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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"

28261 results found.

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

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