Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe IRAC galaxy correlation functions from SWIRE
244
0
0.0
(
0
)
Authors
Ian Waddington
Ask ChatGPT about the research
No Arabic abstract
We present an analysis of large-scale structure from the Spitzer Wide-area Infrared Extragalactic legacy survey, SWIRE. The two-point angular correlation functions were computed for galaxies detected in the 3.6-micron IRAC band, on angular scales up to a degree. Significant evolution in the clustering amplitude was detected, as the median redshift of the samples increases from z=0.2 to 0.6. The galaxy clustering in the GALICS semi-analytic models was compared with the observed correlation functions and found to disagree with the data at faint flux limits.
rate research
Read More
We present the galaxy cluster autocorrelation function of 277 galaxy cluster candidates with 0.25 le z le 1.5 in a 7 deg^2 area of the IRAC Shallow Cluster Survey. We find strong clustering throughout our galaxy cluster sample, as expected for these massive structures. Specifically, at <z> = 0.5 we find a correlation length of r_0 = 17.40^{+3.98}_{-3.10} h^-1 Mpc, in excellent agreement with the Las Campanas Distant Cluster Survey, the only other non-local measurement. At higher redshift, <z> = 1, we find that strong clustering persists, with a correlation length of r_0=19.14^{+5.65}_{-4.56} h^-1 Mpc. A comparison with high resolution cosmological simulations indicates these are clusters with halo masses of sim 10^{14} Msun, a result supported by estimates of dynamical mass for a subset of the sample. In a stable clustering picture, these clusters will evolve into massive (10^{15} Msun) clusters by the present day.
Correlation functions and related statistics have been favorite measures of the distributions of extragalactic objects ever since people started analyzing the clustering of the galaxies in the 1930s. I review the evolving reasons for this choice, and comment on some of the present issues in the application and interpretation of these statistics, with particular attention to the question of how closely galaxies trace mass.
We characterize the SWIRE galaxy populations in the SWIRE validation field within the Lockman Hole, based on the 3.6-24$mu$ Spitzer data and deep U,g,r,r optical imaging within an area ~1/3 sq. deg for ~16,000 Spitzer-SWIRE sources. The entire SWIRE survey will discover over 2.3 million galaxies at 3.6$mu$m and almost 350,000 at 24$mu$m; ~70,000 of these will be 5-band 3.6-24$mu$ detections. The colors cover a broad range, generally well represented by redshifted spectral energy distributions of known galaxy populations, however significant samples of unusually blue objects in the [3.6-4.5]$mu$m color are found, as well as many objects very red in the 3.6-24$mu$m mid-IR. Nine of these are investigated and are interpreted as star-forming systems, starbursts and AGN from z=0.37 to 2.8, with luminosities from L$_{IR}$=10$^{10.3}$ to 10$^{13.7}$ L$_{odot}$
We compute covariance matrices for many observed estimates of the stellar mass function of galaxies from $z=0$ to $zapprox 4$, and for one estimate of the projected correlation function of galaxies split by stellar mass at $zlesssim 0.5$. All covariance matrices include contributions due to large scale structure, the preference for galaxies to be found in groups and clusters, and for shot noise. These covariance matrices are made available for use in constraining models of galaxy formation and the galaxy-halo connection.
We derive a simple formula relating the cross section for light cluster production (defined via a coalescence factor) to the two-proton correlation function measured in heavy-ion collisions. The formula generalises earlier coalescence-correlation relations found by Scheibl & Heinz and by Mrowczynski for Gaussian source models. It motivates joint experimental analyses of Hanbury Brown-Twiss (HBT) and cluster yield measurements in existing and future data sets.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
