La densidad de tasa de formación estelar del Universo a z=0.61 medida en Halpha

En este trabajo estudiamos una muestra de 46 galaxias con formación estelar activa, seleccionadas por su emisión en la línea Halpha a z=0.61. Las observaciones de los objetos fueron realizadas con el instrumento HAWK-I del telescopio VLT en un filtro estrecho del infrarrojo cercano, destacando la extrema profundidad alcanzada (32h de tiempo de exposición). El objetivo principal de este estudio consiste en la determinación de la densidad de tasa de formación estelar (SFRd en inglés) del Universo a z=0.61. Obtenemos la función de luminosidad observada y corregida de extinción para cada galaxia, y además utilizamos la profundidad de los datos para determinar un valor de la pendiente del extremo débil de esta función. Por último realizamos un estudio morfológico y calculamos propiedades físicas de la muestra. Los resultados suponen una conexión de la SFRd entre el Universo local y z~1, confirmando el crecimiento de esta magnitud entre estas épocas de la historia del Universo.---[ABSTRACT]--- In this work we study a sample of 46 active star-forming galaxies, selected for their Halpha emission line at z = 0.61. The observations of the objects were made with the HAWK -I instrument of the VLT telescope in a near-infrared narrow filter, highlighting the extreme depth reached (32h exposure time). The main objective of this study is the determination of the star formation rate density (SFRd) of the universe at z=0.61. We obtain the observed luminosity function and extintion corrected for each galaxy, and also we use the depth data to determine a value of the faint end slope of this function. Finally, we performe a morphological study and we calculate physical properties of the sample. The results imply a connection between the local Universe and z~1 SFRd, confirming the growth of this magnitude between these epochs of cosmic history

The rest-frame optical sizes of massive galaxies with suppressed star formation at z∼4z\sim4

We present the rest-frame optical sizes of massive quiescent galaxies (QGs) at $z\sim4$ measured at $K'$-band with the Infrared Camera and Spectrograph (IRCS) and AO188 on the Subaru telescope. Based on a deep multi-wavelength catalog in the Subaru XMM-Newton Deep Survey Field (SXDS), covering a wide wavelength range from the $u$-band to the IRAC $8.0\mu m$ over 0.7 deg$^2$, we evaluate photometric redshift to identify massive ($M_{\star}\sim10^{11}\ M_\odot$) galaxies with suppressed star formation. These galaxies show a prominent 4000$\rm \AA$break feature at$z\sim4$, suggestive of an evolved stellar population. We then conduct follow-up$K'$-band imaging with adaptive optics for the five brightest galaxies ($K_{AB,total}=22.5\sim23.4$). Compared to lower redshift ones, QGs at$z\sim4$have smaller physical sizes of effective radii$r_{eff}=0.2$to$1.8$kpc. The mean size measured by stacking the four brightest objects is$r_{eff}=0.7\rm\ kpc$. This is the first measurement of the rest-frame optical sizes of QGs at$z\sim4$. We evaluate the robustness of our size measurements using simulations and find that our size estimates are reasonably accurate with an expected systematic bias of$\sim0.2$kpc. If we account for the stellar mass evolution, massive QGs at$z\sim4$are likely to evolve into the most massive galaxies today. We find their size evolution with cosmic time in a form of$\log(r_e/{\rm kpc})= -0.44+1.77 \log(t/\rm Gyr)$. Their size growth is proportional to the square of stellar mass, indicating the size-stellar mass growth driven by minor dry mergers.Comment: 15 pages, 11 figures, ApJ accepte

A comparison between the soft X-ray and [O III] morphologies of active galactic nuclei

Several studies of nearby active galactic nuclei (AGN) have shown that the soft X-ray emission presents a size and morphology that resembles that of the narrow-line region (NLR) traced by [O III]. Since the NLR is mainly constituted by gas photoionised by the AGN, it seems logical to assume that this is also the primary source of the soft X-ray emission. However, these results are based on individual sources or small samples, particularly focused on type-2 Seyfert galaxies. Very little has been said concerning other types of AGN. The purpose of this work is to compare the circumnuclear morphologies of soft X-ray and [O III] images to test whether they match in different optical classes of AGN. Our sample is composed of 27 AGN: nine type-1 Seyferts, 10 type-2 Seyferts, and eight low ionisation nuclear emission-line regions (LINERs). We find a good match in 100% of the type-2 Seyferts in our sample. This correspondence is less frequent in type-1 Seyferts (22%) and it is not seen in LINERs. The good resemblance in type-2 Seyferts constitutes an evidence for a common physical origin. We argue that the lack of correspondence in type-1 Seyferts might be due to the line of sight perpendicular to the accretion disk. Based on the morphologies of the eight LINERs in our sample, we discard a common origin for the soft X-ray and [O III] emissions in these objects. Regarding the X-ray properties, both high column density and hard X-ray luminosity are associated with matched morphologies.Comment: Accepted by MNRAS. 20 pages, 9 figure

