We present the first rest-frame UV population study of 17 heavily reddened, highluminosity (E(B-V) QSO 0.5; L bol > 10 46 ergs −1 ) broad-line quasars at 1.5 < z < 2.7. We combine the first year of deep, optical, ground-based observations from the Dark Energy Survey (DES) with the near infrared VISTA Hemisphere Survey (VHS) and UKIDSS Large Area Survey (ULAS) data, from which the reddened quasars were initially identified. We demonstrate that the significant dust reddening towards the quasar in our sample allows host galaxy emission to be detected at the restframe UV wavelengths probed by the DES photometry. By exploiting this reddening effect, we disentangle the quasar emission from that of the host galaxy via spectral energy distribution (SED) fitting. We find evidence for a relatively unobscured, starforming host galaxy in at least ten quasars, with a further three quasars exhibiting emission consistent with either star formation or scattered light. From the rest-frame UV emission, we derive instantaneous, dust-corrected star formation rates (SFRs) in the range 25 < SFR UV < 365 M yr −1 , with an average SFR UV = 130 ± 95 M yr −1 . We find a broad correlation between SFR UV and the bolometric quasar luminosity. Overall, our results show evidence for coeval star formation and black hole accretion occurring in luminous, reddened quasars at the peak epoch of galaxy formation.

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Abstract Low-ionisation broad absorption line quasars (LoBALs) mark an important, yet poorly understood, population of quasars showing direct evidence for energetic mass outflows. We outline a sample of 12 luminous (Lbol &gt;1046ergs−1) LoBALs at 2.0&lt;z&lt;2.5 - a key epoch in both star formation and black hole accretion, which have been imaged as part of a targeted program with the Herschel Spectral and Photometric Imaging REceiver (SPIRE). We present K-band NOTCam spectra for three of these targets, calculating their spectroscopic redshifts, black hole masses and bolometric luminosities, and increasing the total number of LoBAL targets in our sample with spectral information from five to eight. Based on FIR obeservations from Herschel SPIRE, we derive prolific SFRs ranging 740 - 2380M⊙yr−1 for the detected targets, consistent with LoBALs existing in an evolutionary phase associated with starburst activity. Furthermore, an upper limit of &lt;440M⊙yr−1 is derived for the non-detections, meaning moderate-to-high SFRs cannot be ruled out, even among the undetected targets. Indeed, we detect an enhancement in both the SFRs and FIR fluxes of LoBALs compared to HiBAL and non-BAL quasars, further supporting the evolutionary LoBAL paradigm. Despite this enhancement in SFR however, the environments of LoBALs appear entirely consistent with the general galaxy population at 2.0&lt;z&lt;2.5.

We present new 850µm SCUBA-2 observations for a sample of 19 heavily reddened Type-I quasars at redshifts z ∼2 with dust extinctions of A V 2 − 6 mag. Three of the 19 quasars are detected at >3σ significance corresponding to an 850µm flux-limit of 4.8 mJy. Assuming the 850µm flux is dominated by dust heating due to star formation, very high star formation rates (SFR) of ∼2500-4500 M yr −1 in the quasar host galaxies are inferred. Even when considering a large contribution to the 850µm flux from dust heated by the quasar itself, significant SFRs of ∼600-1500 M yr −1 are nevertheless inferred for two of the three detected quasars. We stack the remaining 16 heavily reddened quasars and derive an average 3σ upper limit on the SFRs in these quasar host galaxies of <880 M yr −1 . The number counts of sub-mm galaxies in the total survey area (134.3 arcmin 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 850µm 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 850µm flux densities of these various quasar populations given the current small sample sizes.