The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year
project to identify and measure light curves for intermediate-redshift (0.05 <
z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging
over an area of 300 sq. deg. The survey region is a stripe 2.5 degrees wide
centered on the celestial equator in the Southern Galactic Cap that has been
imaged numerous times in earlier years, enabling construction of a deep
reference image for discovery of new objects. Supernova imaging observations
are being acquired between 1 September and 30 November of 2005-7. During the
first two seasons, each region was imaged on average every five nights.
Spectroscopic follow-up observations to determine supernova type and redshift
are carried out on a large number of telescopes. In its first two three-month
seasons, the survey has discovered and measured light curves for 327
spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c,
32 confirmed SNe II, plus a large number of photometrically identified SNe Ia,
94 of which have host-galaxy spectra taken so far. This paper provides an
overview of the project and briefly describes the observations completed during
the first two seasons of operation.

SDSS-II 正在进行一项多年计划，通过反复五波段成像，在南银河盖的赤道附近，对中红移（0.05 < z < 0.35）的 Ia 型超新星（SNe Ia）进行识别和发现，进行了两个三个月的季节观测，已经发现和测量了超过 327 个 SNe Ia，成为该领域的重要研究之一。

Sloan 数字天文巡天 - II 超新星巡天：技术总结

The Sloan Digital Sky Survey-II Supernova Survey: Technical Summary

Recent observations of the distant Universe suggest that much of the stellar
mass of bright galaxies was already in place at $z>1$. This presents a
challenge for models of galaxy formation because massive halos are assembled
late in hierarchical cosmologies such as cold dark matter (CDM). In this paper,
we discuss a new implementation of the Durham semi-analytic model in which
feedback due to active galactic nuclei (AGN) is assumed to quench cooling flows
in massive halos. This mechanism naturally creates a break in the local galaxy
luminosity function at bright magnitudes. The model is implemented within the
Millennium N-body simulation; the accurate dark matter merger trees and large
number of realizations of the galaxy formation process that the simulation
provides results in highly accurate statistics. After adjusting the values of
the physical parameters in the model by reference to the properties of local
galaxies, we use it to investigate the evolution of the K-band luminosity and
galaxy stellar mass functions. We also calculate the volume averaged star
formation rate density of the Universe as a function of redshift and the way in
which this is apportioned amongst galaxies of different mass. The model
robustly predicts a substantial population of massive galaxies out to redshift
$z\sim 5$ and a star formation rate density which rises with increasing
redshift in objects of all masses. Although observational data on these
properties have been cited as evidence for ``anti-hierarchical'' galaxy
formation, we find that when AGN feedback is taken into account, the
fundamentally hierachical CDM model provides a very good match to these
observations.

探讨了半解析模型在引力波天体物理方面的新应用， 并据此研究了时空随机半解析模型。

星系形成的被打破的等级结构

The broken hierarchy of galaxy formation

The measurement of the cosmological parameters from Type Ia supernovae hinges
on our ability to compare nearby and distant supernovae accurately. Here we
present an advance on a method for performing generalized K-corrections for
Type Ia supernovae which allows us to compare these objects from the UV to
near-IR over the redshift range 0<z<2. We discuss the errors currently
associated with this method and how future data can improve upon it
significantly. We also examine the effects of reddening on the K-corrections
and the light curves of Type Ia supernovae. Finally, we provide a few examples
of how these techniques affect our current understanding of a sample of both
nearby and distant supernovae.

本文介绍一种新的 Type Ia 超新星广义 K - 校正方法，可以在红移范围 0< z <2 内从紫外到近红外进行比较，并探讨了这种方法的误差和未来数据的改进。此外，本文还研究了灰尘对超新星 K - 校正和光变曲线的影响，并提供了一些近邻和远距离超新星的例子。