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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"

37332 results found.

  1. GRB 260903A: J-band upper limit with WINTER
  2. GRB 260903A: SVOM/ECLAIRs refined analysis
  3. GRB260903A: Liverpool Telescope optical observations
  4. GRB 260903A: SAO RAS optical observations
  5. GRB 260830A: GECAM-B detection of a burst
  6. GRB 260830A: Insight-HXMT/HE detection
  7. GRB 260903A: EP-FXT follow-up observation
  8. GRB 260903A: OHP/T193 optical afterglow detection
  9. GRB 260903A: NOT optical observations and afterglow fading
  10. GRB 260903A: LCO optical observations
  11. GRB 260903A: SVOM/VT optical candidate
  12. GRB 260903A: Retraction of optical counterpart of GCN 45501
  13. GRB 260831A: GECAM-B observation
  14. GRB 260903A: LCO optical counterpart detection
  15. GRB 260827A: Insight-HXMT/HE detection
  16. GRB 260903A: SVOM detection of a soft faint burst
  17. Konus-Wind detection of GRB 260829A
  18. GRB 260829A: SVOM/GRM observation
  19. GRB 260818A: ATCA detection of a candidate radio counterpart
  20. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  21. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  22. SVOM trigger sb26083106 is not a GRB
  23. GRB 260829A: AstroSat CZTI detection
  24. GRB 260831B: EP-FXT follow-up observation
  25. GRB 260830A: NuSTAR detection of prompt emission
  26. GRB 260831B: LCO optical upper limits
  27. GRB 260827A: SVOM/GRM observation
  28. GRB 260831B: SVOM detection of a possible burst
  29. IPN triangulation of GRB 260829A
  30. GRB 260827A: Glowbug gamma-ray detection
  31. GRB 260831A: Fermi GBM Final Real-time Localization
  32. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  33. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  34. GRB 260829A: GECAM-B observation of a long burst
  35. GRB 260825A: SVOM/GRM observation of a long burst
  36. GRB 260825A: GECAM-B observation
  37. GRB 260829A: Fermi GBM Detection
  38. GRB 260825A: AstroSat CZTI detection
  39. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  40. GRB 260829A: Fermi GBM Final Real-time Localization
  41. Fermi GBM trigger 809666623/260829141 is not a GRB
  42. GRB 260818B: Further EP-FXT observation
  43. GRB 260818B: VLT optical and nIR observations
  44. GRB 260818B: TNG NIR observations
  45. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  46. GRB 260827A: Fermi GBM Final Real-time Localization
  47. GRB 260818B: 6 GHz VLA observations
  48. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  49. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  50. GRB 260808B: SAO RAS observations of the optical rebrightening
  51. GRB 260807A: EP-FXT follow-up observations
  52. GRB 260822A: SVOM/ECLAIRs refined analysis
  53. GRB 260809A: SVOM/ECLAIRs refined analysis
  54. GRB 260822A: SVOM/VT optical upper limits
  55. GRB 260825A: Fermi GBM Final Real-time Localization
  56. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  57. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  58. GRB 260822A: EP/FXT follow-up observations
  59. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  60. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  61. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  62. GRB 260822A: GOTO optical counterpart detection
  63. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  64. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  65. GRB 260822A: LCO optical upper limits
  66. GRB260822B: Fermi GBM Final Localization
  67. GRB 260822A: GROWTH-India Telescope Upper Limits
  68. GRB 260822A: GOTO optical upper limit
  69. GRB 260822A: SVOM detection of a short burst
  70. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  71. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  72. GRB 260818B: VLA radio observations
  73. GRB 260818B: SVOM/C-GFT optical upper limit
  74. GRB 260820A: Insight-HXMT/HE detection
  75. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  76. GRB 260818B: SVOM/GRM observation
  77. GRB260820A: Fermi GBM Final Real-Time Localization
  78. GRB 260818B: Insight-HXMT detection
  79. GRB 260818B: EP-FXT follow-up observation
  80. GRB 260818A: J-band observations with WINTER
  81. GRB 260818B: SVOM/ECLAIRs refined analysis
  82. GRB 260818A: SVOM/ECLAIRs refined analysis
  83. GRB 260818B: NOT optical upper limits
  84. GRB 260810A: SVOM/GRM observation
  85. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  86. GRB260818A: EP-FXT follow-up observation
  87. GRB 260818B: LCO optical upper limits
  88. GRB 260818B: SVOM detection of a short burst
  89. SVOM trigger sb26081806 is not a GRB
  90. EP260806a: SAO RAS multicolor optical observations
  91. GRB 260818A: LCO optical upper limits
  92. EP260812a: AbAO optical upper limit
  93. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  94. GRB 260810A: Insight-HXMT/HE detection
  95. GRB 260818A: SVOM possible detection of a long and faint GRB
  96. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  97. GRB 260808B: Liverpool Telescope further optical observations
  98. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  99. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  100. GRB 260813A: Fermi GBM Final Real-time Localization

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