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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"

39059 results found.

  1. GRB 260727A: Liverpool Telescope optical upper limits
  2. GRB 260728A: Fermi GBM Final Localization
  3. GRB 260727A: EP/FXT follow-up observations
  4. GRB 260727A: Glowbug gamma-ray detection
  5. GRB 260726A: J-band upper limit with WINTER
  6. GRB 260727A: J-band upper limit with WINTER
  7. GRB 260726A: SVOM/VT optical candidate
  8. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  9. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  10. GRB 260727A: GOTO early optical upper limit
  11. GRB 260727A: AstroSat CZTI detection
  12. GRB 260727A: Kilonova-Catcher optical upper limit
  13. GRB 260727A: LCO optical upper limits
  14. GRB 260727B: Fermi GBM Final Real-time Localization
  15. Fermi GRB 260726A: Global MASTER-Net observations report
  16. GRB 260727A: SVOM detection of a bright long burst
  17. GRB 260726A: SVOM detection of a burst
  18. GRB 260726A: Fermi GBM Final Real-time Localization
  19. GRB 260616A: cubesat Avion detection
  20. GRB 260602B: cubesat Avion detection
  21. GRB 260601A: cubesat Avion detection
  22. IPN triangulation of GRB 260706B
  23. GRB 260718A: SVOM/ECLAIRs refined analysis
  24. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  25. EP260723a: COLIBRÍ optical observations
  26. GRB 260723A: Fermi GBM Final Localization
  27. IceCube Alert 260722A: Global MASTER-Net observations report
  28. Konus-Wind detection of GRB 260721A
  29. GRB 260722A: Fermi GBM Final Real-time Localization
  30. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  31. Fermi GBM trigger 806384210/260722151 is not a GRB
  32. GRB 260721A: NuSTAR detection of prompt emission
  33. Konus-Wind detection of GRB 260714B
  34. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  35. GRB 260705A: Retraction of optical counterpart
  36. GRB 260714B: Insight-HXMT/HE detection
  37. GRB 260718A: EP-FXT follow-up observation
  38. Fermi trigger No 806104130: Global MASTER-Net observations report
  39. Fermi GRB 260718A: Global MASTER-Net observations report
  40. GRB 260718A: LCO optical upper limits
  41. GRB 260711A: SVOM/GRM observation
  42. GRB 260710A: SVOM/GRM observation
  43. GRB 260718A: Fermi GBM Observation
  44. GRB 260718A : GRANDMA and KNC upper limits
  45. GRB 260718A: SVOM/VT optical upper limits
  46. GRB 260718A: SVOM/VT optical upper limits from VHF data
  47. GRB 260718A: SVOM detection of a burst
  48. GRB 260714B: SVOM/GRM observation
  49. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  50. GRB 260714B: GECAM-B observation of a burst
  51. GRB 260618B: EP-FXT follow-up observation upper limit
  52. GRB 260714B: COLIBRÍ optical counterpart candidate
  53. SVOM sb26071506: Global MASTER-Net observations report
  54. sb26071506: SVOM detection of a X-ray transient
  55. GRB 260715A: Fermi GBM Final Real-time Localization
  56. GRB 260710A: AstroSat CZTI detection
  57. GRB 260709A: AstroSat CZTI detection
  58. GRB 260714B: AstroSat CZTI detection
  59. GRB 260714B: Fermi-LAT detection
  60. GRB 260714B: Fermi GBM Detection
  61. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  62. GRB 260714B: Fermi GBM Final Real-time Localization
  63. GRB 260706A: ATCA detection of possible radio counterpart
  64. GRB 260705A: ATCA radio observations
  65. GRB 260714A: Fermi GBM Final Real-time Localization
  66. GRB 260619A: SVOM/VT continuous optical observations
  67. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  68. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  69. EP260623a: KAIT optical observations
  70. GRB 260708A: GRANDMA Optical Observations
  71. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  72. GRB 260710A: Insight-HXMT/HE detection
  73. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  74. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  75. GRB 260708A: LCO optical observations
  76. GRB 260710A: Fermi GBM Detection
  77. GRB 260709A: SVOM/GRM detection
  78. GRB 260709A: GECAM-B observation
  79. GRB 260705C: AstroSat CZTI detection
  80. GRB 260710A: Fermi GBM Final Real-time Localization
  81. GRB 260708A: Glowbug gamma-ray detection
  82. GRB 260704A: SVOM/ECLAIRs refined analysis
  83. GRB 260706A : GRANDMA Upper limits
  84. GRB 260708A: Kilonova-Catcher optical afterglow detection
  85. GRB 260708A: GECAM-B observation of a burst
  86. GRB 260708A: Fermi-GBM observation
  87. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  88. IceCube Alert 260709A: Global MASTER-Net observations report
  89. GRB 260709A: Fermi GBM Final Real-time Localization
  90. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  91. LAT GRB260708.42: Global MASTER-Net observations report
  92. GRB 260708A: Fermi-LAT detection
  93. GRB 260705B: SVOM/GRM observation
  94. GRB 260708A: Fermi-GBM detection
  95. GRB 260706A: Further EP-FXT follow-up observation
  96. GRB 260706A: SVOM/VT optical upper limits
  97. EP260707a (by EP-FXT): NOT optical upper limit
  98. EP260707a: TRT optical upper limit
  99. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  100. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B

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