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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"

28260 results found.

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

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