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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"

28232 results found.

  1. EP260224a: Einstein Probe detection of an X-ray transient
  2. EP 260225.148: COLIBRÍ Confirmation of flaring star
  3. EP260223a: Xinglong optical upper limit
  4. GRB 260223A: Glowbug gamma-ray detection
  5. EP260213a: Mephisto optical upper limits
  6. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  7. sb26021801: SVOM/C-GFT upper limit
  8. EP260223a: COLIBRÍ optical upper limits
  9. EP260223a: Einstein Probe detection of an X-ray transient
  10. GRB 260223A: SVOM/GRM observation
  11. GRB 260223A: COLIBRÍ further optical observations and a brightening
  12. EP260221a: Optical upper limit with Kinder observations
  13. GRB 260223A: COLIBRÍ optical observations
  14. GRB 260223A: DDOTI Optical Candidate
  15. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  16. Fermi GRB 260223A: Global MASTER-Net observations report
  17. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  18. EP260221a: COLIBRÍ optical counterpart candidate
  19. EP260221a: Gemini South z-band upper limit
  20. EP260221a: Global MASTER-Net observations report
  21. EP260221a: EP-FXT follow-up observation
  22. Fermi GRB 260221B: Global MASTER-Net observations report
  23. EP-WXT01709258519: Xinglong optical upper limit
  24. EP260221a: Xinglong optical upper limit
  25. Fermi GRB 260221A: Global MASTER-Net observations report
  26. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  27. EP260221a: GOTO optical upper limit
  28. EP260221a: COLIBRÍ optical upper limit
  29. SVOM alert sb26021801: LCO optical upper limit
  30. EP260221a: Einstein Probe detection of an X-ray transient
  31. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  32. Fermi GRB 260219A: Global MASTER-Net observations report
  33. SVOM alert sb26021801: LAST optical upper limit
  34. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  35. IceCube Alert 260217A: Global MASTER-Net observations report
  36. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  37. sb26021801: SVOM detection of a long faint X-ray transient
  38. EP-WXT 01709258455: NOT optical upper limits
  39. EP260214b: Mondy optical observations
  40. EP260214b: 1.3m DFOT optical upper limit
  41. EP260210a: Mondy optical upper limits
  42. GRB 260208A: AbAO and Terskol optical upper limits
  43. GRB 260208A: continued Mondy optical observations
  44. IPN triangulation of GRB 260212A
  45. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  46. EP260214b: Liverpool Telescope optical observations
  47. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  48. EP260214b: Optical upper limit with Kinder observations
  49. EP260214a: Optical upper limits with Kinder observations
  50. EP260214b: EP-FXT follow-up observation
  51. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  52. EP260214b: DDOTI Optical Detection
  53. EP260214b: GROWTH-India Telescope optical upper limit
  54. EP260214a: VLT near-infrared observation
  55. EP260214a: NOT optical upper limits
  56. EP260214a: COLIBRÍ optical upper limits
  57. EP260214b: OHP/T120 optical observations
  58. EP260214a: refined analysis of the EP-FXT observation
  59. EP260214b: LCO optical counterpart detection
  60. GRB 260211A: SVOM/VT optical counterpart
  61. EP260214b: COLIBRÍ optical observations
  62. EP260214b: NOT optical counterpart detection
  63. EP260214b: Einstein Probe detection of a fast X-ray transient
  64. EP260214a: Global MASTER-Net observations report
  65. EP260214a: Einstein Probe detection of an X-ray transient
  66. GRB 260212A: AstroSat CZTI detection
  67. GRB 260212A: Fermi GBM Observation
  68. EP260213a: Liverpool Telescope optical upper limits
  69. EP260213a: Global MASTER-Net observations report
  70. EP260213a: COLIBRÍ optical upper limits
  71. EP260213a: Optical upper limits with Kinder observations
  72. EP260213a: Mondy R-band optical upper limit
  73. EP260213a: SVOM/C-GFT upper limit
  74. EP260213a: refined analysis of the EP-FXT observation
  75. EP260213a: Einstein Probe detection of a fast X-ray transient
  76. EP/WXT 01709258378: NOT optical upper limits
  77. GRB 260212A: SVOM/GRM observation of a long burst
  78. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  79. GRB 260211A: EP-FXT follow-up observation
  80. GRB 260211A: SVOM/VT optical observation
  81. GRB 260212A: Glowbug gamma-ray detection
  82. Fermi GRB 260212A: Global MASTER-Net observations report
  83. GRB 260211A: LAST optical upper limit
  84. GRB 260210A: SVOM/GRM observation
  85. Fermi GBM Sub-Threshold Detection of GRB 260211A
  86. GRID detection of GRB 260207B
  87. GRB 260211A: LCO optical upper limits
  88. GRB260131A/B: 3.6m DOT Optical Observations
  89. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  90. Fermi trigger No 792537871: Global MASTER-Net observations report
  91. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  92. EP260209a: COLIBRÍ optical upper limit
  93. Fermi GRB 260210C: Global MASTER-Net observations report
  94. EP260209a: LCO optical upper limits
  95. EP260210a: Global MASTER-Net observations report
  96. EP260210a: refined analysis of the EP-FXT observation
  97. EP260209a: Global MASTER-Net observations report
  98. GRB 260208A: LCO detection of the optical counterpart
  99. EP260209a: Einstein Probe detection of a fast X-ray transient
  100. EP260210a: Optical upper limits with Kinder observations

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