Evolution of Galaxy Star Formation and Metallicity: Impact on Double Compact Object Mergers

In this paper, we study the impact of different galaxy statistics and empirical metallicity scaling relations on the merging rates and properties of compact object binaries. Firstly, we analyze the similarities and differences of using the star formation rate functions versus stellar mass functions as galaxy statistics for the computation of cosmic star formation rate density. We then investigate the effects of adopting the Fundamental Metallicity Relation versus a classic Mass Metallicity Relation to assign metallicity to galaxies with given properties. We find that when the Fundamental Metallicity Relation is exploited, the bulk of the star formation occurs at relatively high metallicities, even at high redshift; the opposite holds when the Mass Metallicity Relation is employed, since in this case the metallicity at which most of the star formation takes place strongly decreases with redshift. We discuss the various reasons and possible biases giving rise to this discrepancy. Finally, we show the impact of these different astrophysical prescriptions on the merging rates and properties of compact object binaries; specifically, we present results for the redshift-dependent merging rates and for the chirp mass and time delay distributions of the merging binaries

The slippery slope of dust attenuation curves: Correlation of dust attenuation laws with star-to-dust compactness up to z = 4

Aims. We investigate dust attenuation of 122 heavily dust-obscured galaxies detected with the Atacama Large Millimeter Array (ALMA) and Herschel in the COSMOS field. We search for correlations between dust attenuation recipes and the variation of physical parameters, mainly the effective radii of galaxies, their star formation rates (SFR), and stellar masses, and aim to understand which of the commonly used laws best describes dust attenuation in dusty star-forming galaxies at high redshift. Methods. We make use of the extensive photometric coverage of the COSMOS data combined with highly-resolved dust continuum maps from ALMA. We use CIGALE to estimate various physical properties of these dusty objects, mainly their SFR, their stellar masses and their attenuation. We infer galaxy effective radii (Re) using GALFIT in the Y band of HSC and ALMA continuum maps. We use these radii to investigate the relative compactness of the dust continuum and the extension of the rest-frame UV/optical Re(y)/Re(ALMA). Results. We find that the physical parameters calculated from our models strongly depend on the assumption of dust attenuation curve. As expected, the most impacted parameter is the stellar mass, which leads to a change in the "starburstiness" of the objects. We find that taking into account the relative compactness of star-to-dust emission prior to SED fitting is crucial, especially when studying dust attenuation of dusty star-forming galaxies. Shallower attenuation curves did not show a clear preference of compactness with attenuation, while the Calzetti attenuation curve preferred comparable spatial extent of unattenuated stellar light and dust emission. The evolution of the Re(UV)/Re(ALMA) ratio with redshift peeks around the cosmic noon in our sample of DSFGs, showing that this compactness is correlated with the cosmic SFR density of these dusty sources.Comment: 18 pages, 13 figures, accepted for publication in A&A. Abstract abridged for arXiv submissio

Unveiling the nature of 11 dusty star-forming galaxies at the peak of cosmic star formation history

We present a panchromatic study of 11 (sub-)millimetre selected DSFGs with spectroscopically confirmed redshift (1.5 < zspec < 3) in the GOODS-S field, with the aim of constraining their astrophysical properties (e.g. age, stellar mass, dust, and gas content) and characterizing their role in the context of galaxy evolution. The multiwavelength coverage of GOODS-S, from X-rays to radio band, allow us to model galaxy SED by using cigale z with a novel approach, based on a physical motivated modelling of stellar light attenuation by dust. Median stellar mass (∼ 6.5 × 1010 M·) and SFR (∼ 241 M· yr-1) are consistent with galaxy main sequence at z ∼2. The galaxies are experiencing an intense and dusty burst of star formation (medianLIR ∼ 2 × 1012L·), with a median age of 750 Myr. The high median content of interstellar dust (Mdust ∼ 5 × 108 M·) suggests a rapid enrichment of the ISM (on time-scales ∼108 yr). We derived galaxy total and molecular gas content from CO spectroscopy and/or Rayleigh-Jeans dust continuum (1010 Mgas/M· 1011), depleted over a typical time-scale τdepl ∼200 Myr. X-ray and radio luminosities (LX = 1042-1044 erg s-1,L1.5, { m GHz}}=1030-C1 erg s-1,L 6, rm GHz=1029-C0 erg s-1) suggest that most of the galaxies hosts an accreting radio-silent/quiet SMBH. This evidence, along with their compact multiwavelength sizes (median rALMA ∼rVLA = 1.8 kpc, rHST = 2.3 kpc) measured from high-resolution imaging (θres 1 arcsec), indicates these objects as the high-z star-forming counterparts of massive quiescent galaxies, as predicted e.g. by the in situ scenario. Four objects show some signatures of a forthcoming/ongoing AGN feedback, which is thought to trigger the morphological transition from star-forming discs to ETGs

In pursuit of giants: I. The evolution of the dust-to-stellar mass ratio in distant dusty galaxies

The dust-to-stellar mass ratio (Mdust/M?) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of Mdust/M? with dierent physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z 5. Additionally, we interpret our findings with dierent models of dusty galaxy formation. We find that Mdust/M? evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is dierent for mainsequence galaxies than it is for starburst galaxies. In both galaxy populations, Mdust/M? increases until z 2, followed by a roughly flat trend towards higher redshifts, suggesting ecient dust growth in the distant universe. We confirm that the inverse relation between Mdust/M? and M? holds up to z 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the Mdust/M? in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of Mdust/M? in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high Mdust/M? is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using Mdust/M? as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations

