Hyper-luminous Reddened Broad-Line Quasars at z~2 from the VISTA Hemisphere Survey and WISE All Sky Survey

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.pd

Cold Gas Outflows, Feedback, and the Shaping of Galaxies

There is wide consensus that galaxy outflows are one of the most important processes determining the evolution of galaxies through cosmic time, for example playing a key role in shaping the galaxy mass function. Our understanding of outflows and their drivers, however, is in its infancy --- this is particularly true for the cold (neutral atomic and molecular) phases of outflows, which present observational and modeling challenges. Here we outline several key open questions, briefly discussing the requirements of the observations necessary to make progress, and the relevance of several existing and planned facilities. It is clear that galaxy outflows, and particularly cold outflows, will remain a topic of active research for the next decade and beyond

Integration of Two Diploid Potato Linkage Maps with the Potato Genome Sequence

To facilitate genome-guided breeding in potato, we developed an 8303 Single Nucleotide Polymorphism (SNP) marker array using potato genome and transcriptome resources. To validate the Infinium 8303 Potato Array, we developed linkage maps from two diploid populations (DRH and D84) and compared these maps with the assembled potato genome sequence. Both populations used the doubled monoploid reference genotype DM1-3 516 R44 as the female parent but had different heterozygous diploid male parents (RH89-039-16 and 84SD22). Over 4,400 markers were mapped (1,960 in DRH and 2,454 in D84, 787 in common) resulting in map sizes of 965 (DRH) and 792 (D84) cM, covering 87% (DRH) and 88% (D84) of genome sequence length. Of the mapped markers, 33.5% were in candidate genes selected for the array, 4.5% were markers from existing genetic maps, and 61% were selected based on distribution across the genome. Markers with distorted segregation ratios occurred in blocks in both linkage maps, accounting for 4% (DRH) and 9% (D84) of mapped markers. Markers with distorted segregation ratios were unique to each population with blocks on chromosomes 9 and 12 in DRH and 3, 4, 6 and 8 in D84. Chromosome assignment of markers based on linkage mapping differed from sequence alignment with the Potato Genome Sequencing Consortium (PGSC) pseudomolecules for 1% of the mapped markers with some disconcordant markers attributable to paralogs. In total, 126 (DRH) and 226 (D84) mapped markers were not anchored to the pseudomolecules and provide new scaffold anchoring data to improve the potato genome assembly. The high degree of concordance between the linkage maps and the pseudomolecules demonstrates both the quality of the potato genome sequence and the functionality of the Infinium 8303 Potato Array. The broad genome coverage of the Infinium 8303 Potato Array compared to other marker sets will enable numerous downstream applications

A population of luminous accreting black holes with hidden mergers

Major galaxy mergers are thought to play an important part in fuelling the growth of supermassive black holes. However, observational support for this hypothesis is mixed, with some studies showing a correlation between merging galaxies and luminous quasars and others showing no such association. Recent observations have shown that a black hole is likely to become heavily obscured behind merger-driven gas and dust, even in the early stages of the merger, when the galaxies are well separated (5 to 40 kiloparsecs). Merger simulations further suggest that such obscuration and black-hole accretion peaks in the final merger stage, when the two galactic nuclei are closely separated (less than 3 kiloparsecs). Resolving this final stage requires a combination of high-spatial-resolution infrared imaging and high-sensitivity hard-X-ray observations to detect highly obscured sources. However, large numbers of obscured luminous accreting supermassive black holes have been recently detected nearby (distances below 250 megaparsecs) in X-ray observations. Here we report high-resolution infrared observations of hard-X-ray-selected black holes and the discovery of obscured nuclear mergers, the parent populations of supermassive-black-hole mergers. We find that obscured luminous black holes (bolometric luminosity higher than 2x10^44 ergs per second) show a significant (P<0.001) excess of late-stage nuclear mergers (17.6 per cent) compared to a sample of inactive galaxies with matching stellar masses and star formation rates (1.1 per cent), in agreement with theoretical predictions. Using hydrodynamic simulations, we confirm that the excess of nuclear mergers is indeed strongest for gas-rich major-merger hosts of obscured luminous black holes in this final stage.Comment: To appear in the 8 November 2018 issue of Nature. This is the authors' version of the wor

