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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"

28038 results found.

  1. sb26071506: SVOM detection of a X-ray transient
  2. EP260703a: SVOM/ECLAIRs Upper Limit
  3. GRB 260710A: AstroSat CZTI detection
  4. GRB 260714B: Fermi GBM Detection
  5. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  6. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  7. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  8. EP260713a: Einstein Probe detection of an X-ray transient
  9. GRB 260619A: SVOM/VT continuous optical observations
  10. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  11. EP260623a: KAIT optical observations
  12. GRB 260708A: GRANDMA Optical Observations
  13. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  14. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  15. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  16. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 260708A: LCO optical observations
  18. EP260711a: Einstein Probe detection of an X-ray transient
  19. GRB 260709A: SVOM/GRM detection
  20. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  21. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  22. GRB 260708A: Glowbug gamma-ray detection
  23. GRB 260706A : GRANDMA Upper limits
  24. GRB 260708A: Kilonova-Catcher optical afterglow detection
  25. IceCube-260708A: One candidate from the Zwicky Transient Facility
  26. GRB 260708A: Fermi-GBM observation
  27. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  28. IceCube Alert 260709A: Global MASTER-Net observations report
  29. LAT GRB260708.42: Global MASTER-Net observations report
  30. GRB260708B: MAXI/GSC detection
  31. GRB 260705B: SVOM/GRM observation
  32. GRB 260706A: Further EP-FXT follow-up observation
  33. EP260707a (by EP-FXT): NOT optical upper limit
  34. EP260707a is not a real source
  35. EP260707a: LCOGT Optical Upper Limit
  36. EP260707a: TRT optical upper limit
  37. EP260707a: Einstein Probe detection of an X-ray transient
  38. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  39. GRB 260705C: Glowbug gamma-ray detection of a short burst
  40. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  41. GRB 260706A: REM optical/NIR observations
  42. GRB 260706A: LCO optical upper limit
  43. GRB 260706A: EP-FXT follow-up observation
  44. The EP-WXT trigger 01709274151 is likely a flaring star
  45. GRB 260706A: Fermi GBM Observation
  46. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 260706A: SVOM detection of a burst
  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 260704A: EP-FXT follow-up observation
  52. GRB 260629A: SVOM/GRM observation of a short burst
  53. GRB 260629A: AstroSat CZTI detection
  54. EP260703a: EP-FXT follow-up observation
  55. GRB 260704A: SVOM detection of a possible GRB
  56. EP260703a: EP-WXT detection of a fast X-ray transient
  57. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  58. Fermi trigger No 804738310: Global MASTER-Net observations report
  59. Fermi GRB 260703A: Global MASTER-Net observations report
  60. GRB 260623A: Glowbug gamma-ray detection
  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. Fermi GRB 260628A: Global MASTER-Net observations report
  67. EP260628a: EP-WXT detection of a fast X-ray transient
  68. EP260626a: further Liverpool Telescope optical upper limits
  69. EP260626a: COLIBRÍ optical upper limit
  70. EP260626a: Liverpool Telescope upper limits
  71. EP260626a: EP-WXT detection of a fast X-ray transient
  72. EP260623a: TNG NIR afterglow detection
  73. GRB 260618A: Fermi GBM Observation
  74. GRB 260619A: SVOM/ECLAIRs refined analysis
  75. EP260623a: Liverpool Telescope optical observations
  76. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  77. EP260623a: WINTER J-band observations
  78. GRB 260617A: Glowbug gamma-ray detection of a short burst
  79. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  80. EP260623a: Optical follow-up observations with Kinder
  81. EP260623a: SVOM/VT optical observations
  82. EP260623a: TRT optical observations
  83. EP260623a: REM optical/NIR afterglow detection
  84. EP 260623a: COLIBRÍ optical observations
  85. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  86. EP260623a: Las Cumbres discovery of the optical counterpart
  87. EP260623a: Einstein Probe detection of an X-ray transient
  88. GRB 260614B: EP-FXT follow-up observation
  89. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  90. EP260618a: Liverpool Telescope optical observations
  91. GRB 260618B: LCO optical observations
  92. EP260618a: JinShan optical observations
  93. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  94. GRB 260618B: Fermi GBM Observation
  95. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  96. GRB 260619A: TRT optical counterpart confirmation
  97. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  98. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  99. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  100. GRB 260616B: AstroSat CZTI detection

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