The contribution of very massive high-redshift SWIRE galaxies to the stellar mass function

S. Berta; C. J. Lonsdale; M. Polletta; R. S. Savage; A. Franceschini; H. Buttery; A. Cimatti; J. Dias; C. Feruglio; F. Fiore; E. V. Held; F. La Franca; R. Maiolino; A. Marconi; I. Matute; S. J. Oliver; E. Ricciardelli; S. Rubele; N. Sacchi; D. Shupe; J. Surace

doi:10.1051/0004-6361:20077491

Home/Archive/arXiv

arXiv · 0710.0300

The contribution of very massive high-redshift SWIRE galaxies to the stellar mass function

View original source ↗Read source document ↗Export metadata ↓

Abstract

(Abridged) We selected high-z massive galaxies at 5.8 microns, in the SWIRE ELAIS-S1 field (1 sq. deg.). Galaxies with the 1.6 microns stellar peak redshifted into the IRAC bands (z~1-3, called ``IR-peakers'') were identified. Stellar masses were derived by means of spectro-photometric fitting and used to compute the stellar mass function (MF) at z=1-2 and 2-3. A parametric fit to the MF was performed, based on a Bayesian formalism, and the stellar mass density of massive galaxies above z=2 determined. We present the first systematic study of the very-massive tail of the galaxy stellar mass function at high redshift. A total of 326 sources were selected. The majority of these galaxies have stellar masses in excess of 1e11 Msun and lie at z>1.5. The availability of mid-IR data turned out to be a valuable tool to constrain the contribution of young stars to galaxy SEDs, and thus their M(stars)/L ratio. The influence of near-IR data and of the chosen stellar library on the SED fitting are also discussed. A significant evolution is found not only for galaxies with M~1e11 Msun, but also in the highest mass bins considered. The comoving number density of these galaxies was lower by more than a factor of 10 at z=2-3, with respect to the local estimate. SWIRE 5.8 micron peakers more massive than 1.6x1e11 Msun provide 30-50% of the total stellar mass density in galaxies at z=2-3.

Explore related subjects

astro-ph

Keep this discovery

BibTeX RIS

S. Berta, C. J. Lonsdale, M. Polletta, R. S. Savage, A. Franceschini, H. Buttery, A. Cimatti, J. Dias, C. Feruglio, F. Fiore, E. V. Held, F. La Franca, R. Maiolino, A. Marconi, I. Matute, S. J. Oliver, E. Ricciardelli, S. Rubele, N. Sacchi, D. Shupe, J. Surace. 2007-10-16. The contribution of very massive high-redshift SWIRE galaxies to the stellar mass function. https://doi.org/10.1051/0004-6361:20077491

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2010

HX-POL - A Balloon-Borne Hard X-Ray Polarimeter

We report on the design and estimated performance of a balloon-borne hard X-ray polarimeter called HX-POL. The experiment uses a combination of Si and Cadmium Zinc Telluride detectors to measure the polarization of 50 keV-400 keV X-rays from cosmic sources through the dependence of the angular distribution of Compton scattered photons on the polarization direction. On a one-day balloon flight, HX-POL would allow us to measure the polarization of bright Crab-like sources for polarization degrees well below 10%. On a longer (15-30 day) flight from Australia or Antarctica, HX-POL would be be able to measure the polarization of bright galactic X-ray sources down to polarization degrees of a few percent. Hard X-ray polarization measurements provide unique venues for the study of particle acceleration processes by compact objects and relativistic outflows. In this paper, we discuss the overall instrument design and performance. Furthermore, we present results from laboratory tests of the Si and CZT detectors.

astro-ph↗

arXiv2010

Quintessence models with an oscillating equation of state and their potentials

In this paper, we investigate the quintessence models with an oscillating equation of state (EoS) and their potentials. From the constructed potentials, which have the EoS of $ω_ϕ=ω_0+ω_1\sin z$, we find they are all the oscillating functions of the field $ϕ$, and the oscillating amplitudes are decreasing (or increasing) with $ϕ$. From the evolutive equation of the field $ϕ$, we find this is caused by the expansion of the universe. This also makes that it is very difficult to build a model whose EoS oscillates forever. However one can build a model with EoS oscillating for a period. Then we discuss three quintessence models, which are the combinations of the invert power law functions and the oscillating functions of the field $ϕ$. We find they all follow the oscillating EoS.

astro-ph↗

arXiv2010

Is "Spike" a Reliable Feature in Porb Distribution of AM HER Stars?

Orbital periods in AM Her stars (polars) are synchronized with spin periods of white dwarf by its high magnetic field. Since the last study of Porb distribution of these systems, the number of known objects of such type has more than doubled. This challenged us to compile a new updated catalogue of cataclysmic variables with highly magnetic white dwarfs (polars) and to study their Porb distribution. In this paper we also discus if "spike" is reliable feature in the distribution. ("Spike" is a concentration of polars in the distribution of their orbital periods near Porb = 114 min and was previously discussed by Ritter & Kolb (1992) and Shahbaz & Wood (1996).)

astro-ph↗