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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"

28115 results found.

  1. GRB 260715A: cubesat Avion detection
  2. GRB 260709A: cubesat Avion detection
  3. GRB 260708A: cubesat Avion detection
  4. GRB 260730B: Glowbug gamma-ray detection
  5. GRB 260805C: Glowbug gamma-ray detection
  6. GRB 260805B: Glowbug gamma-ray detection
  7. Fermi GRB 260805A: Global MASTER-Net observations report
  8. GRB 260804A: Glowbug gamma-ray detection
  9. GRB 260805B: BALROG localization (Fermi Trigger 807622617 / GRB 260805484)
  10. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 260708A: LCO further optical observations show supernova features
  12. Fermi GRB 260802B: Global MASTER-Net observations report
  13. GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
  14. GRB 260802A: SVOM/VT optical upper limits from VHF data
  15. GRB 260802A: LCO optical upper limits
  16. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  17. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  18. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  19. EP260731a: COLIBRÍ optical upper limit
  20. EP260731a: NOT optical upper limit
  21. GRB 260730B: NuSTAR detection of prompt emission
  22. EP260731a: Einstein Probe detection of an X-ray transient
  23. EP260728a: COLIBRÍ optical upper limit
  24. EP260729a: Einstein Probe detection of an X-ray transient
  25. EP260727a: SAO RAS optical observations
  26. GRB 260727A: AbAO and SAO RAS optical observations
  27. EP260728a: EP-FXT follow-up observation
  28. GRB 260726A: EP-FXT follow-up observations
  29. EP260728a: Einstein Probe detection of a fast X-ray transient
  30. GRB 260726A: Fermi GBM Observation
  31. EP260727a: 1.5m OSN optical counterpart detection
  32. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  33. EP260727a: OHP/T193 optical observations
  34. GRB 260726A: Liverpool Telescope optical observations
  35. GRB 260727A: Liverpool Telescope optical upper limits
  36. EP260727a: Liverpool Telescope confirmation of optical counterpart
  37. EP260727a: Einstein Probe detection of an X-ray transient
  38. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  39. GRB 260727A: Glowbug gamma-ray detection
  40. GRB 260726A: J-band upper limit with WINTER
  41. GRB 260727A: J-band upper limit with WINTER
  42. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  43. EP260723a: SVOM/ECLAIRs Upper Limit
  44. GRB 260727A: AstroSat CZTI detection
  45. GRB 260727A: Kilonova-Catcher optical upper limit
  46. GRB 260727A: LCO optical upper limits
  47. Fermi GRB 260726A: Global MASTER-Net observations report
  48. GRB 260726A: SVOM detection of a burst
  49. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  50. EP260723a: further EP-FXT follow-up observation
  51. EP260725a: EP-WXT detection of an X-ray transient
  52. GRB 260616A: cubesat Avion detection
  53. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  54. GRB 260602B: cubesat Avion detection
  55. GRB 260601A: cubesat Avion detection
  56. EP260723a: SVOM/VT optical observation
  57. EP260723a: COLIBRÍ optical observations
  58. EP260723a: NOT optical conterpart confirmation
  59. EP260723a: Liverpool Telescope likely optical counterpart
  60. EP260723a: EP-WXT detection of a fast X-ray transient
  61. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  63. IceCube Alert 260722A: Global MASTER-Net observations report
  64. GRB 260721A: NuSTAR detection of prompt emission
  65. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  66. Fermi trigger No 806104130: Global MASTER-Net observations report
  67. Fermi GRB 260718A: Global MASTER-Net observations report
  68. GRB 260718A: LCO optical upper limits
  69. GRB 260710A: SVOM/GRM observation
  70. GRB 260718A: Fermi GBM Observation
  71. GRB 260718A : GRANDMA and KNC upper limits
  72. GRB 260718A: SVOM/VT optical upper limits
  73. GRB 260718A: SVOM/VT optical upper limits from VHF data
  74. GRB 260714B: SVOM/GRM observation
  75. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  76. GRB 260714B: COLIBRÍ optical counterpart candidate
  77. SVOM sb26071506: Global MASTER-Net observations report
  78. sb26071506: SVOM detection of a X-ray transient
  79. EP260703a: SVOM/ECLAIRs Upper Limit
  80. GRB 260710A: AstroSat CZTI detection
  81. GRB 260714B: Fermi GBM Detection
  82. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  83. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  84. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  85. EP260713a: Einstein Probe detection of an X-ray transient
  86. GRB 260619A: SVOM/VT continuous optical observations
  87. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  88. EP260623a: KAIT optical observations
  89. GRB 260708A: GRANDMA Optical Observations
  90. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  91. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  92. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  93. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 260708A: LCO optical observations
  95. EP260711a: Einstein Probe detection of an X-ray transient
  96. GRB 260709A: SVOM/GRM detection
  97. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  98. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  99. GRB 260708A: Glowbug gamma-ray detection
  100. GRB 260706A : GRANDMA Upper limits

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