Abstract
We use the energy-balance code magphys to determine stellar and dust masses, and dust corrected star formation rates for over 200 000 GAMA galaxies, 170 000 G10-COSMOS galaxies, and 200 000 ...3D-HST galaxies. Our values agree well with previously reported measurements and constitute a representative and homogeneous data set spanning a broad range in stellar-mass (108–1012 M⊙), dust-mass (106–109 M⊙), and star formation rates (0.01–100 M⊙yr−1), and over a broad redshift range (0.0 < z < 5.0). We combine these data to measure the cosmic star formation history (CSFH), the stellar-mass density (SMD), and the dust-mass density (DMD) over a 12 Gyr timeline. The data mostly agree with previous estimates, where they exist, and provide a quasi-homogeneous data set using consistent mass and star formation estimators with consistent underlying assumptions over the full time range. As a consequence our formal errors are significantly reduced when compared to the historic literature. Integrating our CSFH we precisely reproduce the SMD
with an interstellar medium replenishment factor of 0.50 ± 0.07, consistent with our choice of Chabrier initial mass function plus some modest amount of stripped stellar mass. Exploring the cosmic dust density evolution, we find a gradual increase in dust density with lookback time. We build a simple phenomenological model from the CSFH to account for the dust-mass evolution, and infer two key conclusions: (1) For every unit of stellar mass which is formed 0.0065–0.004 units of dust mass is also formed. (2) Over the history of the Universe approximately 90–95 per cent of all dust formed has been destroyed and/or ejected.
We present the largest submillimeter images that have been made of the extragalactic sky. The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 660 deg2 with the PACS and ...SPIRE cameras in five photometric bands: 100, 160, 250, 350, and 500 m. In this paper we present the images from our two largest fields, which account for ∼75% of the survey. The first field is 180.1 deg2 in size, centered on the north Galactic pole (NGP), and the second is 317.6 deg2 in size, centered on the south Galactic pole. The NGP field serendipitously contains the Coma cluster. Over most (∼80%) of the images, the pixel noise, including both instrumental noise and confusion noise, is approximately 3.6, and 3.5 mJy pix−1 at 100 and 160 m, and 11.0, 11.1 and 12.3 mJy beam−1 at 250, 350 and 500 m, respectively, but reaches lower values in some parts of the images. If a matched filter is applied to optimize point-source detection, our total 1 map sensitivity is 5.7, 6.0, and 7.3 mJy at 250, 350, and 500 m, respectively. We describe the results of an investigation of the noise properties of the images. We make the most precise estimate of confusion in SPIRE maps to date, finding values of 3.12 0.07, 4.13 0.02, and 4.45 0.04 mJy beam−1 at 250, 350, and 500 m in our un-convolved maps. For PACS we find an estimate of the confusion noise in our fast-parallel observations of 4.23 and 4.62 mJy beam−1 at 100 and 160 m. Finally, we give recipes for using these images to carry out photometry, both for unresolved and extended sources.
Introduction & BackgroundFinancial transaction data are highly valuable sources of digital footprints data for behavioural and economic research, but to properly create impact we must closely ...consider their limitations. Financial institutions hold a wealth of consumer data with untapped potential for community intelligence. These datasets combine excellent coverage with extremely granular information on consumer finances, income and spending, yet these institutions face great challenges in leveraging this data for social good. Smart Data Foundry is a university-owned, non-profit organisation that facilitates safe access to these datasets for researchers and provides insights to enable government bodies to tackle today's major challenges including the cost-of-living crisis and climate change. Objectives & ApproachWe will explore the opportunities afforded by these datasets for social and economic research. For example, using pseudonymised individual consumer banking data from NatWest Group, we have developed metrics for understanding income volatility and economic insecurity in collaboration with the Joseph Rowntree Foundation. We can also use these data to study consumer spending patterns and responses to economic changes such as interest rate rises and the net zero transition. We will assess the limitations of the data including issues of representativeness, bias, and missing data, and describe methods and mitigations to account for these challenges. We also discuss the barriers to accessing this type of data, in both relationship development with data partners, and privacy and governance concerns. Relevance to Digital FootprintsIndividual level customer transaction data provides a rich and novel form of digital footprint for behavioural and economic analyses. Every point of income or expenditure is recorded in a uniquely valuable digital footprint by financial institutions. These can provide a variety of insights, such as responses to macroeconomic shocks across demographic sets, emerging areas of financial distress, and help us better understand the drivers and risks of financial vulnerability. In both its aggregated and individual form, the data can provide an additional layer of understanding for trends we may see in other data, such as health or administrative data. Conclusions & ImplicationsHaving addressed the challenges of data access and data quality, we demonstrate that consumer banking data is an incredibly valuable form of digital footprints data, capturing key information on consumer behaviour. We conclude with a call for further research to develop use cases of this data for social good.
Abstract
The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models. The Herschel surveys ...reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations – they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population.
In this work we present IRAM 30-m telescope observations of a sample of bulge-dominated galaxies with large dust lanes, which have had a recent minor merger. We find these galaxies are very gas rich, ...with H2 masses between 4 × 108 and 2 × 1010 M⊙. We use these molecular gas masses, combined with atomic gas masses from an accompanying paper, to calculate gas-to-dust and gas-to-stellar-mass ratios. The gas-to-dust ratios of our sample objects vary widely (between ≈50 and 750), suggesting many objects have low gas-phase metallicities, and thus that the gas has been accreted through a recent merger with a lower mass companion. We calculate the implied minor companion masses and gas fractions, finding a median predicted stellar mass ratio of ≈40:1. The minor companion likely had masses between ≈107 and 1010 M⊙. The implied merger mass ratios are consistent with the expectation for low-redshift gas-rich mergers from simulations. We then go on to present evidence that (no matter which star formation rate indicator is used) our sample objects have very low star formation efficiencies (star formation rate per unit gas mass), lower even than the early-type galaxies from ATLAS3D which already show a suppression. This suggests that minor mergers can actually suppress star formation activity. We discuss mechanisms that could cause such a suppression, include dynamical effects induced by the minor merger.
