Search

We present a deep X-Shooter rest-frame UV to optical spectral analysis of the heavily reddened quasar, ULASJ2315+043 at z=2.566, known to reside in a major-merger host galaxy. The rest-frame optical is best-fit by a dust-reddened quasar E(B-V)_QSO = 1.55 with black-hole mass log10(Hbeta, MBH [M_sol]) = 10.26 +\- 0.05, bolometric luminosity L_Bol = 10^48.16 erg s^-1 and Eddington-scaled accretion rate log10(\lambda_Edd) = -0.19. We find remarkable similarities between ULASJ2315+043 and the high-redshift Little Red Dots (LRDs). The rest-frame UV cannot be explained by a dusty quasar component alone and requires an additional blue component consistent with either a star-forming host galaxy or scattered AGN light. We detect broad high-ionisation emission lines in the rest-UV, supporting the scattered light interpretation for the UV excess. The scattering fraction represents just 0.05% of the total luminosity of ULASJ2315+043. Analysis of the mid infra-red SED suggests an absence of hot dust on torus-scales similar to what is observed for LRDs. The obscuring medium is therefore likely on galaxy scales. We detect narrow, blueshifted associated absorption line systems in CIV, NV, SiIV and SiIII. There is evidence for significant high-velocity (>1000 km s^-1) outflows in both the broad and narrow line regions as traced by CIV and [OIII] emission. The kinetic power of the [OIII] wind is e_ion = 10^44.61 erg s^-1 ~ 0.001 L_Bol. ULASJ2315+043 is likely in an important transition phase where star formation, black-hole accretion and multi-phase gas flows are simultaneously occurring., Comment: Accepted to MNRAS: 13th Aug 2024. 18 pages, 12 figures

We present a study of the molecular gas in five closely-spaced ($R_{\perp}<20$ kpc) dual quasars ($L_{\rm bol}\gtrsim10^{44}~\mathrm{erg~s}^{-1}$) at redshifts $0.4

Understanding the links between different phases of outflows from active galactic nuclei is a key goal in extragalactic astrophysics. Here we compare [OIII] $\lambda\lambda$4960,5008 outflow signatures in quasars with and without Broad Absorption Lines (BALs), aiming to test how the broad absorption troughs seen in the rest-frame ultraviolet are linked to the narrow line region outflows seen in the rest-frame optical. We present new near-infrared spectra from Magellan/FIRE which cover [OIII] in 12 quasars with 2.1 < z < 2.3, selected to have strong outflow signatures in CIV $\lambda$1550. Combining with data from the literature, we build a sample of 73 BAL, 115 miniBAL and 125 non-BAL QSOs with 1.5 < z < 2.6. The strength and velocity width of [OIII] correlate strongly with the CIV emission properties, but no significant difference is seen in the [OIII] emission-line properties between the BALs, non-BALs and miniBALs once the dependence on CIV emission is taken into account. A weak correlation is observed between the velocities of CIV BALs and [OIII] emission, which is accounted for by the fact that both outflow signatures correlate with the underlying CIV emission properties. Our results add to the growing evidence that BALs and non-BALs are drawn from the same parent population and are consistent with a scenario wherein BAL troughs are intermittent tracers of persistent quasar outflows, with a part of such outflow becoming optically thick along our line-of-sight for sporadic periods of time within which BALs are observed., Comment: 14 pages, 6 figures. Accepted for publication in MNRAS

We present new frontiers in the modelling of the spectral energy distributions (SED) of active galaxies by introducing the radio-to-X-ray fitting capabilities of the publicly available Bayesian code AGNfitter. The new code release, called AGNfitter-rx, models the broad-band photometry covering the radio, infrared (IR), optical, ultraviolet (UV) and X-ray bands consistently, using a combination of theoretical and semi-empirical models of the AGN and host galaxy emission. This framework enables the detailed characterization of four physical components of the active nuclei: the accretion disk, the hot dusty torus, the relativistic jets/core radio emission, and the hot corona; alongside modeling three components within the host galaxy: stellar populations, cold dust, and the radio emission from the star-forming regions. Applying AGNfitter-rx to a diverse sample of 36 AGN SEDs at z<0.7 from the AGN SED ATLAS, we investigate and compare the performance of state-of-the-art torus and accretion disk emission models on fit quality and inferred physical parameters. We find that clumpy torus models that include polar winds and semi-empirical accretion disk templates including emission line features significantly increase the fit quality in 67% of the sources, by effectively reducing by $2\sigma$ fit residuals in the $1.5-5 \mu \rm m$ and $0.7 \mu \rm m$ regimes.We demonstrate that, by applying AGNfitter-rx on photometric data, we are able to estimate inclination and opening angles of the torus, consistent with spectroscopic classifications within the AGN unified model, as well as black hole mass estimates in agreement with virial estimates based on H$\alpha$. The wavelength coverage and the flexibility for the inclusion of state-of-the-art theoretical models make AGNfitter-rx a unique tool for the further development of SED modelling for AGNs in present and future radio-to-X-ray galaxy surveys., Comment: 20 pages, 10 figures, Accepted for publication by A&A

Blueshifts - or, more accurately, blue asymmetries - in broad emission lines such as CIV $\lambda$1550 are common in luminous quasars and correlate with fundamental properties such as Eddington ratio and broad absorption line (BAL) characteristics. However, the formation of these blueshifts is still not understood, and neither is their physical connection to the BAL phenomenon or accretion disc. In this work, we present Monte Carlo radiative transfer and photoionization simulations using parametrized biconical disc-wind models. We take advantage of the azimuthal symmetry of a quasar and show that we can reproduce CIV blueshifts provided that (i) the disc-midplane is optically thick out to radii beyond the line formation region, so that the receding wind bicone is obscured; and (ii) the system is viewed from relatively low (that is, more face-on) inclinations ($\lesssim40^\circ$). We show that CIV emission line blueshifts and BALs can form in the same wind structure. The velocity profile of the wind has a significant impact on the location of the line formation region and the resulting line profile, suggesting that the shape of the emission lines can be used as a probe of wind-driving physics. While we are successful at producing blueshifts/blue asymmetries in outflows, we struggle to match the detailed shape or skew of the observed emission line profiles. In addition, our models produce redshifted emission-line asymmetries for certain viewing angles. We discuss our work in the context of the CIV $\lambda$1550 emission blueshift versus equivalent-width space and explore the implications for quasar disc wind physics., Comment: 20 pages, 12 figures + 1 appendix. Supplementary material, simulation data and plotting scripts available at: https://github.com/jhmatthews/blueshifts

We analyse the rest-frame UV spectra of 2,531 high-redshift (3.53.5 using a cross-correlation algorithm that employs high signal-to-noise template spectra spanning the full range in UV emission line properties. We then quantify the evolution of C IV and He II emission line properties with redshift. The increase in C IV blueshifts with cosmological redshift can be fully explained by the higher luminosities of quasars observed at high redshifts. We recover broadly similar trends between the He II EW and C IV blueshift at both 1.5 0.2 and Mbh > 10^9 Mo for the entire 1.56 are on average less massive and have higher Eddington-scaled accretion rates than their luminosity-matched counterparts at 1.5

