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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"

32490 results found.

  1. EP260214b: ATCA 6 GHz observations
  2. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  3. GRB 260303A: SVOM/ECLAIRs refined analysis
  4. Fermi GRB 260305A: Global MASTER-Net observations report
  5. GRB 260303B: AstroSat CZTI detection
  6. GRB 260303A: SVOM/VT optical observations
  7. GRB 260303A: J-band observations with WINTER
  8. GRB 260303B: NuSTAR detection of prompt emission
  9. EP260302a: Global MASTER-Net observations report
  10. Fermi GRB 260303B: Global MASTER-Net observations report
  11. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  12. GRB 260228A: SVOM/ECLAIRs refined analysis
  13. GRB 260225A: SVOM/ECLAIRs refined analysis
  14. EP260302a: analysis of the follow-up EP-FXT observation
  15. EP260227a: Gemini-South optical observations
  16. EP260302a: LCO observations
  17. EP260302a: BOOTES-7 optical counterpart detection at early times
  18. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  19. GRB 260228A: EP-FXT follow-up observation
  20. GRB 251130B: TERI Gamma-ray detection
  21. GRB 260208A: TERI Gamma-ray detection
  22. EP260227a: Mondy optical observations
  23. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  24. EP260227a: Mephisto optical detection
  25. GRID detection of GRB 260225D
  26. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  27. EP260227a: further LCO observations
  28. EP260227a: SVOM/VT optical observation
  29. GRB 260228A: SVOM/VT optical upper limits
  30. GRB 260225D: SVOM/GRM observation
  31. EP260227A: 3.6m DOT optical afterglow detection
  32. GRB 260225B: SVOM/GRM observation
  33. EP260227a: FTW optical and NIR observations
  34. EP260227a: Liverpool Telescope optical observations
  35. EP260227a: LCOGT Optical Observations
  36. GRB 260226A: Asiago r-band upper limit
  37. EP260227a: Thai National Telescope observations
  38. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  39. EP260227a: Liverpool Telescope observations
  40. EP260227a: COLIBRÍ optical observations
  41. EP260227a: NOT optical observations
  42. GRB 260225A: SVOM/VT optical continued observations and upper limit
  43. GRID detection of GRB 260223A
  44. EP260227a: Global MASTER-Net observations report
  45. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  46. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  47. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  48. Konus-Wind detection of GRB 260226A
  49. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  50. EP260214a: VLT/FORS2 optical observations
  51. GRB 260225A: WINTER J-band upper limit
  52. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  53. GRB 260226A: COLIBRÍ optical upper limits
  54. GRB 260226A: LCOGT Optical Upper Limit
  55. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  56. GRB 260226A: Glowbug gamma-ray detection
  57. GRB 260226A: NuSTAR detection of bright prompt emission
  58. GRB 260226A : GROWTH-India Telescope optical observations
  59. GRB 260226A: LAST optical upper limit
  60. GRB 260226A: Fermi GBM observation
  61. GRB 260226A: Fermi-LAT refined analysis
  62. Fermi GRB 260226A: Global MASTER-Net observations report
  63. GRB 260226A: AstroSat CZTI detection of bright long burst
  64. EP260214a: VLA 6 GHz detection
  65. GRB 260226A: Fermi-LAT detection of a bright burst
  66. EP260224a: LCO optical upper limits
  67. GRB260225A: SVOM/ECLAIRs refined position
  68. GRB 260225A: EP-FXT follow-up observation
  69. GRB 260225A: SVOM/VT optical observation
  70. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  71. GRB 260223A: Fermi GBM Observation
  72. GRB 260225A: SVOM/VT optical upper limits
  73. EP260126a: VLA 6 GHz detection
  74. EP260223a: Liverpool Telescope upper limits
  75. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  76. EP 260225.148: COLIBRÍ Confirmation of flaring star
  77. EP260223a: Xinglong optical upper limit
  78. GRB 260223A: Glowbug gamma-ray detection
  79. EP260213a: Mephisto optical upper limits
  80. EP260223a: EP-FXT follow-up observation
  81. sb26021801: SVOM/VT optical upper limits
  82. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  83. sb26021801: SVOM/C-GFT upper limit
  84. EP260223a: COLIBRÍ optical upper limits
  85. GRB 260223A: SVOM/VT optical observation
  86. GRB 260223A: SVOM/GRM observation
  87. GRB 260223A: COLIBRÍ further optical observations and a brightening
  88. EP260221a: Optical upper limit with Kinder observations
  89. GRB 260223A: COLIBRÍ optical observations
  90. GRB 260223A: DDOTI Optical Candidate
  91. Fermi GRB 260223A: Global MASTER-Net observations report
  92. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  93. EP260221a: COLIBRÍ optical counterpart candidate
  94. EP260221a: Gemini South z-band upper limit
  95. EP260221a: Global MASTER-Net observations report
  96. EP260221a: EP-FXT follow-up observation
  97. Fermi GRB 260221B: Global MASTER-Net observations report
  98. EP260221a: Xinglong optical upper limit
  99. Fermi GRB 260221A: Global MASTER-Net observations report
  100. EP260221a: GOTO optical upper limit

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