Properties of galaxies at the faint end of the Hα\alpha luminosity function at z∼0.62z\sim0.62

Studies measuring the star formation rate density, luminosity function, and properties of star-forming galaxies are numerous. However, it exists a gap at $0.5<z<0.8$ in H$\alpha$-based studies. Our main goal is to study the properties of a sample of faint H$\alpha$ emitters at $z\sim0.62$. We focus on their contribution to the faint end of the luminosity function and derived star formation rate density, characterising their morphologies and basic photometric and spectroscopic properties. We use a narrow-band technique in the near-infrared, with a filter centred at 1.06 $\mu$m. The data come from ultra-deep VLT/HAWK-I observations in the GOODS-S field with a total of 31.9 h in the narrow-band filter. We perform a visual classification of the sample and study their morphologies from structural parameters available in CANDELS. Our 28 H$\alpha$-selected sample of faint star-forming galaxies reveals a robust faint-end slope of the luminosity function $\alpha=-1.46_{-0.08}^{+0.16}$. The derived star formation rate density at $z\sim0.62$ is $\rho_\mathrm{SFR} = 0.036_{-0.008}^{+0.012} M_{\odot}~\mathrm{yr^{-1}~Mpc^{-3}}$. The sample is mainly composed of disks, but an important contribution of compact galaxies with S\'ersic indexes $n\sim2$ display the highest specific star formation rates. The luminosity function at $z\sim0.62$ from our ultra-deep data points towards a steeper $\alpha$ when an individual extinction correction for each object is applied. Compact galaxies are low-mass, low-luminosity, and starburst-dominated objects with a light profile in an intermediate stage from early to late types.Comment: Published in Astronomy & Astrophysics. 19 pages, 14 figures. New version includes language edited by the journa

La evaluación de los riesgos de deterioro en el patrimonio cultural. Métodos y estrategias para su estudio en el ámbito docente de la conservación preventiva

Se presenta la enseñanza-aprendizaje de la evaluación de riesgos como herramienta de gestión para la conservación del patrimonio complutense. Se propone el uso de distintas métodos de análisis y procedimientos de trabajo a aplicar con actitud crítica de manera colaborativa e interdisciplinar.Fac. de Bellas ArtesFALSEsubmitte

Evaluación continua con Quizzes (ECQ)

La evaluación de la experiencia, tanto por parte de los estudiantes como de los profesores, ha sido muy positiva; por ello la propuesta actual es utilizar las Quizzes del programa Wiris para potenciar un mejor y mayor aprendizaje de los estudiantes y facilitar al profesorado una evaluación continua de los mismos. La utilización de Wiris Quizzes facilita la generación de preguntas con una gran aleatoriedad obteniendo un abanico muy amplio de cuestionarios. El tipo de preguntas que pueden crearse es muy diverso, pueden incluirse gráficas y fórmulas generadas con la calculadora y el editor de Wiris. Los cuestionarios tienen una doble utilidad, tanto de autoevaluación del aprendizaje por parte del estudiante, como de evaluación continuada por parte del profesor de los conocimientos alcanzados por los alumnos. Sus resultados permiten comprobar el nivel de conocimientos adquiridos y ayudan al estudiante en el estudio continuado del temario.Departamento de Matemática Aplicad

Stellar Velocity Dispersion of a Massive Quenching Galaxy at z = 4.01

We present the first stellar velocity dispersion measurement of a massive quenching galaxy at z = 4. The galaxy is first identified as a massive z ≥ 4 galaxy with suppressed star formation from photometric redshifts based on deep multiband data. A follow-up spectroscopic observation with MOSFIRE on Keck revealed strong multiple absorption features, which are identified as Balmer lines, giving a secure redshift of z = 4.01. This is the most distant quiescent galaxy known to date. Thanks to the high S/N of the spectrum, we are able to estimate the stellar velocity dispersion, σ=268±59 km s⁻¹, making a significant leap from the previous highest redshift measurement at z = 2.8. Interestingly, we find that the velocity dispersion is consistent with that of massive galaxies today, implying no significant evolution in velocity dispersion over the last 12 Gyr. Based on a stringent upper limit on its physical size from deep optical images (r_(eff) < 1.3 kpc), we find that its dynamical mass is consistent with the stellar mass inferred from photometry. Furthermore, the galaxy is located on the mass fundamental plane extrapolated from lower redshift galaxies. The observed no strong evolution in σ suggests that the mass in the core of massive galaxies does not evolve significantly, while most of the mass growth occurs in the outskirts of the galaxies, which also increases the size. This picture is consistent with a two-phase formation scenario in which mass and size growth is due to accretion in the outskirts of galaxies via mergers. Our results imply that the first phase may be completed as early as z ~ 4

Fitting pseudo-Sérsic (Spergel) light profiles to galaxies in interferometric data: The excellence of the uυ-plane

