Untitled

Abstract

In the context of a cold big bang (CBB) cosmological model, I estimate the temperature, calculate the evolution, and discuss the anisotropies of a homogeneous radiation background emitted at high redshift by Population III objects and thermalized by a mixture of carbon/silicate dust and iron or carbon whiskers. Assuming that Population III objects supply dark matter remnants and produce the universal helium abundance of D24%, the resulting radiation, if thermal, should have temperature 0.5 K [ T 0 [ 9 K. To calculate its thermalization I limit standard dust density using constraints from maximum allowed metallicity, quasar reddening, Type Ia supernova observations, and high-redshift object visibility and assume a small mass ratio of whiskers to standard dust. For high redshift of generation (z i Z 100) and highly conducting, high aspect ratio (length/diameter iron whiskers, the Ðnal spectrum meets Z1000) the FIRAS spectral distortion limits and does not exceed limits on IR-background light. Energetic considerations probably require if the observed cosmic microwave background (CMB) is star genz i [ 40) b erated. Such a model is marginally viable with baryon density but probably ruled out if5. I comment brieÑy on possible other thermalization mechanisms. In whisker-thermalized models, CMB anisotropies are imprinted at lower redshift and through somewhat di †erent physical processes than in the hot big bang (HBB). Nonlocal thermal equilibrium of the dust causes the Sachs-Wolfe e †ect to disappear on small angular scales. Radiation pressure probably ejects whiskers from luminous regions such as galaxies. If signiÐcant intergalactic magnetic Ðelds are absent, CMB radiation drag probably Ðxes whiskers in the CMB frame, hence large-scale Doppler anisotropies (other than the dipole) do not exist. "" Intrinsic ÏÏ temperature Ñuctuations and the integrated Sachs-Wolfe e †ect operate essentially as in the HBB. Numerical results for the horizon, di †usion, and other length scales relevant to CMB anisotropies for Ðducial thermalization models are provided. Finally, I note that CMB polarization may be higher in the whisker model than in the HBB and that acoustic oscillations should not appear in the CBB power spectrum, and I comment on the amplitude and possible frequency dependence of the anisotropies.

A SUB-SATURN MASS PLANET, MOA-2009-BLG-319Lb

“…The follow-up groups that complete this telescope network are the Microlensing Follow-Up Network (μFUN), RoboNet, Microlensing Network for the Detection of Small Terrestrial Exoplanets (MiNDSTEp), and the Probing Lensing Anomalies NETwork (PLANET). These narrow field-of-view (FOV) follow-up telescopes can provide very high cadence observations of a small number of events that are known to be interesting, due to known or suspected planetary deviations in progress (Sumi et al 2010) or high-magnification events, which have very high planet detection efficiency (Griest & Safizadeh 1998;Rhie et al 2000;Rattenbury et al 2002). The very wide (2.2 deg 2 ) FOV of the MOA-II 1.8 m telescope with 80M pixel CCD camera MOA-cam3 (Sako et al 2008) provides highcadence survey observations of the entire Galactic bulge, and this allows MOA to identify suspected planetary deviations in progress and to predict high magnification (A max 100) for events with relatively short timescales (Einstein radius crossing time t E < 20 days).…”

Resolved young stellar populations in star-forming regions of the Magellanic Clouds

“…The first study of PMS stars in the MCs revealed a sample of 488 strong-line T Tauri stars in the surrounding field of supernova 1987A [120]. Subsequent studies were focused mostly on the star-burst of 30 Doradus [14,148], a region that suffers from severe crowding and high extinction. These factors, which limit the detection of low-mass PMS stars to about 1-2 M [134], are less important in regions of typical stellar associations.…”