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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"

7420 results found.

  1. EP240708a: KAIT optical upper limit
  2. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  3. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  4. EP240703a: KAIT optical upper limit
  5. EP240703a: BTA observations
  6. EP240703a: Liverpool Telescope optical follow-up observations
  7. EP240703a/GRB 240703A: TRT optical candidate likely not real
  8. EP240703a: Kinder optical follow-up observations
  9. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  10. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  11. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  12. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  13. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  14. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  15. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  16. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  18. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  19. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  20. EP240626a: Montarrenti Observatory optical upper limit
  21. EP240626a: KAIT optical upper limit
  22. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  23. EP240625a: NOT optical counterpart candidate
  24. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  25. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  26. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S240624cd: Retraction of GW unmodeled transient candidate
  28. GRB 240619A: detection of a radio counterpart with AMI-LA
  29. LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
  30. EP240618a: NOT further optical observations
  31. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  32. EP240618a: NOT optical counterpart candidate
  33. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  34. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  35. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  36. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  37. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  40. GRB 240619A: Swift-XRT probable afterglow detection
  41. GRB 240619A: Swift ToO observations
  42. GRB 240619A: GOTO candidate optical afterglow
  43. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  44. LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
  45. LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
  46. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  49. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  50. GRB 240615A: Swift ToO observations
  51. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  53. Trigger 1236151: Swift detection of EXO 0748-676
  54. GRB 240529A: radio detection with AMI-LA
  55. GRB 240606B: Swift ToO observations
  56. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  57. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  59. The EP-WXT source triggered on June 1st is likely a flaring star
  60. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  61. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  62. Swift Trigger 1232465 is not a GRB
  63. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  64. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  65. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  67. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  72. GRB 240529A: Swift detection of a burst with an optical counterpart
  73. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  74. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  75. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  77. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  78. GRB 240523A: Swift detection of a burst
  79. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  80. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  81. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  82. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  83. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  85. GRB 240513A: Swift ToO observations
  86. GRB 240514E: A possible candidate BD-21 1074
  87. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  88. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  89. GRB 240516A: Swift detection of a burst
  90. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  91. GRB 240511A: radio detection of afterglow candidate
  92. GRB 240514B: GOTO candidate optical counterpart
  93. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  94. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  96. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  98. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  99. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  100. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO

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