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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"

26867 results found.

  1. GRB 260907A: SVOM/GRM observation
  2. GRB 260909A: CrAO and AbAO optical upper limits
  3. GRB 260909A: SVOM/ECLAIRs refined analysis
  4. GRB 260910B: GOTO tentative optical counterpart candidates
  5. GRB 260910B: Fermi GBM Final Real-time Localization
  6. EP Alert 260909.53: Global MASTER-Net observations report
  7. GRB 260909A: EP-FXT follow-up observation
  8. GRB 260910A: Fermi GBM Final Real-time Localization
  9. GRB 260909A: SVOM/VT optical upper limits
  10. GRB 260909A: SVOM/GRM observation
  11. GRB 260909A: Mondy optical observations and afterglow candidate
  12. GRB 260909A: Xinglong 2.16m optical upper limit
  13. GRB 260909A: SVOM/C-GFT optical upper limit
  14. GRB 260909A: SVOM detection of a burst
  15. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  16. Fermi trigger No 810554827: Global MASTER-Net observations report
  17. EP Alert 260908.60: Global MASTER-Net observations report
  18. Fermi GRB 260907B: Global MASTER-Net observations report
  19. The EP-WXT trigger 01709305715 is likely a flaring star
  20. GRB 260907B: Fermi GBM Final Real-time Localization
  21. Fermi GRB 260907A: Global MASTER-Net observations report
  22. GRB 260907A: Fermi GBM Final Real-time Localization
  23. EP260903a: EP-FXT follow-up observation
  24. EP Alert 260905.11: Global MASTER-Net observations report
  25. The EP-WXT trigger 01709302592 is likely a flaring star
  26. GRB 260903A: J-band upper limit with WINTER
  27. EP Alert 260903.47: Global MASTER-Net observations report
  28. GRB 260903A: SVOM/ECLAIRs refined analysis
  29. GRB260903A: Liverpool Telescope optical observations
  30. GRB 260830A: GECAM-B detection of a burst
  31. EP260903a: EP-WXT detection of a fast X-ray transient
  32. EP Alert 260903.62: Global MASTER-Net observations report
  33. GRB 260903A: EP-FXT follow-up observation
  34. GRB 260903A: NOT optical observations and afterglow fading
  35. SVOM GRB260903A: Global MASTER-Net observations report
  36. GRB 260903A: LCO optical observations
  37. GRB 260903A: SVOM/VT optical candidate
  38. GRB 260831A: GECAM-B observation
  39. GRB 260903A: LCO optical counterpart detection
  40. GRB 260903A: SVOM detection of a soft faint burst
  41. EP260901a: SVOM/VT optical upper limits
  42. EP260901a: EP-FXT follow-up observation
  43. GRB 260829A: SVOM/GRM observation
  44. GRB 260818A: ATCA detection of a candidate radio counterpart
  45. EP260830a: EP-FXT follow-up observation
  46. EP260901a: Global MASTER-Net observations report
  47. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  48. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  49. EP260901a: EP-WXT detection of a fast X-ray transient
  50. SVOM trigger sb26083106 is not a GRB
  51. GRB 260831B: EP-FXT follow-up observation
  52. GRB 260831B: LCO optical upper limits
  53. EP260830a: Global MASTER-Net observations report
  54. EP260830a: EP-WXT detection of a fast X-ray transient
  55. GRB 260827A: SVOM/GRM observation
  56. GRB 260831B: SVOM detection of a possible burst
  57. IPN triangulation of GRB 260829A
  58. EP260727a: ATCA 10 GHz detection
  59. GRB 260831A: Fermi GBM Final Real-time Localization
  60. GRB 260829A: GECAM-B observation of a long burst
  61. GRB 260825A: SVOM/GRM observation of a long burst
  62. GRB 260825A: GECAM-B observation
  63. GRB 260829A: Fermi GBM Detection
  64. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  65. GRB 260829A: Fermi GBM Final Real-time Localization
  66. Fermi GBM trigger 809666623/260829141 is not a GRB
  67. GRB 260818B: Further EP-FXT observation
  68. GRB 260818B: VLT optical and nIR observations
  69. GRB 260818B: TNG NIR observations
  70. MAXI GRB260827.40: Global MASTER-Net observations report
  71. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  72. GRB 260827A: Fermi GBM Final Real-time Localization
  73. GRB 260818B: 6 GHz VLA observations
  74. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  75. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  76. EP260822a: Global MASTER-Net observations report
  77. EP Alert 260820.31: Global MASTER-Net observations report
  78. GRB 260807A: EP-FXT follow-up observations
  79. GRB 260822A: SVOM/ECLAIRs refined analysis
  80. GRB 260809A: SVOM/ECLAIRs refined analysis
  81. GRB 260822A: SVOM/VT optical upper limits
  82. IceCube Alert 260825A: Global MASTER-Net observations report
  83. GRB 260825A: Fermi GBM Final Real-time Localization
  84. GRB 260822A: EP/FXT follow-up observations
  85. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  86. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  87. EP260822a: EP-FXT non-detection and upper limit
  88. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  89. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  90. EP260822a: Einstein Probe detection of a fast X-ray transient
  91. GRB 260822A: LCO optical upper limits
  92. The EP-WXT trigger 01709287395 is likely a flaring star
  93. GRB260822B: Fermi GBM Final Localization
  94. GRB 260822A: GROWTH-India Telescope Upper Limits
  95. GRB 260822A: GOTO optical upper limit
  96. GRB 260822A: SVOM detection of a short burst
  97. GRB 260818B: SVOM/C-GFT optical upper limit
  98. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  99. IceCube Alert 260821A: Global MASTER-Net observations report
  100. The EP-WXT trigger 01709286204 is likely a flaring star

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