. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  89. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  90. EP260623a: WINTER J-band observations
  91. GRB 260617A: Glowbug gamma-ray detection of a short burst
  92. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  93. IPN triangulation of GRB 260605A
  94. EP260623a: Optical follow-up observations with Kinder
  95. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  96. EP260623a: SVOM/VT optical observations
  97. EP260623a: TRT optical observations
  98. EP260623a: REM optical/NIR afterglow detection
  99. EP 260623a: COLIBRÍ optical observations
  100. GRB 260616B/EP260616a: Insight-HXMT/HE detection

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