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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.

"200205A/SWIFT J0840.7-3516" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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"

19592 results found.

  1. GRB 250331B Swift-BAT refined analysis
  2. GRB 250330A Swift-BAT refined analysis
  3. EP250321A: J band upper limit by SYSU 80cm telescope
  4. GRB 250403A: Swift/UVOT Detection
  5. GRB 250402A: Swift/UVOT Upper Limits
  6. GRB 250403A: LCO optical counterpart detection
  7. GRB 250402A: EP-FXT afterglow detection
  8. GRB 250403A: Swift-XRT observations
  9. GRB 250402A: Swift-XRT observations
  10. GRB 250225B: VLT host galaxy redshift z = 0.950
  11. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  12. GRB 250329B: Swift/UVOT Upper Limit
  13. GRB 250329A: Swift/UVOT Upper Limit
  14. GRB 250327B: Swift/UVOT Detection
  15. GRB 250327A: Swift/UVOT Upper Limits
  16. GRB250331D: AbAO optical observations
  17. GRB 250331D: Fermi GBM observation
  18. GRB 250331C: Swift/UVOT Upper Limits
  19. GRB 250331B: Swift/UVOT Upper Limits
  20. GRB 250331D: Swift-XRT observations
  21. GRB 250331C: Swift-XRT refined Analysis
  22. GRB 250331B: Swift-XRT refined Analysis
  23. GRB 250331B: Swift-XRT refined Analysis
  24. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  25. GRB 250327A Swift-BAT refined analysis
  26. GRB 250329B: CAHA 2.2m telescope optical limit
  27. GRB 250331D: Swift ToO observations
  28. Swift GRB 250331C: Global MASTER-Net observations report
  29. Swift GRB 250331B: Global MASTER-Net observations report
  30. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  31. GRB 250331C: Enhanced Swift-XRT position
  32. GRB 250331B: Enhanced Swift-XRT position
  33. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  34. GRB 250329B: Swift-XRT confirmation of fading
  35. GRB20250327B: 45th Parallel Observatory upper limit
  36. GRB 250328A: Swift/UVOT Detection
  37. GRB 250328A: Swift-XRT refined Analysis
  38. GRB 250330A: Fermi GBM Observation
  39. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  40. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  41. GRB 250331C: Prompt enhanced Swift-XRT position
  42. GRB 250331C: Swift detection of a burst
  43. GRB 250331B: Swift detection of a burst
  44. GRB 250330A: SVOM/VT optical upper limit
  45. GRB 250330A: BOOTES-7 early optical upper limit
  46. GRB 250330A: Swift/UVOT Upper Limits
  47. GRB 250330A: Swift-XRT afterglow detection
  48. GRB 250330A: Fermi GBM Final Localization
  49. GRB 250330A: Prompt Swift-XRT position
  50. GRB 250329B: Swift-XRT afterglow detection
  51. GRB 250330A: Swift detection of a burst
  52. Swift GRB250330.26: Global MASTER-Net observations report
  53. GRB 250329B: SVOM/C-GFT optical upper limit
  54. GRB 250329B: SVOM/VT optical upper limit
  55. GRB 250329A: Swift-XRT afterglow detection
  56. GRB 250328A: SVOM/C-GFT optical upper limit
  57. GRB 250328A: VLT/HAWK-I near-infrared afterglow candidate
  58. GRB 250327B: LCO optical counterpart detection
  59. GRB 250322A: GRANDMA/TNOT optical upper limits
  60. GRB 250327A: SVOM/VT upper limits on the XRT position
  61. GRB 250327B: Swift-XRT detection of the X-ray afterglow
  62. GRB 250327A: Swift-XRT refined Analysis
  63. FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts
  64. GRB 250327A: J-band observations with WINTER
  65. GRB 250327A: SVOM/VT optical candidate
  66. GRB 250327A: Fermi GBM observation
  67. Swift GRB 250327A: Global MASTER-Net observations report
  68. GRB 250327A: DDOTI Optical Observations
  69. GRB 250327A: COLIBRÍ optical upper limit
  70. GRB 250327A: Swift detection of a burst
  71. Konus-Wind detection of GRB 250322A (short)
  72. IPN triangulation of GRB 250322B
  73. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  74. GRB 250322A: Swift-BAT refined analysis
  75. GRB 250322A: Swift/UVOT Upper Limits
  76. GRB 250321B: Swift-XRT observations
  77. GRB 250322A: Swift-XRT refined Analysis
  78. GRB 250322A: AstroSat CZTI detection of a short burst
  79. GRB250322A: STEP/T80S optical limits
  80. GRB 250322A: VLT optical observations
  81. GRB 250322A: VLT near-infrared observations
  82. GRB 250322A: NOT optical upper limits
  83. GRB 250322A: Enhanced Swift-XRT position
  84. GRB 250322A: MASTER optical observation
  85. GRB 250322A: Swift detection of a short burst
  86. EP250321a: refined analysis of the EP-WXT and EP-FXT observations
  87. GRB 250225B: GECAM-A detection
  88. GRB 250312A: GECAM-A detection
  89. GRB 250321B: Swift ToO observations
  90. GRB 250321A: Swift-BAT refined analysis
  91. GRB 250321A: Swift-XRT refined Analysis
  92. GRB 250320B: Fermi-LAT detection
  93. GRB 250321A: Swift/UVOT Upper Limits
  94. EP250321a: LCO optical counterpart detection
  95. EP250321a: Swift-XRT detection of an X-ray source
  96. Swift GRB 250321A: Global MASTER-Net observations report
  97. GRB 250321A: GOTO optical upper limits
  98. GRB 250321A: Swift-XRT localisation
  99. GRB 250321A: Fermi GBM Observation
  100. GRB 250321A: Swift detection of a burst

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