We have derived dust temperatures, dust masses, star formation rates andfar-infrared luminosities for 104 gravitationally-lensed quasars at z$\sim$1-4observed with Herschel/SPIRE, the largest such sample ever studied. Bytargeting gravitational lenses we probe intrinsic luminosities more typical ofthe population than the extremely luminous sources otherwise accessible. Wedetect 87 (84 percent) of the sample with SPIRE: 82 (79 percent) quasars havespectra characteristic of dust emission, and we find evidence for dust-obscuredstar formation in at least 72 (69 percent). We find a medianmagnification-corrected SFR of $220^{+840}_{-130}\ {\rm M_{\odot} yr^{-1}}$ and$L_{\rm FIR}$ of $6.7^{+25.5}_{-4.1} \times 10^{11}\ {\rm L_{\odot}}$. Theresults are in line with current models of quasar evolution, but suggest thatmost quasars exist in a transitional phase between a dusty star-forming galaxyand an AGN dominated system. This further indicates that AGN feedback does notquickly quench star formation in these sources. Additionally, we find nosignificant difference in dust luminosities between radio-loud and radio-quietquasars, implying that radio mode feedback has no significant effect on hostgalaxy properties.

The catalogue of protoplanetary nebulae by Vickers et al. has beensupplemented with the line-of-sight velocities and proper motions of theircentral stars from the literature. Based on an exponential densitydistribution, we have estimated the vertical scale height from objects with anage less than 3 Gyr belonging to the Galactic thin disk (luminosities higherthan 5000 Lo) to be h=146+/-15 pc, while from a sample of older objects(luminosities lower than 5000 Lo) it is h=568+/-42 pc. We have produced a listof 147 nebulae in which there are only the line-of-sight velocities for 55nebulae, only the proper motions for 25 nebulae, and both line-of-sightvelocities and proper motions for 67 nebulae. Based on this kinematic sample,we have estimated the Galactic rotation parameters and the residual velocitydispersions of protoplanetary nebulae as a function of their age. We haveestablished that there is a good correlation between the kinematic propertiesof nebulae and their separation in luminosity proposed by Vickers. Most of thenebulae are shown to be involved in the Galactic rotation, with the circularrotation velocity at the solar distance being V_0=227+/-23 km/s. The followingprincipal semiaxes of the residual velocity dispersion ellipsoid have beenfound: (sigma1, sigma2, sigma3) = (47, 41, 29) km/s from a sample of youngprotoplanetary nebulae (with luminosities higher than 5000 Lo), (sigma1,sigma2, sigma3) = (50, 38, 28) km/s from a sample of older protoplanetarynebulae (with luminosities of 4000 Lo or 3500 Lo), and (sigma1, sigma_2,sigma3) = (91, 49, 36) km/s from a sample of halo nebulae (with luminosities of1700 Lo).

I present a dynamical analysis of the measured redshifts and distances of 64dwarf galaxies at distances between 50 kpc and 2.6 Mpc. These dwarfs areassumed to move as test particles in the gravitational field of 12 massiveactors---galaxies and groups of galaxies---under the mixed boundary conditionsimposed by cosmology. The model fits most of the measured dwarf distances andredshifts. But more work, perhaps on the gravitational interaction among dwarfgalaxies, is required to account for the motions of six galaxies in the NGC3109 association and two in the DDO 210 association. The sample of dwarfs islarge enough to constrain the halo mass run in the Milky Way. The evidencepoints to a sharper break from a nearly flat inner rotation curve thanpredicted by the NFW profile.

