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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"

28273 results found.

  1. EP260227a: Mephisto optical detection
  2. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  3. EP260227a: SVOM/VT optical observation
  4. GRB 260228A: SVOM/VT optical upper limits
  5. GRB 260225D: SVOM/GRM observation
  6. EP260227A: 3.6m DOT optical afterglow detection
  7. GRB 260225B: SVOM/GRM observation
  8. EP260227a: Liverpool Telescope optical observations
  9. EP260227a: LCOGT Optical Observations
  10. GRB 260226A: Asiago r-band upper limit
  11. EP260227a: Liverpool Telescope observations
  12. EP260227a: COLIBRÍ optical observations
  13. EP260227a: NOT optical observations
  14. EP260227a: Global MASTER-Net observations report
  15. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  16. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  17. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  18. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  19. EP260214a: VLT/FORS2 optical observations
  20. GRB 260225A: WINTER J-band upper limit
  21. GRB 260226A: COLIBRÍ optical upper limits
  22. GRB 260226A: LCOGT Optical Upper Limit
  23. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  24. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  25. GRB 260226A: Glowbug gamma-ray detection
  26. GRB 260226A: NuSTAR detection of bright prompt emission
  27. GRB 260226A : GROWTH-India Telescope optical observations
  28. GRB 260226A: LAST optical upper limit
  29. GRB 260226A: Fermi GBM observation
  30. LAT GRB260226.44: Global MASTER-Net observations report
  31. Fermi GRB 260226A: Global MASTER-Net observations report
  32. GRB 260226A: AstroSat CZTI detection of bright long burst
  33. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  34. EP260224a: LCO optical upper limits
  35. GRB 260225A: EP-FXT follow-up observation
  36. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  37. GRB 260223A: Fermi GBM Observation
  38. GRB 260225A: SVOM/VT optical upper limits
  39. EP260223a: Liverpool Telescope upper limits
  40. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  41. EP260224a: Einstein Probe detection of an X-ray transient
  42. EP 260225.148: COLIBRÍ Confirmation of flaring star
  43. EP260223a: Xinglong optical upper limit
  44. GRB 260223A: Glowbug gamma-ray detection
  45. EP260213a: Mephisto optical upper limits
  46. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  47. sb26021801: SVOM/C-GFT upper limit
  48. EP260223a: COLIBRÍ optical upper limits
  49. EP260223a: Einstein Probe detection of an X-ray transient
  50. GRB 260223A: SVOM/GRM observation
  51. GRB 260223A: COLIBRÍ further optical observations and a brightening
  52. EP260221a: Optical upper limit with Kinder observations
  53. GRB 260223A: COLIBRÍ optical observations
  54. GRB 260223A: DDOTI Optical Candidate
  55. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  56. Fermi GRB 260223A: Global MASTER-Net observations report
  57. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  58. EP260221a: COLIBRÍ optical counterpart candidate
  59. EP260221a: Gemini South z-band upper limit
  60. EP260221a: Global MASTER-Net observations report
  61. EP260221a: EP-FXT follow-up observation
  62. Fermi GRB 260221B: Global MASTER-Net observations report
  63. EP-WXT01709258519: Xinglong optical upper limit
  64. EP260221a: Xinglong optical upper limit
  65. Fermi GRB 260221A: Global MASTER-Net observations report
  66. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  67. EP260221a: GOTO optical upper limit
  68. EP260221a: COLIBRÍ optical upper limit
  69. SVOM alert sb26021801: LCO optical upper limit
  70. EP260221a: Einstein Probe detection of an X-ray transient
  71. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  72. Fermi GRB 260219A: Global MASTER-Net observations report
  73. SVOM alert sb26021801: LAST optical upper limit
  74. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  75. IceCube Alert 260217A: Global MASTER-Net observations report
  76. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  77. sb26021801: SVOM detection of a long faint X-ray transient
  78. EP-WXT 01709258455: NOT optical upper limits
  79. EP260214b: Mondy optical observations
  80. EP260214b: 1.3m DFOT optical upper limit
  81. EP260210a: Mondy optical upper limits
  82. GRB 260208A: AbAO and Terskol optical upper limits
  83. GRB 260208A: continued Mondy optical observations
  84. IPN triangulation of GRB 260212A
  85. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  86. EP260214b: Liverpool Telescope optical observations
  87. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  88. EP260214b: Optical upper limit with Kinder observations
  89. EP260214a: Optical upper limits with Kinder observations
  90. EP260214b: EP-FXT follow-up observation
  91. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  92. EP260214b: DDOTI Optical Detection
  93. EP260214b: GROWTH-India Telescope optical upper limit
  94. EP260214a: VLT near-infrared observation
  95. EP260214a: NOT optical upper limits
  96. EP260214a: COLIBRÍ optical upper limits
  97. EP260214b: OHP/T120 optical observations
  98. EP260214a: refined analysis of the EP-FXT observation
  99. EP260214b: LCO optical counterpart detection
  100. GRB 260211A: SVOM/VT optical counterpart

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