We present the measurements of Faraday rotation for 477 pulsars observed bythe Parkes 64-m radio telescope and the Green Bank 100-m radio telescope. Usingthese results along with previous measurements for pulsars and extra-galacticsources, we analyse the structure of the large-scale magnetic field in theGalactic disk. Comparison of rotation measures of pulsars in the disk atdifferent distances as well as with rotation measures of background radiosources beyond the disk reveals large-scale reversals of the field directionsbetween spiral arms and interarm regions. We develop a model for the diskmagnetic field, which can reproduce not only these reversals but also thedistribution of observed rotation measures of background sources.

Brightest Cluster Galaxies (BCGs) are believed to have assembled most oftheir stars early in time and, therefore, should be passively evolving at lowredshifts and appear "red-and-dead." However, there have been reports that aminority of low-redshift BCGs still have ongoing star formation rates (SFR) ofa few to even $\sim$100 $M_\odot/yr$. Such BCGs are found in "cool-core" ("CC")clusters, and their star formation is thought to be fueled by "cooling flow."To further investigate the implications of low-redshift, star-forming BCGs, weperform a systematic search using the 22$\mu$m data ("W4" band) from theWide-field Infrared Survey Explorer (WISE) on the GMBCG catalog, which contains55,424 BCGs at $0.1\lesssim z\lesssim 0.55$ identified in the Sloan Digital SkySurvey (SDSS). Our sample consists of 389 BCGs that are bright in W4("W4BCGs"), most being brighter than 5 mJy. While some ($\lesssim 20\%$) mighthost AGN, most W4BCGs should owe their strong mid-IR emissions todust-enshrouded star formation. Their median total IR luminosity ($L_{IR}$) is$5\times10^{11} L_{\odot}$ (SFR $\sim$50 $M_{\odot}/yr)$, and 27\% of the wholesample has $L_{IR}>10^{12} L_{\odot}$ (SFR $>$100 $M_{\odot}/yr$). Using tenW4BCGs that have Chandra X-ray data, we show that seven of them are possibly inCC clusters. However, in most cases (five out of seven) the mass depositionrate cannot account for the observed SFR. This casts doubt to the idea thatcooling flows are the cause of the star formation in non-quiescent BCGs.

The properties of circum-galactic gas in the halo of quasar host galaxies areinvestigated analyzing Mg II 2800 and C IV 1540 absorption-line systems alongthe line of sight close to quasars. We used optical spectroscopy of closelyaligned pairs of quasars (projected distance $\leq$ 200 kpc, but at verydifferent redshift) obtained at the VLT and Gran Telescopio Canarias toinvestigate the distribution of the absorbing gas for a sample of quasars atz$\sim$1. Absorption systems of EW $\geq$ 0.3 $\rm{\AA}$ associated with theforeground quasars are revealed up to 200 kpc from the centre of the hostgalaxy, showing that the structure of the absorbing gas is patchy with acovering fraction quickly decreasing beyond 100 kpc. In this contribution weuse optical and near-IR images obtained at VLT to investigate the relationsbetween the properties of the circum-galactic medium of the host galaxies andof the large scale galaxy environments of the foreground quasars.

