scholarly journals Galaxy Size Evolution at High Redshift and Surface Brightness Selection Effects: Constraints from the Hubble Ultra Deep Field

2004 ◽  
Vol 611 (1) ◽  
pp. L1-L4 ◽  
Author(s):  
R. J. Bouwens ◽  
G. D. Illingworth ◽  
J. P. Blakeslee ◽  
T. J. Broadhurst ◽  
M. Franx
Keyword(s):  
Surface Brightness ◽  
High Redshift ◽  
Selection Effects ◽  
Size Evolution ◽  
Hubble Ultra Deep Field

scholarly journals The Size-Luminosity Relation of Disk Galaxies in EDisCS Clusters

2006 ◽  
Vol 2 (S235) ◽  
pp. 201-201
Author(s):  
Stephanie M. Gogarten ◽  
Julianne J. Dalcanton ◽  
Luc Simard ◽  
Gregory Rudnick ◽  
Vandana Desai ◽  
...  
Keyword(s):  
Surface Brightness ◽  
High Redshift ◽  
Disk Galaxies ◽  
Selection Effects ◽  
Distant Cluster ◽  
Cluster Survey ◽  
Low Surface Brightness ◽  
Advanced Camera For Surveys ◽  
Low Surface Brightness Galaxies

AbstractWe present the size-luminosity relation (SLR) for disk galaxies observed in eight clusters from the ESO Distant Cluster Survey (EDisCS). These clusters, at redshifts 0.4 < z < 0.8, were observed with the Hubble Space Telescope's Advanced Camera for Surveys. While we observe a change in the SLR with redshift, namely that there is an absence of low surface brightness galaxies at high redshift, we demonstrate that this could be a product of selection effects and thus is not a confirmation of evolution. We also compare the SLR for cluster and field galaxies in each redshift bin and see no significant effects of environment on the SLR.

scholarly journals The MUSE Hubble Ultra Deep Field Survey

2017 ◽  
Vol 608 ◽  
pp. A8 ◽  
Author(s):  
Floriane Leclercq ◽  
Roland Bacon ◽  
Lutz Wisotzki ◽  
Peter Mitchell ◽  
Thibault Garel ◽  
...  
Keyword(s):  
High Redshift ◽  
Dark Matter Halo ◽  
Star Forming ◽  
Star Forming Regions ◽  
Size Evolution ◽  
Individual Star ◽  
Hubble Ultra Deep Field ◽  
Gas Accretion ◽  
Scale Length

We report the detection of extended Lyα haloes around 145 individual star-forming galaxies at redshifts 3 ≤ z ≤ 6 in the Hubble Ultra Deep Field observed with the Multi-Unit Spectroscopic Explorer (MUSE) at ESO-VLT. Our sample consists of continuum-faint (− 15 ≥ MUV ≥ −22) Lyα emitters (LAEs). Using a 2D, two-component (continuum-like and halo) decomposition of Lyα emission assuming circular exponential distributions, we measure scale lengths and luminosities of Lyα haloes. We find that 80% of our objects having reliable Lyα halo measurements show Lyα emission that is significantly more extended than the UV continuum detected by HST (by a factor ≈4 to >20). The median exponential scale length of the Lyα haloes in our sample is ≈4.5 kpc with a few haloes exceeding 10 kpc. By comparing the maximal detected extent of the Lyα emission with the predicted dark matter halo virial radii of simulated galaxies, we show that the detected Lyα emission of our selected sample of Lyα emitters probes a significant portion of the cold circum-galactic medium of these galaxies (>50% in average). This result therefore shows that there must be significant HI reservoirs in the circum-galactic medium and reinforces the idea that Lyα haloes are ubiquitous around high-redshift Lyα emitting galaxies. Our characterization of the Lyα haloes indicates that the majority of the Lyα flux comes from the halo (≈65%) and that their scale lengths seem to be linked to the UV properties of the galaxies (sizes and magnitudes). We do not observe a significant Lyα halo size evolution with redshift, although our sample for z> 5 is very small. We also explore the diversity of the Lyα line profiles in our sample and we find that the Lyα lines cover a large range of full width at half maximum (FWHM) from 118 to 512 km s-1. While the FWHM does not seem to be correlated to the Lyα scale length, most compact Lyα haloes and those that are not detected with high significance tend to have narrower Lyα profiles (<350 km s-1). Finally, we investigate the origin of the extended Lyα emission but we conclude that our data do not allow us to disentangle the possible processes, i.e. scattering from star-forming regions, fluorescence, cooling radiation from cold gas accretion, and emission from satellite galaxies.

scholarly journals Luminosity Selection Effects and Linear Size Evolution in the Quasar/Galaxy Unification Scheme

1998 ◽  
Vol 51 (1) ◽  
pp. 143
Author(s):  
A. A. Ubachukwu ◽  
J. N. Ogwo
Keyword(s):  
High Redshift ◽  
Radio Galaxies ◽  
Linear Size ◽  
Selection Effects ◽  
Size Evolution

