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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"

28116 results found.

  1. Fermi GRB 260310A: Global MASTER-Net observations report
  2. GRB 260208A: radio detection with the VLA
  3. GRB 260307A: Glowbug gamma-ray detection
  4. Fermi GBM Sub-Threshold Detection of GRB 260307B
  5. GRB 260307B: Mephisto optical upper limits
  6. GRB 260307B: possible NOT optical counterpart
  7. GRB 260307B: SVOM/VT upper limit with X band data analysis
  8. Fermi GRB 260307A: Global MASTER-Net observations report
  9. GRB260307B: GROWTH-India Telescope optical upper limit
  10. GRB 260307B: SVOM/VT optical candidate
  11. GRB 260307B: SVOM/C-GFT upper limit
  12. GRB 260307B: SVOM detection of a burst
  13. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  14. GRB 260207A: TESS Detection and Possible VLA Counterpart
  15. EP260302a: SVOM/VT optical observation
  16. EP260306a: Gemini-North redshift z = 4.773
  17. EP260306a: SVOM/VT optical observation
  18. EP260302a: Gemini-South redshift z = 1.535
  19. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  20. EP260306a: Einstein Probe detection of an X-ray transient
  21. EP260302a: Optical afterglow rebrightening
  22. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  23. GRB 260303A: 1.3m DFOT optical upper limit
  24. Fermi GRB 260305A: Global MASTER-Net observations report
  25. GRB 260303B: AstroSat CZTI detection
  26. GRB 260303A: SVOM/VT optical observations
  27. GRB 260303A: J-band observations with WINTER
  28. GRB 260303B: NuSTAR detection of prompt emission
  29. EP260302a: Global MASTER-Net observations report
  30. Fermi GRB 260303B: Global MASTER-Net observations report
  31. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  32. EP260302a: analysis of the follow-up EP-FXT observation
  33. EP260302a: LCO observations
  34. EP260302a: BOOTES-7 optical counterpart detection at early times
  35. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  36. GRB 260303A: SVOM detection of a burst
  37. GRB 260228A: EP-FXT follow-up observation
  38. EP260302a: Einstein Probe detection of an X-ray transient
  39. The EP-WXT trigger 01709258736: Las Cumbres discovery of the optical counterpart
  40. GRB 251130B: TERI Gamma-ray detection
  41. GRB 260208A: TERI Gamma-ray detection
  42. EP260227a: Mondy optical observations
  43. GRB 260228A: CAHA 2.2m telescope optical upper limit
  44. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  45. EP260227a: Mephisto optical detection
  46. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  47. EP260227a: SVOM/VT optical observation
  48. GRB 260228A: SVOM/VT optical upper limits
  49. GRB 260225D: SVOM/GRM observation
  50. EP260227A: 3.6m DOT optical afterglow detection
  51. GRB 260225B: SVOM/GRM observation
  52. EP260227a: Liverpool Telescope optical observations
  53. EP260227a: LCOGT Optical Observations
  54. GRB 260226A: Asiago r-band upper limit
  55. EP260227a: Liverpool Telescope observations
  56. EP260227a: COLIBRÍ optical observations
  57. EP260227a: NOT optical observations
  58. EP260227a: Global MASTER-Net observations report
  59. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  60. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  61. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  62. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  63. EP260214a: VLT/FORS2 optical observations
  64. GRB 260225A: WINTER J-band upper limit
  65. GRB 260226A: COLIBRÍ optical upper limits
  66. GRB 260226A: LCOGT Optical Upper Limit
  67. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  68. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  69. GRB 260226A: Glowbug gamma-ray detection
  70. GRB 260226A: NuSTAR detection of bright prompt emission
  71. GRB 260226A : GROWTH-India Telescope optical observations
  72. GRB 260226A: LAST optical upper limit
  73. GRB 260226A: Fermi GBM observation
  74. LAT GRB260226.44: Global MASTER-Net observations report
  75. Fermi GRB 260226A: Global MASTER-Net observations report
  76. GRB 260226A: AstroSat CZTI detection of bright long burst
  77. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  78. EP260224a: LCO optical upper limits
  79. GRB 260225A: EP-FXT follow-up observation
  80. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  81. GRB 260223A: Fermi GBM Observation
  82. GRB 260225A: SVOM/VT optical upper limits
  83. EP260223a: Liverpool Telescope upper limits
  84. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  85. EP260224a: Einstein Probe detection of an X-ray transient
  86. EP 260225.148: COLIBRÍ Confirmation of flaring star
  87. EP260223a: Xinglong optical upper limit
  88. GRB 260223A: Glowbug gamma-ray detection
  89. EP260213a: Mephisto optical upper limits
  90. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  91. sb26021801: SVOM/C-GFT upper limit
  92. EP260223a: COLIBRÍ optical upper limits
  93. EP260223a: Einstein Probe detection of an X-ray transient
  94. GRB 260223A: SVOM/GRM observation
  95. GRB 260223A: COLIBRÍ further optical observations and a brightening
  96. EP260221a: Optical upper limit with Kinder observations
  97. GRB 260223A: COLIBRÍ optical observations
  98. GRB 260223A: DDOTI Optical Candidate
  99. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  100. Fermi GRB 260223A: Global MASTER-Net observations report

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