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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

2445 results found.

  1. EP260727a: Liverpool Telescope confirmation of optical counterpart
  2. EP260727a: NUTTELA-TAO Early Optical Limits
  3. GRB 260728A: Fermi GBM Final Localization
  4. GRB 260727A: EP/FXT follow-up observations
  5. EP260727a: Einstein Probe detection of an X-ray transient
  6. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  7. GRB 260727A: Glowbug gamma-ray detection
  8. GRB 260726A: J-band upper limit with WINTER
  9. GRB 260727A: J-band upper limit with WINTER
  10. GRB 260726A: SVOM/VT optical candidate
  11. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  12. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  13. EP260723a: SVOM/ECLAIRs Upper Limit
  14. GRB 260727A: GOTO early optical upper limit
  15. GRB 260727A: AstroSat CZTI detection
  16. GRB 260727A: LCO optical upper limits
  17. GRB 260727B: Fermi GBM Final Real-time Localization
  18. Fermi GRB 260726A: Global MASTER-Net observations report
  19. GRB 260727A: SVOM detection of a bright long burst
  20. GRB 260726A: SVOM detection of a burst
  21. GRB 260726A: Fermi GBM Final Real-time Localization
  22. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  23. EP260723a: further EP-FXT follow-up observation
  24. EP260725a: EP-WXT detection of an X-ray transient
  25. GRB 260616A: cubesat Avion detection
  26. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  27. GRB 260602B: cubesat Avion detection
  28. GRB 260601A: cubesat Avion detection
  29. EP260723a: EP-FXT follow-up observation
  30. GRB 260718A: SVOM/ECLAIRs refined analysis
  31. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  32. EP260723a: SVOM/VT optical observation
  33. EP260723a: COLIBRÍ optical observations
  34. EP260723a: Liverpool Telescope likely optical counterpart
  35. EP260723a: EP-WXT detection of a fast X-ray transient
  36. GRB 260723A: Fermi GBM Final Localization
  37. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  39. IceCube Alert 260722A: Global MASTER-Net observations report
  40. GRB 260722A: Fermi GBM Final Real-time Localization
  41. Fermi GBM trigger 806384210/260722151 is not a GRB
  42. GRB 260721A: NuSTAR detection of prompt emission
  43. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  44. GRB 260705A: Retraction of optical counterpart
  45. GRB 260714B: Insight-HXMT/HE detection
  46. GRB 260718A: EP-FXT follow-up observation
  47. Fermi trigger No 806104130: Global MASTER-Net observations report
  48. Fermi GRB 260718A: Global MASTER-Net observations report
  49. GRB 260718A: LCO optical upper limits
  50. GRB 260711A: SVOM/GRM observation
  51. GRB 260710A: SVOM/GRM observation
  52. GRB 260718A: Fermi GBM Observation
  53. GRB 260718A : GRANDMA and KNC upper limits
  54. GRB 260718A: SVOM/VT optical upper limits
  55. GRB 260718A: SVOM/VT optical upper limits from VHF data
  56. GRB 260718A: SVOM detection of a burst
  57. GRB 260714B: SVOM/GRM observation
  58. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  59. GRB 260714B: GECAM-B observation of a burst
  60. GRB 260618B: EP-FXT follow-up observation upper limit
  61. GRB 260714B: COLIBRÍ optical counterpart candidate
  62. SVOM sb26071506: Global MASTER-Net observations report
  63. sb26071506: SVOM detection of a X-ray transient
  64. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  65. GRB 260715A: Fermi GBM Final Real-time Localization
  66. EP260703a: SVOM/ECLAIRs Upper Limit
  67. GRB 260710A: AstroSat CZTI detection
  68. GRB 260709A: AstroSat CZTI detection
  69. GRB 260714B: AstroSat CZTI detection
  70. GRB 260714B: Fermi-LAT detection
  71. GRB 260714B: Fermi GBM Detection
  72. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  73. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  74. GRB 260714B: Fermi GBM Final Real-time Localization
  75. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  76. GRB 260706A: ATCA detection of possible radio counterpart
  77. GRB 260705A: ATCA radio observations
  78. GRB 260714A: Fermi GBM Final Real-time Localization
  79. EP260713a: Einstein Probe detection of an X-ray transient
  80. GRB 260619A: SVOM/VT continuous optical observations
  81. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  82. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  83. EP260711a: EP-FXT follow-up observation
  84. GRB 260708A: GRANDMA Optical Observations
  85. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  86. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  87. GRB 260710A: Insight-HXMT/HE detection
  88. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  89. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 260708A: LCO optical observations
  91. EP260711a: Einstein Probe detection of an X-ray transient
  92. GRB 260710A: Fermi GBM Detection
  93. GRB 260709A: SVOM/GRM detection
  94. GRB 260709A: GECAM-B observation
  95. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  96. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  97. GRB 260705C: AstroSat CZTI detection
  98. GRB 260710A: Fermi GBM Final Real-time Localization
  99. GRB 260708A: Glowbug gamma-ray detection
  100. GRB 260704A: SVOM/ECLAIRs refined analysis

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