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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"

32721 results found.

  1. GRB 250924A: DDOTI Detection of the Optical Counterpart
  2. GRB 250920B: AbAO optical upper limits
  3. Konus-Wind detection of GRB 250920C
  4. GRB 250920C: KAIT optical observations
  5. GRB 250920C: VLT redshift confirmation z = 1.399
  6. EP250911a: e-MERLIN radio observations
  7. GRB 250920B: CrAO ZTSH optical observations
  8. GRB 250920C: SALT redshift confirmation
  9. GRB 250920C: COLIBRÍ optical observations
  10. Fermi GRB 250922B: Global MASTER-Net observations report
  11. GRB 250920B: SAO RAS optical observations
  12. GRB 250920C: NIR observations with WINTER
  13. GRB 250920B: NIR observations with WINTER
  14. GRB 250920C: PRIME near-infrared detection
  15. Konus-Wind detection of GRB 250920B
  16. Konus-Wind detection of GRB 250920A
  17. IPN triangulation of GRB 250920A (long/bright)
  18. Konus-Wind detection of GRB 250911A
  19. GRB 250916A: Swift/UVOT Detection
  20. GRB 250920B: Glowbug gamma-ray detection
  21. GRB 250916A: CrAO ZTSh R-band optical observations
  22. GRB 250916A: SAO RAS Zeiss-1000 optical observations
  23. GRB 250920B: Asiago optical observations
  24. GRB 250920B: Kitab-ISON optical upper limit
  25. GRB 250917B: Mondy and Zeiss-1000 SAO RAS optical observations, optical observations, afterglow candidate
  26. GRB 250920C: SVOM/GRM observation
  27. GRB 250920C: GTC/OSIRIS+ spectroscopic redshift z = 1.40
  28. GRB 250917B: KAIT optical upper limit
  29. GRB 250920A: NuSTAR detection of bright prompt emission
  30. GRB 250920C: GROWTH-India Telescope optical observations
  31. GRB 250920C: Swift-BAT refined analysis
  32. GRB 250920B: Swift-BAT refined analysis
  33. GRB 250916A: FTW optical and NIR observations of the counterpart
  34. GRB 250920C: Swift/UVOT Detection
  35. GRB 250920B: Fermi GBM Observation
  36. GRB 250920A: Fermi GBM Detection
  37. GRB 250920C: Fermi GBM Observation
  38. Swift GRB 250920C: Global MASTER-Net observations report
  39. GRB 250920B: Swift/UVOT Detection
  40. GRB 250920B: FTW optical and NIR observations of the counterpart
  41. GRB 250920C: Optical counterpart detection by LCO
  42. GRB 250920A: SVOM/GRM observation
  43. GRB250920C: LCOGT Optical Detection
  44. GRB 250920B: SVOM/C-GFT optical observations
  45. GRB 250920C: GOTO optical counterpart candidate
  46. GRB 250919A / EP250919a: LCO optical observation
  47. Konus-Wind detection of GRB 250919A
  48. Swift GRB 250920B: Global MASTER-Net observations report
  49. GRB 250919A / EP250919a: Insight-HXMT detection
  50. GRB 250920A: AstroSat CZTI detection
  51. GRB 250919A/EP250919a: SVOM/VT optical observation
  52. GRB 250919A / EP250919a: MASTER bright afterglow detection 24h after GRB time
  53. GRB 250916A: Mondy R-band optical observations
  54. GRB 250919A: Glowbug gamma-ray detection
  55. GRB 250919A: Fermi GBM Observation
  56. Fermi GRB 250918A: Global MASTER-Net observations report
  57. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  58. GRB 250918A: SVOM/GRM observation
  59. GRB 250919A/EP250919A: Swift/UVOT afterglow detection
  60. GRB 250919A: Swift-XRT afterglow detection
  61. GRB 250919A: Fermi-LAT detection
  62. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  63. GRB 250919A: SVOM/GRM observation of a very bright GRB
  64. EP250919a: Global MASTER-Net observations report
  65. EP250919a: Einstein Probe detection of an X-ray transient
  66. Correction for GCN 41877: EP-WXT ID is 01709243841
  67. GRB 250916A: Fermi GBM Observation
  68. Fermi GRB 250919A: Global MASTER-Net observations report
  69. GRB 250916A: KAIT optical observations
  70. GRB 250917B: VLT/HAWK-I near-infrared observations
  71. GRB 250916A: NuSTAR detection of the prompt emission
  72. GRB 250916A: further SAO RAS optical observations
  73. GRB 250912A: SVOM/ECLAIRs refined analysis
  74. GRB 250917B: Swift-BAT refined analysis
  75. GRB 250917B: Swift/UVOT Upper Limits
  76. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  77. GRB 250916A: Swift-XRT observations
  78. EP250916a: EP-FXT follow-up observation
  79. GRB 250916A: MAO/AZT-22 optical observations
  80. GRB 250916A: SAO RAS optical observations
  81. GRB 250916A : GIT optical observations
  82. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  83. GRB 250916A: Glowbug gamma-ray detection
  84. GRB250917B: WFST optical observations
  85. GRB 250916A: Swift ToO observations
  86. GRB 250917B: Fermi GBM Observation
  87. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  88. Fermi GRB 250917B: Global MASTER-Net observations report
  89. GRB 250916A: GOTO optical counterpart candidate
  90. GRB 250916A: AstroSat CZTI detection of a bright long burst
  91. GRB 250910A: SVOM/ECLAIRs refined analysis
  92. Fermi GRB 250916A: Global MASTER-Net observations report
  93. EP250827b: VLA Observations
  94. LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
  95. SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
  96. SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
  97. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  98. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  99. GRB 250912A: Swift-XRT observations
  100. GRB250912A: VLT/HAWK-I follow-up observations

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