Carbon monoxide line emission as a CMB foreground: tomography of the star-forming universe with different spectral resolutions

Free access article

Issue		A&A Volume 489, Number 2, October II 2008


Page(s)		489 - 504
Section		Cosmology (including clusters of galaxies)
DOI		http://dx.doi.org/10.1051/0004-6361:200810199
Published online		23 July 2008

A&A 489, 489-504 (2008)
DOI: 10.1051/0004-6361:200810199

Carbon monoxide line emission as a CMB foreground: tomography of the star-forming universe with different spectral resolutions

M. Righi¹, C. Hernández-Monteagudo¹, and R. A. Sunyaev^{1, 2}

¹ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
e-mail: chm@mpa-garching.mpg.de
² Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117810, Russia

Received 14 May 2008 / Accepted 25 June 2008

Abstract
Context. The rotational lines of carbon monoxide and the fine structure lines of CII and of the most abundant metals, emitted during the epoch of enhanced star formation in the universe, are redshifted in the frequency channels where the present-day and future CMB experiments are sensitive.
Aims. We estimate the contribution to the CMB angular power spectrum by the emission in such lines in merging star-forming galaxies.
Methods. We used the Lacey-Cole approach to characterize the distribution of the merging halos, together with a parametrization for the star formation rate in each of them. Using observational data from a sample of local, low-redshift, and high-redshift objects, we calibrated the luminosity in each line as a function of the star formation rate.
Results. We show that the correlation term arising from CO line emission is a significant source of foreground for CMB in a broad range of frequencies (in particular in the 20-60 GHz band) and for 1000<l<8000, corresponding to angular scales smaller than 10 arcmin. Moreover, we demonstrate that observing with different spectral resolutions will give the possibility of increasing the amplitude of the signal up to two orders of magnitude in C_l and will help separate the line contribution from practically all other foreground sources and from the primary fluctuations themselves, since these show no significant dependence on the spectral resolution.
Conclusions. We propose to perform observations with varying spectral bandwidths ( $10^{-3}<\Delta\nu/\nu_{\rm obs}<10^{-1}$ ) as a new tool to construct a tomography of the universe, by probing different redshift slices with varying thickness. This should yield new constraints on the regions responsible for the metal enrichment in the universe and on their clustering pattern and will lead to new hints about the reionization epoch and the cosmological parameters, including $\sigma_8$ .

Key words: cosmology: cosmic microwave background -- cosmology: theory -- galaxies: intergalactic medium

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.