First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe

Details First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe

2008-06-16

arxiv.org/abs/0806.2574v2

A&A, Volume 498, Issue 1, 2009, pp.25-35

Astronomy and Astrophysics

Astrophysics

11 pages, 11 figures, accepted for publication in A&A, v2: references added, discussion extended, conclusions unchanged

Scientific paper

10.1051/0004-6361/200810396

The formation of the first stars (Population III; PopIII) marks the end of the dark ages of the universe, a subject of lively scientific debate. Not (yet) accessible to direct observations, this early stage of the universe is mostly studied via theoretical calculations and numerical simulations. An indirect window is provided by integrated present day observables such as the metal abundance or the diffuse extragalactic photon fields. We aim to derive constraints on the properties of the PopIII and low metallicity Population II (LM PopII) stars utilizing limits on the density of the extragalactic background light (EBL), recently derived from very-high-energy (E > 100 GeV; VHE) observations. A model calculation for the evolving EBL density produced by PopIII/LM PopII stars is presented. The model utilizes stellar population spectra (SPS) for zero and low metallicity stars and accounts for the changing emission of an aging stellar population. Emission from the dense HII regions surrounding the stars (nebula) is included. The resulting EBL density for different scenarios (metallicity, star formation rate, initial mass function) is compared to the limit on the EBL density. The potential for detecting a cut-off in HE/VHE spectra is discussed. Assuming a maximum contribution from PopIII/LM PopII stars to the EBL density of 5 nW m^-2 s-1 at 2 micrometer a limit on the star formation rate (SFR) of the first stars of 0.3 to 3 M_solar Mpc^-3 yr^-1 in the redshift range 7 - 14 is derived. The limit depends on the assumed shape of the SFR and metallicity.

Affiliated with

Also associated with

No associations

Rating

First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and First stars and the extragalactic background light: How recent gamma-ray observations constrain the early universe will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-91999