The implications of linear size evolution and luminosity selection effects in the quasar/galaxy unification scheme have been investigated. We show that both radio galaxies and quasars undergo similar size evolution above some low redshift cut-off zc = 0·2–0·3. However, this evolution can be attributed largely to the strong luminosity selection effects present in the sample. We also observe that there is a marked difference in the luminosity–redshift slope between low and high redshift sources, which may be responsible for the conflicting results in the literature as to whether or not radio galaxies and quasars have similar linear size versus luminosity/redshift relationships. Our present result seems consistent with the quasar/galaxy unification scheme in which the two classes of object are expected to have similar linear size versus luminosity/redshift relationships.

scholarly journals The Tully-Fisher Relation as a Function of Redshift: Disentangling Galaxy Evolution and Selection Biases

2006 ◽  
Vol 2 (S235) ◽  
pp. 3-7
Author(s):  
Nicole P. Vogt
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Velocity Structure ◽  
High Redshift ◽  
Selection Effects ◽  
Groups Of Galaxies ◽  
Wide Range ◽  
Fisher Relation

AbstractWe review the status of current observations of the fundamental parameters of intermediate redshift (z ≤ 1.2) disk galaxies. Advances in instrumentation of 8-10m class telescopes have made possible detailed measurements of galaxy luminosity, morphology, kinematics and mass, in both the optical and the infrared passbands. By studying such well known star formation indicators as [OII]3727A (in the optical) and Hα (redshifted to the infrared), the internal velocity structure and star formation rates of galaxies can be traced through this entire redshift regime. The combination of throughput and optimum seeing conditions yields spectra which can be combined with high resolution multiband imaging to explore the evolution of galaxies of various morphologies, and to place constraints on current models of galaxy formation and star formation histories.Out to redshifts of unity, these data form a high redshift Tully-Fisher relation that spans four magnitudes and extends to well below L*, with no obvious change in shape or slope with respect to the local relation. A comparison of disk surface brightness between local and high redshift samples yields an offset in accordance with distance-dependent surface brightness selection effects, as can the apparent change in disk size with redshift for disks of a given mass. These results support low Ω0 models of formation, and provide further evidence for modest increases in luminosity with lookback time for the bulk of the observed field spiral galaxy population.Finally, a comparison of spatially resolved spectra versus integrated emission line widths for distant galaxies suggests that observational constraints bias each type of observational sample toward different sub-groups of galaxies, with different evolutionary histories. Like varying selection effects, this will lead to a wide range of projected evolutionary trends.

The Quest for Relics: Massive compact galaxies in the local Universe

2019 ◽  
Vol 15 (S359) ◽  
pp. 441-443
Author(s):  
F. S. Lohmann ◽  
A. Schnorr-Müller ◽  
M. Trevisan ◽  
R. Riffel ◽  
N. Mallmann ◽  
...  
Keyword(s):  
High Redshift ◽  
Control Sample ◽  
Sloan Digital Sky Survey ◽  
Integral Field Spectroscopy ◽  
Sky Survey ◽  
Size Evolution ◽  
Compact Galaxies ◽  
Minor Mergers ◽  
Significant Size ◽  
Integral Field

AbstractObservations at high redshift reveal that a population of massive, quiescent galaxies (called red nuggets) already existed 10 Gyr ago. These objects undergo a significant size evolution over time, likely due to minor mergers. In this work we present an analysis of local massive compact galaxies to assess if their properties are consistent with what is expected for unevolved red nuggets (relic galaxies). Using integral field spectroscopy (IFS) data from the MaNGA survey from the Sloan Digital Sky Survey (SDSS), we characterized the kinematics and properties of stellar populations of massive compact galaxies, and find that these objects exhibit, on average, a higher rotational support than a control sample of average sized early-type galaxies. This is in agreement with a scenario in which these objects have a quiet accretion history, rendering them candidates for relic galaxies.

scholarly journals The image plane approach to cosmic telescopes

2015 ◽  
Vol 11 (A29B) ◽  
pp. 783-784
Author(s):  
Masamune Oguri
Keyword(s):  
Gravitational Lensing ◽  
Luminosity Function ◽  
High Redshift ◽  
Selection Effect ◽  
Image Plane ◽  
High Redshift Galaxies ◽  
The Public ◽  
Size Evolution ◽  
Redshift Galaxies

AbstractStudies of high-redshift galaxies behind the cores of mass clusters require the correction of gravitational lensing effects. We present our approach to estimate shapes, magnitudes, and the selection effect of high-redshift galaxies in the image plane, which allows us to include not only lensing magnifications but also lensing distortions and image multiplications. For this purpose we construct new mass models for the Frontier Fields clusters using the public software glafic. We present some results on faint-end slopes of the luminosity function and the size evolution of high-redshift galaxies from the analysis of Frontier Fields clusters.

