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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"

28115 results found.

  1. EP260221a: Gemini South z-band upper limit
  2. EP260221a: Global MASTER-Net observations report
  3. EP260221a: EP-FXT follow-up observation
  4. Fermi GRB 260221B: Global MASTER-Net observations report
  5. EP-WXT01709258519: Xinglong optical upper limit
  6. EP260221a: Xinglong optical upper limit
  7. Fermi GRB 260221A: Global MASTER-Net observations report
  8. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  9. EP260221a: GOTO optical upper limit
  10. EP260221a: COLIBRÍ optical upper limit
  11. SVOM alert sb26021801: LCO optical upper limit
  12. EP260221a: Einstein Probe detection of an X-ray transient
  13. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  14. Fermi GRB 260219A: Global MASTER-Net observations report
  15. SVOM alert sb26021801: LAST optical upper limit
  16. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  17. IceCube Alert 260217A: Global MASTER-Net observations report
  18. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  19. sb26021801: SVOM detection of a long faint X-ray transient
  20. EP-WXT 01709258455: NOT optical upper limits
  21. EP260214b: Mondy optical observations
  22. EP260214b: 1.3m DFOT optical upper limit
  23. EP260210a: Mondy optical upper limits
  24. GRB 260208A: AbAO and Terskol optical upper limits
  25. GRB 260208A: continued Mondy optical observations
  26. IPN triangulation of GRB 260212A
  27. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  28. EP260214b: Liverpool Telescope optical observations
  29. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  30. EP260214b: Optical upper limit with Kinder observations
  31. EP260214a: Optical upper limits with Kinder observations
  32. EP260214b: EP-FXT follow-up observation
  33. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  34. EP260214b: DDOTI Optical Detection
  35. EP260214b: GROWTH-India Telescope optical upper limit
  36. EP260214a: VLT near-infrared observation
  37. EP260214a: NOT optical upper limits
  38. EP260214a: COLIBRÍ optical upper limits
  39. EP260214b: OHP/T120 optical observations
  40. EP260214a: refined analysis of the EP-FXT observation
  41. EP260214b: LCO optical counterpart detection
  42. GRB 260211A: SVOM/VT optical counterpart
  43. EP260214b: COLIBRÍ optical observations
  44. EP260214b: NOT optical counterpart detection
  45. EP260214b: Einstein Probe detection of a fast X-ray transient
  46. EP260214a: Global MASTER-Net observations report
  47. EP260214a: Einstein Probe detection of an X-ray transient
  48. GRB 260212A: AstroSat CZTI detection
  49. GRB 260212A: Fermi GBM Observation
  50. EP260213a: Liverpool Telescope optical upper limits
  51. EP260213a: Global MASTER-Net observations report
  52. EP260213a: COLIBRÍ optical upper limits
  53. EP260213a: Optical upper limits with Kinder observations
  54. EP260213a: Mondy R-band optical upper limit
  55. EP260213a: SVOM/C-GFT upper limit
  56. EP260213a: refined analysis of the EP-FXT observation
  57. EP260213a: Einstein Probe detection of a fast X-ray transient
  58. EP/WXT 01709258378: NOT optical upper limits
  59. GRB 260212A: SVOM/GRM observation of a long burst
  60. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  61. GRB 260211A: EP-FXT follow-up observation
  62. GRB 260211A: SVOM/VT optical observation
  63. GRB 260212A: Glowbug gamma-ray detection
  64. Fermi GRB 260212A: Global MASTER-Net observations report
  65. GRB 260211A: LAST optical upper limit
  66. GRB 260210A: SVOM/GRM observation
  67. Fermi GBM Sub-Threshold Detection of GRB 260211A
  68. GRID detection of GRB 260207B
  69. GRB 260211A: LCO optical upper limits
  70. GRB260131A/B: 3.6m DOT Optical Observations
  71. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  72. Fermi trigger No 792537871: Global MASTER-Net observations report
  73. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  74. EP260209a: COLIBRÍ optical upper limit
  75. Fermi GRB 260210C: Global MASTER-Net observations report
  76. EP260209a: LCO optical upper limits
  77. EP260210a: Global MASTER-Net observations report
  78. EP260210a: refined analysis of the EP-FXT observation
  79. EP260209a: Global MASTER-Net observations report
  80. GRB 260208A: LCO detection of the optical counterpart
  81. EP260209a: Einstein Probe detection of a fast X-ray transient
  82. EP260210a: Optical upper limits with Kinder observations
  83. GRB 260210A: Glowbug gamma-ray detection
  84. GRB 260208C: AstroSat CZTI detection
  85. EP260210a: COLIBRÍ optical upper limit
  86. EP260210a: SVOM/C-GFT upper limit
  87. EP260210a: Einstein Probe detection of an X-ray transient
  88. GRB 260207B: AstroSat CZTI detection
  89. GRB 260208C: SVOM/GRM observation
  90. GRB 260204A: Swift-XRT afterglow detection
  91. GRB 260208B: AstroSat CZTI detection of a bright long burst
  92. GRB260208A: Liverpool Telescope optical follow-up observations
  93. GRB 260208A: Glowbug gamma-ray detection
  94. GRB 260208A: NuSTAR detection of prompt emission
  95. GRB 260208A: Fermi GBM Observation
  96. Fermi GRB 260209A: Global MASTER-Net observations report
  97. GRB 260208B: Swift-XRT observations
  98. GRB 260131A/B: continued Mondy optical observations
  99. GRB 260204A: Swift/UVOT Upper Limits
  100. GRB 260208B: COLIBRÍ optical observations

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