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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.

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

45781 results found.

  1. GRB 250925A: Mondy I-band optical observations
  2. GRB 250916A: SVOM/VT optical observation
  3. LIGO/Virgo/KAGRA S250929c: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo/KAGRA S250927cy: Updated Sky localization
  5. LIGO/Virgo/KAGRA S250927ck: Updated Sky localization
  6. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  7. GRB 250926A: triangulation location with Insight-HXMT/HE and Fermi/GBM
  8. GRB 250924A: SVOM/GRM observation
  9. GRB 250925A: Swift-XRT refined Analysis
  10. LIGO/Virgo/KAGRA S250927cy: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo/KAGRA S250927ck: Identification of a GW compact binary merger candidate
  12. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 250926A: Insight-HXMT detection
  14. GRB 250926B: Fermi GBM Final Localization
  15. Fermi trigger No 780609036: Global MASTER-Net observations report
  16. IceCube Alert 250926.52: Global MASTER-Net observations report
  17. GRB 250920C: ULL-ASTRO-MASTER early detection of the optical afterglow with LCO 40-cm telescope at Siding Spring Observatory
  18. GRB 250926A: AstroSat CZTI detection
  19. GRB 250925A: Swift/UVOT Upper Limits
  20. GRB 250925A: Swift-BAT refined analysis
  21. GRB 250925A: Mondy and AbAO optical observations
  22. GRB 250925A: COLIBRÍ photometric redshift
  23. IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
  24. GRB 250925A: SVOM/GWAC-F60A upper limit
  25. GRB 250925A/EP250925a: EP-WXT detection
  26. GRB 250926A: DDOTI Optical Observations and Spatial Coincidence with the Orion Nebula
  27. GRB 250925A : MITSuME Akeno optical upper limits
  28. GRB 250925A: JinShan optical observations
  29. GRB 250925A: 1.5m OSN optical detection and redshift with the 10.4m GTC/OSIRIS+
  30. GRB 250919A / EP250919a: Global MASTER Net before, during and after trigger optical observations
  31. GRB 250925A: COLIBRÍ optical photometry of the afterglow
  32. Fermi GRB 250926A: Global MASTER-Net observations report
  33. GRB 250926A: Fermi GBM Final Real-time Localization
  34. GRB 250925A: Optical Observations via Virtual Telescope Project, Italy
  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. Swift GRB 250925A: Global MASTER-Net observations report
  43. GRB 250922A: SVOM/GRM observation
  44. GRB 250924A: 1.6m Mephisto optical upper limits
  45. GRB 250924A: SAO RAS optical observations
  46. GRB 250924A: NOT optical observations
  47. GRB 250924A: AstroSat CZTI detection
  48. GRB 250914A: AstroSat CZTI detection
  49. GRB 250920B: AstroSat CZTI detection
  50. GRB 250924A: SVOM/VT optical observation
  51. GRB 250924A: Swift/UVOT Detection
  52. GRB 250924A: Swift-XRT refined Analysis
  53. GRB 250924A: Enhanced Swift-XRT position
  54. GRB 250924A: J-band detection with WINTER
  55. GRB 250924A: GROWTH-India Telescope Upper Limits
  56. GRB 250924A: KAIT optical observations
  57. GRB 250924A: Mondy optical observations, afterglow fading
  58. GRB 250924A: Kilonova-Catcher optical afterglow detection
  59. GRB 250920C: Kilonova-Catcher optical afterglow detection
  60. GRB 250922B: SVOM/GRM observation
  61. GRB 250920C: TRT optical observation
  62. GRB 250924B: Fermi GBM Final Localization
  63. GRB 250924A: COLIBRÍ optical observations
  64. Swift GRB 250924A: Global MASTER-Net observations report
  65. GRB 250919A / EP250919a: further LCO optical observation
  66. GRB 250924A: DDOTI Detection of the Optical Counterpart
  67. GRB 250924A: Swift detection of a burst with an optical counterpart
  68. GRB 250920B: AbAO optical upper limits
  69. Konus-Wind detection of GRB 250920C
  70. GRB 250920C: KAIT optical observations
  71. GRB 250920C: VLT redshift confirmation z = 1.399
  72. EP250911a: e-MERLIN radio observations
  73. GRB 250920B: CrAO ZTSH optical observations
  74. GRB 250920C: SALT redshift confirmation
  75. GRB 250920C: COLIBRÍ optical observations
  76. GRB 250922C: AstroSat CZTI detection of a short burst
  77. Fermi GRB 250922B: Global MASTER-Net observations report
  78. GRB 250920B: SAO RAS optical observations
  79. GRB 250920C: NIR observations with WINTER
  80. GRB 250920B: NIR observations with WINTER
  81. Fermi trigger No 780156732: Global MASTER-Net observations report
  82. GRB 250922B: Fermi GBM Final Real-time Localization
  83. GRB 250920C: PRIME near-infrared detection
  84. Konus-Wind detection of GRB 250920B
  85. Konus-Wind detection of GRB 250920A
  86. IPN triangulation of GRB 250920A (long/bright)
  87. Konus-Wind detection of GRB 250911A
  88. GRB 250916A: Swift/UVOT Detection
  89. GRB 250920B: Glowbug gamma-ray detection
  90. GRB 250916A: CrAO ZTSh R-band optical observations
  91. GRB 250920C: Swift-XRT refined Analysis
  92. GRB 250916A: SAO RAS Zeiss-1000 optical observations
  93. GRB 250922A: Fermi GBM Final Localization
  94. GRB 250920B: Asiago optical observations
  95. GRB 250920B: Kitab-ISON optical upper limit
  96. GRB 250917B: Mondy and Zeiss-1000 SAO RAS optical observations, optical observations, afterglow candidate
  97. GRB 250920C: SVOM/GRM observation
  98. GRB 250920C: GTC/OSIRIS+ spectroscopic redshift z = 1.40
  99. GRB 250917B: KAIT optical upper limit
  100. GRB 250920A: NuSTAR detection of bright prompt emission

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