相关论文: Far UV and X-ray observation: a hot view of shell …

Shell galaxies are widely considered the debris of recent accretion/merging episodes. Their high frequency in low density environment suggests that such episodes could be among the driver of the early-type galaxy secular evolution. We…

We present XMM-Newton X-ray observations of two shell galaxies, NGC 7070A and ESO 2400100, and far UV observations obtained with the Optical Monitor for these and for an additional shell galaxy, NGC 474, for which we also have near and far…

With the aim of characterizing rejuvenation processes in early-type galaxies, we analyzed five barred S0 galaxies showing prominent outer ring in ultraviolet (UV) imaging. We analyzed GALEX far- (FUV) and near- (NUV) UV and optical data…

We are exploring galaxy evolution in low density environments exploiting smooth particle hydrodynamic simulations including chemo-photometric implementation. From a large grid of simulations of galaxy encounters and mergers starting from…

The Galaxy Evolution Explorer (GALEX) detected ultraviolet emission in about 50% of multi-spin early-type galaxies (ETGs), suggesting the occurrence of a recent rejuvenation episode connected to the formation of these kinematical features.…

We present photometric observations of two shell galaxies, NGC 474 and NGC 7600. We examine the photometric colours and surface brightnesses of the shells and their host galaxies, and the isophotal parameters of each galaxy. In the case of…

Systems of shells and polar rings in early-type galaxies are considered "bona fide" tracers of mass accretion and/or mergers. Their high frequency in low density environments suggests that such episodes could drive the evolution of at least…

Rejuvenating galaxies are important probes of galaxy evolution, yet identifying them observationally is challenging as constraining recent star formation histories requires both photometric and spectroscopic data. We present a method for…

The Galaxy Evolution Explorer (GALEX) imaged the sky in the Ultraviolet (UV) for almost a decade, delivering the first sky surveys at these wavelengths. Its database contains far-UV (FUV, $\lambda$$_{eff}$ $\sim$ 1528\AA) and near-UV (NUV,…

Stellar shells are low surface brightness features in the form of open, concentric arcs, formed in close-to-radial collisions of galaxies. They occur in at least 10% of early-type galaxies and a small portion of spirals and their unique…

Low-mass stars are currently the most promising targets for detecting and characterizing habitable planets in the solar neighborhood. However, the ultraviolet (UV) radiation emitted by such stars can erode and modify planetary atmospheres…

The galaxy evolution is believed to be conditioned by the environment. Isolated galaxies or galaxies in poor groups are an excellent laboratory to study evolutionary mechanisms where effects of the environment are minimal. We present new…

We present GALEX far-ultraviolet (FUV, $\lambda_{eff}$=1538 \AA) and near-ultraviolet (NUV, $\lambda_{eff}$=2316 \AA) surface photometry of 40 early-type galaxies (ETGs) selected from a wider sample of 65 nearby ETGs showing emission lines…

We present the GALEX far FUV and near NUV ultraviolet imaging of three nearby shell galaxies, namely NGC 2865, NGC 5018 and NGC 7135. The system of shells and fine structures visible in the optical is detected in the NUV image of NGC 2865…

The UV images of GALEX revealed that ~30% of Early Type Galaxies (ETG) show UV emission indicating a rejuvenation episode. In ETGs with multiple spin components this percentage increases at 50%. We present here the characteristics of this…

GALEX detected a significant fraction of early-type galaxies showing Far-UV bright structures. These features suggest the occurrence of recent star formation episodes. We aim at understanding their evolutionary path[s] and the mechanisms at…

We detected recent star formation in nearby early-type galaxies located in low density environments, with GALEX Ultraviolet (UV) imaging. Signatures of star formation may be present in the nucleus and in outer rings/arm like structures. Our…

The ultraviolet (UV) light from a host star influences a planet's atmospheric photochemistry and will affect interpretations of exoplanetary spectra from future missions like the James Webb Space Telescope. These effects will be…

Far-ultraviolet radiation is a ubiquitous, if unanticipated, phenomenon in elliptical galaxies and early-type spiral bulges. It is the most variable photometric feature associated with old stellar populations. Recent observational and…

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…