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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"

28926 results found.

  1. GRB 260131A/B: radio detection with the VLA
  2. GRB260307A: GECAM-B observation of a burst
  3. GRB 260308A: SVOM/GRM observation of a short GRB
  4. GRB 260310A: AstroSat CZTI detection of a long burst
  5. GRB 260311A: Fermi GBM Final Real-time Localization
  6. Fermi GRB 260310B: Global MASTER-Net observations report
  7. GRB 260310B: Fermi GBM Final Real-time Localization
  8. Fermi GRB 260310A: Global MASTER-Net observations report
  9. GRB 260307B: SVOM/ECLAIRs refined analysis
  10. GRB 260208A: radio detection with the VLA
  11. GRB 260310A: Fermi GBM Final Real-time Localization
  12. GRB 260307A: Glowbug gamma-ray detection
  13. GRB 260308A: Fermi GBM Final Real-time Localization
  14. Fermi GBM Sub-Threshold Detection of GRB 260307B
  15. GRB 260307B: Mephisto optical upper limits
  16. GRB 260307B: possible NOT optical counterpart
  17. Fermi GRB 260307A: Global MASTER-Net observations report
  18. GRB260307B: GROWTH-India Telescope optical upper limit
  19. GRB 260307B: SVOM/VT optical candidate
  20. GRB 260307B: SVOM/C-GFT upper limit
  21. GRB 260307B: SVOM detection of a burst
  22. GRB 260307A: Fermi GBM Final Localization
  23. GRB 260211A: late-time NOT i-band observations consistent with archival flux
  24. GRB 260207A: TESS Detection and Possible VLA Counterpart
  25. EP260302a: SVOM/VT optical observation
  26. EP260306a: Gemini-North redshift z = 4.773
  27. EP260306a: SVOM/VT optical observation
  28. EP260302a: Gemini-South redshift z = 1.535
  29. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  30. The EP-WXT trigger 01709258759: Las Cumbres discovery of the optical counterpart
  31. EP260302a: Optical afterglow rebrightening
  32. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  33. GRB 260303A: 1.3m DFOT optical upper limit
  34. EP260214b: ATCA 6 GHz observations
  35. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  36. GRB 260303A: SVOM/ECLAIRs refined analysis
  37. Fermi GRB 260305A: Global MASTER-Net observations report
  38. GRB 260305A: Fermi GBM Final Real-time Localization
  39. GRB 260303B: AstroSat CZTI detection
  40. SVOM/sb26030408: SVOM detection of an X-ray transient likely associated with Beta Persei
  41. GRB 260303A: SVOM/VT optical observations
  42. GRB 260303A: J-band observations with WINTER
  43. GRB 260303B: NuSTAR detection of prompt emission
  44. EP260302a: Global MASTER-Net observations report
  45. Fermi GRB 260303B: Global MASTER-Net observations report
  46. GRB 260225A: SVOM/ECLAIRs refined analysis
  47. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  48. GRB 260303B: Fermi GBM Final Real-time Localization
  49. EP260302a: analysis of the follow-up EP-FXT observation
  50. EP260302a: LCO observations
  51. EP260302a: BOOTES-7 optical counterpart detection at early times
  52. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  53. GRB 260303A: SVOM detection of a burst
  54. GRB 260228A: EP-FXT follow-up observation
  55. The EP-WXT trigger 01709258736: Las Cumbres discovery of the optical counterpart
  56. GRB 251130B: TERI Gamma-ray detection
  57. GRB 260208A: TERI Gamma-ray detection
  58. GRB 260302A: Fermi GBM Final Real-time Localization
  59. GRB 260228A: CAHA 2.2m telescope optical upper limit
  60. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  61. EP260227a: Mephisto optical detection
  62. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  63. EP260227a: SVOM/VT optical observation
  64. GRB 260228A: SVOM/VT optical upper limits
  65. GRB 260225D: SVOM/GRM observation
  66. EP260227A: 3.6m DOT optical afterglow detection
  67. GRB 260225B: SVOM/GRM observation
  68. GRB 260228A: SVOM detection of a burst
  69. EP260227a: FTW optical and NIR observations
  70. EP260227a: Liverpool Telescope optical observations
  71. EP260227a: LCOGT Optical Observations
  72. GRB 260226A: Asiago r-band upper limit
  73. EP260227a: Thai National Telescope observations
  74. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  75. EP260227a: COLIBRÍ optical observations
  76. EP260227a: NOT optical observations
  77. GRID detection of GRB 260223A
  78. EP260227a: Global MASTER-Net observations report
  79. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  80. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  81. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  82. Konus-Wind detection of GRB 260226A
  83. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  84. EP260214a: VLT/FORS2 optical observations
  85. GRB 260225A: WINTER J-band upper limit
  86. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 260226A: COLIBRÍ optical upper limits
  88. GRB 260226A: LCOGT Optical Upper Limit
  89. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  90. GRB 260226A: Glowbug gamma-ray detection
  91. GRB 260226A: NuSTAR detection of bright prompt emission
  92. GRB 260226A : GROWTH-India Telescope optical observations
  93. GRB 260226A: LAST optical upper limit
  94. GRB 260226A: Fermi GBM observation
  95. GRB 260226A: Fermi-LAT refined analysis
  96. The EP-WXT trigger 01709258652 is likely a flaring star
  97. LAT GRB260226.44: Global MASTER-Net observations report
  98. Fermi GRB 260226A: Global MASTER-Net observations report
  99. GRB 260226A: AstroSat CZTI detection of bright long burst
  100. EP260214a: VLA 6 GHz detection

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