<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "3D map of the dust distribution in the Milky Way"^^ . "In this thesis, I present a new non-parametric model for inferring the three-dimensional\r\n(3D) distribution of dust density in the Milky Way. Our approach uses the extinction\r\nmeasured towards stars at different locations in the Galaxy at known distances. Each\r\nextinction measurement is proportional to the integrated dust density along its line\r\nof sight (l.o.s). Making simple assumptions about the spatial correlation of the dust\r\ndensity, we infer the most probable 3D distribution of dust across the entire observed\r\nregion, including along sight lines which were not observed. This is possible because our\r\nmodel employs a Gaussian process to connect all l.o.s. The result is a smooth, 3D map\r\nof the dust density, which is the local property of the interstellar medium (ISM) rather\r\nthan an integrated quantity. Owing to our smoothness constraint and its isotropy, the\r\nmethod provides one of the first maps without “fingers of God” artefact.\r\nI then present the first continuous map of the dust distribution in the Galactic\r\ndisk out to 7 kpc within 100 pc of the Galactic midplane, using red giant stars from\r\nSDSS APOGEE DR14. The resulting map traces some features of the local Galactic\r\nspiral arms, even though the model contains no prior suggestion of spiral arms, nor any\r\nunderlying model for the Galactic structure. This is the first time that such evident arm\r\nstructures have been captured by a dust density map in the Milky Way. Our resulting\r\nmap also traces some of the known giant molecular clouds in the Galaxy and puts some\r\nconstraints on their distances, some of which were hitherto relatively uncertain.\r\nI also demonstrate a map of the 3D distribution of dust in the Orion complex. Orion\r\nis the closest site of high-mass star formation, making it an excellent laboratory for\r\nstudying the ISM and star formation. We use data from the Gaia-TGAS catalogue\r\ncombined with photometry from 2MASS and WISE to get the distances and extinctions\r\nof individual stars in the vicinity of the Orion complex. We find that the distance and\r\ndepth of the cloud are compatible with other recent works, which show that the method\r\ncan be applied to local molecular clouds to map their 3D dust distribution. We also use\r\ndata from the recent second Gaia data release (GDR2) to update the map that shows\r\ncomplex dust clouds in the Orion region.\r\nI finally show a 3D map of hydrogen density in the local ISM. The hydrogen equivalent\r\ncolumn densities were obtained from the Exploring the X-ray Transient and variable Sky\r\nproject (EXTRAS), which provides equivalent NH values from X-ray spectral fits of\r\nobservations within the XMM-Newton Data Release. A cross-correlation between the\r\nEXTRAS catalogue and the first Gaia Data Release was performed in order to obtain\r\naccurate parallax and distance measurements. The resulting map shows small-scale\r\ndensity structures which can not be modelled using analytic density profiles."^^ . "2018" . . . . . . . "Sara"^^ . "Rezaeikhoshbakht"^^ . "Sara Rezaeikhoshbakht"^^ . . . . . . "3D map of the dust distribution in the Milky Way (PDF)"^^ . . . "thesis.pdf"^^ . . . "3D map of the dust distribution in the Milky Way (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #25664 \n\n3D map of the dust distribution in the Milky Way\n\n" . "text/html" . . . "520 Astronomie"@de . "520 Astronomy and allied sciences"@en . .