We present high spatial resolution (FWHM$\sim$0.14'') observations of theCO($8-7$) line in GDS-14876, a compact star-forming galaxy at $z=2.3$ withtotal stellar mass of $\log(M_{\star}/M_{\odot})=10.9$. The spatially resolvedvelocity map of the inner $r\lesssim1$~kpc reveals a continous velocitygradient consistent with the kinematics of a rotating disk with $v_{\rmrot}(r=1\rm kpc)=163\pm5$ km s$^{-1}$ and $v_{\rm rot}/\sigma\sim2.5$. Thegas-to-stellar ratios estimated from CO($8-7$) and the dust continuum emissionspan a broad range, $f^{\rm CO}_{\rm gas}=M_{\rm gas}/M_{\star}=13-45\%$ and$f^{\rm cont}_{\rm gas}=50-67\%$, but are nonetheless consistent given theuncertainties in the conversion factors. The dynamical modeling yields adynamical mass of$\log(M_{\rm dyn}/M_{\odot})=10.58^{+0.5}_{-0.2}$ which islower, but still consistent with the baryonic mass, $\log$(M$_{\rm bar}$=M$_{\star}$ + M$^{\rm CO}_{\rm gas}$/M$_{\odot}$)$=11.0$, if the smallestCO-based gas fraction is assumed. Despite a low, overall gas fraction, thesmall physical extent of the dense, star-forming gas probed by CO($8-7$),$\sim3\times$ smaller than the stellar size, implies a strong concentrationthat increases the gas fraction up to $f^{\rm CO, 1\rm kpc}_{\rm gas}\sim 85\%$in the central 1 kpc. Such a gas-rich center, coupled with a highstar-formation rate, SFR$\sim$ 500 M$_{\odot}$ yr$^{-1}$, suggests thatGDS-14876 is quickly assembling a dense stellar component (bulge) in a strongnuclear starburst. Assuming its gas reservoir is depleted withoutreplenishment, GDS-14876 will quickly ($t_{\rm depl}\sim27$ Myr) become acompact quiescent galaxy that could retain some fraction of the observedrotational support.

Quasars are the most luminous non-transient objects known, and as such, theyenable unparalleled studies of the universe at the earliest cosmic epochs.However, despite extensive efforts from the astronomical community, the quasarULASJ1120+0641 at z=7.09 (hereafter J1120+0641) has remained as the only oneknown at z>7 for more than half a decade. Here we report observations of thequasar ULAS J134208.10+092838.61 (hereafter J1342+0928) at a redshift ofz=7.54. This quasar has a bolometric luminosity of 4e13 Lsun and a black holemass of 8e8 Msun. The existence of this supermassive black hole when theuniverse was only 690 Myr old, i.e., just 5% its current age, reinforces earlyblack hole growth models that allow black holes with initial masses >1e4 Msunor episodic hyper-Eddington accretion. We see strong evidence of the quasar'sLy-alpha emission line being absorbed by a Gunn-Peterson damping wing from theintergalactic medium, as would be expected if the intergalactic hydrogensurrounding J1342+0928 is significantly neutral. We derive a significantneutral fraction, although the exact value depends on the modeling. However,even in our most conservative analysis we find xHI>0.33 (xHI>0.11) at 68% (95%)probability, indicating that we are probing well within the reionization epoch.

We present IRAM/NOEMA and JVLA observations of the quasar J1342+0928 atz=7.54 and report detections of copious amounts of dust and [CII] emission inthe interstellar medium (ISM) of its host galaxy. At this redshift, the age ofthe universe is 690 Myr, about 10% younger than the redshift of the previousquasar record holder. Yet, the ISM of this new quasar host galaxy issignificantly enriched by metals, as evidenced by the detection of the [CII]158micron cooling line and the underlying far-infrared (FIR) dust continuumemission. To the first order, the FIR properties of this quasar host aresimilar to those found at a slightly lower redshift (z~6), making this sourceby far the FIR-brightest galaxy known at z>7.5. The [CII] emission is spatiallyunresolved, with an upper limit on the diameter of 7 kpc. Together with themeasured FWHM of the [CII] line, this yields a dynamical mass of the host of<1.5x10^11 M_sun. Using standard assumptions about the dust temperature andemissivity, the NOEMA measurements give a dust mass of (0.6-4.3)x10^8 M_sun.The brightness of the [CII] luminosity, together with the high dust mass, implyactive ongoing star formation in the quasar host. Using [CII]-SFR scalingrelations, we derive star formation rates of 85-545 M_sun/yr in the host,consistent with the values derived from the dust continuum. Indeed, an episodeof such past high star formation is needed to explain the presence of ~10^8M_sun of dust implied by the observations.