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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"

27395 results found.

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

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