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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"

24279 results found.

  1. GRB 260714B: COLIBRÍ optical counterpart candidate
  2. SVOM sb26071506: Global MASTER-Net observations report
  3. sb26071506: SVOM detection of a X-ray transient
  4. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  5. GRB 260715A: Fermi GBM Final Real-time Localization
  6. GRB 260714B: Fermi-LAT detection
  7. GRB 260714B: Fermi GBM Detection
  8. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  9. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 260714B: Fermi GBM Final Real-time Localization
  11. GRB 260714A: Fermi GBM Final Real-time Localization
  12. GRB 260619A: SVOM/VT continuous optical observations
  13. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  14. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  15. EP260711a: EP-FXT follow-up observation
  16. GRB 260708A: GRANDMA Optical Observations
  17. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  18. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  19. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  20. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  22. GRB 260708A: LCO optical observations
  23. GRB 260710A: Fermi GBM Detection
  24. GRB 260709A: SVOM/GRM detection
  25. GRB 260709A: GECAM-B observation
  26. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  27. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  28. GRB 260710A: Fermi GBM Final Real-time Localization
  29. GRB 260704A: SVOM/ECLAIRs refined analysis
  30. IceCube-260708A: One candidate from the Zwicky Transient Facility
  31. GRB 260708A: Fermi-GBM observation
  32. IceCube Alert 260709A: Global MASTER-Net observations report
  33. GRB 260709A: Fermi GBM Final Real-time Localization
  34. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  35. LAT GRB260708.42: Global MASTER-Net observations report
  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. EP260707a is not a real source
  41. EP260707a: LCOGT Optical Upper Limit
  42. EP260707a: TRT optical upper limit
  43. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  44. GRB 260706A: SVOM/ECLAIRs refined analysis
  45. GRB 260706A: SVOM/GRM observation
  46. GRB 260706A: REM optical/NIR observations
  47. IceCube-260704A: No candidates from the Zwicky Transient Facility
  48. GRB 260706A: LCO optical upper limit
  49. GRB 260706A: EP-FXT follow-up observation
  50. GRB 260707A: Fermi GBM Final Real-time Localization
  51. The EP-WXT trigger 01709274141 is likely a flaring star
  52. GRB 260706A: Fermi GBM Observation
  53. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  54. IPN triangulation of GRB 260627A
  55. GRB 260705A: SVOM/ECLAIRs refined analysis
  56. GRB 260706A: SVOM detection of a burst
  57. GRB 260706A: Fermi GBM Final Real-time Localization
  58. The EP-WXT trigger 01709274014 is likely a flaring star
  59. GRB 260705A: LCO optical upper limits
  60. GRB 260704A: NOT optical upper limits
  61. GRB 260705C: Fermi GBM Final Localization
  62. GRB 260705B: Fermi GBM Final Real-time Localization
  63. Fermi GBM Sub-Threshold Detection of GRB 260705A
  64. GRB 260705A: SVOM detection of a burst
  65. GRB 260704A: EP-FXT follow-up observation
  66. GRB 260629A: SVOM/GRM observation of a short burst
  67. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  68. EP260703a: EP-FXT follow-up observation
  69. GRB 260704A: SVOM detection of a possible GRB
  70. GRB 260703B: Fermi GBM Final Localization
  71. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  72. Fermi trigger No 804738310: Global MASTER-Net observations report
  73. Fermi GRB 260703A: Global MASTER-Net observations report
  74. GRB 260703A: Fermi GBM Final Localization
  75. GRB 260614B: ATCA Radio Upper Limits
  76. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  77. Fermi trigger No 804552016: Global MASTER-Net observations report
  78. GRB 260701A: Fermi GBM Final Real-time Localization
  79. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  80. EP260628a: EP-FXT follow-up observation
  81. GRB 260629A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 260628A: Global MASTER-Net observations report
  83. GRB 260628A: Fermi GBM Final Real-time Localization
  84. The EP-WXT trigger 01709272671 is likely a flaring star
  85. EP260626a: EP-FXT follow-up observation
  86. Konus-Wind detection of GRB 260623B / EP260623a
  87. EP260623a: TNG NIR afterglow detection
  88. GRB 260618A: Fermi GBM Observation
  89. GRB 260619A: SVOM/ECLAIRs refined analysis
  90. Konus-Wind detection of GRB 260618B
  91. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  92. GRB 260624A: Fermi GBM Final Real-time Localization
  93. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  94. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  95. IPN triangulation of GRB 260605A
  96. GRB 260623A: Fermi GBM Final Real-time Localization
  97. EP260623a: SVOM/VT optical observations
  98. EP260623a: REM optical/NIR afterglow detection
  99. GRB 260614B: EP-FXT follow-up observation
  100. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event

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