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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3402 results found.

  1. GRB 241112B: Swift-XRT afterglow detection
  2. GRB 241108A: Swift-XRT observations
  3. GRB 241105A: Swift/UVOT Detection
  4. GRB 241105A: Swift-XRT afterglow detection
  5. GRB 241104A: Swift-XRT observations
  6. EP241104a: EP detection of GRB 241104A X-ray emission
  7. EP241101a: EP-FXT observations update
  8. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  9. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  10. EP241101a: EP-WXT detection of a fast X-ray transient
  11. GRB 241030B: Swift-XRT refined Analysis
  12. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  13. GRB 241029A: SVOM/VT optical afterglow observations
  14. EP241021a: Swift-UVOT detection
  15. GRB 241030A: Swift-XRT refined Analysis
  16. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  17. GRB 241029A: Swift-XRT observations
  18. GRB 241026A: Swift-XRT refined Analysis
  19. GRB 241025A: Swift-XRT refined Analysis
  20. EP 241021a: Swift-XRT observations
  21. GRB 241018A: Swift-XRT observations
  22. GRB 241017A: Swift-XRT observations
  23. GRB 241001A: EP-FXT afterglow detection
  24. GRB 241009A: Swift-XRT afterglow detection
  25. GRB 241010A: Swift-XRT refined Analysis
  26. GRB 241002B: Swift-XRT afterglow detection
  27. GRB 241006A: Swift-XRT refined Analysis
  28. GRB 241001A: Swift-XRT afterglow detection
  29. GRB 241002B: Swift-XRT observations
  30. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  31. GRB 241002A: Swift-XRT refined Analysis
  32. GRB 241001A: Swift-XRT observations
  33. EP240919a / GRB 240919A: SVOM/VT upper limit
  34. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  35. GRB 240910A: further Swift observations and confirmation of afterglow
  36. GRB 240916A: Swift-XRT afterglow detection
  37. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  38. EP240913a: VLT/HAWK-I near-infrared upper limits
  39. GRB 240914A: Swift-XRT observations
  40. GRB 240910A: SVOM/VT optical observations
  41. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  42. GRB 240911A: Swift-XRT observations
  43. GRB 240912A: Swift-XRT refined Analysis
  44. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  45. GRB 240905E: SVOM/VT optical observations
  46. EP240908a: EP detection of a fast X-ray transient
  47. GRB 240905B: Swift-XRT observations
  48. GRB 240905E: Swift-XRT refined Analysis
  49. GRB 240905B: AstroSat CZTI detection and localization
  50. GRB 240828A: Swift-XRT afterglow detection
  51. GRB 240828B: Swift-XRT afterglow detection
  52. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  53. GRB 240819A: Swift afterglow confirmation
  54. GRB 240825A: Swift-XRT refined Analysis
  55. GRB 240824B: Swift-XRT afterglow detection
  56. GRB 240824A: Swift-XRT observations
  57. GRB 240821A: Swift/UVOT observations of the XRT sources.
  58. GRB 240821A: Swift-XRT observations
  59. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  60. GRB 240819A: Swift-XRT observations
  61. EP240820a: EP detection of a fast X-ray transient
  62. GRB 240819A: X-ray follow-up observation with EP-FXT
  63. GRB 240811A: Swift-XRT refined Analysis
  64. GRB 240809A: Swift-XRT refined Analysis
  65. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  66. GRB 240805B: Swift-XRT refined Analysis
  67. GRB 240805A: Swift-XRT refined Analysis
  68. GRB 240730A: Swift-XRT refined Analysis
  69. GRB 240715A: Swift-XRT afterglow detection
  70. GRB 240727B: Swift-XRT observations
  71. GRB 240727A: Swift-XRT refined Analysis
  72. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  73. GRB 240715A: Swift/UVOT observations of the XRT sources.
  74. GRB 240715A: Swift-XRT observations
  75. GRB240713A: Swift/UVOT Upper LImits
  76. GRB 240713A: Swift-XRT observations
  77. GRB 240712A: Swift-XRT refined Analysis
  78. The EP-WXT source triggered on July 14th is likely a flaring star
  79. GRB240713A: X-ray follow-up observation with EP-FXT
  80. EP240703c: EP-WXT detection of an X-ray transient
  81. EP240618a: Swift/XRT upper limit
  82. EP240617a: tentative Swift/XRT detection of the afterglow
  83. GRB 240619A: Swift-XRT probable afterglow detection
  84. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  85. GRB 240615A: Swift-XRT observations
  86. GRB 240606B: Swift-XRT afterglow detection
  87. Swift Trigger 1235109: a possible GRB 240606A
  88. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  89. Swift Trigger 1232465: consistent with noise
  90. The EP-WXT source triggered on June 1st is likely a flaring star
  91. GRB 240529A: Swift-XRT refined Analysis
  92. GRB 240527B: Swift-XRT afterglow detection
  93. GRB 240523A: Swift-XRT refined Analysis
  94. EP240518a: possibly identified with a flare star by EP-FXT
  95. GRB 240516A: Swift-XRT refined Analysis
  96. GRB 240513A: Swift-XRT observations
  97. GRB 240511A: Swift-XRT refined Analysis
  98. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  99. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  100. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a

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