On the concentration of high redshift quasars in the region of m33

1986 ◽  
Vol 119 ◽  
pp. 511-512
Author(s):  
Vijay K. Kapahi
Keyword(s):  
High Redshift ◽  
Selection Effects ◽  
Large Area ◽  
Strong Concentration

We have investigated the strong concentration of high redshift radio quasars in a large area of the sky near M33 reported by Arp. Selection effects appear to be important in determining the significance of the inhomogeneity.

scholarly journals Number Counts and Evolving Dwarfs

1996 ◽  
Vol 171 ◽  
pp. 431-431
Author(s):  
S. Philllipps ◽  
S.P. Driver
Keyword(s):  
Surface Brightness ◽  
High Redshift ◽  
Redshift Surveys ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Number Counts ◽  
Band Number

Recent redshift surveys (eg. Colless et al. 1993) have shown that the excess galaxies seen in faint B band number counts are not evolved giants at high redshift, but low to moderate luminosity objects at modest redshifts. This led to the suggestion (eg. Cowie et al. 1991) that there was once an extra population of dwarfs which has now disappeared, ie. there is nonconservation of galaxy number. We have investigated a picture in which the dwarfs have merely faded to become very low surface brightness galaxies like those now turning up in nearby clusters (eg. Turner et al. 1993).

scholarly journals Cosmological models and the brightness profile of distant galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 329-329
Author(s):  
I. Olivares-Salaverri ◽  
Marcelo B. Ribeiro
Keyword(s):  
Cosmological Model ◽  
Observational Data ◽  
Galaxy Evolution ◽  
Surface Brightness ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Surface Profile ◽  
Galactic Evolution ◽  
Spectral Energy ◽  
Distant Galaxies

This work aims to determine the feasibility of an assumed cosmological model by means of a detailed analysis of the brightness profiles of distant galaxies. Starting from the theory of Ellis & Perry (1979) connecting the angular diameter distance obtained from a relativistic cosmological model and the detailed photometry of galaxies, we assume the presently most accepted cosmology with Λ ¬ = 0 and seek to predict the brightness profile of a galaxy in a given redshift z. To do so, we have to make assumptions concerning the galactic brightness structure and evolution, assuming a scenario where the specific emitted surface brightness Be,νe can be characterized as, Be,νe (r,z) = B0(z)J(νe,z)f[r(z)/a(z)]. Here r is the intrinsic galactic radius, νe the emitted frequency, B0(z) the central surface brightness, J(νe,z) the spectral energy distribution (SED), f[r(z)/a(z)] characterizes the shape of the surface profile distribution and a(z) is the scaling radius. The dependence on z is due to the galactic evolution. As spacetime curvature affects the received surface brightness, the reciprocity theorem (Ellis 1971) allows us to predict the theoretical received surface brightness. So, we are able to compare the theoretical surface brightness with its equivalent observational data already available for high redshift galaxies in order to test the consistency of the assumed cosmological model. The function f[r(z)/a(z)] is represented in the literature by various different shapes, like the Hubble, Hubble-Oemler and Abell-Mihalas single parameter profiles, characterizing the galactic surface brightness quite well when the disk or bulge dependence is dominant. Sérsic and core-Sérsic profiles use two or more parameters and reproduce the galactic profile almost exactly (Trujillo et al. 2004). If we consider all wavelengths, the theory tells us that the total intensity is equal to the surface brightness, so the chosen bandwidth should include most of the SED. In order to analyze only the effect of the cosmological model in the surface brightness and minimize evolutionary effects, we assume that there exists a homogeneous class of objects, whose properties are similar in all redshifts, allowing us to carry out comparisons at different values of z. Studying the parameters that affect the galactic evolution, as well as in others geometrical tests, we will be able to infer some possible galaxy evolution which could reproduce a theoretical surface brightness profile, in order to compare with the observational data and reach conclusions about the observational feasibility of the underlying cosmological model.

scholarly journals Opaque Spiral Disks: Some Empirical Facts and Consequences

1991 ◽  
Vol 144 ◽  
pp. 245-256
Author(s):  
Edwin A. Valentijn
Keyword(s):  
Surface Brightness ◽  
Axial Ratio ◽  
Recent Analysis ◽  
Line Of Sight ◽  
Selection Effects ◽  
Complete Sample ◽  
Large Samples ◽  
The Galaxy ◽  
Absorbing Material ◽  
Image Position

A recent analysis of the surface brightness profiles of a complete sample of 9381 spiral galaxies extracted from ESO-LV (Lauberts and Valentijn, 1989) showed that many galaxy disks of especially Sb–Sc galaxies are opaque (Valentijn, 1990). This paper studied how the observed surface brightness μobs varies as a function of the observed axial ratio a/b, by fitting the data of samples of spirals with (1) assuming the a/b to give the inclination angle of the disks to the line of sight. A sample of galaxies that were fully transparent at the particular radius used for the test would have C ≃ 1, while C <~ 0.25 signifies opaque conditions, the transition value being heavily dependent on the spatial distribution of the absorbing material and the effect of multiple scatterings (Bruzual et al. 1988). The most frequently-used C values range from 0.5–0.9 (Holmberg 1975, de Vaucouleurs et al. 1976, Sandage and Tammann 1981). However, Valentijn (1990) derived C values well below 0.25 for large samples of spirals throughout the galaxy disks; this result is not significantly affected by selection effects in either magnitude, angular diameter or axial ratio, nor by the presence of bulges (at least for types Sb and later).

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