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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"
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submitter:"Judith Racusin"

20506 results found.

  1. GRB 250924A: COLIBRÍ optical observations
  2. GRB 250919A / EP250919a: further LCO optical observation
  3. GRB 250924A: DDOTI Detection of the Optical Counterpart
  4. GRB 250924A: Swift detection of a burst with an optical counterpart
  5. GRB 250920B: AbAO optical upper limits
  6. GRB 250920C: KAIT optical observations
  7. GRB 250920C: VLT redshift confirmation z = 1.399
  8. GRB 250920B: CrAO ZTSH optical observations
  9. GRB 250920C: COLIBRÍ optical observations
  10. GRB 250920B: SAO RAS optical observations
  11. GRB 250920C: NIR observations with WINTER
  12. GRB 250920B: NIR observations with WINTER
  13. GRB 250920C: PRIME near-infrared detection
  14. GRB 250916A: Swift/UVOT Detection
  15. GRB 250916A: CrAO ZTSh R-band optical observations
  16. GRB 250916A: SAO RAS Zeiss-1000 optical observations
  17. GRB 250920B: Asiago optical observations
  18. GRB 250920B: Kitab-ISON optical upper limit
  19. GRB 250917B: Mondy and Zeiss-1000 SAO RAS optical observations, optical observations, afterglow candidate
  20. GRB 250920C: SVOM/GRM observation
  21. GRB 250920A: NuSTAR detection of bright prompt emission
  22. GRB 250920C: GROWTH-India Telescope optical observations
  23. GRB 250920C: Enhanced Swift-XRT position
  24. GRB 250920C: Swift/UVOT Detection
  25. GRB 250920C: Fermi GBM Observation
  26. GRB 250920B: Swift/UVOT Detection
  27. GRB 250920C: Optical counterpart detection by LCO
  28. GRB 250920A: SVOM/GRM observation
  29. GRB250920C: LCOGT Optical Detection
  30. GRB 250920B: Enhanced Swift-XRT position
  31. GRB 250920B: SVOM/C-GFT optical observations
  32. GRB 250919A / EP250919a: LCO optical observation
  33. Konus-Wind detection of GRB 250919A
  34. GRB 250920C: Swift detection of a burst
  35. GRB 250920B: Swift detection of a burst with a bright optical counterpart.
  36. GRB 250919A/EP250919a: SVOM/VT optical observation
  37. GRB 250916A: Mondy R-band optical observations
  38. GRB 250918A: SVOM/GRM observation
  39. GRB 250919A: Swift-XRT afterglow detection
  40. GRB 250919A: SVOM/GRM observation of a very bright GRB
  41. EP250919a: Einstein Probe detection of an X-ray transient
  42. GRB 250916A: KAIT optical observations
  43. GRB 250917B: VLT/HAWK-I near-infrared observations
  44. GRB 250916A: further SAO RAS optical observations
  45. GRB 250912A: SVOM/ECLAIRs refined analysis
  46. GRB 250917B: Swift/UVOT Upper Limits
  47. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  48. GRB 250916A: MAO/AZT-22 optical observations
  49. GRB 250916A: SAO RAS optical observations
  50. GRB 250916A : GIT optical observations
  51. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  52. GRB250917B: WFST optical observations
  53. GRB 250917B: Swift-XRT observations
  54. GRB 250917B: Swift detection of a short burst
  55. GRB 250916A: GOTO optical counterpart candidate
  56. GRB 250916A: AstroSat CZTI detection of a bright long burst
  57. GRB 250910A: SVOM/ECLAIRs refined analysis
  58. EP250916a: Einstein Probe detection of an X-ray transient
  59. EP250827b: VLA Observations
  60. SVOM/sb25091517: SVOM detection of an X-ray transient
  61. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  62. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  63. GRB250912A: VLT/HAWK-I follow-up observations
  64. GRB 250912A: Fermi GBM Observation
  65. GRB 250912A:SVOM/VT optical upper limit
  66. GRB 250912A: LCO optical upper limit
  67. GRB 250912A: SVOM detection of a burst
  68. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  69. EP250911a: GTC/OSIRIS+ spectroscopic redshift z = 3.84
  70. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  71. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  72. GRB 250910B: SVOM/GRM observation
  73. EP250911a: SVOM/VT optical observation
  74. EP250911a: SAO RAS optical observations
  75. EP250911a: Optical detection with Kinder observations
  76. GRB 250911A: Swift/UVOT Detection
  77. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  78. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  79. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  80. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  81. EP250911a: COLIBRÍ optical observations
  82. EP250911a: Einstein Probe detection of an X-ray transient
  83. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  84. GRB 250903A: SVOM/ECLAIRs refined analysis
  85. GRB 250911A: Enhanced Swift-XRT position
  86. GRB 250911A: Swift-XRT observations
  87. GRB 250911A: COLIBRÍ optical counterpart candidate
  88. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  89. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  90. GRB 250909B: AstroSat CZTI detection of a long burst
  91. GRB 250910A: SVOM/VT optical upper limit
  92. GRB 250910A: LCO optical upper limit
  93. GRB 250702B: Late time Chandra observations
  94. EP250908b/EP#01709240653: Swift/UVOT Detection
  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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