2,493 research outputs found
Reddening Behaviors of Galaxies in the SDSS Photometric System
We analyze the behaviors of reddening vectors in the SDSS photometric system
for galaxies of different morphologies, ages, and redshifts. As seen in other
photometric systems, the dependence of reddening on the spectral energy
distribution (SED) and the nonlinearity of reddening are likewise
non-negligible for the SDSS system if extinction is significant (~> 1 mag).
These behaviors are most significant for the g filter, which has the largest
bandwidth-to-central wavelength ratio among SDSS filters. The SDSS colors
involving adjacent filters show greater SED-dependence and nonlinearity. A
procedure for calculating the correct amount of extinction from an observed
color excess is provided. The relative extinctions between (i.e., the
extinction law for) SDSS filters given by Schlegel et al., which were
calculated with an older version of filter response functions, would
underestimate the amount of extinction in most cases by ~5 to 10 % (maximum ~20
%). We recommend A/A_{5500} values of 1.574, 1.191, 0.876, 0.671 & 0.486 for
the u, g, r, i, & z filters, respectively, as a representative extinction law
for the SDSS galaxies with a small extinction (i.e., for cases where the
nonlinearity and SED-dependence of the reddening is not important). The
dependence of reddening on redshift at low extinction is the largest for colors
involving the g filter as well, which is due to the Balmer break.Comment: Published in PASP, 119, 1449 (Dec. 2007
Medium effects of magnetic moments of baryons on neutron stars under strong magnetic fields
We investigate medium effects due to density-dependent magnetic moments of
baryons on neutron stars under strong magnetic fields. If we allow the
variation of anomalous magnetic moments (AMMs) of baryons in dense matter under
strong magnetic fields, AMMs of nucleons are enhanced to be larger than those
of hyperons. The enhancement naturally affects the chemical potentials of
baryons to be large and leads to the increase of a proton fraction.
Consequently, it causes the suppression of hyperons, resulting in the stiffness
of the equation of state. Under the presumed strong magnetic fields, we
evaluate relevant particles' population, the equation of state and the maximum
masses of neutron stars by including density-dependent AMMs and compare them
with those obtained from AMMs in free space
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