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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"

28125 results found.

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

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