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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"

28711 results found.

  1. GRB 260914A: SVOM/VT optical counterpart confirmation
  2. GRB 260914A: SVOM/VT optical observation from VHF data
  3. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  4. SVOM GRB260914.47: Global MASTER-Net observations report
  5. GRB 260914A: SVOM detection of a burst
  6. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  7. GRB 260818A: Continued ATCA observations
  8. SVOM GRB260913.32: Global MASTER-Net observations report
  9. GRB 260913A: SVOM/C-GFT optical upper limit
  10. GRB 260913A: SVOM detection of a faint burst
  11. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  12. GRB 260907A: SVOM/GRM observation
  13. GRB 260909A: CrAO and AbAO optical upper limits
  14. GRB 260909A: SVOM/ECLAIRs refined analysis
  15. GRB 260910B: GOTO tentative optical counterpart candidates
  16. GRB 260910B: Fermi GBM Final Real-time Localization
  17. EP Alert 260909.53: Global MASTER-Net observations report
  18. GRB 260909A: EP-FXT follow-up observation
  19. GRB 260910A: Fermi GBM Final Real-time Localization
  20. GRB 260909A: SVOM/GRM observation
  21. GRB 260909A: Mondy optical observations and afterglow candidate
  22. GRB 260909A: Xinglong 2.16m optical upper limit
  23. GRB 260909A: SVOM/C-GFT optical upper limit
  24. GRB 260909A: SVOM detection of a burst
  25. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  26. Fermi trigger No 810554827: Global MASTER-Net observations report
  27. EP Alert 260908.60: Global MASTER-Net observations report
  28. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  29. Fermi GRB 260907B: Global MASTER-Net observations report
  30. The EP-WXT trigger 01709305715 is likely a flaring star
  31. GRB 260907B: Fermi GBM Final Real-time Localization
  32. Fermi GRB 260907A: Global MASTER-Net observations report
  33. GRB 260907A: Fermi GBM Final Real-time Localization
  34. EP Alert 260905.11: Global MASTER-Net observations report
  35. The EP-WXT trigger 01709302592 is likely a flaring star
  36. GRB 260903A: J-band upper limit with WINTER
  37. EP Alert 260903.47: Global MASTER-Net observations report
  38. GRB 260903A: SVOM/ECLAIRs refined analysis
  39. GRB260903A: Liverpool Telescope optical observations
  40. EP Alert 260903.62: Global MASTER-Net observations report
  41. GRB 260903A: EP-FXT follow-up observation
  42. GRB 260903A: NOT optical observations and afterglow fading
  43. SVOM GRB260903A: Global MASTER-Net observations report
  44. GRB 260903A: LCO optical observations
  45. GRB 260903A: SVOM/VT optical candidate
  46. GRB 260831A: GECAM-B observation
  47. GRB 260903A: LCO optical counterpart detection
  48. GRB 260827A: Insight-HXMT/HE detection
  49. GRB 260903A: SVOM detection of a soft faint burst
  50. EP260901a: SVOM/VT optical upper limits
  51. Konus-Wind detection of GRB 260829A
  52. GRB 260829A: SVOM/GRM observation
  53. GRB 260818A: ATCA detection of a candidate radio counterpart
  54. EP260901a: Global MASTER-Net observations report
  55. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  56. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  57. SVOM trigger sb26083106 is not a GRB
  58. GRB 260829A: AstroSat CZTI detection
  59. GRB 260831B: EP-FXT follow-up observation
  60. GRB 260831B: LCO optical upper limits
  61. EP260830a: Global MASTER-Net observations report
  62. GRB 260827A: SVOM/GRM observation
  63. GRB 260831B: SVOM detection of a possible burst
  64. IPN triangulation of GRB 260829A
  65. GRB 260827A: Glowbug gamma-ray detection
  66. EP260727a: ATCA 10 GHz detection
  67. GRB 260831A: Fermi GBM Final Real-time Localization
  68. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  69. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  70. GRB 260829A: GECAM-B observation of a long burst
  71. GRB 260825A: SVOM/GRM observation of a long burst
  72. GRB 260825A: GECAM-B observation
  73. GRB 260829A: Fermi GBM Detection
  74. GRB 260825A: AstroSat CZTI detection
  75. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  76. GRB 260829A: Fermi GBM Final Real-time Localization
  77. Fermi GBM trigger 809666623/260829141 is not a GRB
  78. GRB 260818B: Further EP-FXT observation
  79. GRB 260818B: VLT optical and nIR observations
  80. GRB 260818B: TNG NIR observations
  81. MAXI GRB260827.40: Global MASTER-Net observations report
  82. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  83. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  84. GRB 260827A: Fermi GBM Final Real-time Localization
  85. GRB 260818B: 6 GHz VLA observations
  86. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  87. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  88. EP260822a: Global MASTER-Net observations report
  89. EP Alert 260820.31: Global MASTER-Net observations report
  90. GRB 260807A: EP-FXT follow-up observations
  91. GRB 260822A: SVOM/ECLAIRs refined analysis
  92. GRB 260809A: SVOM/ECLAIRs refined analysis
  93. IceCube Alert 260825A: Global MASTER-Net observations report
  94. GRB 260825A: Fermi GBM Final Real-time Localization
  95. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  96. GRB 260822A: EP/FXT follow-up observations
  97. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  98. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  99. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  100. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate

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