Modern (sub)millimeter interferometers, such as ALMA and NOEMA, offer high angular resolution and unprecedented sensitivity. This provides the possibility to characterize the morphology of the gas and dust in distant galaxies. To assess the capabilities of the current software in recovering morphologies and surface brightness profiles in interferometric observations, we tested the performance of the Spergel model for fitting in the uυ-plane, which has been recently implemented in the IRAM software GILDAS (uv_fit). Spergel profiles provide an alternative to the Sérsic profile, with the advantage of having an analytical Fourier transform, making them ideal for modeling visibilities in the uυ-plane. We provide an approximate conversion between the Spergel index and the Sérsic index, which depends on the ratio of the galaxy size to the angular resolution of the data. We show through extensive simulations that Spergel modeling in the uυ-plane is a more reliable method for parameter estimation than modeling in the image plane, as it returns parameters that are less affected by systematic biases and results in a higher effective signal-to-noise ratio. The better performance in the uυ-plane is likely driven by the difficulty of accounting for a correlated signal in interferometric images. Even in the uυ-plane, the integrated source flux needs to be at least 50 times larger than the noise per beam to enable a reasonably good measurement of a Spergel index. We characterized the performance of Spergel model fitting in detail by showing that parameter biases are generally low (<10%) and that uncertainties returned by uv_fit are reliable within a factor of two. Finally, we showcase the power of Spergel fitting by reexamining two claims of extended halos around galaxies from the literature, showing that galaxies and halos can be successfully fitted simultaneously with a single Spergel model

JWSTJWST Insight Into a Lensed HSTHST-dark Galaxy and its Quiescent Companion at z=2.58z=2.58

Using the novel $JWST$/NIRCam observations in the Abell 2744 field, we present a first spatially resolved overview of an $HST$-dark galaxy, spectroscopically confirmed at $z=2.58$ with magnification $\mu\approx1.9$. While being largely invisible at $\sim$1 $\mu$m with NIRCam, except for sparse clumpy sub-structures, the object is well-detected and resolved in the long-wavelength bands with a spiral shape clearly visible in F277W. By combining ancillary ALMA and $Herschel$ data, we infer that this object is an edge-on dusty spiral with an intrinsic stellar mass log$(M_*/M_\odot)\sim11.3$ and a dust-obscured SFR$\sim 300~M_\odot$~yr$^{-1}$. A massive quiescent galaxy (log$(M_*/M_\odot)\sim10.8$) with tidal features lies 2\farcs{0} away ($r$$\sim$9 kpc), at a consistent redshift as inferred by $JWST$ photometry, indicating a potential major merger. The dusty spiral lies on the main-sequence of star formation, and shows high dust attenuation in the optical ($3<A_{\rm V}<4.5$). In the far-infrared, its integrated dust SED is optically thick up to $\lambda_0 \sim 500$ $\mu$m, further supporting the extremely dusty nature. Spatially resolved analysis of the $HST$-dark galaxy reveals a largely uniform $A_{\rm V}\sim 4$ area spanning $\sim$57 kpc$^2$, which spatially matches to the ALMA 1 mm continuum emission. Accounting for the surface brightness dimming and the depths of current $JWST$ surveys, unlensed analogs of the $HST$-dark galaxy at $z>4$ would be only detectable in F356W and F444W in UNCOVER-like survey, and become totally $JWST$-dark at $z\sim6$. This suggests that detecting highly attenuated galaxies in the Epoch of Reionization might be a challenging task for $JWST$.Comment: 15 pages, 5 figures, 1 table. Accepted to ApJ

Massive galaxy formation caught in action at z~5 with JWST

We report the discovery of a compact group of galaxies, CGG-z5, at z~5.2 in the EGS field covered by the JWST/CEERS survey. CGG-z5 was selected as the highest overdensity of galaxies at z>2 in recent JWST public surveys and it consists of six candidate members lying within a projected area of $1.5''\times3''$ (10$\times$20~kpc$^2$). All group members are HST/F435W and HST/F606W dropouts while securely detected in the JWST/NIRCam bands, yielding a narrow range of robust photometric redshifts $5.0<z<5.3$. The most massive galaxy in the group has a stellar mass log$(M_{*}/M_{\odot})\approx9.8$, while the rest are low-mass satellites (log$(M_{*}/M_{\odot})\approx8.4-9.2$). While several group members were already detected in the HST and IRAC bands, the low stellar masses and the compactness of the structure required the sensitivity and resolution of JWST for its identification. To assess the nature and evolutionary path of CGG-z5, we searched for similar compact structures in the \textsc{Eagle} simulations and followed their evolution with time. We find that all the identified structures merge into a single galaxy by z=3 and form a massive galaxy (log$(M_{*}/M_{\odot})>11$) at z~1. This implies that CGG-z5 could be a "proto-massive galaxy" captured during a short-lived phase of massive galaxy formation.Comment: A&A Letter in pres