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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"

32703 results found.

  1. GRB 260211A: late-time NOT i-band observations consistent with archival flux
  2. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  3. GRB 260207A: TESS Detection and Possible VLA Counterpart
  4. EP260302a: SVOM/VT optical observation
  5. EP260306a: Gemini-North redshift z = 4.773
  6. EP260306a: SVOM/VT optical observation
  7. EP260302a: Gemini-South redshift z = 1.535
  8. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  9. EP260306a: Einstein Probe detection of an X-ray transient
  10. EP260302a: Optical afterglow rebrightening
  11. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  12. GRB 260303A: 1.3m DFOT optical upper limit (duplicate submission)
  13. GRB 260303A: 1.3m DFOT optical upper limit
  14. EP260214b: ATCA 6 GHz observations
  15. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  16. GRB 260303A: SVOM/ECLAIRs refined analysis
  17. Fermi GRB 260305A: Global MASTER-Net observations report
  18. GRB 260303B: AstroSat CZTI detection
  19. GRB 260303A: SVOM/VT optical observations
  20. GRB 260303A: J-band observations with WINTER
  21. GRB 260303B: NuSTAR detection of prompt emission
  22. EP260302a: Global MASTER-Net observations report
  23. Fermi GRB 260303B: Global MASTER-Net observations report
  24. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  25. GRB 260228A: SVOM/ECLAIRs refined analysis
  26. GRB 260225A: SVOM/ECLAIRs refined analysis
  27. EP260302a: analysis of the follow-up EP-FXT observation
  28. EP260227a: Gemini-South optical observations
  29. EP260302a: LCO observations
  30. EP260302a: BOOTES-7 optical counterpart detection at early times
  31. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  32. GRB 260228A: EP-FXT follow-up observation
  33. GRB 251130B: TERI Gamma-ray detection
  34. GRB 260208A: TERI Gamma-ray detection
  35. EP260227a: Mondy optical observations
  36. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  37. EP260227a: Mephisto optical detection
  38. GRID detection of GRB 260225D
  39. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  40. EP260227a: further LCO observations
  41. EP260227a: SVOM/VT optical observation
  42. GRB 260228A: SVOM/VT optical upper limits
  43. GRB 260225D: SVOM/GRM observation
  44. EP260227A: 3.6m DOT optical afterglow detection
  45. GRB 260225B: SVOM/GRM observation
  46. EP260227a: FTW optical and NIR observations
  47. EP260227a: Liverpool Telescope optical observations
  48. EP260227a: LCOGT Optical Observations
  49. GRB 260226A: Asiago r-band upper limit
  50. EP260227a: Thai National Telescope observations
  51. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  52. EP260227a: Liverpool Telescope observations
  53. EP260227a: COLIBRÍ optical observations
  54. EP260227a: NOT optical observations
  55. GRB 260225A: SVOM/VT optical continued observations and upper limit
  56. GRID detection of GRB 260223A
  57. EP260227a: Global MASTER-Net observations report
  58. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  59. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  60. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  61. Konus-Wind detection of GRB 260226A
  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: CALET Gamma-Ray Burst Monitor detection
  66. GRB 260226A: COLIBRÍ optical upper limits
  67. GRB 260226A: LCOGT Optical Upper Limit
  68. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  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. GRB 260226A: Fermi-LAT refined analysis
  75. Fermi GRB 260226A: Global MASTER-Net observations report
  76. GRB 260226A: AstroSat CZTI detection of bright long burst
  77. EP260214a: VLA 6 GHz detection
  78. GRB 260226A: Fermi-LAT detection of a bright burst
  79. EP260224a: LCO optical upper limits
  80. GRB260225A: SVOM/ECLAIRs refined position
  81. GRB 260225A: EP-FXT follow-up observation
  82. GRB 260225A: SVOM/VT optical observation
  83. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  84. GRB 260223A: Fermi GBM Observation
  85. GRB 260225A: SVOM/VT optical upper limits
  86. EP260126a: VLA 6 GHz detection
  87. EP260223a: Liverpool Telescope upper limits
  88. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  89. EP 260225.148: COLIBRÍ Confirmation of flaring star
  90. EP260223a: Xinglong optical upper limit
  91. GRB 260223A: Glowbug gamma-ray detection
  92. EP260213a: Mephisto optical upper limits
  93. EP260223a: EP-FXT follow-up observation
  94. sb26021801: SVOM/VT optical upper limits
  95. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  96. sb26021801: SVOM/C-GFT upper limit
  97. EP260223a: COLIBRÍ optical upper limits
  98. GRB 260223A: SVOM/VT optical observation
  99. GRB 260223A: SVOM/GRM observation
  100. GRB 260223A: COLIBRÍ further optical observations and a brightening

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