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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28106 results found.

  1. EP260221a: COLIBRÍ optical upper limit
  2. SVOM alert sb26021801: LCO optical upper limit
  3. EP260221a: Einstein Probe detection of an X-ray transient
  4. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  5. Fermi GRB 260219A: Global MASTER-Net observations report
  6. SVOM alert sb26021801: LAST optical upper limit
  7. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  8. IceCube Alert 260217A: Global MASTER-Net observations report
  9. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  10. sb26021801: SVOM detection of a long faint X-ray transient
  11. EP-WXT 01709258455: NOT optical upper limits
  12. EP260214b: Mondy optical observations
  13. EP260214b: 1.3m DFOT optical upper limit
  14. EP260210a: Mondy optical upper limits
  15. GRB 260208A: AbAO and Terskol optical upper limits
  16. GRB 260208A: continued Mondy optical observations
  17. IPN triangulation of GRB 260212A
  18. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  19. EP260214b: Liverpool Telescope optical observations
  20. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  21. EP260214b: Optical upper limit with Kinder observations
  22. EP260214a: Optical upper limits with Kinder observations
  23. EP260214b: EP-FXT follow-up observation
  24. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  25. EP260214b: DDOTI Optical Detection
  26. EP260214b: GROWTH-India Telescope optical upper limit
  27. EP260214a: VLT near-infrared observation
  28. EP260214a: NOT optical upper limits
  29. EP260214a: COLIBRÍ optical upper limits
  30. EP260214b: OHP/T120 optical observations
  31. EP260214a: refined analysis of the EP-FXT observation
  32. EP260214b: LCO optical counterpart detection
  33. GRB 260211A: SVOM/VT optical counterpart
  34. EP260214b: COLIBRÍ optical observations
  35. EP260214b: NOT optical counterpart detection
  36. EP260214b: Einstein Probe detection of a fast X-ray transient
  37. EP260214a: Global MASTER-Net observations report
  38. EP260214a: Einstein Probe detection of an X-ray transient
  39. GRB 260212A: AstroSat CZTI detection
  40. GRB 260212A: Fermi GBM Observation
  41. EP260213a: Liverpool Telescope optical upper limits
  42. EP260213a: Global MASTER-Net observations report
  43. EP260213a: COLIBRÍ optical upper limits
  44. EP260213a: Optical upper limits with Kinder observations
  45. EP260213a: Mondy R-band optical upper limit
  46. EP260213a: SVOM/C-GFT upper limit
  47. EP260213a: refined analysis of the EP-FXT observation
  48. EP260213a: Einstein Probe detection of a fast X-ray transient
  49. EP/WXT 01709258378: NOT optical upper limits
  50. GRB 260212A: SVOM/GRM observation of a long burst
  51. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  52. GRB 260211A: EP-FXT follow-up observation
  53. GRB 260211A: SVOM/VT optical observation
  54. GRB 260212A: Glowbug gamma-ray detection
  55. Fermi GRB 260212A: Global MASTER-Net observations report
  56. GRB 260211A: LAST optical upper limit
  57. GRB 260210A: SVOM/GRM observation
  58. Fermi GBM Sub-Threshold Detection of GRB 260211A
  59. GRID detection of GRB 260207B
  60. GRB 260211A: LCO optical upper limits
  61. GRB260131A/B: 3.6m DOT Optical Observations
  62. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  63. Fermi trigger No 792537871: Global MASTER-Net observations report
  64. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  65. EP260209a: COLIBRÍ optical upper limit
  66. Fermi GRB 260210C: Global MASTER-Net observations report
  67. EP260209a: LCO optical upper limits
  68. EP260210a: Global MASTER-Net observations report
  69. EP260210a: refined analysis of the EP-FXT observation
  70. EP260209a: Global MASTER-Net observations report
  71. GRB 260208A: LCO detection of the optical counterpart
  72. EP260209a: Einstein Probe detection of a fast X-ray transient
  73. EP260210a: Optical upper limits with Kinder observations
  74. GRB 260210A: Glowbug gamma-ray detection
  75. GRB 260208C: AstroSat CZTI detection
  76. EP260210a: COLIBRÍ optical upper limit
  77. EP260210a: SVOM/C-GFT upper limit
  78. EP260210a: Einstein Probe detection of an X-ray transient
  79. GRB 260207B: AstroSat CZTI detection
  80. GRB 260208C: SVOM/GRM observation
  81. GRB 260204A: Swift-XRT afterglow detection
  82. GRB 260208B: AstroSat CZTI detection of a bright long burst
  83. GRB260208A: Liverpool Telescope optical follow-up observations
  84. GRB 260208A: Glowbug gamma-ray detection
  85. GRB 260208A: NuSTAR detection of prompt emission
  86. GRB 260208A: Fermi GBM Observation
  87. Fermi GRB 260209A: Global MASTER-Net observations report
  88. GRB 260208B: Swift-XRT observations
  89. GRB 260131A/B: continued Mondy optical observations
  90. GRB 260204A: Swift/UVOT Upper Limits
  91. GRB 260208B: COLIBRÍ optical observations
  92. GRB 260208A: Mondy optical observations
  93. GRB 260208A: 1.3m DFOT optical detection
  94. GRB 260208A: COLIBRÍ optical observations
  95. GRB 260208B: EP-FXT observation
  96. Fermi GRB 260208C: Global MASTER-Net observations report
  97. GRB 260208B: SVOM/VT optical candidate
  98. GRB 260208A: GECAM-B observation of a bright burst
  99. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  100. GRB 260208A: SVOM/VT optical observation

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