相关论文: Blue Supergiants as a Tool for Extragalactic Dista…

Charged cosmic rays have been measured up to macroscopic energies. Concerning neutrinos, the detection is still limited to terrestrial ones (apart from supernova production). A new way to search for extragalactic neutrinos is discussed.

Highly magnified stars residing in caustic crossing lensed galaxies at z ~ 0.7-1.5 in galaxy cluster lensing fields inevitably exhibit recurrent brightening events as they traverse a micro caustic network cast down by foreground…

The diagnostic use and detectability of luminous fine structure lines from high redshift galaxies is reviewed in the light of results from COBE concerning the Milky Way and from ISO on low redshift galaxies. At the highest luminosities…

It is difficult to accurately measure the effective gravity (log g) in late-type stars using broadband (eg. UBV or SDSS) or intermediate-band (uvby) photometric systems, especially when the stars can cover a range of metallicities and…

To obtain the accuracy now sought in the extragalactic distance scale through standard candles and rulers, calibration of stellar photometry must be improved. The sensitivity of the V-K color surface brightness relation is examined here by…

Blue supergiants (BSGs) are important objects to study the intermediate phases of massive star evolution, helping to constrain evolutionary models. However, the lack of a holistic study of a statistically significant and unbiased sample of…

In this work, we investigate the properties of young giant planet spectra in the optical and suggest that future space-based direct imaging missions should be considering young planets as a valuable and informative science case. While young…

We explore the use of ground-based surface brightness fluctuation (SBF) measurements to constrain distances to nearby dwarf galaxies. Using archival CFHT Megacam imaging data for a sample of 27 nearby dwarfs, we demonstrate that reliable…

We present different methods used to identify high redshift (z>5) objects in the high-magnification regions of lensing galaxy clusters, taking advantage of very well constrained lensing models. The research procedures are explained and…

The extragalactic background light (EBL) from the infrared to the ultraviolet is difficult to measure directly, but can be constrained with a variety of methods. EBL photons absorb gamma-rays from distant blazars, allowing one to use blazar…

The direct measurement of the extragalactic background light (EBL) is difficult at optical to infrared wavelengths because of the strong foreground radiation originating in the Solar System. Very high energy (VHE, E$>$100 GeV) gamma rays…

The Extragalactic Background Light (EBL) stands for the mean surface brightness of the sky as we would see it from a representative vantage point in the intergalactic space outside of our Milky Way Galaxy. Averaged over the whole 4 pi solid…

Detached eclipsing double line spectroscopic binaries offer an opportunity to measure directly stellar parameters: mass, luminosity, radius, as well as the distance. The only non-trivial step is the need to determine surface brightness of…

I present an overview of the techniques used for detecting and following up binaries in nearby galaxies and present the current census of extragalactic binaries, with a focus on eclipsing systems. The motivation for looking in other…

The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our…

This paper describes the design principles for a CCD-based photometric system that is highly optimized for ground-based measurement of the size of the Balmer jump in stellar energy distributions. It is shown that, among ultraviolet filters…

Clear identifications of Galactic young stellar clusters farther than a few kpc from the Sun are rare, despite the large number of candidate clusters. We aim to improve the selection of candidate clusters rich in massive stars with a…

Strong lensing is a powerful tool to address three major astrophysical issues: understanding the spatial distribution of mass at kpc and sub-kpc scale, where baryons and dark matter interact to shape galaxies as we see them; determining the…

Jets can be probed in their innermost regions (d~0.1 pc) through the study of the relativistically-boosted emission of blazars. On the other extreme of spatial scales, the study of structure and dynamics of extragalactic relativistic jets…

The HST snapshot imaging survey of 110 BL Lac objects (Urry et al. 2000) has clearly shown that the host galaxies are massive and luminous ellipticals. The dispersion of the absolute magnitudes is sufficiently small, so that the measurement…