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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"

45519 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. Fermi GRB 260223A: Global MASTER-Net observations report
  34. GRB 260223A: Fermi GBM Final Real-time Localization
  35. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  36. EP260221a: COLIBRÍ optical counterpart candidate
  37. EP260221a: Gemini South z-band upper limit
  38. GRB 260222A: Fermi GBM Final Real-time Localization
  39. EP260221a: Global MASTER-Net observations report
  40. EP260221a: EP-FXT follow-up observation
  41. Fermi GRB 260221B: Global MASTER-Net observations report
  42. GRB 260221B: Fermi GBM Final Real-time Localization
  43. EP-WXT01709258519: Xinglong optical upper limit
  44. EP260221a: Xinglong optical upper limit
  45. Fermi GRB 260221A: Global MASTER-Net observations report
  46. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  47. GRB 260221A: Fermi GBM Final Real-time Localization
  48. EP260221a: GOTO optical upper limit
  49. EP260221a: COLIBRÍ optical upper limit
  50. SVOM alert sb26021801: LCO optical upper limit
  51. EP260221a: Einstein Probe detection of an X-ray transient
  52. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  53. GRB 260219A: AstroSat CZTI detection
  54. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 260219A: GECAM-B observation of a long burst
  56. Fermi GRB 260219A: Global MASTER-Net observations report
  57. GRB 260219A: Fermi GBM Final Real-time Localization
  58. SVOM alert sb26021801: LAST optical upper limit
  59. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  60. IceCube Alert 260217A: Global MASTER-Net observations report
  61. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  62. GRB 260217A: Fermi GBM Final Localization
  63. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  64. sb26021801: SVOM detection of a long faint X-ray transient
  65. The EP-WXT trigger 01709258455 is likely a flaring star
  66. EP-WXT 01709258455: NOT optical upper limits
  67. EP260214b: Mondy optical observations
  68. EP260214b: 1.3m DFOT optical upper limit
  69. EP260210a: Mondy optical upper limits
  70. Konus-Wind detection of GRB 260212A
  71. GRB 260208A: AbAO and Terskol optical upper limits
  72. GRB 260208A: continued Mondy optical observations
  73. IPN triangulation of GRB 260212A
  74. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  75. GRB 260213A: GECAM-B observation of a short burst
  76. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  77. GRB 260216A: Fermi GBM Final Real-time Localization
  78. EP260214b: Liverpool Telescope optical observations
  79. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  80. EP260214b: Optical upper limit with Kinder observations
  81. EP260214a: Optical upper limits with Kinder observations
  82. EP260214b: EP-FXT follow-up observation
  83. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  84. EP260214b: DDOTI Optical Detection
  85. EP260214b: GROWTH-India Telescope optical upper limit
  86. EP260214a: VLT near-infrared observation
  87. EP260214b: SVOM/VT optical observation
  88. EP260214a: NOT optical upper limits
  89. EP260214a: COLIBRÍ optical upper limits
  90. EP260214b: OHP/T120 optical observations
  91. EP260214a: refined analysis of the EP-FXT observation
  92. EP260214b: LCO optical counterpart detection
  93. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  94. GRB 260211A: SVOM/VT optical counterpart
  95. EP260214b: COLIBRÍ optical observations
  96. EP260214a: SVOM/VT optical upper limits
  97. EP260214b: NOT optical counterpart detection
  98. EP260214b: Einstein Probe detection of a fast X-ray transient
  99. EP260214a: Global MASTER-Net observations report
  100. EP260214a: Einstein Probe detection of an X-ray transient

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