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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"

38621 results found.

  1. GRB260225A: SVOM/ECLAIRs refined position
  2. GRB 260226A: Fermi GBM Final Real-time Localization
  3. GRB 260225A: EP-FXT follow-up observation
  4. GRB 260225A: SVOM/VT optical observation
  5. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  6. GRB 260225C: Fermi GBM Final Real-time Localization
  7. GRB 260223A: Fermi GBM Observation
  8. GRB 260225A: SVOM/VT optical upper limits
  9. GRB 260225B: Fermi GBM Final Real-time Localization
  10. EP260126a: VLA 6 GHz detection
  11. EP260223a: Liverpool Telescope upper limits
  12. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  13. GRB 260225A: SVOM detection of a burst
  14. EP260224a: Einstein Probe detection of an X-ray transient
  15. EP 260225.148: COLIBRÍ Confirmation of flaring star
  16. EP260223a: Xinglong optical upper limit
  17. The EP-WXT trigger 01709258631 is likely a flaring star
  18. GRB 260223A: Glowbug gamma-ray detection
  19. EP260213a: Mephisto optical upper limits
  20. EP260223a: EP-FXT follow-up observation
  21. sb26021801: SVOM/VT optical upper limits
  22. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  23. sb26021801: SVOM/C-GFT upper limit
  24. EP260223a: COLIBRÍ optical upper limits
  25. EP260223a: Einstein Probe detection of an X-ray transient
  26. GRB 260223A: SVOM/VT optical observation
  27. GRB 260223A: SVOM/GRM observation
  28. GRB 260223A: COLIBRÍ further optical observations and a brightening
  29. EP260221a: Optical upper limit with Kinder observations
  30. GRB 260223A: COLIBRÍ optical observations
  31. GRB 260223A: DDOTI Optical Candidate
  32. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  33. GRB 260223A: Fermi GBM Final Real-time Localization
  34. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  35. EP260221a: COLIBRÍ optical counterpart candidate
  36. EP260221a: Gemini South z-band upper limit
  37. GRB 260222A: Fermi GBM Final Real-time Localization
  38. EP260221a: EP-FXT follow-up observation
  39. GRB 260221B: Fermi GBM Final Real-time Localization
  40. EP-WXT01709258519: Xinglong optical upper limit
  41. EP260221a: Xinglong optical upper limit
  42. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  43. GRB 260221A: Fermi GBM Final Real-time Localization
  44. EP260221a: GOTO optical upper limit
  45. EP260221a: COLIBRÍ optical upper limit
  46. SVOM alert sb26021801: LCO optical upper limit
  47. EP260221a: Einstein Probe detection of an X-ray transient
  48. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  49. GRB 260219A: AstroSat CZTI detection
  50. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 260219A: GECAM-B observation of a long burst
  52. GRB 260219A: Fermi GBM Final Real-time Localization
  53. SVOM alert sb26021801: LAST optical upper limit
  54. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  55. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  56. GRB 260217A: Fermi GBM Final Localization
  57. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  58. sb26021801: SVOM detection of a long faint X-ray transient
  59. The EP-WXT trigger 01709258455 is likely a flaring star
  60. EP-WXT 01709258455: NOT optical upper limits
  61. EP260214b: Mondy optical observations
  62. EP260214b: 1.3m DFOT optical upper limit
  63. EP260210a: Mondy optical upper limits
  64. Konus-Wind detection of GRB 260212A
  65. GRB 260208A: AbAO and Terskol optical upper limits
  66. GRB 260208A: continued Mondy optical observations
  67. IPN triangulation of GRB 260212A
  68. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  69. GRB 260213A: GECAM-B observation of a short burst
  70. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  71. GRB 260216A: Fermi GBM Final Real-time Localization
  72. EP260214b: Liverpool Telescope optical observations
  73. EP260214b: Optical upper limit with Kinder observations
  74. EP260214a: Optical upper limits with Kinder observations
  75. EP260214b: EP-FXT follow-up observation
  76. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  77. EP260214b: DDOTI Optical Detection
  78. EP260214b: GROWTH-India Telescope optical upper limit
  79. EP260214a: VLT near-infrared observation
  80. EP260214b: SVOM/VT optical observation
  81. EP260214a: NOT optical upper limits
  82. EP260214a: COLIBRÍ optical upper limits
  83. EP260214b: OHP/T120 optical observations
  84. EP260214a: refined analysis of the EP-FXT observation
  85. EP260214b: LCO optical counterpart detection
  86. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  87. GRB 260211A: SVOM/VT optical counterpart
  88. EP260214b: COLIBRÍ optical observations
  89. EP260214a: SVOM/VT optical upper limits
  90. EP260214b: NOT optical counterpart detection
  91. EP260214b: Einstein Probe detection of a fast X-ray transient
  92. EP260214a: Einstein Probe detection of an X-ray transient
  93. GRB 260212A: AstroSat CZTI detection
  94. GRB 260212A: Fermi GBM Observation
  95. EP260213a: Liverpool Telescope optical upper limits
  96. EP260213a: COLIBRÍ optical upper limits
  97. GRB 260212A: GECAM-B observation
  98. EP260213a: Optical upper limits with Kinder observations
  99. EP260213a: SVOM/VT optical upper limit
  100. EP260213a: Mondy R-band optical upper limit

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