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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

913 results found.

  1. EP#01709175213/IGR J19566+0326: Swift-XRT detection
  2. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  3. GRB 250322B: GRBAlpha detection
  4. GRB 250331A: MAXI/GSC detection
  5. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  6. EP250311a/GRB 250311A: EP-FXT follow-up observation
  7. Fermi trigger No 763509110: Global MASTER-Net observations report
  8. GRB 250311A: Swift-XRT observations
  9. GRB 250311A/EP250311a: TRT optical upper limit
  10. GRB 250311A: Tiled Swift observations
  11. EP250311a/GRB 250311A: EP-WXT detection
  12. GRB 250311A/MAXI J1457-026: MAXI/GSC detection
  13. Fermi GRB 250226A: Global MASTER-Net observations report
  14. GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
  15. LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
  16. GRB 250207B: Swift-XRT observations
  17. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  18. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  19. GRB 250207B: Tiled Swift observations
  20. GRB 250207B: MAXI/GSC detection
  21. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  23. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  24. GRB 250126A: MAXI/GSC detection
  25. GRB 250101A: Swift detection of a burst with an optical counterpart
  26. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  27. GRB241229B: UVOT upper limits
  28. GRB 241213B: Swift-XRT observations
  29. GRB 241213B: Tiled Swift observations
  30. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  31. GRB 241213B: MAXI/GSC detection
  32. GRB 241207C: MASTER optical observations
  33. GRB 241207C: Tiled Swift observations
  34. GRB 241207C: MAXI/GSC detection
  35. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  36. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  37. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  38. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  39. Fermi trigger No 751563375: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  41. EP240913A / GRB 240913C: AstroSat CZTI detection
  42. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  43. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  44. GRB 240824B: Ondrejov D50 optical limit
  45. GRB 240824B: Fermi GBM Observation
  46. GRB 240824B: Swift-XRT afterglow detection
  47. GRB 240824B: Swift/BAT arcminute localization of a burst
  48. GRB 240824B: MAXI/GSC detection
  49. GRB 240809B: MAXI/GSC detection
  50. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  51. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  52. GRB 240523A: Swift-XRT refined Analysis
  53. GRB 240514E: A possible candidate BD-21 1074
  54. MAXI GRB240514.78: Global MASTER-Net observations report
  55. GRB 240514E: MAXI/GSC detection of a probable afterglow
  56. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  57. Fermi trigger No 737173236: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
  59. LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
  60. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  61. X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
  62. GRB 240309A: MAXI/GSC detection
  63. GRB 240225B: Swift-XRT afterglow detection
  64. GRB 240225B: Glowbug gamma-ray detection
  65. GRB 240225B: Swift ToO observations
  66. Konus-Wind detection of GRB 240225B (long)
  67. GRB 240225B: VLT/X-shooter redshift
  68. GRB 240225B : MITSuME Akeno optical afterglow candidate detection
  69. GRB 240225B: 3.6m DOT observation
  70. GRB 240225B: NOT optical observations
  71. GRB 240225B: Nanshan/HMT optical afterglow detection
  72. GRB 240225B: CALET Gamma-Ray Burst Monitor detection
  73. GRB 240225B: Swift-XRT observations
  74. GRB 240225B: GOTO detection of a candidate optical afterglow
  75. GRB 240225B: AstroSat CZTI detection
  76. GRB 240225B: Tiled Swift observations
  77. GRB 240225B: MAXI/GSC detection
  78. VLA X-band observation of EPW20240219aa
  79. GRB 240128A: Further Swift-XRT observations
  80. GRB 240214A: Tiled Swift observations
  81. GRB 240214A/1H 0451-560: MAXI/GSC detection
  82. IPN triangulation of GRB 240125A (short)
  83. GRB 240128A: Glowbug gamma-ray detection
  84. GRB 240128A: Swift-XRT observations
  85. GRB 240128A: GRBAlpha detection
  86. GRB 240128A: Tiled Swift observations
  87. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 240128A: MAXI/GSC detection
  89. GRB 240122A: ATCA detection of radio counterpart
  90. GRB240122A: PRIME near infrared detection
  91. GRB 240122A: Swift/UVOT Upper Limits
  92. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  93. GRB 240122A: Swift-XRT afterglow detection
  94. GRB 240122A: VLT/X-shooter redshift confirmation
  95. GRB 240122A: Redshift from OSIRIS+/GTC
  96. GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
  97. GRB 240122A: GOTO optical counterpart candidate
  98. GRB 240122A: Tiled Swift observations
  99. GRB 240122A: MAXI/GSC detection
  100. GRID detection of GRB 231230A

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