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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"

14866 results found.

  1. IPN triangulation of GRB 250204B (short/hard)
  2. IPN triangulation of GRB 250202B
  3. GRB 250204B: AstroSat CZTI detection of a short burst
  4. GRB 250204B: Fermi GBM Final Localization
  5. GRB 250129A: LCO late afterglow detection
  6. GRB 250204A: Fermi GBM Final Real-time Localization
  7. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  8. GRB 250202B: NuSTAR detection of the prompt emission
  9. GRB 250202C: GRBAlpha detection
  10. GRB 250202B: Fermi GBM Detection
  11. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 250129a: Liverpool Telescope optical follow-up
  13. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  14. GRB 250202C: Fermi GBM Final Real-time Localization
  15. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  16. LIGO/Virgo/KAGRA S250202ad: Retraction of GW compact binary merger candidate
  17. GRB 250202B: Fermi GBM Final Real-time Localization
  18. GRB 250202A: Fermi GBM Final Real-time Localization
  19. GRB 250201A: INTEGRAL SPI/ACS detection
  20. Konus-Wind detection of GRB 250129A
  21. GRB 250129A: 1.3m DFOT Optical observations
  22. GRB 250201A: Fermi GBM Final Real-time Localization
  23. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  24. GRB 250129A: optical photometry from Konkoly
  25. GRB 250128B: VLA possible radio detection
  26. GRB 250129a: Liverpool Telescope optical follow-up
  27. GRB 250129A: TNG NIR afterglow detection
  28. GRB 250129A: AKO Optical Afterglow Detection
  29. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  30. Ep250125A: 1.3m DFOT optical upper limit
  31. GRB 250129A: Skynet optical observations
  32. GRB 250128B: Gemini-North optical extended source detection
  33. GRB 250129A: Swift/UVOT Detection
  34. GRB 250129A: REM optical/NIR afterglow detection
  35. GRB 250129A: Early afterglow detection by LCO.
  36. Swift GRB 250129A: Global MASTER-Net Slowly evolving LC detection
  37. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  38. GRB 250129A: Swift detection of a burst with an optical counterpart
  39. Swift GRB 250129A: Global MASTER-Net OT detection
  40. GRB 250128B: Swift detection of a short burst
  41. GRB 250128B: Fermi GBM Final Real-time Localization
  42. GRB 250127B: DDOTI Upper Limit on the Afterglow
  43. GRB 250127A: EP-FXT afterglow detection
  44. GRB 250128A: Fermi GBM Final Real-time Localization
  45. GRB 250127A: SVOM/VT upper limit
  46. GRB 250127B: Fermi GBM Final Real-time Localization
  47. IPN triangulation of GRB 250119C
  48. GRB 241223A: cubesat Avion detection
  49. GRB 250127A: SVOM detection of a long burst
  50. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  51. EP250125A: Non-detection from Fermi-GBM Observations
  52. GRB 250126A: MAXI/GSC detection
  53. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  54. GRB 250126A: Fermi GBM Final Real-time Localization
  55. GECAM-A detection of a bright burst from SGR 1E1841-045
  56. EP250125a: Optical upper limit with Kinder observations
  57. EP250125a: REM optical counterpart detection
  58. EP250125a: Swift/XRT detection of a fading counterpart
  59. EP250125a: a new X-ray transient detected by Einstein Probe
  60. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  61. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  62. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  63. Konus-Wind detection of GRB 250118B
  64. Konus-Wind detection of GRB 250119B
  65. IPN triangulation of GRB 250119B
  66. GRB 250122A: Fermi GBM Final Real-time Localization
  67. Improved IPN triangulation of GRB 250107C
  68. GRB 250121A: INTEGRAL/SPI-ACS detection
  69. GRB 250121A: Fermi-LAT detection
  70. GRB 250121A: Fermi GBM Final Real-time Localization
  71. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  72. Konus-Wind detection of GRB 250117A
  73. IPN triangulation of GRB 250117A (short)
  74. ATCA detection of possible radio counterpart to GRB 250114A
  75. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  76. GRB 250119B: INTEGRAL/SPI-ACS detection
  77. GRB 250119C: Fermi GBM Final Real-time Localization
  78. GRB 250119B: Fermi GBM Final Real-time Localization
  79. GRB 250119A: Fermi GBM Final Real-time Localization
  80. GRB 250118A: Fermi GBM Final Real-time Localization
  81. Konus-Wind detection of GRB 250116A
  82. GRB 250116A: GECAM-B detection of a long burst
  83. GRB 241217A / EP241217B: radio detection with the VLA
  84. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  85. GRB 250116A: Fermi-LAT detection
  86. GRB 250114B: Swift-XRT afterglow detection
  87. GRB 250114B: SVOM/VT upper limit
  88. Konus-Wind detection of GRB 250113A
  89. IPN triangulation of GRB 250113A
  90. GRB 250114B: Liverpool Telescope optical upper limit
  91. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  92. GRB 250114A: LCO optical counterpart detection.
  93. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  94. GRB 250114A: LCOGT optical afterglow i-band detection
  95. GRB 250113A: INTEGRAL/SPI-ACS detection
  96. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  97. GRB 250114A: REM detection of the optical and NIR counterpart
  98. Swift GRB250114A: Global MASTER-Net OT detection
  99. GRB 250114A: Swift detection of a burst with an optical counterpart
  100. GRB 250107A: VZLUSAT-2 detection

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