Related papers: Spatially resolved spectroscopy of planetary nebul…
We analyze a sample of tens of thousands of spectra of halo turnoff stars, obtained with the optical spectrographs of the Sloan Digital Sky Survey (SDSS), to characterize the stellar halo population "in situ" out to a distance of a few tens…
Numerical simulations of dark matter collapse and structure formation show that in addition to a large halo surrounding the baryonic component of our galaxy, there also exists a significant number of subhalos that extend hundreds of…
We present a direct detection of the stellar halo of the edge-on S0 galaxy NGC 3957, using ultra-deep VLT/VIMOS V and R images. This is achieved with a sky subtraction strategy based on infrared techniques. These observations allow us to…
We present line-of-sight stellar velocity distributions of elliptical galaxy NGC 821 obtained to approximately 100 arcsec (over 2 effective radii) with long-slit spectroscopy from the Hobby-Eberly Telescope. Our measured stellar…
We present low resolution spectroscopic observations for a sample of 53 planetary nebulae (PNe) located in the southern sky between Vela and Norma constellations and pertaining to the Galactic disk with expected Galactocentric distance…
Deep imaging of the diffuse light emitted by the stellar fine structures and outer halos around galaxies is now often used to probe their past mass assembly. Because the extended halos survive longer than the relatively fragile tidal…
We describe high spectral resolution, high dynamic range integral field spectroscopy of IC418 covering the spectral range 3300-8950{\AA} and compare with earlier data. We determine line fluxes, derive chemical abundances, provide a spectrum…
We use the Mitchell Spectrograph (formerly VIRUS-P) on the McDonald Observatory 2.7m Harlan J. Smith Telescope to search for the chemical signatures of massive elliptical galaxy assembly. The Mitchell Spectrograph is an integral-field…
We present a kinematic study of a sample of 298 planetary nebulas (PNs) in the outer halo of the central Virgo galaxy M87 (NGC~4486). The line-of-sight velocities of these PNs are used to identify sub-components, to measure the angular…
A new method for measuring gravitational lensing with high redshift type Ia supernovae is investigated. The method utilizes correlations between foreground galaxies and supernova brightnesses to substantially reduce possible systematic…
A new analysis method to investigate halos in finite many-fermion systems is designed, as existing characterization methods are proven to be incomplete/inaccurate. A decomposition of the internal wave-function of the {$N$-body} system in…
The spectra of the planetary nebulae NGC3242 and NGC6369 are reanalysed using spectral measurements made in the mid-infrared with the Spitzer Space Telescope and the Infrared Space Observatory (ISO). The aim is to determine the chemical…
Quantitative modeling of the spectro-spatial distributions of energetic electrons and protons in galactic halos is needed in order to determine their interactions with the local plasma and radiation fields, and also to estimate their…
Deep spectrophotometry has proved to be a fundamental tool to improve our knowledge on the chemical content of planetary nebulae. With the arrival of very efficient spectrographs installed in the largest ground-based telescopes, outstanding…
The aim of this study is to investigate the physical properties of molecular envelopes of planetary nebulae in their earliest stages of evolution. Using the 100m telescope at Effelsberg, we have undertaken a high sensitivity discrete source…
Using the Hubble Space Telescope (HST), we have carried out a survey of candidate preplanetary nebulae (PPNs). We report here our discoveries of objects having well-resolved geometrical structures, and use the large sample of PPNs now…
The existence of stellar halos around galaxies is a natural prediction of the hierarchical nature of the LambdaCDM model. Recent observations of Milky Way-like galaxies have revealed a wide range in stellar halo mass, including cases with…
Constraints on dark matter halo masses from weak gravitational lensing can be improved significantly by using additional information about the morphology of their density distribution, leading to tighter cosmological constraints derived…
A method to diagnose the gas distribution in the Galactic halo using a shock wave from the Galactic Centre (GC) is presented. Propagation of a shock wave caused by central explosion with released energy $\sim 10^{55}$ erg is calculated for…
We derive the oblateness parameter q of the dark matter halo of a sample of gas rich, face-on disk galaxies. We have assumed that the halos are triaxial in shape but their axes in the disk plane (a and b) are equal, so that q=c/a measures…