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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"

8473 results found.

  1. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  2. IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event
  3. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  4. GRB 231024A: Fermi GBM Observation
  5. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  6. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  7. GRB 231024A: GOTO optical counterpart candidate
  8. LIGO/Virgo/KAGRA S231025a: two counterpart neutrino candidates from IceCube neutrino searches
  9. The photometry of the transient in Messier 31 field: GMG observation
  10. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  12. LIGO/Virgo/KAGRA S231020bw: Updated Sky localization
  13. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  14. LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification
  15. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  16. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  18. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  19. IceCube-231004A: Upper limits from Fermi-GBM Observations
  20. GRB 231017A: Swift/UVOT Upper Limit
  21. GRB 231017A: GOTO optical upper limits
  22. GRB 231017A: JinShan optical upper limit
  23. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  24. LIGO/Virgo/KAGRA S231018cb: One counterpart neutrino candidate event from an IceCube neutrino search
  25. GRB 231017A: LCOGT Optical Upper Limits
  26. GRB 231017A: Swift ToO observations
  27. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  28. IceCube-231014A: Upper limits from a search for additional neutrino events in IceCube
  29. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  30. (correction) Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field
  31. Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field.
  32. IceCube-231014A - IceCube observation of a high-energy neutrino candidate track-like event
  33. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  35. IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
  36. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S231008ap: Updated Sky localization
  38. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  39. IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-231004A: No significant detection in HAWC
  41. LIGO/Virgo/KAGRA S231005ah: Updated Sky localization
  42. LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S231005j: Updated Sky localization
  44. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  45. IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
  46. transient AT2023sva: radio observations with AMI-LA
  47. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  49. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  50. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  51. LIGO/Virgo/KAGRA S230930al: Updated Sky localization
  52. LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
  53. LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
  54. LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  56. AT2023sva / GRB230916B: GIT observations of the afterglow
  57. LIGO/Virgo/KAGRA S230927be: Updated Sky localization
  58. LIGO/Virgo/KAGRA S230927l: Updated Sky localization
  59. LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  62. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  63. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  64. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  66. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  67. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  69. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  70. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  71. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  73. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  74. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  75. Fermi GBM Statement for Trigger 716527670/230916144
  76. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  77. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  78. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  79. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  80. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  81. AT 2023sva: NOT observations of the ZTF candidate afterglow
  82. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  83. LIGO/Virgo/KAGRA S230918aq: Retraction of GW compact binary merger candidate
  84. GRB 230812B: Radio observations with the uGMRT
  85. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  86. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  87. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  88. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  89. GRB 230911A: Swift-XRT afterglow detection
  90. LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
  91. IceCube-230914A - IceCube observation of a high-energy neutrino candidate track-like event
  92. LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  94. GRB 230911A: Swift ToO observations
  95. GRB 230911A: GOTO optical counterpart candidate
  96. LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
  97. GRB 230906A: Chandra detection of the X-ray afterglow
  98. LIGO/Virgo/KAGRA S230911ae: Identification of a GW compact binary merger candidate
  99. GRB 230911C: GOTO optical upper limits
  100. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches

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