نتایج جستجو برای: galaxies size
تعداد نتایج: 599707 فیلتر نتایج به سال:
The discovery[1] of a population of young galaxies at an epoch when the universe was about one tenth of its current age has shed new light on the question of when and how galaxies formed. Within the context of popular models[2] this is the population of primeval galaxies that built themselves up to the size of present–day galaxies through the process of repeated mergers. But the recent detectio...
We have used the Westerbork Northern Sky Survey (WENSS) to define a sample of 47 low redshift (z <∼ 0.4) giant radio galaxies. This is the largest sample yet of such radio sources originating from a single survey. We present radio maps of the newly discovered giants and optical images and spectra of their host galaxies. We present some of their properties and discuss the selection effects. We i...
We present results from an ongoing search for galaxy counterparts of a subgroup of Quasar Absorption Line Systems called Damped Lyα Absorbers (DLAs). DLAs have several characteristics that make them prime candidates for being the progenitors of typical present day galaxies. 1. Damped Lyα Absorbers and high redshift galaxies Damped Lyα Absorbers are QSO absorption line systems with HI column den...
We present high-resolution (0.3) ALMA 870μm imaging of 52 sub-millimeter galaxies (SMGs) in the Ultra Deep Survey (UDS) field and investigate the size and morphology of the sub–millimeter (sub– mm) emission on 2–10kpc scales. We derive a median intrinsic angular size of FWHM=0.30± 0.04 for the 23 SMGs in the sample detected at a signal-to-noise ratio (SNR) > 10. Using the photometric redshifts ...
A simultaneous maximum likelihood approach for galaxy-galaxy lensing and cluster lens reconstruction
In a previous paper we investigated means for constraining the mass distribution of cluster galaxies by weak lensing. We concluded that a comprehensive method should treat the lensing effects of individual cluster galaxies and those resulting from a general cluster component simultaneously. To this end we now develop a non-parametric maximum likelihood cluster reconstruction algorithm that can ...
We present results from a continuing interferometric survey of high-redshift submillimeter galaxies with the Submillimeter Array, including high-resolution (beam size ∼ 2 arcsec) imaging of eight additional AzTEC 1.1mm selected sources in the COSMOS Field, for which we obtain six reliable (peak S/N > 5 or peak S/N > 4 with multiwavelength counterparts within the beam) and two moderate significa...
We examine the radius-luminosity (R-L) relation for blue galaxies in the Team Keck Redshift Survey (TKRS) of GOODS-N. We compare with a volume-limited, Sloan Digital Sky Survey sample and find that the R-L relation has evolved to lower surface brightness since z = 1. Based on the detection limits of GOODS this can not be explained by incompleteness in low surface-brightness galaxies. Number den...
Context. Spatially resolved emission-line spectroscopy is a powerful tool for determining the physical conditions in the narrow-line region (NLR) of active galactic nuclei (AGNs). We recently used optical long-slit spectroscopy to study the NLRs of a sample of six Seyfert-2 galaxies. We have shown that such an approach, in comparison to the commonly used [O iii] narrow-band imaging alone, allow...
In a previous paper we investigated means for constraining the mass distribution of cluster galaxies by weak lensing. We concluded that a comprehensive method should treat the lensing eeects of individual cluster galaxies and those resulting from a general cluster component simultaneously. To this end we now develop a non-parametric maximum likelihood cluster reconstruction algorithm that can i...
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