BAT AGN Spectroscopic Survey. XX. Molecular Gas in Nearby Hard-X-Ray-selected AGN Galaxies

We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01 10.5) tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies, with no evidence that AGN feedback affects the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (~5% versus 49%) compared to inactive galaxies. The likelihood of a given galaxy hosting an AGN (L_(bol) > 10⁴⁴ erg s⁻¹ ) increases by ~10–100 between a molecular gas mass of 10^(8.7) M_⊙ and 10^(10.2) M_⊙. AGN galaxies with a higher Eddington ratio (log(L/L_(Edd)) > −1.3) tend to have higher molecular gas masses and gas fractions. The log(N_H/ cm⁻² ) > 23.4) of AGN galaxies with higher column densities are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy-wide molecular gas. The significant average link of host-galaxy molecular gas supply to supermassive black hole (SMBH) growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties, and the redshift evolution of star formation and SMBH growth

The Role of Host Galaxy for the Environmental Dependence of Active Nuclei in Local Galaxies

We discuss the environment of local hard X-ray selected active galaxies, with reference to two independent group catalogues. We find that the fraction of these AGN in S0 host galaxies decreases strongly as a function of galaxy group size (halo mass) – which contrasts with the increasing fraction of galaxies of S0 type in denser environments. However, there is no evidence for an environmental dependence of AGN in spiral galaxies. Because most AGN are found in spiral galaxies, this dilutes the signature of environmental dependence for the population as a whole. We argue that the differing results for AGN in disc-dominated and bulge-dominated galaxies are related to the source of the gas fuelling the AGN, and so may also impact the luminosity function, duty cycle and obscuration. We find that there is a significant difference in the luminosity function for AGN in spiral and S0 galaxies, and tentative evidence for some difference in the fraction of obscured AGN

EROs found behind lensing clusters. II. Stellar populations and dust properties of optical dropout EROs and comparison with related objects

We determine the nature, redshift, stellar populations and dust properties of optically faint or non-detected extremely red objects (ERO) found from our survey of the lensing clusters A1835 and AC114. We perform SED fitting and use deep optical, HST, VLT, Spitzer data, and for some objects and sub-mm data. For most of the lensed EROs we find photometric redshifts showing a strong degeneracy between "low-z" (z~1-3) and high-z (z~6-7). Although formally best fits are often found at high-z, their resulting bright absolute magnitudes, the number density of these objects, and in some cases Spitzer photometry or longer wavelength observations, suggest strongly that all of these objects are at "low-z". The majority of these objects are best fitted with young (<~ 0.5-0.7 Gyr) and dusty starbursts. Indications for strong extinction, with A_V~2.4-4, are found in some objects. For dusty objects star formation rates (SFR) have been estimated from the bolometric luminosity determined after fitting of semi-empirical starburst, ERO, and ULIRG templates. Typically we find SFR~(1-18) Msun/yr. Again, SMMJ14009+0252 stands out as a LIRG with SFR 1000 Msun/yr. Concerning the comparison objects, we argue that the massive post-starburst z~6.5 galaxy candidate HUDF-J2 showing observed properties very similar to our EROs, is more likely a dusty starburst at z~2.3-2.6. This interpretation also naturally explains the observed 24 micron emission. Both empirically and from our SED fits we find that the IRAC selectec EROs from Yan et al (2004) show very similar properties to our lensed EROs. Reasonable fits are found for most of them with relatively young and dusty stellar populations.Comment: 18 pages, 17 figures, accepted for publication in Astronomy and Astrophysic