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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"

18488 results found.

  1. GRB 250924A: 1.6m Mephisto optical upper limits
  2. GRB 250924A: SAO RAS optical observations
  3. GRB 250924A: AstroSat CZTI detection
  4. GRB 250924A: SVOM/VT optical observation
  5. GRB 250924A: Swift/UVOT Detection
  6. GRB 250924A: Enhanced Swift-XRT position
  7. GRB 250924A: J-band detection with WINTER
  8. GRB 250924A: GROWTH-India Telescope Upper Limits
  9. GRB 250924A: Mondy optical observations, afterglow fading
  10. GRB 250924A: Kilonova-Catcher optical afterglow detection
  11. GRB 250920C: Kilonova-Catcher optical afterglow detection
  12. GRB 250922B: SVOM/GRM observation
  13. GRB 250920C: TRT optical observation
  14. GRB 250924A: COLIBRÍ optical observations
  15. GRB 250919A / EP250919a: further LCO optical observation
  16. GRB 250924A: DDOTI Detection of the Optical Counterpart
  17. GRB 250924A: Swift detection of a burst with an optical counterpart
  18. GRB 250920B: AbAO optical upper limits
  19. Konus-Wind detection of GRB 250920C
  20. GRB 250920C: KAIT optical observations
  21. GRB 250920B: CrAO ZTSH optical observations
  22. GRB 250920C: COLIBRÍ optical observations
  23. GRB 250920B: SAO RAS optical observations
  24. GRB 250920C: NIR observations with WINTER
  25. GRB 250920B: NIR observations with WINTER
  26. GRB 250920C: PRIME near-infrared detection
  27. GRB 250916A: Swift/UVOT Detection
  28. GRB 250916A: CrAO ZTSh R-band optical observations
  29. GRB 250920C: Swift-XRT refined Analysis
  30. GRB 250916A: SAO RAS Zeiss-1000 optical observations
  31. GRB 250920B: Asiago optical observations
  32. GRB 250920B: Kitab-ISON optical upper limit
  33. GRB 250917B: Mondy and Zeiss-1000 SAO RAS optical observations, optical observations, afterglow candidate
  34. GRB 250920C: SVOM/GRM observation
  35. GRB 250920C: GROWTH-India Telescope optical observations
  36. GRB 250920C: Enhanced Swift-XRT position
  37. GRB 250920C: Swift/UVOT Detection
  38. GRB 250920B: Swift/UVOT Detection
  39. GRB 250920C: Optical counterpart detection by LCO
  40. GRB 250920A: SVOM/GRM observation
  41. GRB250920C: LCOGT Optical Detection
  42. GRB 250920B: Enhanced Swift-XRT position
  43. GRB 250920B: SVOM/C-GFT optical observations
  44. GRB 250919A / EP250919a: LCO optical observation
  45. GRB 250920C: Swift detection of a burst
  46. GRB 250920B: Swift detection of a burst with a bright optical counterpart.
  47. GRB 250919A/EP250919a: SVOM/VT optical observation
  48. GRB 250916A: Mondy R-band optical observations
  49. GRB 250918A: SVOM/GRM observation
  50. GRB 250919A: Swift-XRT afterglow detection
  51. GRB 250919A: SVOM/GRM observation of a very bright GRB
  52. EP250919a: Einstein Probe detection of an X-ray transient
  53. GRB 250916A: Fermi GBM Observation
  54. GRB 250916A: KAIT optical observations
  55. GRB 250917B: VLT/HAWK-I near-infrared observations
  56. GRB 250916A: further SAO RAS optical observations
  57. GRB 250917B: Swift/UVOT Upper Limits
  58. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  59. EP250916a: EP-FXT follow-up observation
  60. GRB 250916A: MAO/AZT-22 optical observations
  61. GRB 250916A: SAO RAS optical observations
  62. GRB 250916A : GIT optical observations
  63. GRB250917B: WFST optical observations
  64. GRB 250917B: Swift detection of a short burst
  65. The EP-WXT trigger 01709241037 is likely a flaring star
  66. EP250916a: Einstein Probe detection of an X-ray transient
  67. SVOM/sb25091517: SVOM detection of an X-ray transient
  68. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  69. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  70. GRB250912A: VLT/HAWK-I follow-up observations
  71. GRB 250912A:SVOM/VT optical upper limit
  72. GRB 250912A: LCO optical upper limit
  73. The EP-WXT trigger 01709240768 is likely a flaring star
  74. GRB 250912A: SVOM detection of a burst
  75. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  76. GRB 250910B: SVOM/GRM observation
  77. EP250911a: SVOM/VT optical observation
  78. EP250911a: SAO RAS optical observations
  79. EP250911a: Optical detection with Kinder observations
  80. GRB 250911A: Swift/UVOT Detection
  81. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  82. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  83. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  84. EP250911a: COLIBRÍ optical observations
  85. EP250911a: Einstein Probe detection of an X-ray transient
  86. GRB 250911A: Enhanced Swift-XRT position
  87. GRB 250911A: Swift-XRT observations
  88. GRB 250911A: COLIBRÍ optical counterpart candidate
  89. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  90. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  91. GRB 250910A: SVOM/VT optical upper limit
  92. GRB 250910A: LCO optical upper limit
  93. EP250908b/EP#01709240653: Swift/UVOT Detection
  94. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  95. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  96. EP250908c: SVOM/VT optical observation
  97. EP250908c: VLT/FORS2 optical counterpart identification
  98. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  99. EP250908b: SVOM/VT optical candidate
  100. EP250908c: Einstein Probe detection of an X-ray transient

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