We present the detection of 89 low surface brightness (LSB), and thus lowstellar density galaxy candidates in the Perseus cluster core, of the kindnamed "ultra-diffuse galaxies", with mean effective V-band surface brightnesses24.8-27.1 mag arcsec$^{-2}$, total V-band magnitudes -11.8 to -15.5 mag, andhalf-light radii 0.7-4.1 kpc. The candidates have been identified in a deepmosaic covering 0.3 square degrees, based on wide-field imaging data obtainedwith the William Herschel Telescope. We find that the LSB galaxy population isdepleted in the cluster centre and only very few LSB candidates have half-lightradii larger than 3 kpc. This appears consistent with an estimate of theirtidal radius, which does not reach beyond the stellar extent even if we assumea high dark matter content (M/L=100). In fact, three of our candidates seem tobe associated with tidal streams, which points to their current disruption.Given that published data on faint LSB candidates in the Coma cluster - withits comparable central density to Perseus - show the same dearth of largeobjects in the core region, we conclude that these cannot survive the strongtides in the centres of massive clusters.

Boxy/peanut bulges are considered to be part of the same stellar structure asbars and both could be linked through the buckling instability. The Milky Wayis our closest example. The goal of this letter is determining if the massassembly of the different components leaves an imprint in their stellarpopulations allowing to estimate the time of bar formation and its evolution.To this aim we use integral field spectroscopy to derive the stellar agedistributions, SADs, along the bar and disc of NGC 6032. The analysis showsclearly different SADs for the different bar areas. There is an underlying old(>=12 Gyr) stellar population for the whole galaxy. The bulge shows starformation happening at all times. The inner bar structure shows stars of agesolder than 6 Gyrs with a deficit of younger populations. The outer bar regionpresents a SAD similar to that of the disc. To interpret our results, we use ageneric numerical simulation of a barred galaxy. Thus, we constrain, for thefirst time, the epoch of bar formation, the buckling instability period and theposterior growth from disc material. We establish that the bar of NGC 6032 isold, formed around 10 Gyr ago while the buckling phase possibly happened around8 Gyr ago. All these results point towards bars being long-lasting even in thepresence of gas.

We introduce a new model for the structure and evolution of the gas ingalactic discs. In the model the gas is in vertical pressure and energybalance. Star formation feedback injects energy and momentum, andnon-axisymmetric torques prevent the gas from becoming more than marginallygravitationally unstable. From these assumptions we derive the relationshipbetween galaxies' bulk properties (gas surface density, stellar content, androtation curve) and their star formation rates, gas velocity dispersions, andrates of radial inflow. We show that the turbulence in discs can be poweredprimarily by star formation feedback, radial transport, or a combination of thetwo. In contrast to models that omit either radial transport or star formationfeedback, the predictions of this model yield excellent agreement with a widerange of observations, including the star formation law measured in bothspatially resolved and unresolved data, the correlation between galaxies' starformation rates and velocity dispersions, and observed rates of radial inflow.The agreement holds across a wide range of galaxy mass and type, from localdwarfs to extreme starbursts to high-redshifts discs. We apply the model togalaxies on the star-forming main sequence, and show that it predicts atransition from mostly gravity-driven turbulence at high redshift to starformation-driven turbulence at low redshift. This transition, and the changesin mass transport rates that it produces, naturally explain why galaxy bulgestend to form at high redshift and discs at lower redshift, and why galaxiestend to quench inside-out.