Using 190,000 spectra from the seventeenth data release of the Sloan Digital Sky Survey, we investigate the ultraviolet emission line properties in z=2 quasars. Specifically, we quantify how the shape of CIV 1549A and the equivalent width (EW) of HeII 1640A depend on the black hole mass and Eddington ratio inferred from MgII 2800A. Above L/L_Edd>0.2, there is a strong mass dependence in both CIV blueshift and HeII EW. Large CIV blueshifts are observed only in regions with both high mass and high accretion rate. Including X-ray measurements for a subsample of 5,000 objects, we interpret our observations in the context of AGN accretion and outflow mechanisms. The observed trends in HeII and 2 keV strength are broadly consistent with theoretical QSOSED models of AGN spectral energy distributions (SEDs) for low spin black holes, where the ionizing SED depends on the accretion disc temperature and the strength of the soft excess. High spin models are not consistent with observations, suggesting SDSS quasars at z=2 may in general have low spins. We find a dramatic switch in behaviour at L/L_Edd<0.2: the ultraviolet emission properties show much weaker trends, and no longer agree with QSOSED predictions, hinting at changes in the structure of the broad line region. Overall the observed emission line trends are generally consistent with predictions for radiation line driving where quasar outflows are governed by the SED, which itself results from the accretion flow and hence depends on both the SMBH mass and accretion rate., Comment: Resubmitted to MNRAS. Minor edits to text; figures updated; licence updated

We perform spectral energy distribution (SED) fitting to 711 luminous X-ray AGN at 0.7 < z < 4.5 using 10-bands of optical and infra-red photometric data for objects within XMM-SERVS. This fitting provided 510 reliable (reduced $\chi ^2 < 3$) inferences on AGN and host galaxy properties. The AGN optical (3000\r{A}) luminosity inferred from SED-fitting is found to correlate with the measured X-ray (2-10 keV) luminosity, in good agreement with previous work. Using X-ray hardness as a proxy for AGN obscuration, we also study the differences in the host galaxy properties of obscured and unobscured AGN. Both populations have consistent stellar masses (log$_{10}(M_*/M_{\odot})$ = 10.88 $\pm0.09M_\odot$ and log$_{10}(M_*/M_{\odot})$ = 10.8 $\pm0.1M_\odot$ for unobscured and obscured AGN respectively). We also find evidence for varying AGN emission line properties from a standard AGN template in 18.8% of the sample with a reduced $\chi^2 < 3$ where the inclusion of an additional emission line strength free parameter was found to improve the quality of the fit. Comparison of these fits to SDSS spectra showed that emission line properties inferred from broadband photometry were consistent with the results from spectroscopy for 91% of objects. We find that the presence of weaker, more blueshifted emission lines as inferred from the SED fits are associated with more negative values of $\alpha_{ox}$. While the correlation between the hardness of the ionising SED and the emission line properties has been known for some time, we are able to derive this correlation purely from broadband photometry., Comment: 13 pages, 8 figures. Accepted for publication by MNRAS

This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an initial set of Derived Data products (DDPs) that could realize the science goals enabled by joint processing. All interested Rubin and Euclid data rights holders were invited to contribute via an online discussion forum and a series of virtual meetings. Strong interest in enhancing science with joint DDPs emerged from across a wide range of astrophysical domains: Solar System, the Galaxy, the Local Volume, from the nearby to the primaeval Universe, and cosmology., Comment: Report of the Rubin-Euclid Derived Data Products Working Group, 78 pages, 11 figures

We construct a parametric SED model which is able to reproduce the average observed SDSS-UKIDSS-WISE quasar colours to within one tenth of a magnitude across a wide range of redshift $(0M_i>-29)$. This model is shown to provide accurate predictions for the colours of known quasars which are less luminous than those used to calibrate the model parameters, and also those at higher redshifts $z>5$. Using a single parameter, the model encapsulates an up-to-date understanding of the intra-population variance in the rest-frame ultraviolet and optical emission lines of luminous quasars. At fixed redshift, there are systematic changes in the average quasar colours with apparent i-band magnitude, which we find to be well explained by the contribution from the host galaxy and our parametrization of the emission-line properties. By including redshift as an additional free parameter, the model could be used to provide photometric redshifts for individual objects. For the population as a whole we find that the average emission line and host galaxy contributions can be well described by simple functions of luminosity which account for the observed changes in the average quasar colours across $18.1

We present sub-arcsecond resolution ALMA imaging of the CO(3-2) emission in two $z\sim2.5$ heavily reddened quasars (HRQs) - ULASJ1234+0907 and ULASJ2315+0143 - and their companion galaxies. Dynamical modeling of the resolved velocity fields enables us to constrain the molecular gas morphologies and host galaxy masses. Combining the new data with extensive multi-wavelength observations, we are able to study the relative kinematics of different molecular emission lines, the molecular gas fractions and the locations of the quasars on the M$_{\rm{BH}}$-M$_{\rm{gal}}$ relation. Despite having similar black-hole properties, the two HRQs display markedly different host galaxy properties and local environments. J1234 has a very massive host, M$_{\rm{dyn}} \sim 5 \times 10^{11}$M$_\odot$ and two companion galaxies that are similarly massive located within 200 kpc of the quasar. The molecular gas fraction is low ($\sim$6%). The significant ongoing star formation in the host galaxy is entirely obscured at rest-frame UV and optical wavelengths. J2315 is resolved into a close-separation major-merger ($\Delta$r=15 kpc; $\Delta$v=170 km/s) with a $\sim$1:2 mass ratio. The total dynamical mass is estimated to be $\lesssim$10$^{11}$M$_\odot$ and the molecular gas fraction is high ($>$45%). A new HSC image of the galaxy shows unobscured UV-luminous star-forming regions co-incident with the extended reservoir of cold molecular gas in the merger. We use the outputs from the Illustris simulations to track the growth of such massive black holes from $z\sim6$ to the present day. While J1234 is consistent with the simulated $z\sim2$ relation, J2315 has a black hole that is over-massive relative to its host galaxy., Comment: 18 pages, 12 figures, Accepted for publication in MNRAS

We present an investigation of the low-frequency radio and ultraviolet properties of a sample of $\simeq$10,500 quasars from the Sloan Digital Sky Survey Data Release 14, observed as part of the first data release of the Low-Frequency-Array Two-metre Sky Survey. The quasars have redshifts $1.5 < z < 3.5$ and luminosities $44.6 < \log(L_{\text{bol}}/\text{erg s}^{-1}) < 47.2$. We employ ultraviolet spectral reconstructions based on an independent component analysis to parametrize the CIV$\lambda$1549-emission line that is used to infer the strength of accretion disc winds, and the HeII$\lambda$1640 line, an indicator of the soft X-ray flux. We find that radio-detected quasars are found in the same region of CIV blueshift versus equivalent-width space as radio-undetected quasars, but that the loudest, most luminous and largest radio sources exist preferentially at low CIV blueshifts. Additionally, the radio-detection fraction increases with blueshift whereas the radio-loud fraction decreases. In the radio-quiet population, we observe a range of HeII equivalent widths as well as a Baldwin effect with bolometric luminosity, whilst the radio-loud population has mostly strong HeII, consistent with a stronger soft X-ray flux. The presence of strong HeII is a necessary but not sufficient condition to detect radio-loud emission suggesting some degree of stochasticity in jet formation. Using energetic arguments and Monte Carlo simulations, we explore the plausibility of winds, compact jets and star formation as sources of the radio quiet emission, ruling out none. The existence of quasars with similar ultraviolet properties but differing radio properties suggests, perhaps, that the radio and ultraviolet emission is tracing activity occurring on different timescales., Comment: 13 pages, 10 figures, plus appendices. Minor changes to match published version

