Starburst to Quiescent from HST/ALMA: Stars and Dust Unveil Minor Mergers in Submillimeter Galaxies at z ~ 4.5

Dust-enshrouded, starbursting, submillimeter galaxies (SMGs) at z ≥ 3 have been proposed as progenitors of z ≥ 2 compact quiescent galaxies (cQGs). To test this connection, we present a detailed spatially resolved study of the stars, dust, and stellar mass in a sample of six submillimeter-bright starburst galaxies at z ~ 4.5. The stellar UV emission probed by HST is extended and irregular and shows evidence of multiple components. Informed by HST, we deblend Spitzer/IRAC data at rest-frame optical, finding that the systems are undergoing minor mergers with a typical stellar mass ratio of 1:6.5. The FIR dust continuum emission traced by ALMA locates the bulk of star formation in extremely compact regions (median r e = 0.70 ± 0.29 kpc), and it is in all cases associated with the most massive component of the mergers (median log(M*/M⊙) = 10.49 ± 0.32). We compare spatially resolved UV slope (β) maps with the FIR dust continuum to study the infrared excess (IRX = L_(IR)/L_(UV))–β relation. The SMGs display systematically higher IRX values than expected from the nominal trend, demonstrating that the FIR and UV emissions are spatially disconnected. Finally, we show that the SMGs fall on the mass–size plane at smaller stellar masses and sizes than the cQGs at z = 2. Taking into account the expected evolution in stellar mass and size between z = 4.5 and z = 2 due to the ongoing starburst and mergers with minor companions, this is in agreement with a direct evolutionary connection between the two populations

GOODS-ALMA 2.0: Last gigayear star formation histories of the so-called starbursts within the main sequence

Recently, a population of compact main sequence (MS) galaxies exhibiting starburst-like properties have been identified in the GOODS-ALMA blind survey at 1.1mm. Several evolution scenarios were proposed to explain their particular physical properties (e.g., compact size, low gas content, short depletion time). In this work, we aim at studying the star formation history (SFH) of the GOODS-ALMA galaxies to understand if the so-called ``starburst (SB) in the MS'' galaxies exhibit a different star formation activity over the last Gyr compared to MS galaxies that could explain their specificity. We use the CIGALE SED modelling code to which we add non-parametric SFHs. To compare quantitatively the recent SFH of the galaxies, we define a parameter, the star formation rate (SFR) gradient that provides the angle showing the direction that a galaxy has followed in the SFR vs stellar mass plane over a given period. We show that ``SB in the MS'' have positive or weak negative gradients over the last 100, 300, and 1000 Myr, at odds with a scenario where these galaxies would be transitioning from the SB region at the end of a strong starburst phase. Normal GOODS-ALMA galaxies and ``SB in the MS'' have the same SFR gradients distributions meaning that they have similar recent SFH, despite their different properties (compactness, low depletion time). The ``SBs in the MS'' manage to maintain a star-formation activity allowing them to stay within the MS. This points toward a diversity of galaxies within a complex MS.Comment: Submitted to A&

Spatial and temporal patterns of water quality in Cullera Bay

[EN] The Júcar River, characterized by a very irregular freshwater flow, discharges into the Spanish Mediterranean coastal waters. However, the flow at its mouth is usually insignificant due to the overexploitation of upstream water. Under normal conditions, the final stretch of the river (downstream from the Cullera weir) is nurtured only by water released from the weir and small discharges from lateral irrigation channels. During periods of heavy rain, however, a significant amount of water flows through the Cullera weir. An analysis of data acquired during several field campaigns in Cullera Bay clearly reveals a zonal distribution of nutrients and chlorophyll-a within the bay: a southern area of continental influence, located near the mouth of the Júcar River; a region affected by karst filtrations and minor freshwater inputs, located to the north of the bay around Cullera Cape; and a third zone in between, characterized by higher salinities. Spatial salinity distribution is indicative of the spatial distribution of some of the nutrients discharged by the river, particularly nitrite, nitrate, orthosilicic acid and total phosphorus (TP), since it has been shown that their behavior is inverse to that of salinity. However, neither soluble reactive phosphorus (SRP) nor ammonium, which are mainly affected by biological activity, show this type of behavior. Five different conditions/scenarios were identified during the overall sampling period based on the time-series analysis of wind parameters, rainfall, freshwater flow, salt-wedge thickness at the measuring station on the river, and by comparing the average surface salinity at the sea stations with the values obtained at the coastal stations.This study was financed by the European Union as a part of the ECOSUD project ("Estuaries and Coastal Areas. Basis and Tools for a More Sustainable Development". Reference no. ICA4-CT-2001-10027), AQUAS project ("Water quality and sustainable aquaculture. Links and implications". Reference no. INCO-CT-2005-015105) and by a Special Action by the Spanish Science and Technology Ministry, "Bases y herramientas para el desarrollo sostenible de zonas costeras y estuarinas" (Reference no. REN2001-5510-E).Falco Giaccaglia, SL.; Hermosilla Gómez, Z.; Romero Gil, I.; Martínez Guijarro, MR.; Sierra, J.; Mösso, C.; Mestres, M. (2007). Spatial and temporal patterns of water quality in Cullera Bay. Journal of Coastal Research. SI47:40-47. https://doi.org/10.2112/1551-5036-47.sp1.40S4047SI4

