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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. GRB 260307A: Glowbug gamma-ray detection
  2. Fermi GBM Sub-Threshold Detection of GRB 260307B
  3. GRB 260307B: Mephisto optical upper limits
  4. GRB 260307B: possible NOT optical counterpart
  5. GRB 260307B: SVOM/VT upper limit with X band data analysis
  6. Fermi GRB 260307A: Global MASTER-Net observations report
  7. GRB260307B: GROWTH-India Telescope optical upper limit
  8. GRB 260307B: SVOM/VT optical candidate
  9. GRB 260307B: SVOM/C-GFT upper limit
  10. GRB 260307B: SVOM detection of a burst
  11. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  12. GRB 260207A: TESS Detection and Possible VLA Counterpart
  13. EP260302a: SVOM/VT optical observation
  14. EP260306a: Gemini-North redshift z = 4.773
  15. EP260306a: SVOM/VT optical observation
  16. EP260302a: Gemini-South redshift z = 1.535
  17. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  18. EP260306a: Einstein Probe detection of an X-ray transient
  19. EP260302a: Optical afterglow rebrightening
  20. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  21. GRB 260303A: 1.3m DFOT optical upper limit
  22. Fermi GRB 260305A: Global MASTER-Net observations report
  23. GRB 260303B: AstroSat CZTI detection
  24. GRB 260303A: SVOM/VT optical observations
  25. GRB 260303A: J-band observations with WINTER
  26. GRB 260303B: NuSTAR detection of prompt emission
  27. EP260302a: Global MASTER-Net observations report
  28. Fermi GRB 260303B: Global MASTER-Net observations report
  29. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  30. EP260302a: analysis of the follow-up EP-FXT observation
  31. EP260302a: LCO observations
  32. EP260302a: BOOTES-7 optical counterpart detection at early times
  33. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  34. GRB 260303A: SVOM detection of a burst
  35. GRB 260228A: EP-FXT follow-up observation
  36. EP260302a: Einstein Probe detection of an X-ray transient
  37. The EP-WXT trigger 01709258736: Las Cumbres discovery of the optical counterpart
  38. GRB 251130B: TERI Gamma-ray detection
  39. GRB 260208A: TERI Gamma-ray detection
  40. EP260227a: Mondy optical observations
  41. GRB 260228A: CAHA 2.2m telescope optical upper limit
  42. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  43. EP260227a: Mephisto optical detection
  44. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  45. EP260227a: SVOM/VT optical observation
  46. GRB 260228A: SVOM/VT optical upper limits
  47. GRB 260225D: SVOM/GRM observation
  48. EP260227A: 3.6m DOT optical afterglow detection
  49. GRB 260225B: SVOM/GRM observation
  50. EP260227a: Liverpool Telescope optical observations
  51. EP260227a: LCOGT Optical Observations
  52. GRB 260226A: Asiago r-band upper limit
  53. EP260227a: Liverpool Telescope observations
  54. EP260227a: COLIBRÍ optical observations
  55. EP260227a: NOT optical observations
  56. EP260227a: Global MASTER-Net observations report
  57. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  58. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  59. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  60. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  61. EP260214a: VLT/FORS2 optical observations
  62. GRB 260225A: WINTER J-band upper limit
  63. GRB 260226A: COLIBRÍ optical upper limits
  64. GRB 260226A: LCOGT Optical Upper Limit
  65. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  66. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  67. GRB 260226A: Glowbug gamma-ray detection
  68. GRB 260226A: NuSTAR detection of bright prompt emission
  69. GRB 260226A : GROWTH-India Telescope optical observations
  70. GRB 260226A: LAST optical upper limit
  71. GRB 260226A: Fermi GBM observation
  72. LAT GRB260226.44: Global MASTER-Net observations report
  73. Fermi GRB 260226A: Global MASTER-Net observations report
  74. GRB 260226A: AstroSat CZTI detection of bright long burst
  75. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  76. EP260224a: LCO optical upper limits
  77. GRB 260225A: EP-FXT follow-up observation
  78. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  79. GRB 260223A: Fermi GBM Observation
  80. GRB 260225A: SVOM/VT optical upper limits
  81. EP260223a: Liverpool Telescope upper limits
  82. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  83. EP260224a: Einstein Probe detection of an X-ray transient
  84. EP 260225.148: COLIBRÍ Confirmation of flaring star
  85. EP260223a: Xinglong optical upper limit
  86. GRB 260223A: Glowbug gamma-ray detection
  87. EP260213a: Mephisto optical upper limits
  88. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  89. sb26021801: SVOM/C-GFT upper limit
  90. EP260223a: COLIBRÍ optical upper limits
  91. EP260223a: Einstein Probe detection of an X-ray transient
  92. GRB 260223A: SVOM/GRM observation
  93. GRB 260223A: COLIBRÍ further optical observations and a brightening
  94. EP260221a: Optical upper limit with Kinder observations
  95. GRB 260223A: COLIBRÍ optical observations
  96. GRB 260223A: DDOTI Optical Candidate
  97. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  98. Fermi GRB 260223A: Global MASTER-Net observations report
  99. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  100. EP260221a: COLIBRÍ optical counterpart candidate

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