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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"

45417 results found.

  1. GRB 260619A: SVOM/VT continuous optical observations
  2. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  3. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  4. EP260623a: KAIT optical observations
  5. EP260711a: EP-FXT follow-up observation
  6. GRB 260708A: GRANDMA Optical Observations
  7. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  8. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  9. GRB 260710A: Insight-HXMT/HE detection
  10. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  11. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  12. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  13. GRB 260708A: LCO optical observations
  14. EP260711a: Einstein Probe detection of an X-ray transient
  15. GRB 260710A: Fermi GBM Detection
  16. GRB 260709A: SVOM/GRM detection
  17. GRB 260709A: GECAM-B observation
  18. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  19. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  20. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  21. GRB 260705C: AstroSat CZTI detection
  22. GRB 260710A: Fermi GBM Final Real-time Localization
  23. GRB 260708A: Glowbug gamma-ray detection
  24. GRB 260704A: SVOM/ECLAIRs refined analysis
  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. IceCube Alert 260709A: Global MASTER-Net observations report
  32. GRB 260709A: Fermi GBM Final Real-time Localization
  33. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  34. LAT GRB260708.42: Global MASTER-Net observations report
  35. GRB260708B: MAXI/GSC detection
  36. GRB 260708A: Fermi-LAT detection
  37. GRB 260705B: SVOM/GRM observation
  38. GRB 260708A: Fermi-GBM detection
  39. GRB 260706A: Further EP-FXT follow-up observation
  40. GRB 260706A: SVOM/VT optical upper limits
  41. EP260707a (by EP-FXT): NOT optical upper limit
  42. EP260707a is not a real source
  43. EP260707a: LCOGT Optical Upper Limit
  44. EP260707a: TRT optical upper limit
  45. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  46. EP260707a: Einstein Probe detection of an X-ray transient
  47. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  48. GRB 260705C: Glowbug gamma-ray detection of a short burst
  49. GRB 260706A: SVOM/ECLAIRs refined analysis
  50. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  51. GRB 260706A: SVOM/GRM observation
  52. GRB 260706A: REM optical/NIR observations
  53. IceCube-260704A: No candidates from the Zwicky Transient Facility
  54. GRB 260706A: LCO optical upper limit
  55. GRB 260706A: EP-FXT follow-up observation
  56. GRB 260707A: Fermi GBM Final Real-time Localization
  57. The EP-WXT trigger 01709274151 is likely a flaring star
  58. The EP-WXT trigger 01709274141 is likely a flaring star
  59. GRB 260706A: Fermi GBM Observation
  60. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  61. IPN triangulation of GRB 260627A
  62. GRB 260705A: SVOM/ECLAIRs refined analysis
  63. GRB 260706A: SVOM detection of a burst
  64. GRB 260706A: Fermi GBM Final Real-time Localization
  65. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  66. The EP-WXT trigger 01709274014 is likely a flaring star
  67. IceCube260704A: OHP/T193 optical observations
  68. GRB 260705A: LCO optical upper limits
  69. GRB 260704A: NOT optical upper limits
  70. GRB 260705C: Fermi GBM Final Localization
  71. GRB 260705B: Fermi GBM Final Real-time Localization
  72. Fermi GBM Sub-Threshold Detection of GRB 260705A
  73. GRB 260705A: SVOM detection of a burst
  74. GRB 260704A: EP-FXT follow-up observation
  75. GRB 260629A: SVOM/GRM observation of a short burst
  76. GRB 260629A: GECAM-A observation of a short burst
  77. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  78. GRB 260629A: AstroSat CZTI detection
  79. EP260703a: EP-FXT follow-up observation
  80. GRB 260704A: SVOM detection of a possible GRB
  81. GRB 260703B: Fermi GBM Final Localization
  82. EP260703a: EP-WXT detection of a fast X-ray transient
  83. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  84. Fermi trigger No 804738310: Global MASTER-Net observations report
  85. Fermi GRB 260703A: Global MASTER-Net observations report
  86. GRB 260703A: Fermi GBM Final Localization
  87. GRB 260610B: VLA detection
  88. GRB 260623A: Glowbug gamma-ray detection
  89. GRB 260614B: ATCA Radio Upper Limits
  90. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  91. Fermi trigger No 804552016: Global MASTER-Net observations report
  92. GRB 260701A: Fermi GBM Final Real-time Localization
  93. Fermi GBM trigger 804552016/260630945 is not a GRB
  94. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  95. EP260628a: EP-FXT follow-up observation
  96. GRB 260629A: Fermi GBM Final Real-time Localization
  97. Fermi GRB 260628A: Global MASTER-Net observations report
  98. EP260628a: EP-WXT detection of a fast X-ray transient
  99. GRB 260628A: Fermi GBM Final Real-time Localization
  100. The EP-WXT trigger 01709272671 is likely a flaring star

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