Luminosity Functions of 10 Nearby Clusters of Galaxies. II. Analysis of the Luminosity Function

2002 ◽  
Vol 123 (1) ◽  
pp. 87-99 ◽  
Author(s):  
M. Yagi ◽  
N. Kashikawa ◽  
M. Sekiguchi ◽  
M. Doi ◽  
N. Yasuda ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Clusters Of Galaxies ◽  
Luminosity Functions

USING WEAK-LENSING DILUTION TO MEASURE LIGHT PROPERTIES OF A1689

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1521-1528 ◽  
Author(s):  
ELINOR MEDEZINSKI ◽  
TOM BROADHURST ◽  
KEIICHI UMETSU ◽  
DAN COE
Keyword(s):  
Luminosity Function ◽  
Dilution Effect ◽  
Weak Lensing ◽  
Large Radius ◽  
Clusters Of Galaxies ◽  
New Approach ◽  
Luminosity Functions ◽  
Galaxy Populations ◽  
Constant Slope ◽  
Massive Cluster

Weak-lensing induced by clusters of galaxies can probe the total mass distribution out to the virial radius of the cluster, regardless of the nature of the mass or its dynamical state. To make a robust analysis, the cluster and background galaxy populations need to be separated. The E/S0 sequence of a cluster defines a boundary redward of which a reliable weak-lensing signal can be obtained from background galaxies, uncontaminated by the cluster. Below this limit, the signal is diluted by the proportion of unlensed cluster members. Employing deep Subaru and HST/ACS images of the massive cluster A1689, we use this dilution effect to carefully separate between the cluster members and the background, and thus derive the cluster light profile and luminosity functions to large radius. The light profile of A1689 is found to decline steadily to the limit of the data, r < 2 h−1 Mpc , with a constant slope, d log (L)/d log (r) = −1.12 ± 0.06. We derive a cluster luminosity function with a flat faint-end slope of α = −1.05 ± 0.07, nearly independent of radius and with no faint upturn to Mi′ < −12. The major advantage of this new approach is that no subtraction of far-field background counts is required.

scholarly journals The Westerbork Survey of Rich Clusters of Galaxies

1980 ◽  
Vol 5 ◽  
pp. 715-721 ◽  
Author(s):  
Edwin A. Valentijn
Keyword(s):  
Luminosity Function ◽  
Point Of View ◽  
Clusters Of Galaxies ◽  
Radio Luminosity ◽  
General Reference ◽  
Statistical Point ◽  
Cluster Galaxies ◽  
Luminosity Functions ◽  
The Galaxy ◽  
Radio Luminosity Function

In the Westerbork Survey of Rich Clusters of galaxies (WSRC), seven nearby and rich clusters of galaxies have been observed with the Westerbork Synthesis Radio Telescope. The results obtained at different frequencies are published in several papers of a series, and Table 1 serves as a general reference to these publications. In these papers, both discussions on individual radio sources and the presentation of cluster radio luminosity functions (RLF) are given. Here we summarize some of the results of the WSRC which, from a statistical point of view, impose some constraints on the rate of the radio activity of galaxies and on the influence of the galaxy environments on their activity. The rate of radio activity of a sample of galaxies in a cluster can be described by the integral RLF of the cluster, which represents the fraction of galaxies that emit in the radio domain above a certain power. When it is presented as a function of the optical luminosities of the cluster galaxies, it is called the bivariate radio luminosity function (BRLF). The BRLFs are most suitable for representing in an unbiased way the rate of activity of a sample of galaxies, since they are presented in absolute parameters and are normalized to the optical luminosity function (or distribution) of the galaxy samples. This is important since, both inside and outside clusters, it has been shown that the RLF depends strongly on the optical luminosities.

scholarly journals Type-Specific Luminosity Functions of Nearby Clusters of Galaxies

1999 ◽  
Vol 183 ◽  
pp. 272-272
Author(s):  
M. Yagi ◽  
K. Shimasaku ◽  
N. Yasuda ◽  
M. Doi ◽  
S. Okamura ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Ccd Camera ◽  
Clusters Of Galaxies ◽  
Total Luminosity ◽  
Luminosity Functions ◽  
Band Image