Using data from SDSS, UKIDSS and WISE, we investigate the properties of the high-frequency cutoff to the infrared emission in $\simeq$5000 carefully selected luminous ($L_{bol} \simeq 10^{47}$) type 1 quasars. The strength of $\simeq$2 $\mu$m emission, corresponding to emission from the hottest (T>1200K) dust in the sublimation zone surrounding the central continuum source, is observed to correlate with the blueshift of the C IV $\lambda$1550 emission line. We therefore find that objects with stronger signatures of nuclear outflows tend to have a larger covering fraction of sublimation-temperature dust. When controlling for the observed outflow strength, the hot dust covering fraction does not vary significantly across our sample as a function of luminosity, black hole mass or Eddington fraction. The correlation between the hot dust and the C IV line blueshifts, together with the lack of correlation between the hot dust and other parameters, therefore provides evidence of a link between the properties of the broad emission line region and the infrared-emitting dusty regions in quasars., Comment: 11 pages, 6 figures, plus appendices. Accepted to MNRAS 10 Dec 2020

Binary supermassive black holes (BSBHs) are expected to be a generic byproduct from hierarchical galaxy formation. The final coalescence of BSBHs is thought to be the loudest gravitational wave (GW) siren, yet no confirmed BSBH is known in the GW-dominated regime. While periodic quasars have been proposed as BSBH candidates, the physical origin of the periodicity has been largely uncertain. Here we report discovery of a periodicity (P=1607$\pm$7 days) at 99.95% significance (with a global p-value of ~$10^{-3}$ accounting for the look elsewhere effect) in the optical light curves of a redshift 1.53 quasar, SDSS J025214.67-002813.7. Combining archival Sloan Digital Sky Survey data with new, sensitive imaging from the Dark Energy Survey, the total ~20-yr time baseline spans ~4.6 cycles of the observed 4.4-yr (restframe 1.7-yr) periodicity. The light curves are best fit by a bursty model predicted by hydrodynamic simulations of circumbinary accretion disks. The periodicity is likely caused by accretion rate modulation by a milli-parsec BSBH emitting GWs, dynamically coupled to the circumbinary accretion disk. A bursty hydrodynamic variability model is statistically preferred over a smooth, sinusoidal model expected from relativistic Doppler boost, a kinematic effect proposed for PG1302-102. Furthermore, the frequency dependence of the variability amplitudes disfavors Doppler boost, lending independent support to the circumbinary accretion variability hypothesis. Given our detection rate of one BSBH candidate from circumbinary accretion variability out of 625 quasars, it suggests that future large, sensitive synoptic surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time may be able to detect hundreds to thousands of candidate BSBHs from circumbinary accretion with direct implications for Laser Interferometer Space Antenna., Comment: Accepted to MNRAS, 17 pages, 9 figures

The size of the dust torus in Active Galactic Nuclei (AGN) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared (MIR) torus emission. This dust reverberation mapping (RM) technique has been successfully applied to $\sim 70$ $z\lesssim 0.3$ AGN and quasars. Here we present first results of our dust RM program for distant quasars covered in the SDSS Stripe 82 region combining $\sim 20$-yr ground-based optical light curves with 10-yr MIR light curves from the WISE satellite. We measure a high-fidelity lag between W1-band (3.4 $\mu$m) and $g$ band for 587 quasars over $0.3\lesssim z\lesssim 2$ ($\left\sim 0.8$) and two orders of magnitude in quasar luminosity. They tightly follow (intrinsic scatter $\sim 0.17$ dex in lag) the IR lag-luminosity relation observed for $z<0.3$ AGN, revealing a remarkable size-luminosity relation for the dust torus over more than four decades in AGN luminosity, with little dependence on additional quasar properties such as Eddington ratio and variability amplitude. This study motivates further investigations in the utility of dust RM for cosmology, and strongly endorses a compelling science case for the combined 10-yr Vera C. Rubin Observatory Legacy Survey of Space and Time (optical) and 5-yr Nancy Grace Roman Space Telescope 2$\mu$m light curves in a deep survey for low-redshift AGN dust RM with much lower luminosities and shorter, measurable IR lags. The compiled optical and MIR light curves for 7,384 quasars in our parent sample are made public with this work., Comment: Accepted for publication in ApJ

We present new 850$\mu$m SCUBA-2 observations for a sample of 19 heavily reddened Type-I quasars at redshifts $z\sim$2 with dust extinctions of A$_{\rm{V}} \simeq 2-6$ mag. Three of the 19 quasars are detected at $>$3$\sigma$ significance corresponding to an 850$\mu$m flux-limit of $\gtrsim$4.8 mJy. Assuming the 850$\mu$m flux is dominated by dust heating due to star formation, very high star formation rates (SFR) of $\sim$2500-4500 M$_\odot$ yr$^{-1}$ in the quasar host galaxies are inferred. Even when considering a large contribution to the 850$\mu$m flux from dust heated by the quasar itself, significant SFRs of $\sim$600-1500 M$_\odot$ yr$^{-1}$ are nevertheless inferred for two of the three detected quasars. We stack the remaining 16 heavily reddened quasars and derive an average 3$\sigma$ upper limit on the SFRs in these quasar host galaxies of $<$880 M$_\odot$ yr$^{-1}$. The number counts of sub-mm galaxies in the total survey area (134.3arcmin$^2$) are consistent with predictions from blank-field surveys. There are, however, individual quasars where we find evidence for an excess of associated sub-mm galaxies. For two quasars, higher spatial resolution and spectroscopic ALMA observations confirm the presence of an excess of sub-mm sources. We compare the 850$\mu$m detection rate of our quasars to both unobscured, ultraviolet luminous quasars as well as the much more obscured population of mid-infrared luminous Hot Dust Obscured Galaxies (HotDOGs). When matched by luminosity and redshift, we find no significant differences in the 850$\mu$m flux densities of these various quasar populations given the current small sample sizes., Comment: 11 pages, 9 figures, MNRAS Accepted

Using a sample of $\simeq$144,000 quasars from the Sloan Digital Sky Survey data release 14 we investigate the outflow properties, evident both in absorption and emission, of high-ionization Broad Absorption Line (BAL) and non-BAL quasars with redshifts 1.6 $\lesssim z \leq$ 3.5 and luminosities 45.3 $< \log_{10}(L_{bol}) < $ 48.2 erg s$^{-1}$. Key to the investigation is a continuum and emission-line reconstruction scheme, based on mean-field independent component analysis, that allows the kinematic properties of the CIV$\lambda$1550 emission line to be compared directly for both non-BAL and BAL quasars. CIV-emission blueshift and equivalent-width (EW) measurements are thus available for both populations. Comparisons of the emission-line and BAL-trough properties reveal strong systematic correlations between the emission and absorption properties. The dependence of quantitative outflow indicators on physical properties such as quasar luminosity and luminosity relative to Eddington-luminosity are also shown to be essentially identical for the BAL and non-BAL populations. There is an absence of BALs in quasars with the hardest spectral energy distributions (SEDs), revealed by the presence of strong HeII$\lambda$1640 emission, large CIV$\lambda$1550-emission EW and no measurable blueshift. In the remainder of the CIV-emission blueshift versus EW space, BAL and non-BAL quasars are present at all locations; for every BAL-quasar it is possible to identify non-BAL quasars with the same emission-line outflow properties and SED-hardness. The co-location of BAL and non-BAL quasars as a function of emission-line outflow and physical properties is the key result of our investigation, demonstrating that (high-ionization) BALs and non-BALs represent different views of the same underlying quasar population., Comment: 22 pages, 18 figures, plus Appendices. Minor changes to reflect published version in MNRAS

