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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"

19223 results found.

  1. EP260728a: EP-FXT follow-up observation
  2. GRB 260726A: EP-FXT follow-up observations
  3. EP260728a: Einstein Probe detection of a fast X-ray transient
  4. GRB 260727A: SVOM/GRM observation
  5. GRB 260726A: Fermi GBM Observation
  6. EP260727a: 1.5m OSN optical counterpart detection
  7. EP260727a:refined analysis of the EP-WXT and EP-FXT observation
  8. GRB 260726A: Liverpool Telescope optical observations
  9. GRB 260727A: Liverpool Telescope optical upper limits
  10. EP260727a: Liverpool Telescope confirmation of optical counterpart
  11. EP260727a: NUTTELA-TAO Early Optical Limits
  12. GRB 260728A: Fermi GBM Final Localization
  13. GRB 260727A: EP/FXT follow-up observations
  14. EP260727a: Einstein Probe detection of an X-ray transient
  15. The EP-WXT trigger 01709276927 (EP260727a?): NOT likely optical counterpart
  16. GRB 260727A: Glowbug gamma-ray detection
  17. GRB 260726A: J-band upper limit with WINTER
  18. GRB 260727A: J-band upper limit with WINTER
  19. GRB 260726A: SVOM/VT optical candidate
  20. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  21. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  22. EP260723a: SVOM/ECLAIRs Upper Limit
  23. GRB 260727A: GOTO early optical upper limit
  24. GRB 260727A: AstroSat CZTI detection
  25. GRB 260727A: LCO optical upper limits
  26. GRB 260727B: Fermi GBM Final Real-time Localization
  27. Fermi GRB 260726A: Global MASTER-Net observations report
  28. GRB 260727A: SVOM detection of a bright long burst
  29. GRB 260726A: SVOM detection of a burst
  30. GRB 260726A: Fermi GBM Final Real-time Localization
  31. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  32. EP260723a: further EP-FXT follow-up observation
  33. EP260725a: EP-WXT detection of an X-ray transient
  34. GRB 260616A: cubesat Avion detection
  35. EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
  36. GRB 260602B: cubesat Avion detection
  37. GRB 260601A: cubesat Avion detection
  38. EP260723a: EP-FXT follow-up observation
  39. GRB 260718A: SVOM/ECLAIRs refined analysis
  40. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  41. EP260723a: SVOM/VT optical observation
  42. EP260723a: COLIBRÍ optical observations
  43. EP260723a: Liverpool Telescope likely optical counterpart
  44. EP260723a: EP-WXT detection of a fast X-ray transient
  45. GRB 260723A: Fermi GBM Final Localization
  46. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  47. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  48. IceCube Alert 260722A: Global MASTER-Net observations report
  49. GRB 260722A: Fermi GBM Final Real-time Localization
  50. Fermi GBM trigger 806384210/260722151 is not a GRB
  51. GRB 260721A: NuSTAR detection of prompt emission
  52. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  53. GRB 260705A: Retraction of optical counterpart
  54. GRB 260714B: Insight-HXMT/HE detection
  55. GRB 260718A: EP-FXT follow-up observation
  56. Fermi trigger No 806104130: Global MASTER-Net observations report
  57. Fermi GRB 260718A: Global MASTER-Net observations report
  58. GRB 260718A: LCO optical upper limits
  59. GRB 260711A: SVOM/GRM observation
  60. GRB 260710A: SVOM/GRM observation
  61. GRB 260718A: Fermi GBM Observation
  62. GRB 260718A : GRANDMA and KNC upper limits
  63. GRB 260718A: SVOM/VT optical upper limits
  64. GRB 260718A: SVOM/VT optical upper limits from VHF data
  65. GRB 260718A: SVOM detection of a burst
  66. GRB 260714B: SVOM/GRM observation
  67. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  68. GRB 260714B: GECAM-B observation of a burst
  69. GRB 260618B: EP-FXT follow-up observation upper limit
  70. GRB 260714B: COLIBRÍ optical counterpart candidate
  71. SVOM sb26071506: Global MASTER-Net observations report
  72. sb26071506: SVOM detection of a X-ray transient
  73. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  74. GRB 260715A: Fermi GBM Final Real-time Localization
  75. EP260703a: SVOM/ECLAIRs Upper Limit
  76. GRB 260710A: AstroSat CZTI detection
  77. GRB 260709A: AstroSat CZTI detection
  78. GRB 260714B: AstroSat CZTI detection
  79. GRB 260714B: Fermi-LAT detection
  80. GRB 260714B: Fermi GBM Detection
  81. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  82. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  83. GRB 260714B: Fermi GBM Final Real-time Localization
  84. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  85. GRB 260706A: ATCA detection of possible radio counterpart
  86. GRB 260705A: ATCA radio observations
  87. GRB 260714A: Fermi GBM Final Real-time Localization
  88. EP260713a: Einstein Probe detection of an X-ray transient
  89. GRB 260619A: SVOM/VT continuous optical observations
  90. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  91. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  92. EP260711a: EP-FXT follow-up observation
  93. GRB 260708A: GRANDMA Optical Observations
  94. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  95. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  96. GRB 260710A: Insight-HXMT/HE detection
  97. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  98. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 260708A: LCO optical observations
  100. EP260711a: Einstein Probe detection of an X-ray transient

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