A multi-wavelength study of the evolution of Early-Type Galaxies in Groups: the ultraviolet view

ABRIDGED- The UV-optical color magnitude diagram (CMD) of rich galaxy groups is characterised by a well developed Red Sequence (RS), a Blue Cloud (BC) and the so-called Green Valley (GV). Loose, less evolved groups of galaxies likely not virialized yet may lack a well defined RS. This is actually explained in the framework of galaxy evolution. We are focussing on understanding galaxy migration towards the RS, checking for signatures of such a transition in their photometric and morphological properties. We report on the UV properties of a sample of ETGs galaxies inhabiting the RS. The analysis of their structures, as derived by fitting a Sersic law to their UV luminosity profiles, suggests the presence of an underlying disk. This is the hallmark of dissipation processes that still must have a role in the evolution of this class of galaxies. SPH simulations with chemo-photometric implementations able to match the global properties of our targets are used to derive their evolutionary paths through UV-optical CDM, providing some fundamental information such as the crossing time through the GV, which depends on their luminosity. The transition from the BC to the RS takes several Gyrs, being about 3-5 Gyr for the the brightest galaxies and more long for fainter ones, if it occurs. The photometric study of nearby galaxy structures in UV is seriously hampered by either the limited FoV of the cameras (e.g in HST) or by the low spatial resolution of the images (e.g in the GALEX). Current missions equipped with telescopes and cameras sensitive to UV wavelengths, such as Swift-UVOT and Astrosat-UVIT, provide a relatively large FoV and better resolution than the GALEX. More powerful UV instruments (size, resolution and FoV) are obviously bound to yield fundamental advances in the accuracy and depth of the surface photometry and in the characterisation of the galaxy environment.Comment: 12 pages, 6 figures: accepted for publication in Astrophysics & Space Science as contributions to the workshop: "UV astronomy, the needs and the means

On the Orbital Period of the Intermediate Polar 1WGA J1958.2+3232

Recently, Norton et al. 2002, on the basis of multiwavelength photometry of 1WGA J1958.2+3232, argued that the -1 day alias of the strongest peak in the power spectrum is the true orbital period of the system, casting doubts on the period estimated by Zharikov et al. 2001. We re-analyzed this system using our photometric and spectroscopic data along with the data kindly provided by Andy Norton and confirm our previous finding. After refining our analysis we find that the true orbital period of this binary system is 4.35h.Comment: 4 pages, 5 figures, Accepted for publication in A&A Letter

Near-infrared adaptive optics imaging of high redshift quasars

The properties of high redshift quasar host galaxies are studied, in order to investigate the connection between galaxy evolution, nuclear activity, and the formation of supermassive black holes. We combine new near-infrared observations of three high redshift quasars (2 < z < 3), obtained at the ESO Very Large Telescope equipped with adaptive optics, with selected data from the literature. For the three new objects we were able to detect and characterize the properties of the host galaxy, found to be consistent with those of massive elliptical galaxies of M(R) ~ -24.7 for the one radio loud quasar, and M(R) ~ -23.8 for the two radio quiet quasars. When combined with existing data at lower redshift, these new observations depict a scenario where the host galaxies of radio loud quasars are seen to follow the expected trend of luminous (~5L*) elliptical galaxies undergoing passive evolution. This trend is remarkably similar to that followed by radio galaxies at z > 1.5. Radio quiet quasars hosts also follow a similar trend but at a lower average luminosity (~0.5 mag dimmer). The data indicate that quasar host galaxies are already fully formed at epochs as early as ~2 Gyr after the Big Bang and then passively fade in luminosity to the present epoch.Comment: Accepted for publication in ApJ, 24 pages, 10 figure

The nuclear to host galaxy relation of high redshift quasars

We present near-infrared imaging with ESO VLT+ISAAC of the host galaxies of low luminosity quasars in the redshift range 1 < z < 2, aimed at investigating the relationship between the nuclear and host galaxy luminosities at high redshift. This work complements our previous study to trace the cosmological evolution of the host galaxies of high luminosity quasars (Falomo et al. 2004). The new sample includes 15 low luminosity quasars, nine radio-loud (RLQ) and six radio-quiet (RQQ). They have similar distribution of redshift and optical luminosity, and together with the high luminosity quasars they cover a large range (~4 mag) of the quasar luminosity function. The host galaxies of both types of quasars are in the range of massive inactive ellipticals between L* and 10 L*. RLQ hosts are systematically more luminous than RQQ hosts by a factor of ~2. This difference is similar to that found for the high luminosity quasars. This luminosity gap appears to be independent of the rest-frame U-band luminosity but clearly correlated with the rest-frame R-band luminosity. The color difference between the RQQs and the RLQs is likely a combination of an intrinsic difference in the strength of the thermal and nonthermal components in the SEDs of RLQs and RQQs, and a selection effect due to internal dust extinction. For the combined set of quasars, we find a reasonable correlation between the nuclear and the host luminosities. This correlation is less apparent for RQQs than for RLQs. If the R-band luminosity is representative of the bolometric luminosity, and assuming that the host luminosity is proportional to the black hole mass, as observed in nearby massive spheroids, quasars emit with a relatively narrow range of power with respect to their Eddington luminosity and with the same distribution for RLQs and RQQs.Comment: Accepted for publication in ApJ, 24 pages, 4 figure

Size-independent cylindrical resonator half-filled with DNG metamaterial

A circular cylindrical metallic resonator half filled with DPS material and half with DNG metamaterial is analyzed, in the frequency domain. The two materials are linear, lossless, homogeneous, and anti-isorefractive to each other. The electric field is assumed to be parallel to the cylinder axis. It is shown that the resonator performs independently of diameter size. Numerical results are presented and discussed for a resonator excited by a line source parallel to the axis

Efectividad del cipionato de estradiol inyectado al final de un tratamiento con progesterona sobre la eficiencia reproductiva

El cipionato de estradiol (CPE) ha sido utilizado para reemplazar al benzoato de estradiol (BE) administrado vía IM 24 h después de retirado el dispositivo intravaginal con progesterona (DISP), sin afectar los porcentajes de preñez. El objetivo del trabajo fue evaluar el efecto de dos dosis de CPE inyectado al retirar un DISP, sobre el porcentaje de preñez post inseminación artificial a tiempo fijo (IATF). Como objetivo secundario, se planteó comparar la eficiencia reproductiva de los tratamientos utilizados. Se emplearon 79 vaquillonas de 15 meses de edad. El día 0, se les colocó un DISP más BE. El día 7 se retiró el DISP, se administró D(+) cloprostenol y en forma aleatoria se inyectó 0,5 mg de CPE, 1 mg de CPE o BE 24 h después. Para la IATF (52–56 h) se utilizó semen proveniente de un toro de probada fertilidad. El día 22 se colocó a todas las vaquillonas un DISP de segundo uso, retirándolo 7 días después. Se continuó con detección de celo e IA. El diagnóstico de gestación se realizó por ultrasonografía en dos oportunidades para evaluar preñez de IATF y retorno, así como para verificar mortalidad embrionaria. Se evaluó el efecto de los tratamientos sobre la preñez a la IATF, del retorno y final. No se observaron efectos del tratamiento (p&gt;0,05) sobre los porcentajes de preñez a la IATF (51,9%), del retorno (61,1%) y final (65,8%). Se observó un 7,3% de pérdidas embrionarias (p&gt;0,05). Se concluye que la administración de 0,5 o 1 mg de CPE al retirar un DISP con progesterona en lugar de BE a las 24 h posteriores es igualmente efectiva para implementar una IATF. Además, no resulta afectada la eficiencia reproductiva del rodeo.