22 research outputs found
Detecting metal-rich intermediate-age globular clusters in NGC4570 using K-band photometry
âThe original publication is available at www.springerlink.comâ. Copyright Springer. DOI: 10.1007/s10509-009-0093-8Globular cluster systems (GCSs) of most early-type galaxies feature two peaks in their optical colour distributions. Blue-peak globular clusters (GCs) are believed to be old and metal-poor, whereas the ages, metallicities, and the origin of the red-peak GCs are still being debated. We obtained deep K-band photometry and combined it with Hubble Space Telescope observations in g and z to yield a full spectral energy distribution from the optical to the near-infrared. This now allows us to break the ageâmetallicity degeneracy. We used our evolutionary synthesis models galev for star clusters to compute a large grid of models with different metallicities and a wide range of ages. Comparing these models to our observations revealed a large population of intermediate-age (1â3 Gyr) and metal-rich (âsolar-metallicity) GCs, that will give us further insights into the formation history of this galaxy.Peer reviewe
Revista de Vertebrados de la Estación Biológica de Doñana
Clave preliminar de las escamas de los peces de agua dulce de España, a nivel de familiaExito reproductor del Buitre leonado (Gyps fulvus) en NavarraAlimentaciĂłn del GavilĂĄn (Accipiter nisus) en la Isla de TenerifeEl Verdecillo (Serinus serinus): Tendencias en la estaciĂłn de nidificaciĂłn, en el tamaño del huevo y en la supervivencia.las batidas como mĂ©todo de censo en especiesde caza mayor: aplicaciĂłn al caso del JabalĂ (Sus scrofa L.) en la provincia de Burgos (Norte de España)La adquisiciĂłn de madurez sexual en el camaleĂłn comĂșn (Chamaeleo chamaeleon)Nuevas citas de Hemidactylus turcicus en la provincia de CĂĄceresLa focha comĂșn (Fulica atra) en la isla de Gran Canaria: nueva especie nidificante en el archipiĂ©lago CanarioTraslado de huevos en incubaciĂłn por la urraca (Pica pica)PredaciĂłn de Falco peregrinus sobre Oryctolagus cuniculusCuatro nuevas especies de aves para Bolivia.Sobre la utilizaciĂłn de nidos de golondrina comĂșn abandonados.Parasitismo mĂșltiple del crĂalo (Clamator glandarius)PredaciĂłn del topo de rio (Galemys pyrenaicus, Geoffroy 1811) por parte de la lechuza comĂșn (Tyto alba, Scopoli 1769)PredaciĂłn del zorro (Vulpes vulpes) sobre un pollo de buitre leonado (Gyps fulvus).Vulpes vulpes L. criando en una colonia de marmota (Marmota marmota L.) en el pirineo de LĂ©ridaObservaciones sobre la incidencia de Rattus (Fischer, 1803) en los cultivos ibĂ©ricos de caña de azĂșcaSituaciĂłn actual de la jutiita de la tierra Capromys sanfelipensis (Rodentia, Mammalia)Notas sobre la intraducciĂłn y expansiĂłn de la ardilla comĂșn en Sierra Nevada, sureste de EspañaPeer reviewe
Volatile profile of yellow passion fruit juice by static headspace and solid phase microextraction techniques
Star clusters near and far; tracing star formation across cosmic time
© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio
The Physics of Star Cluster Formation and Evolution
© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe
An ultrahot Neptune in the Neptune desert
About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet1,2. All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (Râ), or apparently rocky planets smaller than 2 Râ. Such lack of planets of intermediate size (the âhot Neptune desertâ) has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 Râ and a mass of 29 Mâ, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite3 revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planetâs mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0â2.9+2.7% of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this âultrahot Neptuneâ managed to retain such an envelope. Follow-up observations of the planetâs atmosphere to better understand its origin and physical nature will be facilitated by the starâs brightness (Vmag = 9.8)
TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images
We present the discovery and characterization of five hot and warm Jupiters - TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960) - based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (R P = 1.01-1.77 R J) and have masses that range from 0.85 to 6.33 M J. The host stars of these systems have F and G spectral types (5595 †T eff †6460 K) and are all relatively bright (9.5 1.7 R J, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of 6.31-0.30+0.28 M J and a statistically significant, nonzero orbital eccentricity of e = 0.074-0.022+0.021. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals
Spectral properties of X-ray binaries in Centaurus A
We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N , and present the spectral parameters of sources with L âł 2 Ă 10 erg s. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent "gap" in the mass distribution of compact objects between âŒ2-5 M . We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (âŒ70%-80%) of potential Roche lobe filling donors in the Cen A halo are âł 12 Gyr old, while BH LMXBs require donors âł 1 M to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at L â„ 5 Ă 10 erg s for the XB population of early-type galaxies; for older stellar populations, there are fewer stars âł 1 M , which are required to form the more luminous sources.Peer reviewe