We study the total luminosity function (LF) and the type-specific LF of 7 nearby clusters of galaxies (A1060, S805, A2063, A1736, A1644, A1631, and A754) using the R-band image (1.0 × 0.5 deg2) taken with our mosaic CCD camera mounted on 1-m telescope at the Las Campanas Observatory.

scholarly journals Carbon stars as standard candles – II. The median J magnitude as a distance indicator

2020 ◽  
Vol 501 (1) ◽  
pp. 933-947
Author(s):  
Javiera Parada ◽  
Jeremy Heyl ◽  
Harvey Richer ◽  
Paul Ripoche ◽  
Laurie Rousseau-Nepton
Keyword(s):  
Luminosity Function ◽  
Asymptotic Giant Branch ◽  
Distance Modulus ◽  
Asymptotic Giant Branch Stars ◽  
Luminosity Functions ◽  
Best Fitting ◽  
Distance Indicator ◽  
Ngc 6822 ◽  
The Given ◽  
Giant Branch Stars

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

scholarly journals Cosmological evolution of the AGN kinetic luminosity function

2006 ◽  
Vol 2 (S238) ◽  
pp. 65-70
Author(s):  
Andrea Merloni ◽  
Sebastian Heinz
Keyword(s):  
Galaxy Formation ◽  
Luminosity Function ◽  
Cosmological Evolution ◽  
Energy Output ◽  
Theoretical Assumption ◽  
X Ray ◽  
Spectrum Radio ◽  
Luminosity Functions ◽  
Jet Power ◽  
Joint Evolution

AbstractWe present a first attempt to derive the cosmological evolution of the kinetic luminosity function of AGN based on the joint evolution of the flat spectrum radio and hard X-ray selected AGN luminosity functions. An empirical correlation between jet power and radio core luminosity is found, which is consistent with the theoretical assumption that, below a certain Eddington ratio, SMBH accrete in a radiatively inefficient way, while most of the energy output is in the form of kinetic energy.We show how the redshift evolution of the kinetic power density from such a low-ṁ mode of accretion makes it a good candidate to explain the so-called “radio mode” of AGN feedback as outlined in many galaxy formation schemes.

Extragalactic X-ray sources and the diffuse X-ray background

1979 ◽  
Vol 366 (1726) ◽  
pp. 391-402 ◽  
Keyword(s):  
Spatial Distribution ◽  
Euclidean Space ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Optical Identification ◽  
X Ray ◽  
Luminosity Functions ◽  
Sky Survey ◽  
Order Of Magnitude ◽  
X Ray Background

Results from the Ariel 5 sky survey instrument relating to the properties and the spatial distribution of extragalactic X-ray sources are discussed. The lg N -lg S relation for sources in the 2A catalogue is consistent with a uniform distribution of sources in Euclidean space. In addition, measure­ments of fluctuations in the X-ray background suggest that the Euclidean form of the source counts can be extrapolated to flux levels at least an order of magnitude fainter than the 2A catalogue limit. Information is also available from the optical identification of 2A sources which, through redshift measurements, enables the X-ray luminosity functions of the two main classes of source, namely clusters of galaxies and active galaxies, to be determined. The luminosity functions can be used to calculate the contribution of clusters of galaxies and active galaxies to the diffuse X-ray background in the 2-10 keV range. It is found that cosmological evolution of one or both populations is required to account for the diffuse X-ray background entirely in terms of the integrated emission from these sources.

scholarly journals Evolution of the AGN UV luminosity function from redshift 7.5

2019 ◽  
Vol 488 (1) ◽  
pp. 1035-1065 ◽  
Author(s):  
Girish Kulkarni ◽  
Gábor Worseck ◽  
Joseph F Hennawi
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
Galactic Nuclei ◽  
Systematic Errors ◽  
Selection Function ◽  
Data Sets ◽  
Multiple Data ◽  
Luminosity Functions ◽  
Multiple Data Sets ◽  
Photoionization Rate