We present a detailed analysis of a H$_2$-rich, extremely strong interveningDamped Ly-$\alpha$ Absorption system (DLA) at $z_{\rm abs}=2.786$ towards thequasar J$\,$0843+0221, observed with the Ultraviolet and Visual EchelleSpectrograph on the Very Large Telescope. The total column density of molecular(resp. atomic) hydrogen is $\log N$(H$_2$)=$21.21\pm0.02$ (resp. $\logN$(H$\,$I)=$21.82\pm0.11$), making it to be the first case in quasar absorptionlines studies with H$_2$ column density as high as what is seen in$^{13}$CO-selected clouds in the Milky-Way. We find that this system has one of the lowest metallicity detected amongH$_2$-bearing DLAs, with $\rm [Zn/H]=-1.52^{+0.08}_{-0.10}$. This can be thereason for the marked differences compared to systems with similar H$_2$ columndensities in the local Universe: $(i)$ the kinetic temperature, $T\sim$120~K,derived from the $J=0,1$ H$_2$ rotational levels is at least twice higher thanexpected; $(ii)$ there is little dust extinction with A$_V < 0.1$; $(iii)$ noCO molecules are detected, putting a constraint on the $X_{\rm CO}$ factor$X_{\rm CO}> 2\times 10^{23} $ cm$^{-2}$/(km/s\,K), in the very low metallicitygas. Low CO and high H$_2$ contents indicate that this system represents"CO-dark/faint" gas. We investigate the physical conditions in the H$_2$-bearing gas using thefine-structure levels of C$\,$I, C$\,$II, Si$\,$II and the rotational levels ofHD and H$_2$. We find the number density to be about $n \sim260-380\,$cm$^{-3}$, implying a high thermal pressure of $(3-5) \times10^4\,$cm$^{-3}\,$K. We further identify a trend of increasing pressure withincreasing total hydrogen column density. This independently supports thesuggestion that extremely strong DLAs (with $\log\,$N(H) $\sim 22$) probehigh-z galaxies at low impact parameters.

We compile a sample of spectroscopically- and photometrically-selectedcluster galaxies from four high-redshift galaxy clusters ($1.59 < z < 1.71$)from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS), and acomparison field sample selected from the UKIDSS Deep Survey. Usingnear-infrared imaging from the \textit{Hubble Space Telescope} we classifypotential mergers involving massive ($M_* \geq 3\times10^{10}\mathrm{M}_\odot$) cluster members by eye, based on morphologicalproperties such as tidal distortions, double nuclei, and projected nearneighbors within 20 kpc. With a catalogue of 23 spectroscopic and 32photometric massive cluster members across the four clusters and 65spectroscopic and 26 photometric comparable field galaxies, we find that aftertaking into account contamination from interlopers, $11.0 ^{+7.0}_{-5.6}\%$ ofthe cluster members are involved in potential mergers, compared to$24.7^{+5.3}_{-4.6}\%$ of the field galaxies. We see no evidence of mergerenhancement in the central cluster environment with respect to the field,suggesting that galaxy-galaxy merging is not a stronger source of galaxyevolution in cluster environments compared to the field at these redshifts.

The star formation properties of early-type galaxies (ETGs) are currently thesubject of considerable interest, particularly whether they differ from thoseof gas-rich spirals. We perform a systematic study of star formation in a largesample of local ETGs using polycyclic aromatic hydrocarbon (PAH) and dustemission, focusing on the galaxies' star formation rates (SFRs) and starformation efficiencies (SFEs). Our sample is composed of the 260 ETGs from theATLAS3D survey, from which we use the cold gas measurements (HI and CO). TheSFRs are estimated from stellar, PAH and dust fits to spectral energydistributions created from new AKARI measurements and literature data from WISEand 2MASS. The mid-infrared luminosities of non-CO-detected galaxies are wellcorrelated with their stellar luminosities, showing that they trace(circum)stellar dust emission. CO-detected galaxies show an excess above thesecorrelations, uncorrelated with their stellar luminosities, indicating thatthey likely contain PAHs and dust of interstellar origin. PAH and dustluminosities of CO-detected galaxies show tight correlations with theirmolecular gas masses, and the derived current SFRs are typically 0.01-1Msun/yr. These SFRs systematically decrease with stellar age at fixed stellarmass, while they correlate nearly linearly with stellar mass at fixed age. Themajority of local ETGs follow the same star-formation law as local star-forminggalaxies, and their current SFEs do not depend on either stellar mass or age.Our results clearly indicate that molecular gas is fueling current starformation in local ETGs, that appear to acquire this gas via mechanismsregulated primarily by stellar mass. The current SFEs of local ETGs are similarto those of local star-forming galaxies, indicating that their low SFRs arelikely due to smaller cold gas fractions rather than a suppression of starformation.