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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"

37944 results found.

  1. GRB 260727A: LCO optical upper limits
  2. GRB 260727B: Fermi GBM Final Real-time Localization
  3. Fermi GRB 260726A: Global MASTER-Net observations report
  4. GRB 260727A: SVOM detection of a bright long burst
  5. GRB 260726A: SVOM detection of a burst
  6. GRB 260726A: Fermi GBM Final Real-time Localization
  7. GRB 260616A: cubesat Avion detection
  8. GRB 260602B: cubesat Avion detection
  9. GRB 260601A: cubesat Avion detection
  10. IPN triangulation of GRB 260706B
  11. GRB 260718A: SVOM/ECLAIRs refined analysis
  12. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  13. GRB 260723A: Fermi GBM Final Localization
  14. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  15. IceCube Alert 260722A: Global MASTER-Net observations report
  16. Konus-Wind detection of GRB 260721A
  17. GRB 260722A: Fermi GBM Final Real-time Localization
  18. Fermi GBM trigger 806384210/260722151 is not a GRB
  19. GRB 260721A: NuSTAR detection of prompt emission
  20. Konus-Wind detection of GRB 260714B
  21. GRB 260705A: Retraction of optical counterpart
  22. GRB 260714B: Insight-HXMT/HE detection
  23. GRB 260718A: EP-FXT follow-up observation
  24. Fermi trigger No 806104130: Global MASTER-Net observations report
  25. Fermi GRB 260718A: Global MASTER-Net observations report
  26. GRB 260718A: LCO optical upper limits
  27. GRB 260711A: SVOM/GRM observation
  28. GRB 260710A: SVOM/GRM observation
  29. GRB 260718A: Fermi GBM Observation
  30. GRB 260718A : GRANDMA and KNC upper limits
  31. GRB 260718A: SVOM/VT optical upper limits
  32. GRB 260718A: SVOM/VT optical upper limits from VHF data
  33. GRB 260718A: SVOM detection of a burst
  34. GRB 260714B: SVOM/GRM observation
  35. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  36. GRB 260714B: GECAM-B observation of a burst
  37. GRB 260618B: EP-FXT follow-up observation upper limit
  38. GRB 260714B: COLIBRÍ optical counterpart candidate
  39. SVOM sb26071506: Global MASTER-Net observations report
  40. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  41. GRB 260715A: Fermi GBM Final Real-time Localization
  42. GRB 260710A: AstroSat CZTI detection
  43. GRB 260709A: AstroSat CZTI detection
  44. GRB 260714B: AstroSat CZTI detection
  45. GRB 260714B: Fermi-LAT detection
  46. GRB 260714B: Fermi GBM Detection
  47. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  48. GRB 260714B: Fermi GBM Final Real-time Localization
  49. GRB 260706A: ATCA detection of possible radio counterpart
  50. GRB 260705A: ATCA radio observations
  51. GRB 260714A: Fermi GBM Final Real-time Localization
  52. GRB 260619A: SVOM/VT continuous optical observations
  53. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  54. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  55. EP260623a: KAIT optical observations
  56. GRB 260708A: GRANDMA Optical Observations
  57. GRB 260710A: Insight-HXMT/HE detection
  58. GRB 260708A: LCO optical observations
  59. GRB 260710A: Fermi GBM Detection
  60. GRB 260709A: SVOM/GRM detection
  61. GRB 260709A: GECAM-B observation
  62. GRB 260705C: AstroSat CZTI detection
  63. GRB 260710A: Fermi GBM Final Real-time Localization
  64. GRB 260708A: Glowbug gamma-ray detection
  65. GRB 260704A: SVOM/ECLAIRs refined analysis
  66. GRB 260706A : GRANDMA Upper limits
  67. GRB 260708A: Kilonova-Catcher optical afterglow detection
  68. GRB 260708A: GECAM-B observation of a burst
  69. IceCube-260708A: One candidate from the Zwicky Transient Facility
  70. GRB 260708A: Fermi-GBM observation
  71. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  72. IceCube Alert 260709A: Global MASTER-Net observations report
  73. GRB 260709A: Fermi GBM Final Real-time Localization
  74. LAT GRB260708.42: Global MASTER-Net observations report
  75. GRB 260708A: Fermi-LAT detection
  76. GRB 260705B: SVOM/GRM observation
  77. GRB 260708A: Fermi-GBM detection
  78. GRB 260706A: Further EP-FXT follow-up observation
  79. GRB 260706A: SVOM/VT optical upper limits
  80. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  81. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  82. GRB 260705C: Glowbug gamma-ray detection of a short burst
  83. GRB 260706A: SVOM/ECLAIRs refined analysis
  84. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  85. GRB 260706A: SVOM/GRM observation
  86. GRB 260706A: REM optical/NIR observations
  87. IceCube-260704A: No candidates from the Zwicky Transient Facility
  88. GRB 260706A: LCO optical upper limit
  89. GRB 260706A: EP-FXT follow-up observation
  90. GRB 260707A: Fermi GBM Final Real-time Localization
  91. GRB 260706A: Fermi GBM Observation
  92. IPN triangulation of GRB 260627A
  93. GRB 260705A: SVOM/ECLAIRs refined analysis
  94. GRB 260706A: SVOM detection of a burst
  95. GRB 260706A: Fermi GBM Final Real-time Localization
  96. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  97. GRB 260705A: LCO optical upper limits
  98. GRB 260704A: NOT optical upper limits
  99. GRB 260705C: Fermi GBM Final Localization
  100. GRB 260705B: Fermi GBM Final Real-time Localization

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