相关论文: Mapping Metal-Enriched High Velocity Clouds to Ver…

We use archival UV absorption-line data from HST/STIS to statistically analyse the absorption characteristics of the high-velocity clouds (HVCs) in the Galactic halo towards more than 40 extragalactic background sources. We determine…

We perform a systematic study of physical properties and distribution of neutral and ionised gas in the halo of the Milky Way (MW). Beside the large neutral intermediate- and high-velocity cloud (IVC, HVC) complexes there exists a…

We report on the detection of a population of weak metal-line absorbers in the halo or nearby intergalactic environment of the Milky Way. Using high-resolution ultraviolet absorption-line spectra of bright QSOs obtained with the Space…

We investigate interstellar absorption from molecular hydrogen (H_2) and metals in an intermediate-velocity cloud (IVC) in the direction of the LMC star Sk -68 80 (HD 36521), based on data from the Far Ultraviolet Spectroscopic Explorer…

We present a detailed study of HI and metals for 110 MgII absorption systems discovered at 1.98 <= z <= 5.33 in the infrared spectra of high redshift QSOs. Using new measurements of rest-frame UV lines from optical spectra of the same…

The current status and remaining questions of MgII absorbers are reviewed with an eye toward new results incorporating high quality Hubble Space Telescope images of the absorbing galaxies. In the end, we find that our current picture of…

We study the frequency of Mg II absorption in the outer haloes of galaxies at z = 0.6 - 1.4 (with median z = 0.87), using new spectra obtained of ten background quasars with galaxy impact parameters of b < 100 kpc. The quasar sightlines…

We report on a population of absorption systems selected by the presence of very weak Mg II doublets. A sub-population of these systems are iron enriched and have near solar metallicities. This would indicated advanced stages (i.e. few Gyr)…

We aim at analysing systematically the distribution and physical properties of neutral and mildly ionised gas in the Milky Way halo, based on a large absorption-selected data set. Multi-wavelength studies were performed combining optical…

We present initial results from the first systematic survey for MgII quasar absorption lines at z > 2.5. Using infrared spectra of 46 high-redshift quasars, we discovered 111 MgII systems over a path covering 1.9 < z < 6.3. Five systems…

Recent studies of the circumgalactic gaseous environment of the Milky Way have concentrated on the distribution, chemical composition, and physical properties of the most massive neutral gas clouds and the highly-ionized halo absorbers.…

We obtained ESI/Keck rotation curves of 10 MgII absorption selected galaxies (0.3 < z < 1.0) for which we have WFPC-2/HST images and high resolution HIRES/Keck and UVES/VLT quasar spectra of the MgII absorption profiles. We perform a…

We report on the detection of low-column density neutral hydrogen clumps in the halo of the Milky Way. Using high-resolution (FWHM~7 km/s) optical spectra obtained with the VLT/UVES spectrograph we detect narrow interstellar absorption by…

Absorption-line spectroscopy of multiply-lensed QSOs near a known foreground galaxy provides a unique opportunity to go beyond the traditional one-dimensional application of QSO probes and establish a crude three-dimensional (3D) map of…

We report the first measurements of MgII absorption systems associated with spectroscopically confirmed z~0.1 star-forming galaxies at projected distances of D<6kpc. We demonstrate the data are consistent with the well known…

We have obtained Keck HIRES spectra of three images of the gravitationally lensed QSO 2237+0305 to study low ionization absorption systems and their differences in terms of projected velocity and column density across the lines of sight. We…

We study the properties of low-column density gas clumps in the halo of the Milky Way based on high-resolution 21-cm observations. Using interferometric data from the WSRT and the VLA we study HI emission at low-, intermediate- and high…

We analyse absorption characteristics and physical conditions of extraplanar intermediate- and high-velocity gas to study the distribution of the neutral and weakly ionised Milky Way halo gas and its relevance for the evolution of the Milky…

We use spectroscopic data from HST and FUSE to study the wide range of ionization states of the "highly ionized high-velocity clouds". Studied extensively in OVI absorption, these clouds are usually assumed to be infalling gas in the…

We describe a search for MgII(2796,2803) absorption lines in Sloan Digital Sky Survey (SDSS) spectra of QSOs whose lines of sight pass within impact parameters of 200 kpc of galaxies with photometric redshifts of z=0.46-0.6 and redshift…