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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"

8474 results found.

  1. LIGO/Virgo/KAGRA S230908b: one counterpart neutrino candidate from IceCube neutrino searches
  2. GRB 230818A: radio observation with the VLA
  3. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  4. GRB 230906A: Swift ToO observations
  5. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  6. LIGO/Virgo/KAGRA S230904n: Updated Sky localization and EM Bright Classification
  7. LIGO/Virgo/KAGRA S230904n: 1 counterpart neutrino candidate from IceCube neutrino searches
  8. LIGO/Virgo/KAGRA S230904n: Identification of a GW compact binary merger candidate
  9. GRB 230903A: Swift detection of a burst
  10. LIGO/Virgo/KAGRA S230831e: Updated Sky localization
  11. LIGO/Virgo/KAGRA S230831e: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S230715bw: Reissue of Retraction of GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S230830b: Retraction of GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S230820bq: Updated Sky localization
  15. GRB 230827B: Swift ToO observations
  16. LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
  17. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  18. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  19. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  20. GRB 230826A: Mondy optical observations
  21. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  22. GRB 230812B: radio detection with the VLA
  23. LIGO/Virgo/KAGRA S230825k: Updated Sky localization
  24. LIGO/Virgo/KAGRA S230825k: Identification of a GW compact binary merger candidate
  25. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  26. GRB 230824A: AKO Optical Afterglow Candidate
  27. LIGO/Virgo/KAGRA S230824r: Updated Sky localization
  28. LIGO/Virgo/KAGRA S230824r: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  30. IceCube-230823A: Event likely due to background
  31. IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
  32. LIGO/Virgo/KAGRA S230822bm: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230822bm: Identification of a GW compact binary merger candidate
  34. Konus-Wind detection of GRB 230818A
  35. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  37. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  38. GRB 230818A: Swift detection of a burst
  39. GRB 230816A: Swift detection of a burst
  40. GRB 230815A: Swift detection of a burst
  41. GRB 230812B: AMI-LA radio detection of afterglow candidate
  42. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  43. GRB 230812B: Upper limits from a neutrino search with IceCube
  44. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  45. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  46. GRB 230812B: GIT optical follow-up
  47. LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S230812aj: two counterpart neutrino candidates from IceCube neutrino searches
  49. GRB 230812B: Detected Optical Afterglow Candidate
  50. GRB 230812: Swift/UVOT Detection
  51. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  52. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  53. GRB 230812B: KAIT Optical Afterglow Candidate
  54. GRB 230812B: Fermi GBM Observation of a very bright burst
  55. GRB 230812B: Tiled Swift observations
  56. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  57. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  58. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S230810af: Retraction of GW compact binary merger candidate
  60. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  61. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  62. LIGO/Virgo/KAGRA S230808i: retraction of a GW unmodeled transient candidate
  63. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  64. LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
  65. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  67. LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
  68. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  69. GRB 230805B: NOT optical afterglow confirmation
  70. LIGO/Virgo/KAGRA S230805x: Updated Sky localization
  71. GRB 230805B: Swift detection of a burst
  72. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  74. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  75. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  76. LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
  77. GRB 230802A: Swift detection of a burst
  78. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  79. LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
  80. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  81. LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S230729z: Updated Sky localization
  83. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  84. GRB 230723B: MITSuME Ishigaki optical observation
  85. IceCube-230727A: No candidates from the Zwicky Transient Facility
  86. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  87. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  89. GRB 230728A: Swift detection of a burst
  90. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  91. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
  93. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  94. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  95. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  96. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  97. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  98. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  99. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  100. GRB 230723B: Optical afterglow candidate from CAHA

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