scholarly journals The luminosity function and space density of the most luminous galaxies in the IRAS survey

1986 ◽  
Vol 303 ◽  
pp. L41 ◽  
Author(s):  
B. T. Soifer ◽  
D. B. Sanders ◽  
G. Neugebauer ◽  
G. E. Danielson ◽  
Carol J. Lonsdale ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Space Density ◽  
Luminous Galaxies

scholarly journals The Surface Density of Quasars

1978 ◽  
Vol 79 ◽  
pp. 295-303 ◽  
Author(s):  
J.G. Bolton ◽  
Ann Savage
Keyword(s):  
Surface Density ◽  
Luminosity Function ◽  
Statistical Significance ◽  
Comprehensive Investigation ◽  
Space Density ◽  
Close Pairs

A knowledge of the surface density of quasars as a function of magnitude is important for two reasons. Firstly it is necessary in order to assess the possible statistical significance of close pairs of quasars or the association between quasars and bright galaxies. Secondly it is a necessary step in the determination of the space density or luminosity function of QSOs. We have carried out what we believe to be currently the most comprehensive investigation into the surface density of quasars. Three techniques have been used in this investigation. These are

scholarly journals The Space Density of Spiral Galaxies as function of their Luminosity, Surface Brightness and Scalesize

1999 ◽  
Vol 171 ◽  
pp. 52-59 ◽  
Author(s):  
Roelof S. de Jong ◽  
Cedric Lacey
Keyword(s):  
Surface Brightness ◽  
Luminosity Function ◽  
Spiral Galaxies ◽  
Structural Parameters ◽  
Space Density ◽  
Cosmological Redshift ◽  
Density Distributions ◽  
Low Surface Brightness ◽  
Local Space ◽  
Log Normal

AbstractThe local space density of galaxies as a function of their basic structural parameters -like luminosity, surface brightness and scalesize-is still poorly known. Our poor knowledge is mainly the result of strong selection biases against low surface brightness and small scalesize galaxies in any optically selected sample. We show that in order to correct for selection biases one has to obtain accurate surface photometry and distance estimates for a large (≳ 1000) sample of galaxies. We derive bivariate space density distributions in the (scalesize, surface brightness)-plane and the (luminosity, scalesize)-plane for a sample of ~1000 local Sb-Sdm spiral galaxies. We present a parameterization of these bivariate distributions, based on a Schechter type luminosity function and a log-normal scalesize distribution at a given luminosity. We show how surface brightness limits and (1+z)4 cosmological redshift dimming can influence interpretation of luminosity function determinations and deep galaxy counts.

The Stromlo-APM Redshift Survey. I - The luminosity function and space density of galaxies

1992 ◽  
Vol 390 ◽  
pp. 338 ◽  
Author(s):  
J. Loveday ◽  
B. A. Peterson ◽  
G. Efstathiou ◽  
S. J. Maddox
Keyword(s):  
Luminosity Function ◽  
Space Density ◽  
Redshift Survey

scholarly journals Radio Source Evolution Derived from Low Frequency Surveys

2002 ◽  
Vol 199 ◽  
pp. 50-53
Author(s):  
C.A. Jackson ◽  
J.V. Wall
Keyword(s):  
Radio Source ◽  
Luminosity Function ◽  
Low Frequency ◽  
Radio Galaxies ◽  
Parametric Models ◽  
Radio Luminosity ◽  
Space Density ◽  
Radio Data ◽  
Radio Luminosity Function

We find simple parametric models to describe the space density evolution of radio-loud AGN, treating FRI and FRII radio galaxies separately as the two parent populations in our dual-population unified scheme. In this we use low frequency radio data (v < 500 MHz), where radio samples are unbiased by Doppler beaming. Incorporated into this latest analysis is a new determination of the local radio luminosity function at 1.4 GHz from galaxies common to both the 2dFGRS and NVSS surveys.

scholarly journals Properties of cD Galaxies

1987 ◽  
Vol 127 ◽  
pp. 89-98
Author(s):  
John L. Tonry
Keyword(s):  
Surface Brightness ◽  
Luminosity Function ◽  
Elliptical Galaxies ◽  
The Other ◽  
Cluster Evolution ◽  
Cluster Of Galaxies ◽  
Luminous Galaxies ◽  
Cd Galaxies ◽  
The Universe ◽  
Inner Parts

cD galaxies are the most luminous galaxies in the universe. They are characterized by a surface brightness profile that falls off more slowly with radius than most elliptical galaxies. In most respects D galaxies are a continuous extrapolation from other ellipticals: their M/L and their colors are comparable to other ellipticals, their inner parts are fitted by an r1/4 law, and they follow the same relation between L and σ. On the other hand, their luminosity is too bright to be consistent with the luminosity function of other ellipticals and they are always found at the center of a cluster of other galaxies. Being at the center of a cluster of galaxies often endows D galaxies with a very faint, very extended halo of luminosity and multiple nuclei, but these are more properly associated with the cluster than the D galaxy itself. The connection between the formation of cD galaxies and the formation of clusters remains a mystery. It is still unresolved whether cDs are a byproduct of cluster evolution, whether they formed in parallel with clusters, or whether primeval D are galaxies the seed around which clusters accreted.