We present XMM-Newton X-ray observations and analysis of three DES $z>6.5$ quasars (VDES J0020$-$3653 at $z=6.824$, VDES J0244$-$5008 at $z=6.724$ and VDES J0224$-$4711 at $z=6.526$) and six other quasars with $6.438 < z < 6.747$ from the XMM-Newton public archive. Two of the nine quasars are detected at a high ($>$4$\sigma$) significance level: VDES J0224$-$4711(z=6.53) at $9\sigma$ and PSO J159$-$02 ($z=6.38$) at $8\sigma$. They have a photon index of $\Gamma=1.82^{+0.29}_{-0.27}$ and $\Gamma=1.94^{+0.31}_{-0.29}$ respectively, which is consistent with the mean value of $\sim1.9$ found for quasars at all redshifts. The rest-frame $2-10$ keV luminosity of VDES J0224$-$4711, is $L_{2-10\mathrm{keV}} = (2.92\pm0.43)\times10^{45}\;\mathrm{erg\;s^{-1}}$, which makes this quasar one of the most X-ray luminous quasars at $z>5.5$ and the most X-ray luminous quasar at $z>6.5$, with a luminosity 6 times and 2.5 times larger than ULAS J1120+0641 ($z=7.08$) and ULAS J1342+0928 ($z=7.54$) respectively. The X-ray-to-optical power-law slopes of the nine quasars are consistent with the previously observed anti-correlation of $\alpha_{ox}$ with UV luminosity $L_{2500\mathrm{\AA}}$. We find no evidence for evolution of $\alpha_{ox}$ with redshift when the anti-correlation with UV luminosity is taken into account. Similar to previous studies at z$\sim$6 we have found remarkably consistent X-ray spectral properties between low (z$\sim$1) and high-redshift quasars. Our results add further evidence to the picture that the observable properties of high luminosity quasars over the UV to X-ray spectral region have not evolved significantly from $z\sim7$ to the present day and that quasars comparable to local versions existed 800 million years after the big bang., Comment: 8 pages; resubmitted to MNRAS

Through the lens of the LSST Science Collaborations' experience, this paper advocates for new and improved ways to fund large, complex collaborations at the interface of data science and astrophysics as they work in preparation for and on peta-scale, complex surveys, of which LSST is a prime example. We advocate for the establishment of programs to support both research and infrastructure development that enables innovative collaborative research on such scales., Comment: White Paper submitted to the Astro2020 (The "2020 Decadal Survey") APC call for "State of the Profession Considerations"

We present VLT-SINFONI near infra-red spectra of 26 new heavily reddened quasar candidates selected from the UKIDSS-LAS, VISTA VHS and VIKING imaging surveys. This new sample extends our reddened quasar search to both brighter and fainter luminosities. 25 of the 26 candidates are confirmed to be broad line quasars with redshifts $0.72$. We present the first comparison of the [OIII] line properties in high luminosity obscured quasars to a large sample of 111 unobscured quasars in the same luminosity and redshift range. Broad wings extending to velocities of 2500 km/s are seen in the [OIII] emission line profiles of our reddened quasars, suggesting that strong outflows are affecting the ionised gas kinematics. However, we find no significant difference between the kinematics of the [OIII] emission in reddened and unobscured quasars when the two samples are matched in luminosity and redshift. Our results are consistent with a model where quasar-driven outflows persist for some time after the obscuring dust has been cleared from along the line of sight. Assuming the amount of ionised gas in obscured and unobscured quasars is similar, we use the equivalent width distribution of the [OIII] emission to constrain the location of the obscuring dust in our reddened quasars. We find that the dust is most likely to be located on galactic scales, outside the [OIII] emitting region., Comment: 12 pages, 7 figures, plus Appendices. Accepted for publication in MNRAS

We characterise ionised gas outflows using a large sample of ~330 high-luminosity (45.5 < log(L_bol/erg s^-1) < 49.0), high-redshift (1.5 < z < 4.0) quasars via their [OIII]4960,5008 emission. The median velocity width of the [OIII] emission line is 1540 kms^-1, increasing with increasing quasar luminosity. Broad, blue-shifted wings are seen in the [OIII] profiles of 42 per cent of the sample. Rest-frame ultraviolet spectra with well-characterised CIV 1550 emission line properties are available for more than 210 quasars, allowing an investigation of the relationship between the Broad Line Region (BLR) and Narrow Line Region (NLR) emission properties. The [OIII] blueshift is correlated with CIV blueshift, even when the dependence of both quantities on quasar luminosity has been taken into account. A strong anti-correlation between the [OIII] equivalent width (EW) and CIV blueshift also exists. Furthermore, [OIII] is very weak, with EW<1A, in ~10 per cent of the sample, a factor of 10 higher compared to quasars at lower luminosities and redshifts. If the [OIII] emission originates in an extended NLR, the observations suggest that quasar-driven winds are capable of influencing the host-galaxy environment out to kilo-parsec scales. The mean kinetic power of the ionised gas outflows is then 10^44.7 erg s^-1, which is ~0.15 per cent of the bolometric luminosity of the quasar. These outflow efficiencies are broadly consistent with those invoked in current active galactic nuclei feedback models., Comment: MNRAS in press

The Sloan Digital Sky Survey (SDSS) was revolutionary because of the extraordinary breadth and ambition of its optical imaging and spectroscopy. We argue that a 'sub-millimeter SDSS' - a sensitive large-area imaging+spectroscopic survey in the sub-mm window - will revolutionize our understanding of galaxy evolution in the early Universe. By detecting the thermal dust continuum emission and atomic and molecular line emission of galaxies out to z~10 it will be possible to measure the redshifts, star formation rates, dust and gas content of hundreds of thousands of high-z galaxies down to ~L*. Many of these galaxies will have counterparts visible in the deep optical imaging of the Large Synoptic Survey Telescope. This 3D map of galaxy evolution will span the peak epoch of galaxy formation all the way back to cosmic dawn, measuring the co-evolution of the star formation rate density and molecular gas content of galaxies, tracking the production of metals and charting the growth of large-scale structure., Comment: Science White paper submitted to the Astro2020 Decadal Survey

We present the discovery of a new $z \sim 6.8$ quasar discovered with the near-IR VISTA Hemisphere Survey (VHS) which has been spectroscopically confirmed by the ESO New Technology Telescope (NTT) and the Magellan telescope. This quasar has been selected by spectral energy distribution (SED) classification using near infrared data from VISTA, optical data from Pan-STARRS, and mid-IR data from WISE. The SED classification algorithm is used to statistically rank two classes; foreground Galactic low-mass stars and high redshift quasars, prior to spectroscopic observation. Forced photometry on Pan-STARRS pixels for VHS J0411-0907 allows to improve the SED classification reduced-$\chi^2$ and photometric redshift. VHS J0411-0907 ($z=6.82$, $y_{AB} = 20.1$ mag, $J_{AB} = 20.0$ mag) has the brightest J-band continuum magnitude of the nine known quasars at $z > 6.7$ and is currently the highest redshift quasar detected in the Pan-STARRS survey. This quasar has one of the lowest black hole mass ($M_{\rm{BH}}= (6.13 \pm 0.51)\times 10^8\:\mathrm{M_{\odot}}$) and the highest Eddington ratio ($2.37\pm0.22$) of the known quasars at $z>6.5$. The high Eddington ratio indicates that some very high-$z$ quasars are undergoing super Eddington accretion. We also present coefficients of the best polynomials fits for colours vs spectral type on the Pan-STARRS, VISTA and WISE system for MLT dwarfs and present a forecast for the expected numbers of quasars at $z>6.5$., Comment: 14 pages, accepted for publication by MNRAS

