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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').
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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"

2409 results found.

  1. GRB 250222A: SVOM/GRM observation of a burst
  2. GRB 250210A: VZLUSAT-2 detection
  3. EP250223a: SVOM/VT optical observation
  4. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  5. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  6. SVOM trigger sb25022102 is not an astrophysical event
  7. SVOM/sb25022102: SVOM detection of an X-ray transient
  8. Konus-Wind detection of GRB 250217C (short)
  9. GRB 250219A: Swift/UVOT Upper Limits
  10. GRB 250219A: NOT optical observations
  11. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  12. GRB 250219A: 1.6m Mephisto optical upper limits
  13. GRB 250219A: SVOM/VT optical counterpart
  14. GRB 250219A: Swift-XRT observations
  15. GRB 250219A: Swift ToO observations
  16. GRB 250219A: SVOM detection of a burst
  17. Konus-Wind detection of GRB 250215A / EP250215a
  18. SVOM/sb25021804: COLIBRÍ/DDRAGO Confirmation of Variability
  19. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  20. GRB 250217C: SVOM/GRM observation
  21. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  22. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  23. SVOM/sb25021804: SVOM detection of a long X-ray transient
  24. GRB 250213A: Swift-XRT observations
  25. GRB 250215A / EP250215a: LCO detection of the afterglow
  26. EP250215a / GRB 250215A : GTC redshift z = 4.61
  27. GRB 250215A: Fermi GBM Observation
  28. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  29. GRB 250215A: SVOM/GRM observation
  30. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  31. GRB 250213A:SVOM/VT optical candidate
  32. GRB 250213A: Swift ToO observations
  33. GRB 250213A: SVOM detection of a burst
  34. GRB 250205A: Leavitt Observatory optical upper limit
  35. GRB 250210A: GRBAlpha detection
  36. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  37. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  38. GRB 250211A: Swift ToO observations
  39. GRB 250210A: SVOM/GRM observation of a long burst
  40. GRB 250204B: GRBAlpha detection
  41. GRB 250205A: 1.3m DFOT optical upper limit
  42. Konus-Wind detection of GRB 250204B
  43. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  44. GRB 250205A: Fermi GBM Observation
  45. GRB 250205A: REM NIR upper limit
  46. GRB 250205A: Swift/UVOT Upper Limits
  47. EP250205a/GRB 250205A: Einstein Probe observation
  48. GRB 250127C: SVOM/GRM observation of a burst
  49. GRB 250204B: SVOM/GRM observation of a likely short burst
  50. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  51. GRB 250205A: Swift/XRT detection
  52. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  53. GRB250205A: SVOM/VT optical afterglow detection
  54. GRB 250205A: GOTO optical upper limits
  55. GRB 250205A: SVOM detection of a burst
  56. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  57. GRB 250129A: SVOM/C-GFT optical observations
  58. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  59. GRB 250129A: COLIBRÍ Optical Observations
  60. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  61. GRB 250127A: CrAO and Terskol optical upper limits
  62. GRB 250127A: Swift-XRT observations
  63. GRB 250127A: EP-FXT afterglow detection
  64. GRB 250117A: Fermi GBM Observation
  65. GRB 250127A: SVOM/VT upper limit
  66. GRB 250127A: Swift ToO observations
  67. GRB 250127A: LCO optical upper limit
  68. GRB 250127A: SVOM detection of a long burst
  69. GECAM-A detection of a bright burst from SGR 1E1841-045
  70. IPN triangulation of a bright burst from SGR 1E1841-045
  71. Improved IPN triangulation of GRB 250107C
  72. Konus-Wind detection of GRB 250117A
  73. IPN triangulation of GRB 250117A (short)
  74. GRB 250117A: SVOM/GRM observation of a short burst
  75. GRB 250114B: SVOM/VT upper limit
  76. Konus-Wind detection of GRB 250113A
  77. IPN triangulation of GRB 250113A
  78. GRB 250113A: INTEGRAL/SPI-ACS detection
  79. GRB 250113A: SVOM/GRM observation of a long burst
  80. GRB 250106A: Swift-XRT afterglow detection
  81. GRB 250109A / EP250109a: Mephisto optical upper limits
  82. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  83. GRB 250101B: Fermi GBM Observation
  84. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  85. GRB 250108A: Swift/XRT afterglow fading
  86. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  87. Konus-Wind detection of GRB 250107C
  88. GRB 250109A: Fermi GBM Observation
  89. EP250109a: Swift/UVOT non-detection
  90. IPN triangulation of GRB 250107C
  91. EP250109a: SVOM/VT optical candidate
  92. GRB 250107C: SVOM/GRM observation
  93. GRB 250108A: Swift/UVOT Upper Limits
  94. GRB 250108A: NOT optical upper limit
  95. GRB 250103A: 1.6m Mephisto optical observations
  96. GRB 250108A: Swift-XRT afterglow detection
  97. GRB 250108A:SVOM/VT optical candidate
  98. GRB 250103A: Swift-XRT afterglow detection
  99. GRB 250108A: Swift ToO observations
  100. GRB 250108A: SVOM detection of a soft long burst

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