Recent results on the kinematics of the Draco and Ursa Minor dwarf spheroidals are reviewed.

We present new FUSE and HST/STIS observations of two high Galactic latitude AGN that we use to measure the nuclear wind velocity of the Milky Way for the first time. We find high velocity C III & O VI at a heliocentric velocity of $+163 \pm 8 {\rm km s^{-1}}$ and C III & N V at $-105 \pm 14 {\rm km s^{-1}}$ toward PKS 2005–489 ($l=350^{\circ}, b=-33^{\circ}$) and C III, C IV, & Si IV and C III & O VI toward Mrk 1383 ($l=349^{\circ}, b=55^{\circ}$) at $+48 \pm 4 {\rm km s^{-1}}$ and $+94 \pm 7 {\rm km s^{-1}}$, respectively. We have estimated the Galactocentric escape velocity of gas above the Galactic Centre along the PKS 2005–489 and Mrk 1383 sight-lines to be $\geq\,$$215 \pm 35$ and $\geq\,$$145 \pm 25 {\rm km s^{-1}}$, respectively. Thus, we have detected both infalling and bound outflowing gas from the Galactic Centre, indicating that the Milky Way does not produce a starburst wind, but a bound Galactic “fountain” instead.

We study the cross-correlation between 716 Mg II quasar absorption systems and $\sim 100,000$ Luminous Red Galaxies (LRGs) selected from the Sloan Digital Sky Survey Data Release 3 in the redshift range $0.4\!\leq\!z\!\leq\!0.8$. The Mg II systems were selected to have $\lambda\lambda$ 2796 & 2803 rest-frame equivalent widths $\geq\!1.0$ $\AA\$ and identifications confirmed by the FeII $\lambda 2600$ or MgI $\lambda 2852$ lines. Over co-moving scales 0.2–13$h^{-1}{\rm \,Mpc}$, the MgII–LRG cross-correlation has an amplitude $0.69 \pm 0.09$ times that of the LRG–LRG auto-correlation. Since LRGs have halo-masses of $10^{13}$ M$_{\odot}$, this strong cross-correlation signal implies that the absorber host-galaxies have halo-masses $1-2\times 10^{12}$ M$_{\odot}$.

We combine FUV spectra obtained with FUSE and STIS/E140M of HE 0226–4116 ($z=0.495$), PG 1116+215 ($z_{\rm em}=0.177$), and PG 1259+593 ($z_{\rm em}=0.478$) to determine the distribution of column density and Doppler width of the Ly$\alpha$ absorber population at $z<0.5$ detected in the spectra of these 3 quasars. The high spectral resolution UV spectra allow us to derive simultaneously the redshift, column density, and Doppler width of each absorber. Two different populations of H I absorbers appear to be present: narrow and broad H I absorptions that could be tracers of the warm photoionised IGM ($T < 10^5$ K) and warm-hot ionised medium (WHIM, $T \sim 10^5-10^6$ K). For a reliable assessment of the baryonic content of the Ly$\alpha$ forest at low $z$ it is crucial to determine the relative numbers of photoionised absorbers vs. hot collisionally ionised absorbers. Preliminary results indicate that 30–40% of the total baryons are in the photoionised IGM and at least 20% in the WHIM. We also discuss the observed evolution of the Doppler parameter with redshift.

Large volumes of CCD imaging data that will become available from wide-field cameras at telescopes such as the CFHT, SUBARU, VST, or VISTA in the near future are highly suitable for systematic distance surveys of early-type galaxies using the Surface Brightness Fluctuation (SBF) method. For the efficient processing of such large data sets, we are developing the first semi-automatic SBF analysis pipeline named SAPAC. After a brief description of the SBF method we discuss the image quality needed for a successful distance measurement and give some background information on SAPAC.

Damped Lyman-$\alpha$ (DLA) and sub-DLA quasar absorption lines provide powerful probes of the evolution of metals, gas, and stars in galaxies. One major obstacle in trying to understand the evolution of DLAs and sub-DLAs has been the small number of metallicity measurements at $z<1.5$, an epoch spanning $\sim 70$% of the cosmic history. In recent surveys with the Hubble Space Telescope and Multiple Mirror Telescope, we have doubled the DLA Zn sample at $z<1.5$. Combining our results with those at higher redshifts from the literature, we find that the global mean metallicity of DLAs does not rise to the Solar value at low redshifts. These surprising results appear to contradict the near-Solar mean metallicity observed for nearby ($z \approx 0$) galaxies and the predictions of cosmic chemical evolution models based on the global star formation history. Finally, we discuss direct constraints on the star formation rates (SFRs) in the absorber galaxies from our deep Fabry-Perot Ly-$\alpha$ imaging study and other emission-line studies in the literature. A large fraction of the observed heavy-element quasar absorbers at $0<z<3.4$ appear to have SFRs substantially below the global mean SFR, consistent with the low metallicities observed in the spectroscopic studies.

