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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

32488 results found.

  1. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  2. GRB 260303A: SVOM/ECLAIRs refined analysis
  3. Fermi GRB 260305A: Global MASTER-Net observations report
  4. GRB 260303B: AstroSat CZTI detection
  5. GRB 260303A: SVOM/VT optical observations
  6. GRB 260303A: J-band observations with WINTER
  7. GRB 260303B: NuSTAR detection of prompt emission
  8. EP260302a: Global MASTER-Net observations report
  9. Fermi GRB 260303B: Global MASTER-Net observations report
  10. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  11. GRB 260228A: SVOM/ECLAIRs refined analysis
  12. GRB 260225A: SVOM/ECLAIRs refined analysis
  13. EP260302a: analysis of the follow-up EP-FXT observation
  14. EP260227a: Gemini-South optical observations
  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 260228A: EP-FXT follow-up observation
  19. GRB 251130B: TERI Gamma-ray detection
  20. GRB 260208A: TERI Gamma-ray detection
  21. EP260227a: Mondy optical observations
  22. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  23. EP260227a: Mephisto optical detection
  24. GRID detection of GRB 260225D
  25. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  26. EP260227a: further LCO observations
  27. EP260227a: SVOM/VT optical observation
  28. GRB 260228A: SVOM/VT optical upper limits
  29. GRB 260225D: SVOM/GRM observation
  30. EP260227A: 3.6m DOT optical afterglow detection
  31. GRB 260225B: SVOM/GRM observation
  32. EP260227a: FTW optical and NIR observations
  33. EP260227a: Liverpool Telescope optical observations
  34. EP260227a: LCOGT Optical Observations
  35. GRB 260226A: Asiago r-band upper limit
  36. EP260227a: Thai National Telescope observations
  37. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  38. EP260227a: Liverpool Telescope observations
  39. EP260227a: COLIBRÍ optical observations
  40. EP260227a: NOT optical observations
  41. GRB 260225A: SVOM/VT optical continued observations and upper limit
  42. GRID detection of GRB 260223A
  43. EP260227a: Global MASTER-Net observations report
  44. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  45. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  46. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  47. Konus-Wind detection of GRB 260226A
  48. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  49. EP260214a: VLT/FORS2 optical observations
  50. GRB 260225A: WINTER J-band upper limit
  51. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  52. GRB 260226A: COLIBRÍ optical upper limits
  53. GRB 260226A: LCOGT Optical Upper Limit
  54. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  55. GRB 260226A: Glowbug gamma-ray detection
  56. GRB 260226A: NuSTAR detection of bright prompt emission
  57. GRB 260226A : GROWTH-India Telescope optical observations
  58. GRB 260226A: LAST optical upper limit
  59. GRB 260226A: Fermi GBM observation
  60. GRB 260226A: Fermi-LAT refined analysis
  61. Fermi GRB 260226A: Global MASTER-Net observations report
  62. GRB 260226A: AstroSat CZTI detection of bright long burst
  63. EP260214a: VLA 6 GHz detection
  64. GRB 260226A: Fermi-LAT detection of a bright burst
  65. EP260224a: LCO optical upper limits
  66. GRB260225A: SVOM/ECLAIRs refined position
  67. GRB 260225A: EP-FXT follow-up observation
  68. GRB 260225A: SVOM/VT optical observation
  69. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  70. GRB 260223A: Fermi GBM Observation
  71. GRB 260225A: SVOM/VT optical upper limits
  72. EP260126a: VLA 6 GHz detection
  73. EP260223a: Liverpool Telescope upper limits
  74. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  75. EP 260225.148: COLIBRÍ Confirmation of flaring star
  76. EP260223a: Xinglong optical upper limit
  77. GRB 260223A: Glowbug gamma-ray detection
  78. EP260213a: Mephisto optical upper limits
  79. EP260223a: EP-FXT follow-up observation
  80. sb26021801: SVOM/VT optical upper limits
  81. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  82. sb26021801: SVOM/C-GFT upper limit
  83. EP260223a: COLIBRÍ optical upper limits
  84. GRB 260223A: SVOM/VT optical observation
  85. GRB 260223A: SVOM/GRM observation
  86. GRB 260223A: COLIBRÍ further optical observations and a brightening
  87. EP260221a: Optical upper limit with Kinder observations
  88. GRB 260223A: COLIBRÍ optical observations
  89. GRB 260223A: DDOTI Optical Candidate
  90. Fermi GRB 260223A: Global MASTER-Net observations report
  91. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  92. EP260221a: COLIBRÍ optical counterpart candidate
  93. EP260221a: Gemini South z-band upper limit
  94. EP260221a: Global MASTER-Net observations report
  95. EP260221a: EP-FXT follow-up observation
  96. Fermi GRB 260221B: Global MASTER-Net observations report
  97. EP260221a: Xinglong optical upper limit
  98. Fermi GRB 260221A: Global MASTER-Net observations report
  99. EP260221a: GOTO optical upper limit
  100. EP260221a: COLIBRÍ optical upper limit

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