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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"

28228 results found.

  1. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  2. sb26021801: SVOM/C-GFT upper limit
  3. EP260223a: COLIBRÍ optical upper limits
  4. EP260223a: Einstein Probe detection of an X-ray transient
  5. GRB 260223A: SVOM/GRM observation
  6. GRB 260223A: COLIBRÍ further optical observations and a brightening
  7. EP260221a: Optical upper limit with Kinder observations
  8. GRB 260223A: COLIBRÍ optical observations
  9. GRB 260223A: DDOTI Optical Candidate
  10. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  11. Fermi GRB 260223A: Global MASTER-Net observations report
  12. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  13. EP260221a: COLIBRÍ optical counterpart candidate
  14. EP260221a: Gemini South z-band upper limit
  15. EP260221a: Global MASTER-Net observations report
  16. EP260221a: EP-FXT follow-up observation
  17. Fermi GRB 260221B: Global MASTER-Net observations report
  18. EP-WXT01709258519: Xinglong optical upper limit
  19. EP260221a: Xinglong optical upper limit
  20. Fermi GRB 260221A: Global MASTER-Net observations report
  21. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  22. EP260221a: GOTO optical upper limit
  23. EP260221a: COLIBRÍ optical upper limit
  24. SVOM alert sb26021801: LCO optical upper limit
  25. EP260221a: Einstein Probe detection of an X-ray transient
  26. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi GRB 260219A: Global MASTER-Net observations report
  28. SVOM alert sb26021801: LAST optical upper limit
  29. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  30. IceCube Alert 260217A: Global MASTER-Net observations report
  31. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  32. sb26021801: SVOM detection of a long faint X-ray transient
  33. EP-WXT 01709258455: NOT optical upper limits
  34. EP260214b: Mondy optical observations
  35. EP260214b: 1.3m DFOT optical upper limit
  36. EP260210a: Mondy optical upper limits
  37. GRB 260208A: AbAO and Terskol optical upper limits
  38. GRB 260208A: continued Mondy optical observations
  39. IPN triangulation of GRB 260212A
  40. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  41. EP260214b: Liverpool Telescope optical observations
  42. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  43. EP260214b: Optical upper limit with Kinder observations
  44. EP260214a: Optical upper limits with Kinder observations
  45. EP260214b: EP-FXT follow-up observation
  46. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  47. EP260214b: DDOTI Optical Detection
  48. EP260214b: GROWTH-India Telescope optical upper limit
  49. EP260214a: VLT near-infrared observation
  50. EP260214a: NOT optical upper limits
  51. EP260214a: COLIBRÍ optical upper limits
  52. EP260214b: OHP/T120 optical observations
  53. EP260214a: refined analysis of the EP-FXT observation
  54. EP260214b: LCO optical counterpart detection
  55. GRB 260211A: SVOM/VT optical counterpart
  56. EP260214b: COLIBRÍ optical observations
  57. EP260214b: NOT optical counterpart detection
  58. EP260214b: Einstein Probe detection of a fast X-ray transient
  59. EP260214a: Global MASTER-Net observations report
  60. EP260214a: Einstein Probe detection of an X-ray transient
  61. GRB 260212A: AstroSat CZTI detection
  62. GRB 260212A: Fermi GBM Observation
  63. EP260213a: Liverpool Telescope optical upper limits
  64. EP260213a: Global MASTER-Net observations report
  65. EP260213a: COLIBRÍ optical upper limits
  66. EP260213a: Optical upper limits with Kinder observations
  67. EP260213a: Mondy R-band optical upper limit
  68. EP260213a: SVOM/C-GFT upper limit
  69. EP260213a: refined analysis of the EP-FXT observation
  70. EP260213a: Einstein Probe detection of a fast X-ray transient
  71. EP/WXT 01709258378: NOT optical upper limits
  72. GRB 260212A: SVOM/GRM observation of a long burst
  73. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  74. GRB 260211A: EP-FXT follow-up observation
  75. GRB 260211A: SVOM/VT optical observation
  76. GRB 260212A: Glowbug gamma-ray detection
  77. Fermi GRB 260212A: Global MASTER-Net observations report
  78. GRB 260211A: LAST optical upper limit
  79. GRB 260210A: SVOM/GRM observation
  80. Fermi GBM Sub-Threshold Detection of GRB 260211A
  81. GRID detection of GRB 260207B
  82. GRB 260211A: LCO optical upper limits
  83. GRB260131A/B: 3.6m DOT Optical Observations
  84. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  85. Fermi trigger No 792537871: Global MASTER-Net observations report
  86. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  87. EP260209a: COLIBRÍ optical upper limit
  88. Fermi GRB 260210C: Global MASTER-Net observations report
  89. EP260209a: LCO optical upper limits
  90. EP260210a: Global MASTER-Net observations report
  91. EP260210a: refined analysis of the EP-FXT observation
  92. EP260209a: Global MASTER-Net observations report
  93. GRB 260208A: LCO detection of the optical counterpart
  94. EP260209a: Einstein Probe detection of a fast X-ray transient
  95. EP260210a: Optical upper limits with Kinder observations
  96. GRB 260210A: Glowbug gamma-ray detection
  97. GRB 260208C: AstroSat CZTI detection
  98. EP260210a: COLIBRÍ optical upper limit
  99. EP260210a: SVOM/C-GFT upper limit
  100. EP260210a: Einstein Probe detection of an X-ray transient

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