For a long time it has been usual to search for the objects that host the gas from which absorption line systems arise. However, the spatial distribution of metals around galaxies and more generally in the intergalactic medium is complex, and it is often very difficult to associate one absorption system with one galaxy. Except for possibly in the special case of DLA systems, it may be more appropriate to discuss the clustering properties of different classes of objects and to measure their correlation functions. I illustrate this approach with three examples: the distribution of metals around galaxies at intermediate redshift, the modelling of the clustering of C IV systems, and the determination of the transverse correlation function of the Lyman-$\alpha$ forest.

Quasar absorption lines have long been recognised to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be studied by any other means. While some pre-Hubble Space Telescope (HST) observations indicated that Mg II absorption lines arise in gaseous galactic halos with a large covering factor, many early QSO absorber studies were hampered by a lack of information about the context of the absorbers and their connections with galaxies. By providing access to crucial ultraviolet resonance lines at low redshifts, deployment of HST and the Far Ultraviolet Spectroscopic Explorer enabled detailed studies of the relationships between QSO absorbers and galaxies. The advent of large surveys such as the Sloan Digital Sky Survey (SDSS) has also advanced the topic by greatly improving the size of absorber and galaxy samples. This paper briefly reviews some observational results on absorber-galaxy connections that have been obtained in the HST/SDSS era, including Mg II absorbers, the low$-z$ Ly$\alpha$ forest, Lyman limit and damped Ly$\alpha$ absorbers, and O VI systems.

We examine the properties of ten compact objects in the vicinity of M87 using HST imaging and Keck spectroscopy. We find three objects to be larger and brighter than typical globular clusters; they resemble the nuclei of nucleated dEs in Virgo, having similar mass-to-light ratios, luminosities and colors. Their properties are consistent with models of tidally stripping of nucleated dEs. One object could be an old “stellar supercluster”, formed through the amalgamation of multiple young massive clusters. Two other objects appear to be massive versions of otherwise “normal” globular clusters.

The epochs when many dwarf ellipticals were forming their stellar populations have recently become accessible to direct observation, as surveys at $z = 1$–5 have now uncovered thousands of galaxies. I briefly review the properties of various categories of high redshift galaxies in search of clues for possible links to today's galaxy populations. While much of the emphasis up to now has been on massive elliptical galaxies, with several groups claiming to have identified their progenitors with a variety of different techniques, dwarf galaxies have generally been overlooked—no doubt because the observational difficulties at high redshift are still considerable. Based on available data, it is possible that at least some of the ‘Ly$\alpha$ emitters’ and the damped Ly$\alpha$ systems may be on evolutionary paths which will transform them into the galaxies which are the subject of this meeting.

We investigate the variations in the broadband luminosities of low and intermediate redshift galaxies due to the stochastic nature of the neutral hydrogen distribution present in the form of Ly$\alpha$ absorbers in the intergalactic medium. This effect is caused by variations in the distribution and properties (redshift, column density, Doppler parameter) of the absorbers along different lines-of-sight out to a given redshift. Using a set of observationally constrained redshift-, column density-, and Doppler parameter distributions we perform Monte Carlo simulations for a large number of lines-of-sight towards galaxies at a given redshift $z_{em}$ and calculate attenuated FUV/NUV magnitudes and corresponding 1-, 2-, and 3$\sigma$ variations. We predict significant variations in luminosity ranging from -0.22 to +0.48 magnitudes at the 1$\sigma$ level for galaxies at $z=1.5$ in GALEX data.

Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionisation MgII absorbers over the redshift interval $0.36<z<2.28$ which is over two orders of magnitude larger than anything previously assembled. Hubble Space Telescope (HST) UV spectroscopy has been used to measure neutral hydrogen column densities for a small subset of them. These data empirically show that MgII absorbers with rest equivalent widths $W^{\lambda2796}_0 \ge 0.6$ Å have a mean neutral hydrogen column density that is roughly constant at $N(HI) \approx 4\times10^{20}$ atoms cm$^{-2}$, with individual systems lying in the damped Ly$\alpha$ (DLA) and sub-DLA regimes. Since the MgII doublets generally exhibit saturation, the $W^{\lambda2796}_0$ values are an indication of the absorbers' velocity spreads. Thus, we can study neutral-gas-phase metallicities as a function of kinematics by forming SDSS composite spectra and measuring weak unsaturated metal lines that form in neutral gas (e.g., CrII, FeII, MnII, SiII, ZnII) as a function of $W^{\lambda2796}_0$. We use this method on SDSS composite spectra to show how metallicity and kinematics are positively correlated for large-$N(HI)$ absorbers, including trends related to dust depletion and the enhancement of $\alpha$-elements. We also discuss the need to account for selection effects in DLA surveys, and we make inferences about models for DLA absorption and their contribution to cosmic star formation.

