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تسجيل مستخدم جديدA deeper look at the dust attenuation law of star-forming galaxies at high redshift
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A diverse range of dust attenuation laws is found in star-forming galaxies. In particular, Tress et al. (2018) studied the SHARDS survey to constrain the NUV bump strength (B) and the total-to selective ratio (Rv) of 1,753 star-forming galaxies in the GOODS-N field at 1.5<z<3. We revisit here this sample to assess the implications and possible causes of the correlation found between Rv and B. The UVJ bicolour plot and main sequence of star formation are scrutinised to look for clues into the observed trend. The standard boundary between quiescent and star-forming galaxies is preserved when taking into account the wide range of attenuation parameters. However, an additional degeneracy, regarding the effective attenuation law, is added to the standard loci of star-forming galaxies in the UVJ diagram. A simple phenomenological model with an age-dependent extinction (at fixed dust composition) is compatible with the observed trend between Rv and B, whereby the opacity decreases with the age of the populations, resulting in a weaker NUV bump when the overall attenuation is shallower (greyer). In addition, we compare the constraints obtained by the SHARDS sample with dust models from the literature, supporting a scenario where geometry could potentially drive the correlation between Rv and B
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We make use of SHARDS, an ultra-deep (<26.5AB) galaxy survey that provides optical photo-spectra at resolution R~50, via medium band filters (FWHM~150A). This dataset is combined with ancillary optical and NIR fluxes to constrain the dust attenuation
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We present the results of a study investigating the dust attenuation law at $zsimeq 5$, based on synthetic spectral energy distributions (SEDs) calculated for a sample of N=498 galaxies drawn from the First Billion Years (FiBY) simulation project. Th
e simulated galaxies at $zsimeq 5$, which have M$_{1500} leq -18.0$ and $7.5 leq rm{log(M/M}_{odot}rm{)} leq 10.2$, display a mass-dependent $alpha$-enhancement, with a median value of $[alpha/rm{Fe}]_{z=5}~simeq~4~times~[alpha/rm{Fe}]_{Z_{odot}}$. The median Fe/H ratio of the simulated galaxies is $0.14pm0.05$ which, even including the effects of nebular continuum, produces steep intrinsic UV continuum slopes; $langle beta_{i} rangle = -2.4 pm 0.05$. Using a set of simple dust attenuation models, in which the wavelength-dependent attenuation is assumed to be of the form $A(lambda) propto lambda^{n}$, we explore the parameter values which best reproduce the observed $z=5$ luminosity function (LF) and colour-magnitude relation (CMR). We find that a simple model in which the absolute UV attenuation is a linearly increasing function of log stellar mass, and the dust attenuation slope ($n$) is within the range $-0.7 leq n leq-0.3$, can successfully reproduce the LF and CMR over a wide range of stellar population synthesis model (SPS) assumptions. This range of attenuation curves is consistent with a power-law fit to the Calzetti attenuation law in the UV ($n=-0.55$), and other similarly `grey star-forming galaxy attenuation curves recently derived at $zsimeq2$. In contrast, attenuation curves as steep as the Small Magellanic Cloud (SMC) extinction curve ($n=-1.24$) are formally ruled out. Finally, we show that our models are consistent with recent 1.3mm ALMA observations of the Hubble Ultra Deep Field (HUDF), and predict the form of the $zsimeq5$ IRX$-beta$ relation.
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We present the results of a new study of dust attenuation at redshifts $3 < z < 4$ based on a sample of $236$ star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we
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