Amyloid beta-peptide (Abeta) is a major component of plaques in Alzheimer's disease, and formation of senile plaques has been suggested to originate from regions of neuronal membrane rich in ...gangliosides. Here we demonstrate using NMR on 15N-labelled Abeta-(1-40) and Abeta-(1-42) that the interaction with ganglioside G(M1) micelles is localized to the N-terminal region of the peptide, particularly residues His13 to Leu17, which become more helical when bound. The key interaction is with His13, which undergoes a G(M1)-specific conformational change. The sialic acid residue of the ganglioside headgroup is important for determining the nature of the conformational change. The isolated pentasaccharide headgroup of G(M1) is not bound, suggesting the need for a polyanionic surface. Binding to heparin confirms this suggestion, since binding is of similar affinity but does not produce the same conformational changes in the peptide. A comparison of Abeta-(1-40) and Abeta-(1-42) indicates that binding to G(M1) micelles is not related to oligomerization, which occurs at the C-terminal end. These results imply that binding to ganglioside micelles causes a transition from random coil to alpha-helix in the N-terminal region, leaving the C-terminal region unstructured.
Submillimeter galaxies (SMGs) at are luminous in the far-infrared, and have star formation rates, SFR, of hundreds to thousands of solar masses per year. However, it is unclear whether they are true ...analogs of local ULIRGs or whether the mode of their star formation is more similar to that in local disk galaxies. We target these questions by using Herschel-PACS to examine the conditions in the interstellar medium (ISM) in far-infrared luminous SMGs at -4. We present 70-160 m photometry and spectroscopy of the O iv26 m, Fe ii26 m, S iii33 m, Si ii34 m, O iii52 m, N iii57 m, and O i63 m fine-structure lines and the S(0) and S(1) hydrogen rotational lines in 13 lensed SMGs identified by their brightness in early Herschel data. Most of the 13 targets are not individually spectroscopically detected; we instead focus on stacking these spectra with observations of an additional 32 SMGs from the Herschel archive-representing a complete compilation of PACS spectroscopy of SMGs. We detect O i63 m, Si ii34 m, and N iii57 m at in the stacked spectra, determining that the average strengths of these lines relative to the far-IR continuum are , , and , respectively. Using the O iii52 m/N iii57 m emission line ratio, we show that SMGs have average gas-phase metallicities . By using PDR modeling and combining the new spectral measurements with integrated far-infrared fluxes and existing C ii158 m data, we show that SMGs have average gas densities, n, of and FUV field strengths, (in Habing units: ), consistent with both local ULIRGs and lower luminosity star-forming galaxies.
Interstellar dust in galaxies can be traced either through its extinction effects on the star light or through its thermal emission at infrared wavelengths. Recent radiative transfer studies of ...several nearby edge-on galaxies have found an apparent inconsistency in the dust energy balance: the radiative transfer models that successfully explain the optical extinction underestimate the observed fluxes by an average factor of 3. We investigate the dust energy balance for IC 4225 and NGC 5166, two edge-on spiral galaxies observed by the Herschel Space Observatory in the frame of the H-ATLAS survey. We start from models which were constrained from optical data and extend them to construct the entire spectral energy distribution of our galaxies. These predicted values are subsequently compared to the observed far-infrared fluxes. We find that including a young stellar population in the modelling is necessary as it plays a non-negligible part in the heating of the dust grains. While the modelling approach for both galaxies is nearly identical, we find two very different results. As is often seen in other edge-on spiral galaxies, the far-infrared emission of our radiative transfer model of IC 4225 underestimates the observed fluxes by a factor of about 3. For NGC 5166 on the other hand, we find that both the predicted spectral energy distribution as well as the simulated images match the observations particularly well. We explore possible reasons for this difference and conclude that it is unlikely that one single mechanism is the cause of the dust energy balance problem in spiral galaxies. We discuss the different approaches that can be considered in order to get a conclusive answer on the origin this discrepancy.
We investigate a sample of 40 local, main-sequence, edge-on disc galaxies using integral field spectroscopy with the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to ...understand the link between properties of the extraplanar gas and their host galaxies. The kinematics properties of the extraplanar gas, including velocity asymmetries and increased dispersion, are used to differentiate galaxies hosting large-scale galactic winds from those dominated by the extended diffuse ionized gas. We find rather that a spectrum of diffuse gas-dominated to wind-dominated galaxies exist. The wind-dominated galaxies span a wide range of star formation rates (...) across the whole stellar mass range of the sample (...). The wind galaxies also span a wide range in SFR surface densities (...) that is much lower than the canonical threshold of 0.1 ... The wind galaxies on average have higher SFR surface densities and higher H delta A values than those without strong wind signatures. The enhanced H delta A indicates that bursts of star formation in the recent past are necessary for driving large-scale galactic winds. We demonstrate with Sloan Digital Sky Survey data that galaxies with high SFR surface density have experienced bursts of star formation in the recent past. Our results imply that the galactic winds revealed in our study are indeed driven by bursts of star formation, and thus probing star formation in the time domain is crucial for finding and understanding galactic winds. (ProQuest: ... denotes formulae/symbols omitted.)
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