We present a series of N-body simulations examining the tidal impact of satellite dwarfs on galactic disks, in particular on the abilities of satellites to excite warps like the one seen in the disk of the Milky Way. We have examined satellites with masses spanning 1.5 orders of magnitude, ranging from the Sgr dSph to the LMC. Orbits similar to the eccentric polar orbit of Sgr were examined, along with orbits of intermediate inclination and of lower eccentricity. The fundamental physical processes which govern the transfer of angular momentum between the satellite and disk, and within the disk, are identified to be precession of the satellite orbit, shrinking of the satellite orbit due to dynamical friction, warping of the disk within a slewing potential, and differential precession. We find that although very large satellites can tidally excite warps shortly after each perigalactic passage, the effects of such satellites are quite destructive and the resulting disks have smaller warps and appear more disturbed than the disks of the Milky Way and other strongly-warped galaxies. Smaller satellites, however, may be capable of producing the minor warps typical of many disk galaxies.

Globular clusters (GCs) and nuclei in dEs are important probes for for studying cosmology and galaxy evolution. GCs and nuclei are usually formed in the high pressures of starbursts, therefore resolved stellar color-magnitude diagrams and integrated colors, magnitudes, or spectra yield ages and metallicities which are snapshots of the conditions during the most violent and important star forming episodes of the galaxies. Most are older, more metal-poor, and more enriched in $\alpha$-elements than the underlying dE field stars. About 25% have formed within the last $\sim$6~Gyr from enriched gas. Many nuclei have the properties of brights GCs but some can be distinguished by large sizes and composite stellar populations. The relatively large numbers of GCs in dEs shows that they are an important source of GCs to galaxies that accrete them.

The evidence is becoming strong that the luminosity function of galaxies varies with environment. Higher density, more dynamically evolved regions appear to have more dwarfs per giant. The situation is becoming clearer as a result of wide field imaging surveys with the Canada-France-Hawaii and Subaru telescopes and spectroscopy of faint dwarfs with the Keck telescope. We report here on extensive observations of the small but dense NGC 5846 Group. The faint end of the luminosity function rises relatively steeply in this case.

Search for the time variation of the fundamental constants is motivated by various unification theories. Here we present constraints on the variation of the fine-structure constant $\alpha$($\equiv {e^2/\hbar c}$) obtained using UVES/VLT samples of QSO absorption systems. We find ${<\Delta\alpha/\alpha}>_{w}={(-0.06\pm0.06)\times10^{-5}}$ using 23 Mg II systems and the many-multiplet (MM) method. Well selected 15 Si IV systems provide ${<\Delta\alpha/\alpha}>_{w}={(0.15\pm0.43)\times10^{-5}}$. Absence of detectable variation in $\alpha$ is also confirmed by our new very high resolution ($R\sim 100,000$) observation of $z_{\rm abs}=1.1508$ toward HE 0515–4414 using HARPS on the ESO 3.6m telescope.

ω Centauri, the largest globular cluster of our Milky Way, is an outstanding object in many aspects. Studies on the red giant branch (RGB) revealed a large spread in iron abundance, which ranges from [Fe/H]∼-2.0 to -0.4 dex and the existence of multiple sub-populations that do not only differ in their element abundances but also in their spatial and kinematic distributions (e.g. Norris et al. 1997). Furthermore more recent photometric studies suggested the existence of an age spread between these subpopulations (e.g. Hilker & Richtler 2000).

We present a study of the evolution of late-type field dwarfs over the last 1.5 Gyr, based on HST ACS observations carried out as part of the GEMS survey. This study is amongst the first to probe the evolution of dwarfs over such a large timescale. The comparison of structural properties, particularly size and scale length, indicates that the dwarfs in the redshift range $z \sim$ 0.01 to 0.15 (look-back times up to 1.8 Gyr) are more extended than local dwarfs. We argue that this difference is due to the star formation activity becoming more centrally concentrated in late-type dwarfs over the last ${\sim} 1.5$ Gyr. We discuss several possible causes for this evolution. We also find a lack of blue compact dwarfs in the GEMS sample and interpret this as indication of the fact that strong, centrally concentrated star formation is a feature of evolved dwarfs that are entering their final stages of evolution.

With the new discoveries that some dEs are rotationally supported and that dIs may show a large variety in star formation histories, the perceived relationships between these two families of galaxies are changing. There are at least three viable channels for the origin of dwarf elliptical galaxies with strong observational evidence that support their reality. I will discuss the observational evidence for each of these channels and the likely physical processes which determine each channel.

We studied a sample of 38 intermediate redshift MgII absorption-selected galaxies using (1) Keck/HIRES and VLT/UVES quasar spectra to measure the halo gas kinematics from MgII absorption profiles and (2) HST/WFPC–2 images to study the absorbing galaxy morphologies. We have searched for correlations between quantified gas absorption properties, and host galaxy impact parameters, inclinations, position angles, and quantified morphological parameters. We report a $3.2\sigma$ correlation between asymmetric perturbations in the host galaxy morphology and the MgII absorption equivalent width. We suggest that this correlation may indicate a connection between past merging and/or interaction events in MgII absorption-selected galaxies and the velocity dispersion and quantity of gas surrounding these galaxies.