Cosmic Dragons: A Two-Component Mixture Model of COSMOS Galaxies
The Open Journal of Astrophysics(2023)
摘要
Using the photometric population prediction method Red Dragon, we
characterize the Red Sequence (RS) and Blue Cloud (BC) of DES galaxies in the
COSMOS field. Red Dragon (RD) uses a redshift-evolving, error-corrected
Gaussian mixture model to detail the distribution of photometric colors,
smoothly parameterizing the two populations with relative weights, mean colors,
intrinsic scatters, and inter-color correlations. This resulting fit of RS and
BC yields RS membership probabilities P_ RS for each galaxy. Even when
training on only DES main bands griz, RD selects the quiescent population
(defined here as galaxies with sSFR · yr < -11) with ≳
90% balanced accuracy out to z=2; augmenting with extended photometry from
VIRCAM improves this accuracy to ∼ 95% out to z=3. We measure redshift
evolution of sSFR and galactic age in several stellar mass bins, finding that
the BC is consistently more star-forming (by ≳ 1 dex) and
typically younger (by ≳ 1 Gyr) than the RS (up to z ∼ 1.4).
This characterization of both RS and BC as functions of redshift and stellar
mass improves our understanding of both populations and opens the door to more
precise galaxy population characterization in future deep optical and IR
systems.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要