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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"

45735 results found.

  1. EP260227a: Liverpool Telescope optical observations
  2. EP260227a: LCOGT Optical Observations
  3. GRB 260226A: Asiago r-band upper limit
  4. EP260227a: Thai National Telescope observations
  5. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  6. EP260227a: Liverpool Telescope observations
  7. EP260227a: COLIBRÍ optical observations
  8. EP260227a: NOT optical observations
  9. GRB 260225A: SVOM/VT optical continued observations and upper limit
  10. GRID detection of GRB 260223A
  11. EP260227a: Global MASTER-Net observations report
  12. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  13. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  14. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  15. IceCube cascade alert 142200_1517143 retraction
  16. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  17. Konus-Wind detection of GRB 260226A
  18. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  19. EP260214a: VLT/FORS2 optical observations
  20. GRB 260225A: WINTER J-band upper limit
  21. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  22. GRB 260226A: COLIBRÍ optical upper limits
  23. GRB 260226A: LCOGT Optical Upper Limit
  24. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  25. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  26. GRB 260226A: Glowbug gamma-ray detection
  27. GRB 260226A: NuSTAR detection of bright prompt emission
  28. GRB 260226A : GROWTH-India Telescope optical observations
  29. GRB 260226A: LAST optical upper limit
  30. GRB 260226A: Fermi GBM observation
  31. GRB 260226A: Fermi-LAT refined analysis
  32. The EP-WXT trigger 01709258652 is likely a flaring star
  33. LAT GRB260226.44: Global MASTER-Net observations report
  34. Fermi GRB 260226A: Global MASTER-Net observations report
  35. GRB 260226A: AstroSat CZTI detection of bright long burst
  36. EP260214a: VLA 6 GHz detection
  37. GRB 260226A: Fermi-LAT detection of a bright burst
  38. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  39. EP260224a: LCO optical upper limits
  40. GRB260225A: SVOM/ECLAIRs refined position
  41. GRB 260226A: Fermi GBM Final Real-time Localization
  42. GRB 260225A: EP-FXT follow-up observation
  43. GRB 260225A: SVOM/VT optical observation
  44. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  45. GRB 260225C: Fermi GBM Final Real-time Localization
  46. GRB 260223A: Fermi GBM Observation
  47. GRB 260225A: SVOM/VT optical upper limits
  48. GRB 260225B: Fermi GBM Final Real-time Localization
  49. EP260126a: VLA 6 GHz detection
  50. EP260223a: Liverpool Telescope upper limits
  51. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  52. GRB 260225A: SVOM detection of a burst
  53. EP260224a: Einstein Probe detection of an X-ray transient
  54. EP 260225.148: COLIBRÍ Confirmation of flaring star
  55. EP260223a: Xinglong optical upper limit
  56. The EP-WXT trigger 01709258631 is likely a flaring star
  57. GRB 260223A: Glowbug gamma-ray detection
  58. EP260213a: Mephisto optical upper limits
  59. EP260223a: EP-FXT follow-up observation
  60. sb26021801: SVOM/VT optical upper limits
  61. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  62. sb26021801: SVOM/C-GFT upper limit
  63. EP260223a: COLIBRÍ optical upper limits
  64. EP260223a: Einstein Probe detection of an X-ray transient
  65. GRB 260223A: SVOM/VT optical observation
  66. GRB 260223A: SVOM/GRM observation
  67. GRB 260223A: COLIBRÍ further optical observations and a brightening
  68. EP260221a: Optical upper limit with Kinder observations
  69. GRB 260223A: COLIBRÍ optical observations
  70. GRB 260223A: DDOTI Optical Candidate
  71. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  72. Fermi GRB 260223A: Global MASTER-Net observations report
  73. GRB 260223A: Fermi GBM Final Real-time Localization
  74. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  75. EP260221a: COLIBRÍ optical counterpart candidate
  76. EP260221a: Gemini South z-band upper limit
  77. GRB 260222A: Fermi GBM Final Real-time Localization
  78. EP260221a: Global MASTER-Net observations report
  79. EP260221a: EP-FXT follow-up observation
  80. Fermi GRB 260221B: Global MASTER-Net observations report
  81. GRB 260221B: Fermi GBM Final Real-time Localization
  82. EP-WXT01709258519: Xinglong optical upper limit
  83. EP260221a: Xinglong optical upper limit
  84. Fermi GRB 260221A: Global MASTER-Net observations report
  85. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  86. GRB 260221A: Fermi GBM Final Real-time Localization
  87. EP260221a: GOTO optical upper limit
  88. EP260221a: COLIBRÍ optical upper limit
  89. SVOM alert sb26021801: LCO optical upper limit
  90. EP260221a: Einstein Probe detection of an X-ray transient
  91. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  92. GRB 260219A: AstroSat CZTI detection
  93. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 260219A: GECAM-B observation of a long burst
  95. Fermi GRB 260219A: Global MASTER-Net observations report
  96. GRB 260219A: Fermi GBM Final Real-time Localization
  97. SVOM alert sb26021801: LAST optical upper limit
  98. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  99. IceCube Alert 260217A: Global MASTER-Net observations report
  100. Fermi-LAT Gamma-ray Observations of IceCube-260217A

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