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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"

8474 results found.

  1. GRB 231205B: Swift detection of a burst
  2. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  3. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  5. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  6. Optical transient in the field of Messier 31, likely a new blazar: back to bright state
  7. GRB 231129C: Tiled Swift observations
  8. LIGO/Virgo/KAGRA S231129ac: Updated Sky localization
  9. GRB 231129B: Tiled Swift observations
  10. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  11. GRB 231129A: Swift detection of a burst
  12. LIGO/Virgo/KAGRA S231127cg: Updated Sky localization
  13. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  14. LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
  15. GRB 231117A: MeerKAT 1.3GHz detection
  16. Update of IceCube-231125A - Corrected errors
  17. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  18. LIGO/Virgo/KAGRA S231118an: Updated Sky localization and EM Bright Classification
  19. LIGO/Virgo/KAGRA S231123cg: Identification of a GW compact binary merger candidate
  20. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  22. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S231119u: Updated Sky localization and Source Classification
  25. LIGO/Virgo/KAGRA S231118ab: Updated Sky localization and Source Classification
  26. LIGO/Virgo/KAGRA S231118d: Updated Sky localization and Source Classification
  27. GRB 231117A: AMI-LA radio observations
  28. GRB 231117A: LDT Confirmation of Optical Fading
  29. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  30. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  31. LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
  32. GRB 231117A: OHP/T120 optical observations
  33. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  34. LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
  35. GRB 231117A: AKO Follow-Up Observation
  36. GRB 231118A: LCOGT Optical Observations
  37. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  38. GRB 231117A: Lowell Discovery Telescope Observations
  39. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  40. LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
  41. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  42. GRB 231117A: Keck spectroscopy of afterglow candidate
  43. LIGO/Virgo/KAGRA S231118d: Identification of a GW compact binary merger candidate
  44. GRB 231117A: GIT optical follow-up
  45. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  46. GRB 231117A: AKO Optical Upper Limit
  47. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  48. GRB 231115A : OHP/T120 optical upper limit
  49. GRB 231115A: optical observations from INAF observatories
  50. GRB 231117A: Swift detection of a bright short burst
  51. GRB 231115A: Non-detection of radio emission with CHIME/FRB
  52. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  53. GRB231115A: Liverpool Telescope imaging
  54. Konus-Wind detection of GRB 231115A (a probable Magnetar Giant Flare from M82)
  55. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  56. GRB 231115A / AT2023xvj: Updated GIT analysis
  57. GRB 231115A: archival Chandra X-ray observations
  58. GRB 231115A: Upper limits from a neutrino search with IceCube
  59. GRB231115A: GRANDMA Observations
  60. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  61. GRB 231106A: TESS identification of candidate optical counterpart
  62. GRB 231115A: archival HST observations
  63. GRB 231115A: Swift ToO observations
  64. LIGO/Virgo/KAGRA S231113bw: Updated Sky localization, EM Bright Classification, and Source Classification
  65. LIGO/Virgo/KAGRA S231114n: Updated Sky localization
  66. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  67. LIGO/Virgo/KAGRA S231114n: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  69. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  70. LIGO/Virgo/KAGRA S231113bb: Updated Sky localization
  71. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  72. LIGO/Virgo/KAGRA S231113bw: Identification of a GW compact binary merger candidate
  73. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S231112ag: Retraction of GW compact binary merger candidate
  75. GRB 231111A: Swift detection of a burst with an optical counterpart
  76. LIGO/Virgo/KAGRA S231110g: Updated Sky localization
  77. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  78. IceCube-231103A: No candidates from the Zwicky Transient Facility
  79. LIGO/Virgo/KAGRA S231108u: Updated Sky localization
  80. LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  82. GRB 231104A: 3.6m DOT optical upper limit
  83. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  84. LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
  85. LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
  86. GRB 231104A: AKO Upper Limit
  87. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  88. GRB231104A: LCOGT Optical Upper Limits
  89. GRB 231104A: Swift detection of a bright burst
  90. IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
  91. LIGO/Virgo/KAGRA S231102w: Updated Sky localization
  92. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  93. LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
  94. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  95. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  96. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  97. LIGO/Virgo/KAGRA S231030av: Retraction of GW compact binary merger candidate
  98. GRB 231024A: AKO Optical Counterpart Candidate
  99. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  100. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate

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