相关论文: Morphological number-counts from the ultradeep HST…
The unprecedented resolution of the refurbished Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST) has led to major advances in our understanding of galaxy formation. The high image quality in the Medium Deep…
The excess numbers of blue galaxies at faint magnitudes are a long-standing cosmological puzzle. We present new number-magnitude counts as a function of galactic morphology from the first deep fields of the Cycle 4 Hubble Space Telescope…
We summarise recent Hubble Space Telescope results on the morphology of faint field galaxies. Our two principle results are: (1) the galaxies responsible for the faint blue excess have late-type/irregular morphology and (2) the number…
The excess numbers of blue galaxies at faint magnitudes is a subject of much controversy. Recent Hubble Space Telescope results has revealed a plethora of galaxies with peculiar morphologies tentatively identified as the evolving…
Pure luminosity evolution models for galaxies provide an unacceptable fit to the redshifts and colors of faint galaxies. In this paper we demonstrate, using HST morphological number counts derived both from the $I_{814}$-band of WFPC2 in…
I review two observational programs which, together, promise to unravel the detailed astrophysical evolution of normal field galaxies over the last 5-7 Gyr. Systematic ground-based spectroscopy of faint galaxies have revealed an increasing…
The longstanding faint blue galaxy problem is gradually subsiding as a result of technological advancement, most notably from high-resolution Hubble Space Telescope imaging. In particular two categorical facts have recently been…
We present a complete morphologically classified sample of 144 faint field galaxies from the HST Medium Deep Survey with 20.0 < I <22.0 mag. We compare the global properties of the ellipticals, early and late-type spirals, and find a…
The physical properties of the faint blue galaxy population are reviewed in the context of observational progress made via deep spectroscopic surveys and Hubble Space Telescope imaging of field galaxies at various limits, and theoretical…
We present high resolution NICMOS images of random fields obtained in parallel to other HST observations. We present galaxy number counts reaching H=24. The H-band galaxy counts show good agreement with the deepest I- and K-band counts…
We present optical morphologies obtained from deep HST and ground-based images for galaxies selected from the first sub-millimeter survey of the distant Universe. Our sample comprises galaxies detected in deep 850-micron continuum maps of…
Morphological classifications are reported for Hubble Space Telescope (HST) images of 241 galaxies in the Hubble Deep Field (HDF) and its Flanking Fields (FF) with measured redshifts in the interval 0.25 < z < 1.2, drawn from a…
The morphological properties of galaxies between $21 {\rm~mag} < I < 25 {\rm~mag}$ in the {\em Hubble Deep Field} are investigated using a quantitative classification system based on measurements of the central concentration and asymmetry…
We determine the morphological mix of field galaxies down to $m_{I}\simeq 24.25$ mag ($m_{B}\sim 26.0$ mag) from a single ultradeep HST WFPC2 image in both the $V_{606}$ and $I_{814}$ filters. In total, we find 227 objects with $m_{I}\le…
We have started a survey of galaxies at intermediate redshifts using the HST-STIS parallel fields. Our main goal is to analyse the morphology of faint galaxies in order to estimate the epoch of formation of the Hubble classification…
Both theoretical and observational lines of reasoning suggest that the very faint (B > 24) galaxies seen in deep images of the sky are small low-mass galaxies that experienced starburst at 0.5<z<1 and have since faded into low luminosity,…
The statistical properties of the ellipticities of galaxy images depend on how galaxies form and evolve, and therefore constrain models of galaxy morphology, which are key to the removal of the intrinsic alignment contamination of…
We present very deep $HST$ WFPC2 images in the F814W filter of two Hawaii Survey fields, SSA13 and SSA22. Using these data with previous ground-based imaging and spectroscopy, we compare the colors, star-forming properties and morphologies…
Intrinsic galaxy alignments constitute the major astrophysical systematic of forthcoming weak gravitational lensing surveys but also yield unique insights into galaxy formation and evolution. We build analytic models for the distribution of…
Several independent lines of reasoning suggest that many of the very faint (B > 24) blue galaxies are low-mass objects that experienced a short epoch of star formation at redshifts 0.5 < z < 1 and have since faded into low luminosity, low…