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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"

11609 results found.

  1. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  2. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  3. GRB 251013C: Early and late-time optical counterpart detection by LCO
  4. GRB 251013C: Fermi GBM Observation
  5. GRB 251013D: Swift ToO observations
  6. GRB 251014A: DDOTI Upper Limit
  7. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  8. GRB 251013C: Asiago optical observations
  9. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  10. GRB 251013C: ABObservatory optical observations
  11. GRB 251014A: SAO RAS optical upper limit
  12. GRB 251014A: Fermi GBM Observation
  13. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  14. GRB 251013C: EP-FXT counterpart detection
  15. GRB 251013C: AstroSat CZTI detection
  16. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  17. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  18. GRB 251013C: ALMA detection
  19. GRB 251013C: DDOTI detection of the optical afterglow
  20. GRB 251014A: Fermi GBM Final Real-time Localization
  21. Fermi trigger No 782044789: Global MASTER-Net observations report
  22. Fermi GRB 251013C: Global MASTER-Net observations report
  23. Fermi GRB 251013B: Global MASTER-Net observations report
  24. Fermi GRB 251013D: Global MASTER-Net observations report
  25. GRB 251013C: GOTO optical afterglow detection
  26. GRB 251013C: SAO RAS optical observations
  27. GRB 251013C: LCO optical afterglow detection
  28. GRB 251013C: NOT spectroscopic redshift z = 0.572
  29. GRB 251013C: LAST detection of optical counterpart
  30. GRB 251013D: Fermi GBM Final Real-time Localization
  31. GRB 251013C: SVOM detection of a burst
  32. GRB 251013C: Fermi GBM Final Real-time Localization
  33. GRB 251013B: SVOM/GRM observation
  34. GRB 251013A: SVOM/GRM observation
  35. GRB 251003A: Mondy optical upper limit
  36. GRB 251013B: Fermi GBM Final Real-time Localization
  37. Fermi GRB 251013A: Global MASTER-Net observations report
  38. GRB 251013A: Fermi GBM Final Real-time Localization
  39. GRB 251011B inspection: MASTER orphan GRB detection
  40. GRB 251011A: Insight-HXMT detection
  41. Fermi GRB 251011A: Global MASTER-Net observations report
  42. GRB 251012A: Fermi GBM Final Real-time Localization
  43. GRB 251011B: SVOM/GRM observation
  44. GRB 251011B: Fermi GBM Observation
  45. GRB 251011B : MASTER optical observations
  46. GRB 251011C: Fermi GBM Final Real-time Localization
  47. GRB 251010A: AstroSat CZTI detection
  48. GRB 251011A: AstroSat CZTI detection
  49. GRB 251011B: Fermi GBM Final Real-time Localization
  50. GRB 251011A: Fermi GBM Final Real-time Localization
  51. Fermi Gamma-ray Burst Monitor trigger 781824269/251010892 is not a GRB
  52. GRB 251010A: Fermi GBM Final Real-time Localization
  53. GRB 251009A: GECAM-B detection of a short burst
  54. GRB 251009A: Insight-HXMT detection of a short burst
  55. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  56. GRB 251007A: SVOM/GRM observation
  57. GRB 251007A: Insight-HXMT detection
  58. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 251009A: Fermi GBM Final Localization
  60. GRB 250916A: TERI Gamma-ray detection
  61. GRB 250919A: TERI gamma-ray detection
  62. GRB 251006A: Fermi GBM Observation
  63. GRB 251003A: Fermi GBM Observation
  64. GRB 251006B: Fermi GBM Observation
  65. GRB 251007A: AstroSat CZTI detection
  66. GRB 250917B: iTelescope T-26 upper limit
  67. GRB 251006B: Insight-HXMT detection
  68. GRB 250702B/EP250702a: JWST/NIRCam Observations
  69. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  70. GRB 251005B: Glowbug gamma-ray detection
  71. GRB 251006B/EP251006a: SVOM/VT optical candidate
  72. GRB 251006B: SVOM/GRM observation
  73. GRB 251006B: COLIBRÍ optical upper limit
  74. GRB 251005C: SVOM/GRM observation of a likely short GRB
  75. Fermi GRB 251006B: Global MASTER-Net observations report
  76. GRB 251006B: BALROG localization (Fermi Trigger 781473909 / GRB 251006837)
  77. GRB 251006B: Fermi GBM Final Real-time Localization
  78. GRB 251006A (short): Glowbug gamma-ray detection
  79. Fermi GRB 251006A: Global MASTER-Net observations report
  80. GRB 251003A: LAST optical observations
  81. GRB 251006A: Fermi GBM Final Real-time Localization
  82. GRB 251005C: SVOM/VT optical candidate
  83. GRB 251005C: AstroSat CZTI detection
  84. GRB 250902A: MSU cubesats detection
  85. GRB 251005C: Fermi GBM Observation
  86. Fermi trigger No 781367244: Global MASTER-Net observations report
  87. GRB 251005B: Fermi GBM Final Real-time Localization
  88. GRB 251005A: Fermi GBM Final Localization
  89. GRB 251002A: Insight-HXMT detection
  90. GRB 251002A: Insight-HXMT detection
  91. GRB 251003A: J-band detection with WINTER
  92. Fermi GBM Sub-Threshold Detection of GRB 250910A
  93. GRB 251001B: NIR observations with WINTER
  94. GRB 251001A: AstroSat CZTI detection
  95. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  96. GRB 251003A: COLIBRÍ photometric redshift
  97. GRB 251003A: GOTO detection of the optical counterpart
  98. GRB 251002A: Fermi GBM Observation
  99. GRB 251003A: GTC/OSIRIS+ spectroscopic redshift z = 4.412
  100. GRB 251003A: Kilonova-Catcher optical afterglow detection

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