An ALMA view of 11 dusty star-forming galaxies at the peak of cosmic star formation history

We present the ALMA view of 11 main-sequence dusty star-forming galaxies (DSFGs) (sub-)millimetre selected in the Great Observatories Origins Survey South (GOODS-S) field and spectroscopically confirmed to be at the peak of cosmic star formation history (z ∼2). Our study combines the analysis of galaxy spectral energy distribution with ALMA continuum and CO spectral emission by using ALMA Science Archive products at the highest spatial resolution currently available for our sample (Δθ 1 arcsec). We include galaxy multiband images and photometry (in the optical, radio, and X-rays) to investigate the interlink between dusty, gaseous, and stellar components and the eventual presence of AGN. We use multiband sizes and morphologies to gain an insight on the processes that lead galaxy evolution, e.g. gas condensation, star formation, AGN feedback. The 11 DSFGs are very compact in the (sub-)millimetre (median rALMA = 1.15 kpc), while the optical emission extends to larger radii (median rH/rALMA = 2.05). CO lines reveal the presence of a rotating disc of molecular gas, but we cannot exclude the presence of interactions and/or molecular outflows. Images at higher (spectral and spatial) resolution are needed to disentangle from the possible scenarios. Most of the galaxies are caught in the compaction phase, when gas cools and falls into galaxy centre, fuelling the dusty burst of star formation and the growing nucleus. We expect these DSFGs to be the high-z star-forming counterparts of massive quiescent galaxies. Some features of CO emission in three galaxies are suggestive of forthcoming/ongoing AGN feedback, which is thought to trigger the morphological transition from star-forming discs to early-type galaxies

Variation of optical and infrared properties of galaxies with their surface brightness

Although low surface brightness galaxies (LSBs) contribute a large fraction to the number density of galaxies, their properties are still poorly known. LSBs are often considered dust poor, based only on a few studies. We use, for the first time, a large sample of LSBs and high surface brightness galaxies (HSBs) with deep observational data to study their dust properties as a function of surface brightness. Our sample consists of 1631 optically selected galaxies at $z < 0.1$ from the North Ecliptic Pole (NEP) wide field. We use the large set of data available in this field, from UV to FIR. We measured the optical size and the surface brightness of the targets, and analyzed their spectral energy distribution using the CIGALE fitting code. We found that the specific star formation rate and specific infrared luminosity (total infrared luminosity per stellar mass) remain mostly flat as a function of surface brightness for both LSBs and HSBs that are star-forming but decline steeply for the quiescent galaxies. The majority of LSBs in our sample have negligible dust attenuation (A$_{V} < 0.1$ mag), except for about 4% of them that show significant attenuation with a mean A$_{V}$ of 0.8 mag. We found that these LSBs also have a high $\textit{r}$-band mass-to-light ratio ($M/L_r>3$ M$_{\odot}$/L$_{\odot}$), and show similarity to the extreme giant LSBs from the literature, indicating a possibly higher dust attenuation in giant LSBs as well. This work provides a large catalog of LSBs and HSBs with detailed measurements of their several optical and infrared physical properties. Our results suggest that the dust content of LSBs is more varied than previously thought, with some of them having significant attenuation making them fainter than their intrinsic value. This will have serious implications for the observation and analysis of LSBs with current/upcoming surveys like JWST and LSST.Comment: 16 pages, 12 figures, accepted for publication in A&

An ALMA view of 11 dusty star-forming galaxies at the peak of cosmic star formation history

We present the ALMA view of 11 main-sequence dusty star-forming galaxies (DSFGs) (sub-)millimetre selected in the Great Observatories Origins Survey South (GOODS-S) field and spectroscopically confirmed to be at the peak of cosmic star formation history (z ~ 2). Our study combines the analysis of galaxy spectral energy distribution with ALMA continuum and CO spectral emission by using ALMA Science Archive products at the highest spatial resolution currently available for our sample (Δθ ≲ 1 arcsec). We include galaxy multiband images and photometry (in the optical, radio, and X-rays) to investigate the interlink between dusty, gaseous, and stellar components and the eventual presence of AGN. We use multiband sizes and morphologies to gain an insight on the processes that lead galaxy evolution, e.g. gas condensation, star formation, AGN feedback. The 11 DSFGs are very compact in the (sub-)millimetre (median rALMA = 1.15 kpc), while the optical emission extends to larger radii (median rH/rALMA = 2.05). CO lines reveal the presence of a rotating disc of molecular gas, but we cannot exclude the presence of interactions and/or molecular outflows. Images at higher (spectral and spatial) resolution are needed to disentangle from the possible scenarios. Most of the galaxies are caught in the compaction phase, when gas cools and falls into galaxy centre, fuelling the dusty burst of star formation and the growing nucleus. We expect these DSFGs to be the high-z star-forming counterparts of massive quiescent galaxies. Some features of CO emission in three galaxies are suggestive of forthcoming/ongoing AGN feedback, which is thought to trigger the morphological transition from star-forming discs to early-type galaxies

Analysis of multiphase switched-capacitor networks using the node method

Switched-capacitor networks (SC networks) deserve attention, since they provide an optimum method for implementing precision filters in a monolithic integrated circuit. Classical SC networks contain capacitors and two- phase switches (see [1–4]). In certain applications it is preferable to use multiphase networks (see [5]), but the methods for analyzing them are complex (see [1]).The present paper proposes a comparatively simple method for the mathematical description of multiphase SC networks. It is a generalization of the method of analysis developed in [2]. Moreover, the present work emphasizes the fact that SC networks belong to a more general class of discrete time-varying networks