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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"

27393 results found.

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

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