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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28228 results found.

  1. GRB 250930A: SVOM/GRM observation
  2. GRB 251001B: TRT optical afterglow detection and potential host galaxy
  3. GRB 251001B: Swift detection of a burst
  4. GRB 251001B: Fermi GBM Final Real-time Localization
  5. GRB 251001A: Fermi GBM Detection
  6. GRB 250910A / EP250910a: VLT limits on the possible associated supernova
  7. GRB 251001A: BALROG localization (Fermi Trigger 780979261 / GRB 251001112)
  8. GRB 251001A: Fermi GBM Final Real-time Localization
  9. LIGO/Virgo/KAGRA S250818k: further MeerKAT monitoring
  10. GRB 250925A: MAO/AZT-22 optical observations
  11. LIGO/Virgo/KAGRA S250929c: Updated Sky localization
  12. GRB 250925A: Mondy I-band optical observations
  13. LIGO/Virgo/KAGRA S250929c: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S250927cy: Updated Sky localization
  15. LIGO/Virgo/KAGRA S250927ck: Updated Sky localization
  16. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  17. GRB 250926A: triangulation location with Insight-HXMT/HE and Fermi/GBM
  18. GRB 250924A: SVOM/GRM observation
  19. GRB 250925A: Swift-XRT refined Analysis
  20. LIGO/Virgo/KAGRA S250927cy: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S250927ck: Identification of a GW compact binary merger candidate
  22. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
  24. GRB 250926A: AstroSat CZTI detection
  25. GRB 250925A: Swift-BAT refined analysis
  26. GRB 250925A: Mondy and AbAO optical observations
  27. GRB 250925A: COLIBRÍ photometric redshift
  28. GRB 250925A: SVOM/GWAC-F60A upper limit
  29. GRB 250925A/EP250925a: EP-WXT detection
  30. GRB 250926A: DDOTI Optical Observations and Spatial Coincidence with the Orion Nebula
  31. GRB 250925A : MITSuME Akeno optical upper limits
  32. GRB 250925A: JinShan optical observations
  33. GRB 250919A / EP250919a: Global MASTER Net before, during and after trigger optical observations
  34. GRB 250925A: COLIBRÍ optical photometry of the afterglow
  35. GRB250925A: Liverpool Telescope optical observations
  36. GRB 250925A: NOT optical afterglow candidate
  37. GRB 250925A: Leavitt Observatory optical upper limit
  38. GRB 250925A: Enhanced Swift-XRT position
  39. GRB 250924A: Swift-BAT refined analysis
  40. GRB 250925A: GROWTH-India Telescope Upper Limits
  41. GRB 250925A: Swift detection of a burst
  42. GRB 250922A: SVOM/GRM observation
  43. GRB 250924A: 1.6m Mephisto optical upper limits
  44. GRB 250924A: SAO RAS optical observations
  45. GRB 250924A: AstroSat CZTI detection
  46. GRB 250924A: SVOM/VT optical observation
  47. GRB 250924A: Swift/UVOT Detection
  48. GRB 250924A: Swift-XRT refined Analysis
  49. GRB 250924A: Enhanced Swift-XRT position
  50. GRB 250924A: J-band detection with WINTER
  51. GRB 250924A: GROWTH-India Telescope Upper Limits
  52. GRB 250924A: KAIT optical observations
  53. GRB 250924A: Mondy optical observations, afterglow fading
  54. GRB 250924A: Kilonova-Catcher optical afterglow detection
  55. GRB 250920C: Kilonova-Catcher optical afterglow detection
  56. GRB 250922B: SVOM/GRM observation
  57. GRB 250920C: TRT optical observation
  58. GRB 250924A: COLIBRÍ optical observations
  59. GRB 250919A / EP250919a: further LCO optical observation
  60. GRB 250924A: DDOTI Detection of the Optical Counterpart
  61. GRB 250924A: Swift detection of a burst with an optical counterpart
  62. GRB 250920B: AbAO optical upper limits
  63. GRB 250920C: KAIT optical observations
  64. GRB 250920B: CrAO ZTSH optical observations
  65. GRB 250920C: COLIBRÍ optical observations
  66. GRB 250922C: AstroSat CZTI detection of a short burst
  67. GRB 250920B: SAO RAS optical observations
  68. GRB 250920C: NIR observations with WINTER
  69. GRB 250920B: NIR observations with WINTER
  70. Fermi trigger No 780156732: Global MASTER-Net observations report
  71. GRB 250920C: PRIME near-infrared detection
  72. GRB 250916A: Swift/UVOT Detection
  73. GRB 250920B: Glowbug gamma-ray detection
  74. GRB 250916A: CrAO ZTSh R-band optical observations
  75. GRB 250920C: Swift-XRT refined Analysis
  76. GRB 250916A: SAO RAS Zeiss-1000 optical observations
  77. GRB 250920B: Asiago optical observations
  78. GRB 250920B: Kitab-ISON optical upper limit
  79. GRB 250917B: Mondy and Zeiss-1000 SAO RAS optical observations, optical observations, afterglow candidate
  80. GRB 250920C: SVOM/GRM observation
  81. GRB 250917B: KAIT optical upper limit
  82. GRB 250920A: NuSTAR detection of bright prompt emission
  83. GRB 250920C: GROWTH-India Telescope optical observations
  84. GRB 250920C: Swift-BAT refined analysis
  85. GRB 250920B: Swift-BAT refined analysis
  86. GRB 250920C: Enhanced Swift-XRT position
  87. GRB 250920C: Swift/UVOT Detection
  88. GRB 250920B: Fermi GBM Observation
  89. GRB 250920A: Fermi GBM Detection
  90. GRB 250920C: Fermi GBM Observation
  91. GRB 250920B: Swift/UVOT Detection
  92. GRB 250920C: Optical counterpart detection by LCO
  93. GRB 250920A: SVOM/GRM observation
  94. GRB250920C: LCOGT Optical Detection
  95. GRB 250920B: Enhanced Swift-XRT position
  96. GRB 250920B: Swift-XRT refined Analysis
  97. GRB 250920B: SVOM/C-GFT optical observations
  98. GRB 250919A / EP250919a: LCO optical observation
  99. GRB 250920C: Swift detection of a burst
  100. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations

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