We study the interstellar medium (ISM) properties of three heavily reddened quasars at $z\sim2.5$ as well as three millimetre-bright companion galaxies near these quasars. New JVLA and ALMA observations constrain the CO(1-0), CO(7-6) and [CI]$^3$P$_2-^3$P$_1$ line emission as well as the far infrared to radio continuum. The gas excitation and physical properties of the ISM are constrained by comparing our observations to photo-dissociation region (PDR) models. The ISM in our high-redshift quasars is composed of very high-density, high-temperature gas which is already highly enriched in elements like carbon. One of our quasar hosts is shown to be a close-separation ($<$2 arcsec) major merger with different line emission properties in the millimeter-bright galaxy and quasar components. Low angular resolution observations of high-redshift quasars used to assess quasar excitation properties should therefore be interpreted with caution as they could potentially be averaging over multiple components with different ISM conditions. Our quasars and their companion galaxies show a range of CO excitation properties spanning the full extent from starburst-like to quasar-like spectral line energy distributions. We compare gas masses based on CO, CI and dust emission, and find that these can disagree when standard assumptions are made regarding the values of $\alpha_{\rm{CO}}$, the gas-to-dust ratio and the atomic carbon abundances. We conclude that the ISM properties of our quasars and their companion galaxies are diverse and likely vary spatially across the full extent of these complex, merging systems., Comment: Accepted for publication in MNRAS (18 pages, 10 figures and 5 tables)

Quasars may have played a key role in limiting the stellar mass of massive galaxies. Identifying those quasars in the process of removing star formation fuel from their hosts is an exciting ongoing challenge in extragalactic astronomy. In this paper we present X-ray observations of eleven extremely red quasars (ERQs) with $L_{\rm bol}\sim 10^{47}$ erg s$^{-1}$ at $z=1.5-3.2$ with evidence for high-velocity ($v > 1000$ km s$^{-1}$) [OIII]$\lambda$5007\AA\ outflows. X-rays allow us to directly probe circumnuclear obscuration and to measure the instantaneous accretion luminosity. We detect ten out of eleven extremely red quasars available in targeted and archival data. Using a combination of X-ray spectral fitting and hardness ratios, we find that all of the ERQs show signs of absorption in the X-rays with inferred column densities of $N_{\rm H}\approx 10^{23}$ cm$^{-2}$, including four Compton-thick candidates ($N_{\rm H} > 10^{24}$ cm$^{-2}$). We stack the X-ray emission of the seven weakly detected sources, measuring an average column density of $N_{\rm H}\sim 8\times 10^{23}$ cm$^{-2}$. The absorption-corrected (intrinsic) $2-10$ keV X-ray luminosity of the stack is $2.7\times 10^{45}$ erg s$^{-1}$, consistent with X-ray luminosities of type 1 quasars of the same infrared luminosity. Thus, we find that ERQs are a highly obscured, borderline Compton-thick population, and based on optical and infrared data we suggest that these objects are partially hidden by their own equatorial outflows. However, unlike some quasars with known outflows, ERQs do not appear to be intrinsically underluminous in X-rays for their bolometric luminosity. Our observations indicate that low X-rays are not necessary to enable some types of radiatively driven winds., Comment: 16 pages, 6 figures, 2 tables. Re-submitted to ApJ following referee's comments

The Large Synoptic Survey Telescope (LSST) will enable revolutionary studies of galaxies, dark matter, and black holes over cosmic time. The LSST Galaxies Science Collaboration has identified a host of preparatory research tasks required to leverage fully the LSST dataset for extragalactic science beyond the study of dark energy. This Galaxies Science Roadmap provides a brief introduction to critical extragalactic science to be conducted ahead of LSST operations, and a detailed list of preparatory science tasks including the motivation, activities, and deliverables associated with each. The Galaxies Science Roadmap will serve as a guiding document for researchers interested in conducting extragalactic science in anticipation of the forthcoming LSST era., Comment: For more information, see https://galaxies.science.lsst.org

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey (SDSS) and 3-Year Dark Energy Survey (DES) imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum g band magnitude change of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L_bol~10^45-10^47 erg/s and L/L_Edd~0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30-50% among all g<~22 quasars over a baseline of ~15 years. These EVQs are good candidates for so-called "changing-look quasars", where a spectral transition between the two types of quasars (broad-line and narrow-line) is observed between the dim and bright states. We performed detailed multi-wavelength, spectral and variability analyses for the EVQs and compared to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggest that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low accretion rates, where the accretion flow is more likely to experience instabilities that drive the factor of few changes in flux on multi-year timescales., Comment: submitted to ApJ; comments welcome

The CIV broad emission line is visible in optical spectra to redshifts exceeding z~5. CIV has long been known to exhibit significant displacements to the blue and these `blueshifts' almost certainly signal the presence of strong outflows. As a consequence, single-epoch virial black hole (BH) mass estimates derived from CIV velocity-widths are known to be systematically biased compared to masses from the hydrogen Balmer lines. Using a large sample of 230 high-luminosity (log $L_{\rm Bol}$ = 45.5-48 erg/s), redshift 1.55000 km/s. Using the monotonically increasing relationship between the CIV blueshift and the mass ratio BH(CIV)/BH(H$\alpha$) we derive an empirical correction to all CIV BH-masses. The scatter between the corrected CIV masses and the Balmer masses is 0.24 dex at low CIV blueshifts (~0 km/s) and just 0.10 dex at high blueshifts (~3000 km/s), compared to 0.40 dex before the correction. The correction depends only on the CIV line properties - i.e. full-width at half maximum and blueshift - and can therefore be applied to all quasars where CIV emission line properties have been measured, enabling the derivation of un-biased virial BH mass estimates for the majority of high-luminosity, high-redshift, spectroscopically confirmed quasars in the literature., Comment: Accepted for publication in MNRAS; fixed typo in CIV wavelength

We present ALMA observations of cold dust and molecular gas in four high-luminosity, heavily reddened (A$_{\rm{V}} \sim 2.5-6$ mag) Type 1 quasars at $z\sim2.5$ with virial M$_{\rm{BH}} \sim 10^{10}$M$_\odot$, to test whether dusty, massive quasars represent the evolutionary link between submillimetre bright galaxies (SMGs) and unobscured quasars. All four quasars are detected in both the dust continuum and in the $^{12}$CO(3-2) line. The mean dust mass is 6$\times$10$^{8}$M$_\odot$ assuming a typical high redshift quasar spectral energy distribution (T=41K, $\beta$=1.95 or T=47K, $\beta$=1.6). The implied star formation rates are very high - $\gtrsim$1000 M$_\odot$ yr$^{-1}$ in all cases. Gas masses estimated from the CO line luminosities cover $\sim$1-5$\times10^{10}$($\alpha_{\rm{CO}} / 0.8$)M$_\odot$ and the gas depletion timescales are very short - $\sim5-20$Myr. A range of gas-to-dust ratios is observed in the sample. We resolve the molecular gas in one quasar - ULASJ2315$+$0143 ($z=2.561$) - which shows a strong velocity gradient over $\sim$20 kpc. The velocity field is consistent with a rotationally supported gas disk but other scenarios, e.g. mergers, cannot be ruled out at the current resolution of these data. In another quasar - ULASJ1234+0907 ($z=2.503$) - we detected molecular line emission from two millimetre bright galaxies within 200 kpc of the quasar, suggesting that this quasar resides in a significant over-density. The high detection rate of both cold dust and molecular gas in these sources, suggests that reddened quasars could correspond to an early phase in massive galaxy formation associated with large gas reservoirs and significant star formation., Comment: MNRAS Accepted; Very minor changes to match accepted version

