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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"

45684 results found.

  1. The EP-WXT trigger 01709131153 is not a real source
  2. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  3. LIGO/Virgo/KAGRA S250202ad: Retraction of GW compact binary merger candidate
  4. GRB 250202B: Fermi GBM Final Real-time Localization
  5. Swift GRB250129A: MASTER 4 days observations report
  6. GRB 250202A: Fermi GBM Final Real-time Localization
  7. GRB 250201A: INTEGRAL SPI/ACS detection
  8. Konus-Wind detection of GRB 250129A
  9. GRB 250129A: 1.3m DFOT Optical observations
  10. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  11. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  12. GRB 250201A: Fermi GBM Final Real-time Localization
  13. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  14. GRB 250129A: Skynet Continued Optical Observations
  15. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  16. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  17. GRB 250129A: SAO RAS optical observations
  18. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  19. GRB 250129A: optical photometry from Konkoly
  20. GRB 250129A: COLIBRÍ Optical Observations
  21. GRB 250128B: VLA possible radio detection
  22. GRB 250129A: continued KAIT observations indicating steep decay after 28.5h
  23. GRB 250129A: iTelescope optical observation
  24. GRB 250129A: NOT optical observations of continuining activity
  25. GRB 250129a: Liverpool Telescope optical follow-up
  26. GRB 250129A: TNG NIR afterglow detection
  27. GRB 250129A: AKO Optical Afterglow Detection
  28. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  29. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  30. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  31. GRB 250128B: VLA radio upper limit
  32. Ep250125A: 1.3m DFOT optical upper limit
  33. GRB 250129A: Skynet optical observations
  34. GRB 250129A: KAIT optical observations of the rebrightening around 5.1 hours
  35. GRB 250129A: Swift-XRT refined Analysis
  36. GRB 250128B: Gemini-North optical extended source detection
  37. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  38. GRB 250128B: TNG optical upper limit
  39. GRB 250129A: Swift/UVOT Detection
  40. GRB 250128B: VLT/HAWKI near-infrared observations
  41. GRB 250127A: CrAO and Terskol optical upper limits
  42. GRB 250129A: Enhanced Swift-XRT position
  43. GRB 250128B: NOT optical upper limit
  44. GRB 250128B: VLT/FORS2 optical observations
  45. GRB 250129A: REM optical/NIR afterglow detection
  46. GRB 250129A: OHP/T193 optical and spectroscopy observations
  47. GRB 250129A: Early afterglow detection by LCO.
  48. GRB 250128B: OHP/T193 optical upper limit
  49. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  50. GRB 250129A: LCO optical observations
  51. GRB 250129A: NOT optical observations and redshift confirmation
  52. GRB 250129A: GOTO optical observations show brightening afterglow
  53. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  54. Swift GRB 250129A: Global MASTER-Net observations report
  55. GRB 250128B: Enhanced Swift-XRT position
  56. The EP-WXT trigger 01709131085 is likely a flaring star
  57. Fermi GRB 250128B: Global MASTER-Net observations report
  58. GRB 250129A: Swift detection of a burst with an optical counterpart
  59. Swift GRB 250129A: Global MASTER-Net OT detection
  60. GRB 250128B: Swift-XRT refined Analysis
  61. GRB 250128B: Fermi GBM Observation
  62. GRB 250128B: GOTO optical upper limit
  63. Swift GRB 250128B: Global MASTER-Net observations report
  64. EP250125a: Upper limits from Swift/BAT-GUANO
  65. GRB 250128B: LCO optical observations
  66. GRB 250128B: Swift detection of a short burst
  67. GRB 250128B: Fermi GBM Final Real-time Localization
  68. GRB 250127A: Swift-XRT observations
  69. GRB 250127B: DDOTI Upper Limit on the Afterglow
  70. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  71. GRB 250127A: EP-FXT afterglow detection
  72. Fermi GRB 250128A: Global MASTER-Net observations report
  73. GRB 250128A: Fermi GBM Final Real-time Localization
  74. GRB 250117A: Fermi GBM Observation
  75. Fermi GRB 250127B: Global MASTER-Net observations report
  76. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  77. GRB 250127A: SVOM/VT upper limit
  78. GRB 250127B: Fermi GBM Final Real-time Localization
  79. IPN triangulation of GRB 250119C
  80. GRB 250127A: Swift ToO observations
  81. GRB 250127A: LCO optical upper limit
  82. GRB 241223A: cubesat Avion detection
  83. GRB 250127A: SVOM detection of a long burst
  84. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  85. EP250125A: Non-detection from Fermi-GBM Observations
  86. GRB 250126A: MAXI/GSC detection
  87. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  88. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  89. GRB 250126A: Fermi GBM Final Real-time Localization
  90. GECAM-A detection of a bright burst from SGR 1E1841-045
  91. GRB 250118A: Fermi GBM Observation
  92. EP250125a: Optical upper limit with Kinder observations
  93. EP250125a: REM optical counterpart detection
  94. GRB 250119C: Fermi GBM Observation
  95. EP250125a: Swift/XRT detection of a fading counterpart
  96. EP250125a: a new X-ray transient detected by Einstein Probe
  97. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  98. The EP-WXT trigger 01709130758 is a false trigger
  99. The EP-WXT trigger 01709130758 is a false trigger
  100. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23

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