A sample of distant ($z>0.4$) luminous infrared galaxies (LIRGs) selected from ISOCAM deep survey fields (CFRS, UDSR, UDSF) have been studied on the basis of their high-quality optical spectra from VLT/FORS2 (R=5Å). Robust estimates of dust extinction can be considered via the energy balance between the infrared and H$\beta$ luminosities, after correcting the underlying Balmer absorption properly. Oxygen abundances [12+log(O/H)] in the interstellar medium of the sample galaxies estimated from the “strong-line” method show a range from 8.36 to 8.93, with a median value of 8.67, which is 0.5 lower than that of local bright disks (i.e. $L^*$) at the given magnitude. The timescale to double the stellar masses of such LIRGs can be very short, 0.1-1 Gyr. A significant fraction of distant large disks are indeed LIRGs. Such massive disks could have formed $\sim50$% of their metals and stellar masses since $z\sim1$.

The galaxy-IGM part of the Lyman-break survey currently consists of measured redshifts for more than 1000 galaxies with redshift $1.5\lesssim z\lesssim 3.5$ along the sight-lines to 25 background QSOs. One of the goals of the survey was to measure the influence on the intergalactic medium of energetic feedback from star and black-hole formation. This talk begins with a description of the observed correlations between galaxies and intergalactic absorption lines and ends with a discussion of whether any of the observations provide clear evidence for Mpc-scale superwinds. Although our own observations remain fairly ambiguous, other observations strongly disfavour a very high redshift ($z\sim 10$) for the creation of intergalactic metals.

Using 138 low column density (N$_{\rm HI}=10^{12.5-16.5}$ cm$^{-2}$) Ly$\alpha$ “forest” absorbers discovered by HST at $z \leq 0.15$ and nearly one million low-$z$ galaxy redshifts from on-going surveys, we find that:

1. Although nearly 80% of Ly$\alpha$ forest absorbers are found within galaxy filaments, very few of them can be identified plausibly with bright ($\geq\,0.1\;{\rm L}^*$) galaxies. Either these absorbers are not related to any one individual galaxy or the individual galaxy to which they are related is fainter than $0.1\;{\rm L}^*$ (M$_B \geq -17$). O VI absorbers (H I+O VI) are found exclusively in galaxy filaments at median distances half as far away from the nearest galaxy as the Ly$\alpha$ absorber population from which they were selected (N$_{\rm HI}=10^{13.5-16.5}$ cm$^{-2}$).

2. Our work on individual absorber-galaxy associations at the lowest redshifts finds cases where low column density (N$_{\rm HI} = 10^{13.5-16.5}$ cm$^{-2}$) metal-enriched absorbers appear to be due to unbound winds from dwarf galaxies while higher column density (N$_{\rm HI}=10^{17.3-20}$ cm$^{-2}$) absorbers are found in the bound halos of massive galaxies. Therefore, both the statistics and a few well-studied examples lead us to propose that the low-$z$ IGM (and the Ly$\alpha$ forest absorbers in particular) are enriched in metals by outflowing winds from dwarf galaxies.

Using H I absorption alone, we attempt to separate H I absorption lines in quasar spectra into two categories; HDLs (Higher Density Lines) and LDLs (Lower Density Lines), and we discuss the difference in their physical properties. We deblend and fit all H I lines with Voigt profiles, and make an unbiased sample of H I lines covering a wide column density range ($12 < \log N_{HI} < 19$ cm$^{-2}$). To reduce the influence of line blending, we simultaneously fit several Lyman series lines. As a result of a two-point correlation analysis, we found that higher column density H I lines are clustering at $\Delta v < 200$ km s$^{-1}$, while lower ones at $\Delta v < 100$ km s$^{-1}$. We define HDLs as H I lines with $15<\log N_{HI} < 19$ cm$^{-2}$ and all H I lines within $\pm$200 km s$^{-1}$ of a line with $\log N_{HI} > 15$ cm$^{-2}$, and LDLs as others with $12 < \log N_{HI} < 15$ cm$^{-2}$. We found that the HDLs have smaller minimum $b$-values for a given column density than the LDLs. This difference is successfully reproduced by our hydrodynamic simulation. The LDLs seem to be cool or shock-heated diffuse IGM gas, while the HDLs are likely to be cooler dense gas near to galaxies.

We explore the recently proposed idea that the Galactic dwarf spheroidal galaxies are significantly (by 2 orders of magnitude) more massive than the conventional mass estimates of ${\sim}10^7$ M$_\odot$. In the larger mass case, the observed distribution of stars in these galaxies should have been entirely shaped by internal processes (formation and dynamic relaxation of stars in the potential of the dark matter halo), and not by the Galactic tidal field. We carried out numerical n-body simulations aimed at testing this scenario. Observed properties of three Galactic dwarf spheroidal galaxies were found to be consistent with our model. From our analysis, these dwarfs appear to be massive enough to alleviate the “missing satellites” problem of cold dark matter cosmologies.

We analyze the Luminosity Functions (LFs) of a subsample of 69 clusters from the RASS-SDSS galaxy cluster catalog. The cluster LFs are computed within the physical sizes of the galaxy systems, $r_{500}$ and $r_{200}$. When calculated within the cluster physical sizes, all the cluster LFs appear to have the same shape, well fitted by a composite of two Schechter functions with a marked upturn and a steepening at the faint-end.

We determine the composite LF for early- and late-type galaxies, where the typing is based on the galaxy $u-r$ colors. The late-type LF is well fitted by a single Schechter function with a steep slope. The early-type LF instead cannot be fitted by a single Schechter function, and a composite of two Schechter functions is needed. The faint-end upturn of the global cluster LF is due to the early-type cluster galaxies. The shape of the bright-end tail of the early-type LF does not seem to depend upon the local galaxy density or the distance from the cluster center. The late-type LF shows a significant variation only very near the cluster center. On the other hand, the faint-end tail of the early-type LF shows a significant and continuous variation with the environment.

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.