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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"

38659 results found.

  1. EP260227A: 3.6m DOT optical afterglow detection
  2. GRB 260225B: SVOM/GRM observation
  3. GRB 260228A: SVOM detection of a burst
  4. EP260227a: Liverpool Telescope optical observations
  5. EP260227a: LCOGT Optical Observations
  6. GRB 260226A: Asiago r-band upper limit
  7. EP260227a: Thai National Telescope observations
  8. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  9. EP260227a: Liverpool Telescope observations
  10. EP260227a: COLIBRÍ optical observations
  11. EP260227a: NOT optical observations
  12. GRB 260225A: SVOM/VT optical continued observations and upper limit
  13. GRID detection of GRB 260223A
  14. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  15. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  16. IceCube cascade alert 142200_1517143 retraction
  17. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  18. Konus-Wind detection of GRB 260226A
  19. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  20. EP260214a: VLT/FORS2 optical observations
  21. GRB 260225A: WINTER J-band upper limit
  22. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  23. GRB 260226A: COLIBRÍ optical upper limits
  24. GRB 260226A: LCOGT Optical Upper Limit
  25. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  26. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  27. GRB 260226A: Glowbug gamma-ray detection
  28. GRB 260226A: NuSTAR detection of bright prompt emission
  29. GRB 260226A : GROWTH-India Telescope optical observations
  30. GRB 260226A: LAST optical upper limit
  31. GRB 260226A: Fermi GBM observation
  32. GRB 260226A: Fermi-LAT refined analysis
  33. The EP-WXT trigger 01709258652 is likely a flaring star
  34. GRB 260226A: AstroSat CZTI detection of bright long burst
  35. EP260214a: VLA 6 GHz detection
  36. GRB 260226A: Fermi-LAT detection of a bright burst
  37. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  38. EP260224a: LCO optical upper limits
  39. GRB260225A: SVOM/ECLAIRs refined position
  40. GRB 260226A: Fermi GBM Final Real-time Localization
  41. GRB 260225A: EP-FXT follow-up observation
  42. GRB 260225A: SVOM/VT optical observation
  43. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  44. GRB 260225C: Fermi GBM Final Real-time Localization
  45. GRB 260223A: Fermi GBM Observation
  46. GRB 260225A: SVOM/VT optical upper limits
  47. GRB 260225B: Fermi GBM Final Real-time Localization
  48. EP260126a: VLA 6 GHz detection
  49. EP260223a: Liverpool Telescope upper limits
  50. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  51. GRB 260225A: SVOM detection of a burst
  52. EP260224a: Einstein Probe detection of an X-ray transient
  53. EP 260225.148: COLIBRÍ Confirmation of flaring star
  54. EP260223a: Xinglong optical upper limit
  55. The EP-WXT trigger 01709258631 is likely a flaring star
  56. GRB 260223A: Glowbug gamma-ray detection
  57. EP260213a: Mephisto optical upper limits
  58. EP260223a: EP-FXT follow-up observation
  59. sb26021801: SVOM/VT optical upper limits
  60. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  61. sb26021801: SVOM/C-GFT upper limit
  62. EP260223a: COLIBRÍ optical upper limits
  63. EP260223a: Einstein Probe detection of an X-ray transient
  64. GRB 260223A: SVOM/VT optical observation
  65. GRB 260223A: SVOM/GRM observation
  66. GRB 260223A: COLIBRÍ further optical observations and a brightening
  67. EP260221a: Optical upper limit with Kinder observations
  68. GRB 260223A: COLIBRÍ optical observations
  69. GRB 260223A: DDOTI Optical Candidate
  70. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  71. GRB 260223A: Fermi GBM Final Real-time Localization
  72. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  73. EP260221a: COLIBRÍ optical counterpart candidate
  74. EP260221a: Gemini South z-band upper limit
  75. GRB 260222A: Fermi GBM Final Real-time Localization
  76. EP260221a: EP-FXT follow-up observation
  77. GRB 260221B: Fermi GBM Final Real-time Localization
  78. EP-WXT01709258519: Xinglong optical upper limit
  79. EP260221a: Xinglong optical upper limit
  80. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  81. GRB 260221A: Fermi GBM Final Real-time Localization
  82. EP260221a: GOTO optical upper limit
  83. EP260221a: COLIBRÍ optical upper limit
  84. SVOM alert sb26021801: LCO optical upper limit
  85. EP260221a: Einstein Probe detection of an X-ray transient
  86. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  87. GRB 260219A: AstroSat CZTI detection
  88. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  89. GRB 260219A: GECAM-B observation of a long burst
  90. GRB 260219A: Fermi GBM Final Real-time Localization
  91. SVOM alert sb26021801: LAST optical upper limit
  92. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  93. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  94. GRB 260217A: Fermi GBM Final Localization
  95. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  96. sb26021801: SVOM detection of a long faint X-ray transient
  97. The EP-WXT trigger 01709258455 is likely a flaring star
  98. EP-WXT 01709258455: NOT optical upper limits
  99. EP260214b: Mondy optical observations
  100. EP260214b: 1.3m DFOT optical upper limit

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