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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"

26507 results found.

  1. GRB 260312B: Glowbug gamma-ray detection
  2. GRB 260310A: Fermi GBM Observation
  3. GRB 260310A: potential optical counterpart
  4. GRB 260131A/B: radio detection with the VLA
  5. EP260302a: MeerKAT radio counterpart
  6. GRB 260308A: SVOM/GRM observation of a short GRB
  7. EP260306a: Mondy optical upper limit
  8. GRB 260310A: AstroSat CZTI detection of a long burst
  9. GRB 260307B: SVOM/ECLAIRs refined analysis
  10. GRB 260208A: radio detection with the VLA
  11. GRB 260307A: Glowbug gamma-ray detection
  12. GRB 260307B: Mephisto optical upper limits
  13. GRB 260307B: possible NOT optical counterpart
  14. GRB 260307B: SVOM/VT upper limit with X band data analysis
  15. GRB260307B: GROWTH-India Telescope optical upper limit
  16. GRB 260307B: SVOM/VT optical candidate
  17. GRB 260307B: SVOM/C-GFT upper limit
  18. GRB 260307B: SVOM detection of a burst
  19. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  20. GRB 260207A: TESS Detection and Possible VLA Counterpart
  21. EP260302a: SVOM/VT optical observation
  22. EP260306a: SVOM/VT optical observation
  23. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  24. EP260306a: Einstein Probe detection of an X-ray transient
  25. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  26. GRB 260303A: 1.3m DFOT optical upper limit
  27. GRB 260304A: AstroSat CZTI detection of a long burst
  28. SVOM/sb26030408: SVOM detection of an X-ray transient likely associated with Beta Persei
  29. GRB 260303A: SVOM/VT optical observations
  30. GRB 260303A: J-band observations with WINTER
  31. GRB 260228A: SVOM/ECLAIRs refined analysis
  32. GRB 260225A: SVOM/ECLAIRs refined analysis
  33. EP260302a: analysis of the follow-up EP-FXT observation
  34. EP260302a: LCO observations
  35. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  36. GRB 260303A: SVOM detection of a burst
  37. EP260302a: Einstein Probe detection of an X-ray transient
  38. GRB 260302A: Fermi GBM Final Real-time Localization
  39. EP260227a: Mondy optical observations
  40. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  41. EP260227a: Mephisto optical detection
  42. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  43. EP260227a: SVOM/VT optical observation
  44. GRB 260228A: SVOM/VT optical upper limits
  45. GRB 260225D: SVOM/GRM observation
  46. EP260227A: 3.6m DOT optical afterglow detection
  47. GRB 260225B: SVOM/GRM observation
  48. GRB 260228A: SVOM detection of a burst
  49. EP260227a: Liverpool Telescope optical observations
  50. EP260227a: LCOGT Optical Observations
  51. GRB 260226A: Asiago r-band upper limit
  52. EP260227a: Liverpool Telescope observations
  53. EP260227a: COLIBRÍ optical observations
  54. EP260227a: NOT optical observations
  55. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  56. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  57. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  58. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  59. EP260214a: VLT/FORS2 optical observations
  60. GRB 260225A: WINTER J-band upper limit
  61. GRB 260226A: COLIBRÍ optical upper limits
  62. GRB 260226A: LCOGT Optical Upper Limit
  63. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  64. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  65. GRB 260226A: Glowbug gamma-ray detection
  66. GRB 260226A : GROWTH-India Telescope optical observations
  67. GRB 260226A: LAST optical upper limit
  68. GRB 260226A: Fermi GBM observation
  69. The EP-WXT trigger 01709258652 is likely a flaring star
  70. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  71. EP260224a: LCO optical upper limits
  72. GRB 260225A: EP-FXT follow-up observation
  73. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  74. GRB 260223A: Fermi GBM Observation
  75. GRB 260225A: SVOM/VT optical upper limits
  76. EP260223a: Liverpool Telescope upper limits
  77. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  78. GRB 260225A: SVOM detection of a burst
  79. EP260224a: Einstein Probe detection of an X-ray transient
  80. EP 260225.148: COLIBRÍ Confirmation of flaring star
  81. EP260223a: Xinglong optical upper limit
  82. The EP-WXT trigger 01709258631 is likely a flaring star
  83. GRB 260223A: Glowbug gamma-ray detection
  84. EP260213a: Mephisto optical upper limits
  85. EP260223a: EP-FXT follow-up observation
  86. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  87. sb26021801: SVOM/C-GFT upper limit
  88. EP260223a: COLIBRÍ optical upper limits
  89. EP260223a: Einstein Probe detection of an X-ray transient
  90. GRB 260223A: SVOM/GRM observation
  91. GRB 260223A: COLIBRÍ further optical observations and a brightening
  92. EP260221a: Optical upper limit with Kinder observations
  93. GRB 260223A: COLIBRÍ optical observations
  94. GRB 260223A: DDOTI Optical Candidate
  95. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  96. EP260221a: COLIBRÍ optical counterpart candidate
  97. EP260221a: Gemini South z-band upper limit
  98. EP260221a: EP-FXT follow-up observation
  99. EP-WXT01709258519: Xinglong optical upper limit
  100. EP260221a: Xinglong optical upper limit

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