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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"

2426 results found.

  1. GRB 260726A: SVOM detection of a burst
  2. GRB 260726A: Fermi GBM Final Real-time Localization
  3. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  4. EP260723a: further EP-FXT follow-up observation
  5. EP260725a: EP-WXT detection of an X-ray transient
  6. GRB 260616A: cubesat Avion detection
  7. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  8. GRB 260602B: cubesat Avion detection
  9. GRB 260601A: cubesat Avion detection
  10. EP260723a: EP-FXT follow-up observation
  11. GRB 260718A: SVOM/ECLAIRs refined analysis
  12. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  13. EP260723a: SVOM/VT optical observation
  14. EP260723a: COLIBRÍ optical observations
  15. EP260723a: Liverpool Telescope likely optical counterpart
  16. EP260723a: EP-WXT detection of a fast X-ray transient
  17. GRB 260723A: Fermi GBM Final Localization
  18. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  19. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  20. IceCube Alert 260722A: Global MASTER-Net observations report
  21. GRB 260722A: Fermi GBM Final Real-time Localization
  22. Fermi GBM trigger 806384210/260722151 is not a GRB
  23. GRB 260721A: NuSTAR detection of prompt emission
  24. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  25. GRB 260705A: Retraction of optical counterpart
  26. GRB 260714B: Insight-HXMT/HE detection
  27. GRB 260718A: EP-FXT follow-up observation
  28. Fermi trigger No 806104130: Global MASTER-Net observations report
  29. Fermi GRB 260718A: Global MASTER-Net observations report
  30. GRB 260718A: LCO optical upper limits
  31. GRB 260711A: SVOM/GRM observation
  32. GRB 260710A: SVOM/GRM observation
  33. GRB 260718A: Fermi GBM Observation
  34. GRB 260718A : GRANDMA and KNC upper limits
  35. GRB 260718A: SVOM/VT optical upper limits
  36. GRB 260718A: SVOM/VT optical upper limits from VHF data
  37. GRB 260718A: SVOM detection of a burst
  38. GRB 260714B: SVOM/GRM observation
  39. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  40. GRB 260714B: GECAM-B observation of a burst
  41. GRB 260618B: EP-FXT follow-up observation upper limit
  42. GRB 260714B: COLIBRÍ optical counterpart candidate
  43. SVOM sb26071506: Global MASTER-Net observations report
  44. sb26071506: SVOM detection of a X-ray transient
  45. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  46. GRB 260715A: Fermi GBM Final Real-time Localization
  47. EP260703a: SVOM/ECLAIRs Upper Limit
  48. GRB 260710A: AstroSat CZTI detection
  49. GRB 260709A: AstroSat CZTI detection
  50. GRB 260714B: AstroSat CZTI detection
  51. GRB 260714B: Fermi-LAT detection
  52. GRB 260714B: Fermi GBM Detection
  53. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  54. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 260714B: Fermi GBM Final Real-time Localization
  56. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  57. GRB 260706A: ATCA detection of possible radio counterpart
  58. GRB 260705A: ATCA radio observations
  59. GRB 260714A: Fermi GBM Final Real-time Localization
  60. EP260713a: Einstein Probe detection of an X-ray transient
  61. GRB 260619A: SVOM/VT continuous optical observations
  62. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  63. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  64. EP260711a: EP-FXT follow-up observation
  65. GRB 260708A: GRANDMA Optical Observations
  66. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  67. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  68. GRB 260710A: Insight-HXMT/HE detection
  69. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  70. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 260708A: LCO optical observations
  72. EP260711a: Einstein Probe detection of an X-ray transient
  73. GRB 260710A: Fermi GBM Detection
  74. GRB 260709A: SVOM/GRM detection
  75. GRB 260709A: GECAM-B observation
  76. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  77. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  78. GRB 260705C: AstroSat CZTI detection
  79. GRB 260710A: Fermi GBM Final Real-time Localization
  80. GRB 260708A: Glowbug gamma-ray detection
  81. GRB 260704A: SVOM/ECLAIRs refined analysis
  82. GRB 260706A : GRANDMA Upper limits
  83. GRB 260708A: GECAM-B observation of a burst
  84. IceCube-260708A: One candidate from the Zwicky Transient Facility
  85. GRB 260708A: Fermi-GBM observation
  86. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  87. IceCube Alert 260709A: Global MASTER-Net observations report
  88. GRB 260709A: Fermi GBM Final Real-time Localization
  89. LAT GRB260708.42: Global MASTER-Net observations report
  90. GRB260708B: MAXI/GSC detection
  91. GRB 260708A: Fermi-LAT detection
  92. GRB 260705B: SVOM/GRM observation
  93. GRB 260708A: Fermi-GBM detection
  94. GRB 260706A: Further EP-FXT follow-up observation
  95. GRB 260706A: SVOM/VT optical upper limits
  96. EP260707a (by EP-FXT): NOT optical upper limit
  97. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  98. EP260707a: Einstein Probe detection of an X-ray transient
  99. Nova AT2026oyp (ASASSN-26dt): Pre-outburst Swift UVOT observation
  100. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B

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