The effect of active galactic nuclei on the cold interstellar medium in distant star-forming galaxies

In the framework of a systematic study with the ALMA interferometer of IR-selected main-sequence and starburst galaxies at z ∼ 1 − 1.7 at typical ∼1″ resolution, we report on the effects of mid-IR- and X-ray-detected active galactic nuclei (AGN) on the reservoirs and excitation of molecular gas in a sample of 55 objects. We find widespread detectable nuclear activity in ∼30% of the sample. The presence of dusty tori influences the IR spectral energy distribution of galaxies, as highlighted by the strong correlation among the AGN contribution to the total IR luminosity budget (fAGN = LIR,  AGN/LIR), its hard X-ray emission, and the Rayleigh-Jeans to mid-IR (S1.2 mm/S24 μm) observed color, with evident consequences on the ensuing empirical star formation rate estimates. Nevertheless, we find only marginal effects of the presence and strength of AGN on the carbon monoxide CO (J = 2, 4, 5, 7) or neutral carbon ([C I](3P1  −  3P0), [C I](3P2  −  3P1)) line luminosities and on the derived molecular gas excitation as gauged by line ratios and the full spectral line energy distributions. The [C I] and CO emission up to J = 5, 7 thus primarily traces the properties of the host in typical IR luminous galaxies. However, our analysis highlights the existence of a large variety of line luminosities and ratios despite the homogeneous selection. In particular, we find a sparse group of AGN-dominated sources with the highest LIR,  AGN/LIR,  SFR ratios, ≳3, that are more luminous in CO (5−4) than what is predicted by the L′CO(5-4)−LIR, SFR relation, which might be the result of the nuclear activity. For the general population, our findings translate into AGN having minimal effects on quantities such as gas and dust fractions and star formation efficiencies. If anything, we find hints of a marginal tendency of AGN hosts to be compact at far-IR wavelengths and to display 1.8 times larger dust optical depths. In general, this is consistent with a marginal impact of the nuclear activity on the gas reservoirs and star formation in average star-forming AGN hosts with LIR > 5 × 1011 L⊙, typically underrepresented in surveys of quasars and submillimeter galaxies

CO emission in distant galaxies on and above the main sequence

We present the detection of multiple carbon monoxide CO line transitions with ALMA in a few tens of infrared-selected galaxies on and above the main sequence at z = 1.1−1.7. We reliably detected the emission of CO (5−4), CO (2−1), and CO (7−6)+[C I](3P2 − 3P1) in 50, 33, and 13 galaxies, respectively, and we complemented this information with available CO (4 − 3) and [C I](3P1 − 3P0) fluxes for part of the sample, and by modeling of the optical-to-millimeter spectral energy distribution. We retrieve a quasi-linear relation between LIR and CO (5 − 4) or CO (7 − 6) for main-sequence galaxies and starbursts, corroborating the hypothesis that these transitions can be used as star formation rate (SFR) tracers. We find the CO excitation to steadily increase as a function of the star formation efficiency, the mean intensity of the radiation field warming the dust (hUi), the surface density of SFR (ΣSFR), and, less distinctly, with the distance from the main sequence (∆MS). This adds to the tentative evidence for higher excitation of the CO+[C I] spectral line energy distribution (SLED) of starburst galaxies relative to that for main-sequence objects, where the dust opacities play a minor role in shaping the high-J CO transitions in our sample. However, the distinction between the average SLED of upper main-sequence and starburst galaxies is blurred, driven by a wide variety of intrinsic shapes. Large velocity gradient radiative transfer modeling demonstrates the existence of a highly excited component that elevates the CO SLED of high-redshift main-sequence and starbursting galaxies above the typical values observed in the disk of the Milky Way. This excited component is dense and it encloses ∼50% of the total molecular gas mass in main-sequence objects. We interpret the observed trends involving the CO excitation as to be mainly determined by a combination of large SFRs and compact sizes, as a large ΣSFR is naturally connected with enhanced dense molecular gas fractions and higher dust and gas temperatures, due to increasing ultraviolet radiation fields, cosmic ray rates, as well as dust and gas coupling. We release the full data compilation and the ancillary information to the community

