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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"

28720 results found.

  1. GRB 260915A: SVOM/VT optical upper limits from VHF data
  2. Fermi GBM Sub-Threshold Detection of GRB 260915A
  3. GRB 260915A: LCO optical upper limits
  4. EP Alert 260914.53: Global MASTER-Net observations report
  5. GRB 260914A: EP-FXT follow-up observation
  6. GRB 260915A: SVOM detection of a burst
  7. Fermi GBM Sub-Threshold Detection of GRB 260914A
  8. GRB 260914A: LCO optical observation
  9. GRB 260914A: SVOM/C-GFT optical observations
  10. GRB 260914A: SVOM/VT optical counterpart confirmation
  11. GRB 260914A: SVOM/VT optical observation from VHF data
  12. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  13. SVOM GRB260914.47: Global MASTER-Net observations report
  14. GRB 260914A: SVOM detection of a burst
  15. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  16. GRB 260818A: Continued ATCA observations
  17. SVOM GRB260913.32: Global MASTER-Net observations report
  18. GRB 260913A: SVOM/C-GFT optical upper limit
  19. GRB 260913A: SVOM detection of a faint burst
  20. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  21. GRB 260907A: SVOM/GRM observation
  22. GRB 260909A: CrAO and AbAO optical upper limits
  23. GRB 260909A: SVOM/ECLAIRs refined analysis
  24. GRB 260910B: GOTO tentative optical counterpart candidates
  25. GRB 260910B: Fermi GBM Final Real-time Localization
  26. EP Alert 260909.53: Global MASTER-Net observations report
  27. GRB 260909A: EP-FXT follow-up observation
  28. GRB 260910A: Fermi GBM Final Real-time Localization
  29. GRB 260909A: SVOM/GRM observation
  30. GRB 260909A: Mondy optical observations and afterglow candidate
  31. GRB 260909A: Xinglong 2.16m optical upper limit
  32. GRB 260909A: SVOM/C-GFT optical upper limit
  33. GRB 260909A: SVOM detection of a burst
  34. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  35. Fermi trigger No 810554827: Global MASTER-Net observations report
  36. EP Alert 260908.60: Global MASTER-Net observations report
  37. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  38. Fermi GRB 260907B: Global MASTER-Net observations report
  39. The EP-WXT trigger 01709305715 is likely a flaring star
  40. GRB 260907B: Fermi GBM Final Real-time Localization
  41. Fermi GRB 260907A: Global MASTER-Net observations report
  42. GRB 260907A: Fermi GBM Final Real-time Localization
  43. EP Alert 260905.11: Global MASTER-Net observations report
  44. The EP-WXT trigger 01709302592 is likely a flaring star
  45. GRB 260903A: J-band upper limit with WINTER
  46. EP Alert 260903.47: Global MASTER-Net observations report
  47. GRB 260903A: SVOM/ECLAIRs refined analysis
  48. GRB260903A: Liverpool Telescope optical observations
  49. EP Alert 260903.62: Global MASTER-Net observations report
  50. GRB 260903A: EP-FXT follow-up observation
  51. GRB 260903A: NOT optical observations and afterglow fading
  52. SVOM GRB260903A: Global MASTER-Net observations report
  53. GRB 260903A: LCO optical observations
  54. GRB 260903A: SVOM/VT optical candidate
  55. GRB 260831A: GECAM-B observation
  56. GRB 260903A: LCO optical counterpart detection
  57. GRB 260827A: Insight-HXMT/HE detection
  58. GRB 260903A: SVOM detection of a soft faint burst
  59. EP260901a: SVOM/VT optical upper limits
  60. Konus-Wind detection of GRB 260829A
  61. GRB 260829A: SVOM/GRM observation
  62. GRB 260818A: ATCA detection of a candidate radio counterpart
  63. EP260901a: Global MASTER-Net observations report
  64. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  65. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  66. SVOM trigger sb26083106 is not a GRB
  67. GRB 260829A: AstroSat CZTI detection
  68. GRB 260831B: EP-FXT follow-up observation
  69. GRB 260831B: LCO optical upper limits
  70. EP260830a: Global MASTER-Net observations report
  71. GRB 260827A: SVOM/GRM observation
  72. GRB 260831B: SVOM detection of a possible burst
  73. IPN triangulation of GRB 260829A
  74. GRB 260827A: Glowbug gamma-ray detection
  75. EP260727a: ATCA 10 GHz detection
  76. GRB 260831A: Fermi GBM Final Real-time Localization
  77. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  78. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  79. GRB 260829A: GECAM-B observation of a long burst
  80. GRB 260825A: SVOM/GRM observation of a long burst
  81. GRB 260825A: GECAM-B observation
  82. GRB 260829A: Fermi GBM Detection
  83. GRB 260825A: AstroSat CZTI detection
  84. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  85. GRB 260829A: Fermi GBM Final Real-time Localization
  86. Fermi GBM trigger 809666623/260829141 is not a GRB
  87. GRB 260818B: Further EP-FXT observation
  88. GRB 260818B: VLT optical and nIR observations
  89. GRB 260818B: TNG NIR observations
  90. MAXI GRB260827.40: Global MASTER-Net observations report
  91. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  92. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  93. GRB 260827A: Fermi GBM Final Real-time Localization
  94. GRB 260818B: 6 GHz VLA observations
  95. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  96. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  97. EP260822a: Global MASTER-Net observations report
  98. EP Alert 260820.31: Global MASTER-Net observations report
  99. GRB 260807A: EP-FXT follow-up observations
  100. GRB 260822A: SVOM/ECLAIRs refined analysis

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