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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').

777 results found.

  1. GRB 250213A: SVOM detection of a burst
  2. GRB 250205A: Leavitt Observatory optical upper limit
  3. GRB 250210A: GRBAlpha detection
  4. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  5. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  6. GRB 250211A: Swift ToO observations
  7. GRB 250210A: SVOM/GRM observation of a long burst
  8. GRB 250204B: GRBAlpha detection
  9. GRB 250205A: 1.3m DFOT optical upper limit
  10. Konus-Wind detection of GRB 250204B
  11. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  12. GRB 250205A: Fermi GBM Observation
  13. GRB 250205A: REM NIR upper limit
  14. GRB 250205A: Swift/UVOT Upper Limits
  15. EP250205a/GRB 250205A: Einstein Probe observation
  16. GRB 250127C: SVOM/GRM observation of a burst
  17. GRB 250204B: SVOM/GRM observation of a likely short burst
  18. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  19. GRB 250205A: Swift/XRT detection
  20. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  21. GRB250205A: SVOM/VT optical afterglow detection
  22. GRB 250205A: GOTO optical upper limits
  23. GRB 250205A: SVOM detection of a burst
  24. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  25. GRB 250129A: SVOM/C-GFT optical observations
  26. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  27. GRB 250129A: COLIBRÍ Optical Observations
  28. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  29. GRB 250127A: CrAO and Terskol optical upper limits
  30. GRB 250127A: Swift-XRT observations
  31. GRB 250127A: EP-FXT afterglow detection
  32. GRB 250117A: Fermi GBM Observation
  33. GRB 250127A: SVOM/VT upper limit
  34. GRB 250127A: Swift ToO observations
  35. GRB 250127A: LCO optical upper limit
  36. GRB 250127A: SVOM detection of a long burst
  37. GECAM-A detection of a bright burst from SGR 1E1841-045
  38. IPN triangulation of a bright burst from SGR 1E1841-045
  39. Improved IPN triangulation of GRB 250107C
  40. Konus-Wind detection of GRB 250117A
  41. IPN triangulation of GRB 250117A (short)
  42. GRB 250117A: SVOM/GRM observation of a short burst
  43. GRB 250114B: SVOM/VT upper limit
  44. Konus-Wind detection of GRB 250113A
  45. IPN triangulation of GRB 250113A
  46. GRB 250113A: INTEGRAL/SPI-ACS detection
  47. GRB 250113A: SVOM/GRM observation of a long burst
  48. GRB 250106A: Swift-XRT afterglow detection
  49. GRB 250109A / EP250109a: Mephisto optical upper limits
  50. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  51. GRB 250101B: Fermi GBM Observation
  52. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  53. GRB 250108A: Swift/XRT afterglow fading
  54. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  55. Konus-Wind detection of GRB 250107C
  56. GRB 250109A: Fermi GBM Observation
  57. EP250109a: Swift/UVOT non-detection
  58. IPN triangulation of GRB 250107C
  59. EP250109a: SVOM/VT optical candidate
  60. GRB 250107C: SVOM/GRM observation
  61. GRB 250108A: Swift/UVOT Upper Limits
  62. GRB 250108A: NOT optical upper limit
  63. GRB 250103A: 1.6m Mephisto optical observations
  64. GRB 250108A: Swift-XRT afterglow detection
  65. GRB 250108A:SVOM/VT optical candidate
  66. GRB 250103A: Swift-XRT afterglow detection
  67. GRB 250108A: Swift ToO observations
  68. GRB 250108A: SVOM detection of a soft long burst
  69. GRB 250106A: SVOM/VT 2nd optical deep observation
  70. GRB 250106A: NOT optical observations
  71. GRB 250103B: REM optical/NIR upper limits
  72. GRB 250106A: Swift-XRT observations
  73. GRB 250106A: SVOM/VT optical candidate
  74. GRB 250106A: Swift ToO observations
  75. GRB 250106A: SVOM detection of a long burst
  76. GRB 241229A: SVOM/VT optical upperlimit
  77. GRB 250103B: LCO/1m optical afterglow candidate detection
  78. GRB 250103A: Bassano Bresciano Observatory upper limit
  79. GRB 250103A: Swift-XRT observations
  80. GRB 250101A: 1.3m DFOT optical afterglow detection
  81. GRB 241229A: 1.3m DFOT upper limit
  82. GRB 250103A: NOT spectroscopic redshift
  83. GRB 250103B：SVOM/VT optical counterpart
  84. GRB 250103A: Montarrenti Observatory optical detection
  85. GRB 250103A: NOT optical observations
  86. GRB 250103A: TSHAO optical upper limit
  87. GRB 250103A: Fermi GBM Observation
  88. GRB 250103A: SVOM/VT optical counterpart confirmation
  89. GRB 250103A: Swift ToO observations
  90. GRB 250103B: SVOM detection of a long burst
  91. GRB 250103A: Xinglong 2.16m Optical Candidate
  92. GRB 250101B: SVOM/GRM observation
  93. GRB 250103A: GOTO optical upper limit
  94. GRB 250103A: SVOM/C-GFT optical upper limit
  95. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  96. GRB 250103A: SVOM detection of a long burst
  97. GRB 250101A: SVOM/C-GFT early optical observations
  98. GRB 241229B: Continued CrAO ZTSh observations
  99. GRB 241229A: EP-FXT X-ray afterglow confirmation
  100. GRB 241229B: SVOM/GRM observation

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