scholarly journals Uncovering Ultra-Luminous Galaxies in the IRAS FSC Through Radio and Optical Cross-Identification

1998 ◽  
Vol 179 ◽  
pp. 273-274
Author(s):  
G. Aldering
Keyword(s):  
Reliable Method ◽  
Infrared Galaxies ◽  
Space Density ◽  
Large Sample ◽  
Present Epoch ◽  
Luminous Galaxies ◽  
Ultraluminous Infrared Galaxies ◽  
Do So

Ultraluminous infrared galaxies (ULIRGs) have luminosities (1012L⊙) once exclusive to QSOs. This suggests they might be the early, dust-enshrouded stages of QSOs. ULIRGs have ∼ 3.5× the space density of QSOs at the present epoch. Quasars reached their peak space density at z ∼ 2, so if ULIRGs are QSO precursors, there should be a dramatic increase in their space density up to z ∼ 2. The small number of known ULIRGs makes it difficult to explore links between ULIRGs and QSOs, much less measure their evolution. To do so, a large sample of ULIRG candidates must be identified. The IRAS FSC contains ∼ 60,000 probable galaxies, of which 1%–3% should have LFIR > 1012L⊙. We discuss an efficient and reliable method which uses IRAS-VLA-APS cross-identification and flux ratios to mine the FSC for likely ULIRGs.

scholarly journals Challenges of Using Planetary Nebulae for Extragalactic Distances

1995 ◽  
Vol 10 ◽  
pp. 504-506
Author(s):  
L. Bottinelli ◽  
L. Gouguenheim ◽  
G. Paturel ◽  
P. Teerikorpi
Keyword(s):  
Crucial Role ◽  
Luminosity Function ◽  
Dwarf Galaxy ◽  
Planetary Nebulae ◽  
Absolute Magnitude ◽  
Distance Scale ◽  
Distance Determination ◽  
Luminous Galaxies ◽  
Intrinsic Scatter ◽  
Selection Of

The planetary nebulae (hereafter PN) distance criterion (Ciardullo et al. 1989a) relies on the shape adopted for the luminosity function (hereafter LF) and its adequate fit to the observed data. Crucial hypothesis concerning the LF are its universal shape with an universal value of the absolute magnitude cut-off and concerning the sample, its completeness and the selection of the rejected data.Because the completeness is achieved only in the bright part of the LF, the brighest PN play a crucial role in the distance determination and it is well known that the brightest objects (with intrinsic scatter) in a giant galaxy are brighter than in a dwarf galaxy. Thus more luminous galaxies are given smaller distances. Because giant galaxies are rare they are not seen at small distances; on the contrary, they are typically observed at large distances. This effect induces a progressive compression of the distance scale.

scholarly journals Cosmological Interpretation of Redshift Data on Quasars through the V/VMax Test

1977 ◽  
Vol 74 ◽  
pp. 259-268
Author(s):  
M. Schmidt
Keyword(s):  
Emission Line ◽  
Spectral Index ◽  
Luminosity Function ◽  
Radio Luminosity ◽  
Space Density ◽  
Statistical Studies ◽  
Formation And Evolution

The ultimate aim of statistical studies of redshift, magnitudes and flux densities of quasars is to derive the general luminosity function Φ(z, Fopt, Frad, α, …) which describes the space density as a function of redshift, intrinsic optical luminosity, intrinsic radio luminosity, spectral index, etc. We assume throughout that the emission-line redshifts z of quasars are cosmological. The function Φ contains information that will be pertinent for any theory of the formation and evolution of quasars.

scholarly journals Evolution of the Luminosity Function

1986 ◽  
Vol 119 ◽  
pp. 429-438
Author(s):  
Richard F. Green
Keyword(s):  
Luminosity Function ◽  
Cosmic Time ◽  
Volume Density ◽  
Density Evolution ◽  
Space Density ◽  
Mathematical Representations ◽  
Long Lifetime ◽  
Luminosity Evolution ◽  
Fixed Population ◽  
Intrinsic Luminosity

In this review, the currently published, complete, spectroscopically identified samples of quasars are assembled to produce a composite luminosity function, independent of evolutionary assumptions. Two interpretations of the change with cosmic time provide reasonable fits to the data. Luminosity evolution implies a fixed population of host objects, with nuclear luminosity that fades with advancing cosmic time; some dependence of the timescale on intrinsic luminosity is required. Density evolution traces objects of comparable luminosity to find the change in space density, without a requirement of long lifetime. The change in co-moving volume density depends on luminosity; newer data suggest that somewhat stronger evolution is required at the low luminosity end than the models of Schmidt and Green allowed. Caution is advised in drawing direct physical conclusions about the evolution of individual quasars from mathematical representations of ensemble properties.

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