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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"

28099 results found.

  1. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  2. EP260306a: Einstein Probe detection of an X-ray transient
  3. EP260302a: Optical afterglow rebrightening
  4. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  5. GRB 260303A: 1.3m DFOT optical upper limit
  6. Fermi GRB 260305A: Global MASTER-Net observations report
  7. GRB 260303B: AstroSat CZTI detection
  8. GRB 260303A: SVOM/VT optical observations
  9. GRB 260303A: J-band observations with WINTER
  10. GRB 260303B: NuSTAR detection of prompt emission
  11. EP260302a: Global MASTER-Net observations report
  12. Fermi GRB 260303B: Global MASTER-Net observations report
  13. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  14. EP260302a: analysis of the follow-up EP-FXT observation
  15. EP260302a: LCO observations
  16. EP260302a: BOOTES-7 optical counterpart detection at early times
  17. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  18. GRB 260303A: SVOM detection of a burst
  19. GRB 260228A: EP-FXT follow-up observation
  20. EP260302a: Einstein Probe detection of an X-ray transient
  21. The EP-WXT trigger 01709258736: Las Cumbres discovery of the optical counterpart
  22. GRB 251130B: TERI Gamma-ray detection
  23. GRB 260208A: TERI Gamma-ray detection
  24. EP260227a: Mondy optical observations
  25. GRB 260228A: CAHA 2.2m telescope optical upper limit
  26. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  27. EP260227a: Mephisto optical detection
  28. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  29. EP260227a: SVOM/VT optical observation
  30. GRB 260228A: SVOM/VT optical upper limits
  31. GRB 260225D: SVOM/GRM observation
  32. EP260227A: 3.6m DOT optical afterglow detection
  33. GRB 260225B: SVOM/GRM observation
  34. EP260227a: Liverpool Telescope optical observations
  35. EP260227a: LCOGT Optical Observations
  36. GRB 260226A: Asiago r-band upper limit
  37. EP260227a: Liverpool Telescope observations
  38. EP260227a: COLIBRÍ optical observations
  39. EP260227a: NOT optical observations
  40. EP260227a: Global MASTER-Net observations report
  41. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  42. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  43. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  44. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  45. EP260214a: VLT/FORS2 optical observations
  46. GRB 260225A: WINTER J-band upper limit
  47. GRB 260226A: COLIBRÍ optical upper limits
  48. GRB 260226A: LCOGT Optical Upper Limit
  49. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  50. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  51. GRB 260226A: Glowbug gamma-ray detection
  52. GRB 260226A: NuSTAR detection of bright prompt emission
  53. GRB 260226A : GROWTH-India Telescope optical observations
  54. GRB 260226A: LAST optical upper limit
  55. GRB 260226A: Fermi GBM observation
  56. LAT GRB260226.44: Global MASTER-Net observations report
  57. Fermi GRB 260226A: Global MASTER-Net observations report
  58. GRB 260226A: AstroSat CZTI detection of bright long burst
  59. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  60. EP260224a: LCO optical upper limits
  61. GRB 260225A: EP-FXT follow-up observation
  62. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  63. GRB 260223A: Fermi GBM Observation
  64. GRB 260225A: SVOM/VT optical upper limits
  65. EP260223a: Liverpool Telescope upper limits
  66. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  67. EP260224a: Einstein Probe detection of an X-ray transient
  68. EP 260225.148: COLIBRÍ Confirmation of flaring star
  69. EP260223a: Xinglong optical upper limit
  70. GRB 260223A: Glowbug gamma-ray detection
  71. EP260213a: Mephisto optical upper limits
  72. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  73. sb26021801: SVOM/C-GFT upper limit
  74. EP260223a: COLIBRÍ optical upper limits
  75. EP260223a: Einstein Probe detection of an X-ray transient
  76. GRB 260223A: SVOM/GRM observation
  77. GRB 260223A: COLIBRÍ further optical observations and a brightening
  78. EP260221a: Optical upper limit with Kinder observations
  79. GRB 260223A: COLIBRÍ optical observations
  80. GRB 260223A: DDOTI Optical Candidate
  81. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  82. Fermi GRB 260223A: Global MASTER-Net observations report
  83. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  84. EP260221a: COLIBRÍ optical counterpart candidate
  85. EP260221a: Gemini South z-band upper limit
  86. EP260221a: Global MASTER-Net observations report
  87. EP260221a: EP-FXT follow-up observation
  88. Fermi GRB 260221B: Global MASTER-Net observations report
  89. EP-WXT01709258519: Xinglong optical upper limit
  90. EP260221a: Xinglong optical upper limit
  91. Fermi GRB 260221A: Global MASTER-Net observations report
  92. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  93. EP260221a: GOTO optical upper limit
  94. EP260221a: COLIBRÍ optical upper limit
  95. SVOM alert sb26021801: LCO optical upper limit
  96. EP260221a: Einstein Probe detection of an X-ray transient
  97. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  98. Fermi GRB 260219A: Global MASTER-Net observations report
  99. SVOM alert sb26021801: LAST optical upper limit
  100. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit

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