We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift $z_{s}=2.74$ and image separation of $2.9"$ lensed by a foreground $z_{l}=0.40$ elliptical galaxy. Since the images of gravitationally lensed quasars are the superposition of multiple point sources and a foreground lensing galaxy, we have developed a morphology independent multi-wavelength approach to the photometric selection of lensed quasar candidates based on Gaussian Mixture Models (GMM) supervised machine learning. Using this technique and $gi$ multicolour photometric observations from the Dark Energy Survey (DES), near IR $JK$ photometry from the VISTA Hemisphere Survey (VHS) and WISE mid IR photometry, we have identified a candidate system with two catalogue components with $i_{AB}=18.61$ and $i_{AB}=20.44$ comprised of an elliptical galaxy and two blue point sources. Spectroscopic follow-up with NTT and the use of an archival AAT spectrum show that the point sources can be identified as a lensed quasar with an emission line redshift of $z=2.739\pm0.003$ and a foreground early type galaxy with $z=0.400\pm0.002$. We model the system as a single isothermal ellipsoid and find the Einstein radius $\theta_E \sim 1.47"$, enclosed mass $M_{enc} \sim 4 \times 10^{11}$M$_{\odot}$ and a time delay of $\sim$52 days. The relatively wide separation, month scale time delay duration and high redshift make this an ideal system for constraining the expansion rate beyond a redshift of 1., Comment: 11 pages, 7 figures, 7 tables, MNRAS accepted

Black-hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z > 2.1, black hole masses are normally derived using the velocity-width of the CIV broad emission line, based on the assumption that the observed velocity-widths arise from virial-induced motions. In many quasars, the CIV-emission line exhibits significant blue asymmetries (`blueshifts') with the line centroid displaced by up to thousands of km/s to the blue. These blueshifts almost certainly signal the presence of strong outflows, most likely originating in a disc wind. We have obtained near-infrared spectra, including the H$\alpha$ emission line, for 19 luminous ($L_{Bol}$ = 46.5-47.5 erg/s) Sloan Digital Sky Survey quasars, at redshifts 2 < z < 2.7, with CIV emission lines spanning the full-range of blueshifts present in the population. A strong correlation between CIV-velocity width and blueshift is found and, at large blueshifts, > 2000 km/s, the velocity-widths appear to be dominated by non-virial motions. Black-hole masses, based on the full width at half maximum of the CIV-emission line, can be overestimated by a factor of five at large blueshifts. A larger sample of quasar spectra with both CIV and H$\beta$, or H$\alpha$, emission lines will allow quantitative corrections to CIV-based black-hole masses as a function of blueshift to be derived. We find that quasars with large CIV blueshifts possess high Eddington luminosity ratios and that the fraction of high-blueshift quasars in a flux-limited sample is enhanced by a factor of approximately four relative to a sample limited by black hole mass., Comment: Accepted for publication in MNRAS (21 pages, 11 figures, 4 tables)

We present the discovery of a z=0.65 low-ionization broad absorption line (LoBAL) quasar in a post-starburst galaxy in data from the Dark Energy Survey (DES) and spectroscopy from the Australian Dark Energy Survey (OzDES). LoBAL quasars are a minority of all BALs, and rarer still is that this object also exhibits broad FeII (an FeLoBAL) and Balmer absorption. This is the first BAL quasar that has signatures of recently truncated star formation, which we estimate ended about 40 Myr ago. The characteristic signatures of an FeLoBAL require high column densities, which could be explained by the emergence of a young quasar from an early, dust-enshrouded phase, or by clouds compressed by a blast wave. The age of the starburst component is comparable to estimates of the lifetime of quasars, so if we assume the quasar activity is related to the truncation of the star formation, this object is better explained by the blast wave scenario., Comment: 7 pages, 4 figures, and 1 table; Submitted to MNRAS. For a brief video summarizing the paper, please see the Coffee Brief at this link: https://www.youtube.com/watch?v=jLhHSFU9u3g&feature=youtu.be Authors updated!

We use near infrared integral field unit (IFU) spectroscopy to search for H$\alpha$ emission associated with star formation in a sample of 28 heavily reddened ($E(B-V)\simeq$0.5-1.9), hyperluminous ($log(L_{bol}/ergs^{-1})\simeq$47-48) broad-line quasars at $z\simeq$1.4-2.7. Sixteen of the 28 quasars show evidence for star formation with an average extinction-corrected star formation rate (SFR) of 320$\pm$70M$_\odot$yr$^{-1}$. A stacked spectrum of the detections shows weak [NII], consistent with star formation as the origin of the narrow H$\alpha$ emission. The star-forming regions are spatially unresolved in 11 of the 16 detections and constrained to lie within $\sim$6kpc of the quasar emission. In the five resolved detections we find the star-forming regions are extended on scales of $\sim$8kpc around the quasar emission. The prevalence of high SFRs is consistent with the identification of the heavily reddened quasar population as representing a transitional phase from apparent `starburst galaxies' to optically-luminous quasars. Upper limits are determined for 10 quasars in which star formation is undetected. In two of the quasars the SFR is constrained to be relatively modest, $<$50M$_\odot$yr$^{-1}$, but significantly higher levels of star formation could be present in the other eight quasars. The combination of the 16 strong star formation detections and the eight high SFR limits means that high levels of star formation may be present in the majority of the sample. Higher spatial resolution data, of multiple emission lines, will allow us to better understand the interplay between star formation and Active Galactic Nucleus (AGN) activity in these transitioning quasars., Comment: 20 pages, 26 figures, accepted for publication in MNRAS

We study the 850um emission in X-ray selected AGN in the 2 sq-deg COSMOS field using new data from the SCUBA-2 Cosmology Legacy Survey. We find 19 850um bright X-ray AGN in a high-sensitivity region covering 0.89 sq-deg with flux densities of S850=4-10 mJy. The 19 AGN span the full range in redshift and hard X-ray luminosity covered by the sample - 0.71 X-ray AGN - S850=0.71+/-0.08mJy. We explore trends in the stacked 850um flux densities with redshift, finding no evolution in the average cold dust emission over the redshift range probed. For Type 1 AGN, there is no significant correlation between the stacked 850um flux and hard X-ray luminosity. However, in Type 2 AGN the stacked submm flux is a factor of 2 higher at high luminosities. When averaging over all X-ray luminosities, no significant differences are found in the stacked submm fluxes of Type 1 and Type 2 AGN as well as AGN separated on the basis of X-ray hardness ratios and optical-to-infrared colours. However, at log10(LX) >44.4, dependences in average submm flux on the optical-to-infrared colours become more pronounced. We argue that these high luminosity AGN represent a transition from a secular to a merger-driven evolutionary phase where the star formation rates and accretion luminosities are more tightly coupled. Stacked AGN 850um fluxes are compared to the stacked fluxes of a mass-matched sample of K-band selected non-AGN galaxies. We find that at 10.5

We present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry and extended morphology in DES images. Images of DES J0115-5244 show two blue point sources at either side of a red galaxy. Our long-slit data confirm that both point sources are images of the same quasar at $z_{s}=1.64.$ The Einstein Radius estimated from the DES images is $0.51$". DES J2200+0110 is in the area of overlap between DES and the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fiber spectrum shows a quasar component at $z_{s}=2.38$ and absorption compatible with Mg II and Fe II at $z_{l}=0.799$, which we tentatively associate with the foreground lens galaxy. The long-slit Magellan spectra show that the blue components are resolved images of the same quasar. The Einstein Radius is $0.68$" corresponding to an enclosed mass of $1.6\times10^{11}\,M_{\odot}.$ Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data-mining and model-based selection that is being applied to the entire DES dataset., Comment: 7 pages, 1 figure, 2 tables, MNRAS subm. This paper includes data gathered with the 6.5m Baade Telescopes located at Las Campanas Observatory, Chile. This paper has gone through internal review by the DES collaboration, FERMILAB-PUB-15-341-AE