ABSTRACTDeterminations of the ultraviolet (UV) luminosity function of active galactic nuclei (AGN) at high redshifts are important for constraining the AGN contribution to reionization and understanding the growth of supermassive black holes. Recent inferences of the luminosity function suffer from inconsistencies arising from inhomogeneous selection and analysis of data. We address this problem by constructing a sample of more than 80 000 colour-selected AGN from redshift $z$ = 0 to 7.5 using multiple data sets homogenized to identical cosmologies, intrinsic AGN spectra, and magnitude systems. Using this sample, we derive the AGN UV luminosity function from redshift $z$ = 0 to 7.5. The luminosity function has a double power-law form at all redshifts. The break magnitude M* shows a steep brightening from M* ∼ −24 at $z$ = 0.7 to M* ∼ −29 at $z$ = 6. The faint-end slope β significantly steepens from −1.9 at $z$ < 2.2 to −2.4 at $z$ ≃ 6. In spite of this steepening, the contribution of AGN to the hydrogen photoionization rate at $z$ ∼ 6 is subdominant (<3 per cent), although it can be non-negligible (∼10 per cent) if these luminosity functions hold down to M1450 = −18. Under reasonable assumptions, AGN can reionize He ii by redshift $z$ = 2.9. At low redshifts ($z$ < 0.5), AGN can produce about half of the hydrogen photoionization rate inferred from the statistics of H i absorption lines in the intergalactic medium. Our analysis also reveals important systematic errors in the data, which need to be addressed and incorporated in the AGN selection function in future in order to improve our results. We make various fitting functions, codes, and data publicly available.

scholarly journals The WIRCam Ultra Deep Survey (WUDS)

2018 ◽  
Vol 620 ◽  
pp. A51 ◽  
Author(s):  
R. Pelló ◽  
P. Hudelot ◽  
N. Laporte ◽  
Y. Mellier ◽  
H. J. McCracken ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Formation Rate ◽  
Forthcoming Paper ◽  
Spectroscopic Studies ◽  
Photometric Redshifts ◽  
Near Ir ◽  
Luminosity Functions ◽  
The Galaxy ◽  
Deep Survey ◽  
Galaxy Population

The aim of this paper is to introduce the WIRCam Ultra Deep Survey (WUDS), a near-IR photometric survey carried out at the CFH Telescope in the field of the CFHTLS-D3 field (Groth Strip). WUDS includes four near-IR bands (Y, J, H and Ks) over a field of view of ∼400 arcmin2. The typical depth of WUDS data reaches between ∼26.8 in Y and J, and ∼26 in H and Ks (AB, 3σ in 1.3″ aperture), whereas the corresponding depth of the CFHTLS-D3 images in this region ranges between 28.6 and 29 in ugr, 28.2 in i and 27.1 in z (same S/N and aperture). The area and depth of this survey were specifically tailored to set strong constraints on the cosmic star formation rate and the luminosity function brighter or around L⋆ in the z ∼ 6 − 10 redshift domain, although these data are also useful for a variety of extragalactic projects. This first paper is intended to present the properties of the public WUDS survey in details: catalog building, completeness and depth, number counts, photometric redshifts, and global properties of the galaxy population. We have also concentrated on the selection and characterization of galaxy samples at z ∼ [4.5 − 7] in this field. For these purposes, we include an adjacent shallower area of ∼1260 arcmin2 in this region, extracted from the WIRCam Deep Survey (WIRDS), and observed in J, H and Ks bands. UV luminosity functions were derived at z ∼ 5 and z ∼ 6 taking advantage from the fact that WUDS covers a particularly interesting regime at intermediate luminosities, which allows a combined determination of M⋆ and Φ⋆ with increased accuracy. Our results on the luminosity function are consistent with a small evolution of both M⋆ and Φ⋆ between z = 5 and z = 6, irrespective of the method used to derive them, either photometric redshifts applied to blindly-selected dropout samples or the classical Lyman Break Galaxy color-preselected samples. Our results lend support to higher Φ⋆ determinations at z = 6 than usually reported. The selection and combined analysis of different galaxy samples at z ≥ 7 will be presented in a forthcoming paper, as well as the evolution of the UV luminosity function between z ∼ 4.5 and 9. WUDS is intended to provide a robust database in the near-IR for the selection of targets for detailed spectroscopic studies, in particular for the EMIR/GTC GOYA Survey.

Sign in / Sign up

Export Citation Format

Share Document