Uncovering the MIR emission of quiescent galaxies with JWSTJWST

We present a study of the mid-IR (MIR) emission of quiescent galaxies (QGs) beyond the local universe. Using deep $JWST$ imaging in the SMACS-0723 cluster field we identify a mass limited ($M_{*} >10^{9}$M$_{\odot}$) sample of intermediate redshift QGs ($0.2<z<0.7$) and perform modeling of their rest-frame UV to MIR photometry. We find that QGs exhibit a range of MIR spectra that are composed of a stellar continuum and a dust component that is 1-2 orders of magnitude fainter to that of star-forming galaxies. The observed scatter in the MIR spectra, especially at $\lambda_{\rm rest} > 5 \mu$m, can be attributed to different dust continuum levels and/or the presence of Polycyclic Aromatic Hydrocarbons (PAHs) features. The latter would indicate enhanced 11.3- and 12.7 $\mu$m PAHs strengths with respect to those at 6.2- and 7.7$\mu$m, consistent with the observed spectra of local ellipticals and indicative of soft radiation fields. Finally, we augment the average UV-to-MIR spectrum of the population with cold dust and gas emission in the far-IR/mm and construct a panchromatic UV-to-radio SED that can serve as a template for the future exploration of the interstellar medium of $z>0$ QGs with ALMA and $JWST$.Comment: The panchromatic QG SED has been made publicly available at http://www.georgiosmagdis.com/softwar

Evaluación continua y análisis de resultados en las asignaturas del grado de química impartidas por el departamento de química orgánica

En esta comunicación se pondrán en común las experiencias de distintos docentes del Departamento que han impartido asignaturas de Química Orgánica tanto en la antigua Licenciatura como en el nuevo Grado de Químicas. Las asignaturas en que se focaliza el estudio, debido a que son de obligada realización, son: Química Orgánica, Estereoquímica Orgánica, Determinación Estructural de Compuestos Orgánicos y Química Orgánica Avanzada. El objetivo de este estudio permitirá evaluar los cambios que se han llevado a cabo desde el punto de vista de las nuevas metodologías docentes que se han debido aplicar así como de los cambios de contenido que han sufrido las asignaturas. También se pretende evaluar los resultados obtenidos por los alumnos resaltando y comparando las ventajas e inconvenientes encontradas en el nuevo plan de estudios. Además, como fin último este estudio pretende poner en común aquellas estrategias que mejor resultado hayan dado desde distintos ámbitos docentes para aplicarlas en futuros cursos

Synthesis of γ-, δ-, and ε-Lactams by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)iminoesters

Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee’s up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary

GOODS-ALMA: The slow downfall of star formation in z = 2–3 massive galaxies

We investigate the properties of a sample of 35 galaxies, detected with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 1.1 mm in the GOODS-ALMA field (area of 69 arcmin2, resolution = 0.60″, rms ≃ 0.18 mJy beam−1). Using the ultraviolet-to-radio deep multiwavelength coverage of the GOODS–South field, we fit the spectral energy distributions of these galaxies to derive their key physical properties. The galaxies detected by ALMA are among the most massive at z = 2−4 (M⋆, med = 8.5 × 1010 M⊙) and they are either starburst or located in the upper part of the galaxy star-forming main sequence. A significant portion of our galaxy population (∼40%), located at z ∼ 2.5 − 3, exhibits abnormally low gas fractions. The sizes of these galaxies, measured with ALMA, are compatible with the trend between the rest-frame 5000 Å size and stellar mass observed for z ∼ 2 elliptical galaxies, suggesting that they are building compact bulges. We show that there is a strong link between star formation surface density (at 1.1 mm) and gas depletion time: The more compact a galaxy’s star-forming region is, the shorter its lifetime will be (without gas replenishment). The identified compact sources associated with relatively short depletion timescales (∼100 Myr) are the ideal candidates to be the progenitors of compact elliptical galaxies at z ∼ 2