As part of the OzDES spectroscopic survey we are carrying out a large scale reverberation mapping study of $\sim$500 quasars over five years in the 30 deg$^2$ area of the Dark Energy Survey (DES) supernova fields. These quasars have redshifts ranging up to 4 and have apparent AB magnitudes between $16.8

We present a new population of z>2 dust-reddened, Type 1 quasars with 0.510^{13}L_0), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different H$\alpha$ equivalent widths relative to unobscured quasars. The average black-hole masses (~10^9-10^10 M_0) and bolometric luminosities (~10^{47} erg/s) are comparable to the most luminous unobscured quasars at the same redshift, but with a tail extending to very high luminosities of ~10^{48} erg/s. Sixty-six per cent of the reddened quasars are detected at $>3\sigma$ at 22um by WISE. The average 6um rest-frame luminosity is log10(L6um/erg/s)=47.1+/-0.4, making the objects among the mid-infrared brightest AGN currently known. The extinction-corrected space-density estimate now extends over three magnitudes (-30 < M_i < -27) and demonstrates that the reddened quasar luminosity function is significantly flatter than that of the unobscured quasar population at z=2-3. At the brightest magnitudes, M_i < -29, the space density of our dust-reddened population exceeds that of unobscured quasars. A model where the probability that a quasar becomes dust-reddened increases at high luminosity is consistent with the observations and such a dependence could be explained by an increase in luminosity and extinction during AGN-fuelling phases. The properties of our obscured Type 1 quasars are distinct from the heavily obscured, Compton-thick AGN that have been identified at much fainter luminosities and we conclude that they likely correspond to a brief evolutionary phase in massive galaxy formation., Comment: 16 pages, 9 figures (+ 2 appendices), Accepted for publication in MNRAS

We present the combination of optical data from the Science Verification phase of the Dark Energy Survey (DES) with near infrared data from the ESO VISTA Hemisphere Survey (VHS). The deep optical detections from DES are used to extract fluxes and associated errors from the shallower VHS data. Joint 7-band ($grizYJK$) photometric catalogues are produced in a single 3 sq-deg DECam field centred at 02h26m$-$04d36m where the availability of ancillary multi-wavelength photometry and spectroscopy allows us to test the data quality. Dual photometry increases the number of DES galaxies with measured VHS fluxes by a factor of $\sim$4.5 relative to a simple catalogue level matching and results in a $\sim$1.5 mag increase in the 80\% completeness limit of the NIR data. Almost 70\% of DES sources have useful NIR flux measurements in this initial catalogue. Photometric redshifts are estimated for a subset of galaxies with spectroscopic redshifts and initial results, although currently limited by small number statistics, indicate that the VHS data can help reduce the photometric redshift scatter at both $z<0.5$ and $z>1$. We present example DES+VHS colour selection criteria for high redshift Luminous Red Galaxies (LRGs) at $z\sim0.7$ as well as luminous quasars. Using spectroscopic observations in this field we show that the additional VHS fluxes enable a cleaner selection of both populations with $<$10\% contamination from galactic stars in the case of spectroscopically confirmed quasars and $<0.5\%$ contamination from galactic stars in the case of spectroscopically confirmed LRGs. The combined DES+VHS dataset, which will eventually cover almost 5000 sq-deg, will therefore enable a range of new science and be ideally suited for target selection for future wide-field spectroscopic surveys., Comment: 18 pages, 11 figures, Accepted for publication in MNRAS

We present Herschel and XMM-Newton observations of ULASJ1234+0907 ($z=2.503$), the reddest broad-line Type 1 quasar currently known with (i-K)>7.1. Herschel observations indicate that the quasar host is a hyperluminous infrared galaxy (HyLIRG) with a total infrared luminosity of log10(LIR/L0)=13.90+/-0.02. A greybody fit gives a dust temperature of Td=60+/-3K assuming an emissivity index of beta=1.5, considerably higher than in submillimeter bright galaxies observed at similar redshifts. The star formation rate is estimated to be >2000M0/yr even accounting for a significant contribution from an AGN component to the total infrared luminosity or requiring that only the far infra-red luminosity is powered by a starburst. XMM-Newton observations constrain the hard X-ray luminosity to be L(2-10keV)=1.3e45 erg/s putting ULASJ1234+0907 among the brightest X-ray quasars known. Through very deep optical and near infra-red imaging of the field at sub-arcsecond seeing, we demonstrate that despite its extreme luminosity, it is highly unlikely that ULASJ1234+0907 is being lensed. We measure a neutral hydrogen column density of NH=9e21/cm^2 corresponding to AV~6 mags. The observed properties of ULASJ1234+0907 - high luminosity and Eddington ratio, broad lines, moderate column densities and significant infra-red emission from re-processed dust - are similar to those predicted by galaxy formation simulations for the AGN blowout phase. The high Eddington ratio combined with the presence of significant amounts of dust in this quasar, is expected to drive strong outflows due to the effects of radiation pressure on dust. We conclude that ULASJ1234+0907 is a prototype galaxy caught at the peak epoch of galaxy formation, which is transitioning from a starburst to optical quasar via a dusty quasar phase., Comment: 5 pages, 3 figures, 1 table, Resubmitted to MNRAS Letters following referee report

We characterise the stellar masses and star formation rates in a sample of almost 40000 spectroscopically confirmed UV luminous galaxies at 0.35sigma in the UKIDSS-LAS at all redshifts. An even more luminous subset of 15% are also detected in the WISE 3.4 and 4.6um bands. We compute stellar masses for this very large sample of extremely blue galaxies and quantify the sensitivity of the stellar mass estimates to various assumptions made during the SED fitting. The median stellar masses are log10(M*/M0)=9.6\pm0.7, 10.2\pm0.5 and 10.4\pm0.4 for the IR-undetected, UKIDSS detected and UKIDSS+WISE detected galaxies respectively. We demonstrate that the inclusion of NIR photometry can lead to tighter constraints on the stellar masses. The mass estimates are found to be most sensitive to the inclusion of secondary bursts of star formation as well as changes in the stellar population synthesis models, both of which can lead to median discrepancies of the order of 0.3dex in the stellar masses. We find that the best-fit M/LK is significantly lower (by ~0.4 dex) than that predicted by simple optical colour based estimators, in particular for the bluer galaxies with younger best-fit ages. The WiggleZ galaxies have star formation rates of 3-10 M0/yr and mostly lie at the upper end of the main sequence of star-forming galaxies at these redshifts. Their rest-frame UV luminosities and stellar masses are comparable to both local compact UV-luminous galaxies as well as Lyman break galaxies at z~2-3.(abridged), Comment: 25 pages including two appendices, Accepted for publication in MNRAS

We present the first sample of spectroscopically confirmed heavily reddened broad-line quasars selected using the new near infra-red VISTA Hemisphere Survey and WISE All-Sky Survey. Observations of four candidates with (J-K)>2.5 and K<=16.5 over ~180 sq deg, leads to confirmation that two are highly dust-reddened broad-line Type 1 quasars at z~2. The typical dust extinctions are AV ~ 2-2.5 mags. We measure black-hole masses of ~10^9 M0 and extinction corrected bolometric luminosities of ~10^47 erg/s, making these among the brightest Type 1 quasars currently known. Despite this, these quasars lie well below the detection limits of wide-field optical surveys like the SDSS with iAB > 22. We also present WISE photometry at 3--22um, for our full sample of spectroscopically confirmed reddened quasars including those selected from the UKIDSS Large Area Survey (Banerji et al. 2012a). We demonstrate that the rest-frame infrared SEDs of these reddened quasars are similar to UV-luminous Type 1 quasars with significant hot dust emission and starburst quasar hosts like Mrk231. The average 12um flux density of our reddened quasars is similar to that of the recently discovered HyLIRG WISE1814+3412 (z=2.452) at similar redshifts, with two of our reddened quasars also having comparable 22um flux densities to this extreme HyLIRG. These optically faint, heavily reddened broad-line quasars are therefore among the most mid infrared luminous galaxies at z~2, now being discovered using WISE., Comment: 5 pages, MNRAS Letters, in press, Full photometric catalogue available in online version of manuscript and at http://www.ast.cam.ac.uk/~mbanerji/VHSWISE/redqso_vhs_wise_photom.pdf

