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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"

27392 results found.

  1. GRB 260208A: AbAO and Terskol optical upper limits
  2. GRB 260208A: continued Mondy optical observations
  3. IPN triangulation of GRB 260212A
  4. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  5. EP260214b: Liverpool Telescope optical observations
  6. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  7. EP260214b: Optical upper limit with Kinder observations
  8. EP260214a: Optical upper limits with Kinder observations
  9. EP260214b: EP-FXT follow-up observation
  10. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  11. EP260214b: DDOTI Optical Detection
  12. EP260214b: GROWTH-India Telescope optical upper limit
  13. EP260214a: VLT near-infrared observation
  14. EP260214a: NOT optical upper limits
  15. EP260214a: COLIBRÍ optical upper limits
  16. EP260214b: OHP/T120 optical observations
  17. EP260214a: refined analysis of the EP-FXT observation
  18. EP260214b: LCO optical counterpart detection
  19. GRB 260211A: SVOM/VT optical counterpart
  20. EP260214b: COLIBRÍ optical observations
  21. EP260214b: NOT optical counterpart detection
  22. EP260214b: Einstein Probe detection of a fast X-ray transient
  23. EP260214a: Global MASTER-Net observations report
  24. EP260214a: Einstein Probe detection of an X-ray transient
  25. GRB 260212A: AstroSat CZTI detection
  26. GRB 260212A: Fermi GBM Observation
  27. EP260213a: Liverpool Telescope optical upper limits
  28. EP260213a: Global MASTER-Net observations report
  29. EP260213a: COLIBRÍ optical upper limits
  30. EP260213a: Optical upper limits with Kinder observations
  31. EP260213a: Mondy R-band optical upper limit
  32. EP260213a: SVOM/C-GFT upper limit
  33. EP260213a: refined analysis of the EP-FXT observation
  34. EP260213a: Einstein Probe detection of a fast X-ray transient
  35. EP/WXT 01709258378: NOT optical upper limits
  36. GRB 260212A: SVOM/GRM observation of a long burst
  37. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  38. GRB 260211A: EP-FXT follow-up observation
  39. GRB 260211A: SVOM/VT optical observation
  40. GRB 260212A: Glowbug gamma-ray detection
  41. Fermi GRB 260212A: Global MASTER-Net observations report
  42. GRB 260211A: LAST optical upper limit
  43. GRB 260210A: SVOM/GRM observation
  44. Fermi GBM Sub-Threshold Detection of GRB 260211A
  45. GRID detection of GRB 260207B
  46. GRB 260211A: LCO optical upper limits
  47. GRB260131A/B: 3.6m DOT Optical Observations
  48. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  49. Fermi trigger No 792537871: Global MASTER-Net observations report
  50. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  51. EP260209a: COLIBRÍ optical upper limit
  52. Fermi GRB 260210C: Global MASTER-Net observations report
  53. EP260209a: LCO optical upper limits
  54. EP260210a: Global MASTER-Net observations report
  55. EP260210a: refined analysis of the EP-FXT observation
  56. EP260209a: Global MASTER-Net observations report
  57. GRB 260208A: LCO detection of the optical counterpart
  58. EP260209a: Einstein Probe detection of a fast X-ray transient
  59. EP260210a: Optical upper limits with Kinder observations
  60. GRB 260210A: Glowbug gamma-ray detection
  61. GRB 260208C: AstroSat CZTI detection
  62. EP260210a: COLIBRÍ optical upper limit
  63. EP260210a: SVOM/C-GFT upper limit
  64. EP260210a: Einstein Probe detection of an X-ray transient
  65. GRB 260207B: AstroSat CZTI detection
  66. GRB 260208C: SVOM/GRM observation
  67. GRB 260204A: Swift-XRT afterglow detection
  68. GRB 260208B: AstroSat CZTI detection of a bright long burst
  69. GRB260208A: Liverpool Telescope optical follow-up observations
  70. GRB 260208A: Glowbug gamma-ray detection
  71. GRB 260208A: NuSTAR detection of prompt emission
  72. GRB 260208A: Fermi GBM Observation
  73. Fermi GRB 260209A: Global MASTER-Net observations report
  74. GRB 260208B: Swift-XRT observations
  75. GRB 260131A/B: continued Mondy optical observations
  76. GRB 260204A: Swift/UVOT Upper Limits
  77. GRB 260208B: COLIBRÍ optical observations
  78. GRB 260208A: Mondy optical observations
  79. GRB 260208A: 1.3m DFOT optical detection
  80. GRB 260208A: COLIBRÍ optical observations
  81. GRB 260208B: EP-FXT observation
  82. Fermi GRB 260208C: Global MASTER-Net observations report
  83. GRB 260208B: SVOM/VT optical candidate
  84. GRB 260208A: GECAM-B observation of a bright burst
  85. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  86. GRB 260208A: SVOM/VT optical observation
  87. Fermi GRB 260208D: Global MASTER-Net observations report
  88. GRB 260208A: Swift-XRT observations
  89. GRB 260208B: SVOM/GRM observation of a bright burst
  90. GRB 260208B: Fermi GBM Detection
  91. LAT GRB 260208B: Global MASTER-Net observations report
  92. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  93. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  94. Fermi GRB 260208A: Global MASTER-Net observations report
  95. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  96. GRB 260131A/B: Mondy and Terskol optical observations
  97. Fermi GRB 260207B: Global MASTER-Net observations report
  98. GRB 260206A: Swift-XRT observations
  99. Fermi trigger No 792135758: Global MASTER-Net observations report
  100. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection

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