相关论文: Limiting the dimming of distant type Ia supernovae
Colour measurements of quasars are used to constrain the abundance and properties of intergalactic dust and the related extinction effects on high-z sources. For Type Ia supernovae at z = 1, we derive an upper limit on the possible dimming…
Scattering and absorption of light by a homogeneous distribution of intergalactic large dust grains has been proposed as an alternative, non-cosmological explanation for the faintness of Type Ia supernovae at $z\s im 0.5$. We investigate…
Extinction by intergalactic gray dust introduces a magnitude redshift dependent offset in the standard-candle relation of SN Ia. This leads to overestimated luminosity distances compared to a dust-free universe. Quantifying the amplitude of…
Recently Csaki, Kaloper and Terning (hep-ph/0111311) suggested that the observed dimming of distant type Ia supernovae may be a consequence of mixing of the photons with very light axions. We point out that the effect of the plasma, in…
Observations of high-redshift Type Ia supernovae (SNe~Ia) are used to study the cosmic transparency at optical wavelengths. Assuming a flat $\Lambda$CDM cosmological model based on BAO and CMB results, redshift dependent deviations of SN~Ia…
Supernova measurements have become a key ingredient in current determinations of cosmological parameters. These sources can however be used as standard candles only after correcting their apparent brightness for a number of effects. In this…
Using a high-resolution cosmological hydrodynamic simulation, we present a method to constrain extinction due to intergalactic grey dust based on the observed magnitudes of distant Type IA supernovae. We apply several simple prescriptions…
Recent measurements of type Ia supernovae indicate that distant supernovae are substantially fainter than expected from the standard flat cold dark matter model. One possible explanation is that the energy density in our universe is in fact…
Unless properly corrected for, the existence of intergalactic dust will introduce a redshift dependent magnitude offset to standard candle sources. This would lead to overestimated luminosity distances compared to a dust-free universe and…
Condensation in the outer regions of decaying supernovae is an efficient source of dust with grain size up to 1 micron. The largest grains leave the parent galaxy, thus forming "grey" intergalactic dust, which can explain the observed…
Here we present some critical discussions about the systematic uncertainty by dust extinction in the recent cosmological results of high-redshift Type Ia supernovae. First we argue that the currently available data do not robustly exclude…
In this paper, I revoke a debate about an origin of Type Ia supernova (SN Ia) dimming. I argue that except for a commonly accepted accelerating expansion of the Universe, a conceivable alternative for explaining this observation is universe…
We have recently proposed a mechanism of photon-axion oscillations as a way of rendering supernovae dimmer without cosmic acceleration. Subsequently, it has been argued that the intergalactic plasma may interfere adversely with this…
Using quasar spectra from the SDSS survey, we constrain the possibility of photon-axion oscillations as a source of dimming of high redshift objects. Such a process has been suggested as an explanation of the apparent faintness of distant…
We review some results of the past 12 years derived from optical and infrared photometry of Type Ia supernovae. A combination of optical and infrared photometry allows us to determine accurately the extinction along the line of sight. The…
An explanation is given of the low value of $R_\lambda \equiv A_\lambda/E(B-V) $, the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the…
We present a simple model where photons propagating in extra-galactic magnetic fields can oscillate into very light axions. The oscillations may convert some of the photons departing a distant supernova into axions, making the supernova…
The observation of SN 1997ff at redshift 1.7 has been claimed to refute alternative models such as grey dust or evolution for the faintness of distant supernovae, leaving only an accelerating Universe as a viable model. However, a very…
Estimates of the cosmic star formation rate and of cluster metallicities independently imply that at z < 0.5 the gas in the universe has substantial average metallicity: 1/10 < Z/Z_solar < 1/3 for Omega_gas = 0.05. This metal density…
Free electrons deplete photons from type Ia supernovae through the (inverse) Compton scattering. This Compton dimming increases with redshift and reaches 0.004 mag at $z=1$ and 0.01 mag at $z=2$. Although far from sufficient to invalidate…