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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"

28229 results found.

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

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