The 4MOST consortium is currently halfway through a Conceptual Design study for ESO with the aim to develop a wide-field (>3 square degree, goal >5 square degree), high-multiplex (>1500 fibres, goal 3000 fibres) spectroscopic survey facility for an ESO 4m-class telescope (VISTA). 4MOST will run permanently on the telescope to perform a 5 year public survey yielding more than 20 million spectra at resolution R~5000 ({\lambda}=390-1000 nm) and more than 2 million spectra at R~20,000 (395-456.5 nm & 587-673 nm). The 4MOST design is especially intended to complement three key all-sky, space-based observatories of prime European interest: Gaia, eROSITA and Euclid. Initial design and performance estimates for the wide-field corrector concepts are presented. We consider two fibre positioner concepts, a well-known Phi-Theta system and a new R-Theta concept with a large patrol area. The spectrographs are fixed configuration two-arm spectrographs, with dedicated spectrographs for the high- and low-resolution. A full facility simulator is being developed to guide trade-off decisions regarding the optimal field-of-view, number of fibres needed, and the relative fraction of high-to-low resolution fibres. Mock catalogues with template spectra from seven Design Reference Surveys are simulated to verify the science requirements of 4MOST. The 4MOST consortium aims to deliver the full 4MOST facility by the end of 2018 and start delivering high-level data products for both consortium and ESO community targets a year later with yearly increments., Comment: To appear in the proceedings of the SPIE Astronomical Instrumentation + Telescopes conference, Amsterdam, 2012. 15 pages, 16 figures

We present a new sample of purely near infra-red selected KVega<16.5 extremely red ((J-K)>2.5) quasar candidates at z~2 from 900 sq deg of data in the UKIDSS Large Area Survey (LAS). Five of these are spectroscopically confirmed to be heavily reddened Type 1 AGN with broad emission lines bringing our total sample of reddened quasars from the UKIDSS-LAS to 12 at z=1.4-2.7. At these redshifts, Ha (6563A) is in the K-band. However, the mean Ha equivalent width of the reddened quasars is only ten per cent larger than that of the optically selected population and cannot explain the extreme colours. Instead, dust extinction of Av~2-6 mags is required to reproduce the continuum colours of our sources. This is comparable to the dust extinctions seen in submillimetre galaxies at similar redshifts. We argue that the AGN are likely being observed in a relatively short-lived breakout phase when they are expelling gas and dust following a massive starburst, subsequently turning into UV-luminous quasars. Some of our quasars show direct evidence for strong outflows (v~800-1000 km/s) affecting the Ha line consistent with this scenario. We predict that a larger fraction of reddened quasar hosts are likely to be submillimetre bright compared to the UV-luminous quasar population. We use our sample to place new constraints on the fraction of obscured Type 1 AGN likely to be missed in optical surveys. Taken at face-value our findings suggest that the obscured fraction depends on quasar luminosity. The space density of obscured quasars is ~5x that inferred for UV-bright quasars from the SDSS luminosity function at Mi<-30 but seems to drop at lower luminosities even accounting for various sources of incompleteness in our sample (abridged)., Comment: 18 pages, 10 figures, Accepted for publication in MNRAS

We present a spectroscopic catalogue of 40 luminous starburst galaxies at z=0.7--1.7 (median z=1.3). 19 of these are submillimetre galaxies (SMGs) and 21 are submillimetre-faint radio galaxies (SFRGs). This sample helps to fill in the redshift desert at z=1.2--1.7 in previous studies as well as probing a lower luminosity population of galaxies. Radio fluxes are used to determine star-formation rates for our sample which range from around 50 to 500 M$_\odot$ yr$^{-1}$ and are generally lower than those in z$\sim$2 SMGs. We identify nebular [OII] 3727 emission in the rest-UV spectra and use the linewidths to show that SMGs and SFRGs in our sample have larger linewidths and therefore dynamical masses than optically selected star-forming galaxies at similar redshifts. The linewidths are indistinguishable from those measured in the z$\sim$2 SMG populations suggesting little evolution in the dynamical masses of the galaxies between redshift 1--2. [NeV] and [NeIII] emission lines are identified in a subset of the spectra indicating the presence of an active galactic nucleus (AGN). In addition, a host of interstellar absorption lines corresponding to transitions of MgII and FeII ions are also detected. These features show up prominently in composite spectra and we use these composites to demonstrate that the absorption lines are present at an average blueshift of $-240\pm$50 kms$^{-1}$ relative to the systemic velocities of the galaxies derived from [OII]. This indicates the presence of large-scale outflowing interstellar gas in these systems (Abridged), Comment: Accepted for publication in MNRAS

A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwave background experiments. The Herschel-SPIRE Legacy Survey (HSLS), will lead to imaging data over 4000 sq. degrees at 250, 350, and 500 micron. Major Goals of HSLS are: (a) produce a catalog of 2.5 to 3 million galaxies down to 26, 27 and 33 mJy (50% completeness; 5 sigma confusion noise) at 250, 350 and 500 micron, respectively, in the southern hemisphere (3000 sq. degrees) and in an equatorial strip (1000 sq. degrees), areas which have extensive multi-wavelength coverage and are easily accessible from ALMA. Two thirds of the of the sources are expected to be at z > 1, one third at z > 2 and about a 1000 at z > 5. (b) Remove point source confusion in secondary anisotropy studies with Planck and ground-based CMB data. (c) Find at least 1200 strongly lensed bright sub-mm sources leading to a 2% test of general relativity. (d) Identify 200 proto-cluster regions at z of 2 and perform an unbiased study of the environmental dependence of star formation. (e) Perform an unbiased survey for star formation and dust at high Galactic latitude and make a census of debris disks and dust around AGB stars and white dwarfs., Comment: White paper supplement to the proposal submitted by the HSLS science team to ESA for Herschel open-time programs

We present an analysis of the evolution of 8625 Luminous Red Galaxies between z = 0.4 and z = 0.8 in the 2dF and SDSS LRG and QSO (2SLAQ) survey. The LRGs are split into redshift bins and the evolution of both the luminosity and stellar mass function with redshift is considered and compared to the assumptions of a passive evolution scenario. We draw attention to several sources of systematic error that could bias the evolutionary predictions made in this paper. While the inferred evolution is found to be relatively unaffected by the exact choice of spectral evolution model used to compute K+e corrections, we conclude that photometric errors could be a source of significant bias in colour-selected samples such as this, in particular when using parametric maximum likelihood based estimators. We find that the evolution of the most massive LRGs is consistent with the assumptions of passive evolution and that the stellar mass assembly of the LRGs is largely complete by z ~ 0.8. Our findings suggest that massive galaxies with stellar masses above 10^11 solar masses must have undergone merging and star formation processes at a very early stage (z > 1). This supports the emerging picture of downsizing in both the star formation as well as the mass assembly of early type galaxies. Given that our spectroscopic sample covers an unprecedentedly large volume and probes the most massive end of the galaxy mass function, we find that these observational results present a significant challenge for many current models of galaxy formation, Comment: 17 pages, 15 figures, Accepted for publication in MNRAS, Some changes to match accepted version