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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"

28047 results found.

  1. GRB231017A: GROWTH-India upper limits on the optical afterglow
  2. GRB 231015A: AstroSat CZTI detection
  3. GRB 231018A: Fermi GBM Detection
  4. GRB 231017A: Swift-XRT observations
  5. GRB 231018A: BALROG localization (Fermi Trigger / GRB 231018521)
  6. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  7. Fermi-LAT gamma-ray observations of IceCube-231014A
  8. GRB231017A: Fermi GBM Final Localization
  9. IceCube-231014A: Upper limits from a search for additional neutrino events in IceCube
  10. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  11. (correction) Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field
  12. Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field.
  13. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  14. GRB 231004A: Glowbug gamma-ray detection
  15. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  16. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S231008ap: Updated Sky localization
  18. LIGO/Virgo/KAGRA S231008ap: Identification of a GW compact binary merger candidate
  19. IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-231004A: No significant detection in HAWC
  21. Fermi-LAT gamma-ray observations of IceCube-231004A
  22. LIGO/Virgo/KAGRA S231005ah: Updated Sky localization
  23. LIGO/Virgo/KAGRA S231005ah: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S231005j: Updated Sky localization
  25. LIGO/Virgo/KAGRA S231005j: Identification of a GW compact binary merger candidate
  26. transient AT2023sva: radio observations with AMI-LA
  27. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  30. GRB 230827B: 10.4m GTC spectroscopic redshift
  31. LIGO/Virgo/KAGRA S231001aq: Updated Sky localization
  32. LIGO/Virgo/KAGRA S230930al: Updated Sky localization
  33. LIGO/Virgo/KAGRA S230928cb: Updated Sky localization
  34. LIGO/Virgo/KAGRA S231001aq: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S230930al: Identification of a GW compact binary merger candidate
  36. NuEm-230927A: Swift-XRT follow-up
  37. LIGO/Virgo/KAGRA S230928cb: Identification of a GW compact binary merger candidate
  38. AT2023sva / GRB230916B: GIT observations of the afterglow
  39. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  40. LIGO/Virgo/KAGRA S230927be: Updated Sky localization
  41. LIGO/Virgo/KAGRA S230927l: Updated Sky localization
  42. LIGO/Virgo/KAGRA S230927be: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo/KAGRA S230922q: Updated Sky localization
  45. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  47. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  48. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  49. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  50. LIGO/Virgo/KAGRA S230924an: Updated Sky localization
  51. LIGO/Virgo/KAGRA S230924an: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  53. LIGO/Virgo/KAGRA S230922g: Updated Sky localization
  54. LIGO/Virgo/KAGRA S230922g: Identification of a GW compact binary merger candidate
  55. LIGO/Virgo/KAGRA S230922q: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  57. IPN triangulation of GRB 230919A (short)
  58. LIGO/Virgo/KAGRA S230904n: Classification of the candidate AT2023rkw with DBSP
  59. Fermi GBM Statement for Trigger 716527670/230916144
  60. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  61. LIGO/Virgo/KAGRA S230920al: Updated Sky localization
  62. LIGO/Virgo/KAGRA S230919bj: Updated Sky localization
  63. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  64. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  65. GRB 230919A: AstroSat CZTI detection
  66. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  68. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  69. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  70. GRB 230918A (short): Glowbug gamma-ray detection
  71. GRB 230916B: Glowbug gamma-ray detection
  72. GRB 230915A: Fermi GBM observation
  73. GRB 230812B: Radio observations with the uGMRT
  74. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  75. GRB 230915B: Glowbug gamma-ray detection
  76. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  77. GRB 230911A: Fermi GBM Observation
  78. LIGO/Virgo/KAGRA S230904n: Correction of the coordinates of the ZTF candidate counterpart
  79. Fermi-LAT gamma-ray observations of IceCube-230914A
  80. GRB 230915A: Swift/BAT-GUANO detection of a burst
  81. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  82. Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
  83. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 230911A: Swift-XRT afterglow detection
  85. Swift Trigger 1192088 is not an astrophysical event
  86. GRB 230913A: Glowbug gamma-ray detection
  87. LIGO/Virgo/KAGRA S230914ak: Updated Sky localization
  88. LIGO/Virgo/KAGRA S230914ak: Identification of a GW compact binary merger candidate
  89. GRB 230913A: Fermi GBM Observation
  90. LIGO/Virgo/KAGRA S230904n: One ZTF candidate counterpart to coincident neutrino event
  91. Swift Trigger 1191903 is not an astrophysical event
  92. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  93. GRB 230911A: GOTO optical counterpart candidate
  94. GRB 230911D: NuSTAR Detection of Prompt Emission
  95. GRB 230911C: Swift-XRT refined Analysis
  96. GRB 230911C: Swift-BAT refined analysis
  97. LIGO/Virgo/KAGRA S230911ae: Updated Sky localization
  98. GRB 230911D: Fermi GBM observation
  99. IPN triangulation of GRB 230911D (long)
  100. GRB230911C: LCOGT Optical Upper Limits

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