19 research outputs found
How Cosmic Web Environment Affects Galaxy Quenching Across Cosmic Time
We investigate how cosmic web structures affect galaxy quenching in the
IllustrisTNG (TNG-100) cosmological simulations by reconstructing the cosmic
web in each snapshot using the DisPerSE framework. We measure the distance from
each galaxy with stellar mass log(M*/Msun)>=8 to the nearest node (dnode) and
the nearest filament spine (dfil) and study the dependence of both median
specific star formation rate () and median gas fraction () on these
distances. We find that of galaxies is only dependent on cosmic web
environment at z<2, with the dependence increasing with time. At z<=0.5,
8<=log(M*/Msun)<9 galaxies are quenched at dnode<1 Mpc, and significantly star
formation-suppressed at dfil<1 Mpc, trends which are driven mostly by satellite
galaxies. At z of
log(M*/Msun)=10 galaxies
actually experience an upturn in at dnode<0.2 Mpc (this is caused by
both satellites and centrals). Much of this cosmic web-dependence of star
formation activity can be explained by the evolution in . Our results
suggest that in the past ~10 Gyr, low-mass satellites are quenched by rapid gas
stripping in dense environments near nodes and gradual gas starvation in
intermediate-density environments near filaments, while at earlier times cosmic
web structures efficiently channeled cold gas into most galaxies.
State-of-the-art ongoing spectroscopic surveys such as SDSS and DESI, as well
as those planned with JWST and Roman are required to test our predictions
against observations.Comment: 5 Figures, 15 pages, submitted to ApJ Letter
Filaments of The Slime Mold Cosmic Web And How They Affect Galaxy Evolution
We present a novel method for identifying cosmic web filaments using the
IllustrisTNG (TNG100) cosmological simulations and investigate the impact of
filaments on galaxies. We compare the use of cosmic density field estimates
from the Delaunay Tessellation Field Estimator (DTFE) and the Monte Carlo
Physarum Machine (MCPM), which is inspired by the slime mold organism, in the
DisPerSE structure identification framework. The MCPM-based reconstruction
identifies filaments with higher fidelity, finding more low-prominence/diffuse
filaments and better tracing the true underlying matter distribution than the
DTFE-based reconstruction. Using our new filament catalogs, we find that most
galaxies are located within 1.5-2.5 Mpc of a filamentary spine, with little
change in the median specific star formation rate and the median galactic gas
fraction with distance to the nearest filament. Instead, we introduce the
filament line density, {\Sigma}fil(MCPM), as the total MCPM overdensity per
unit length of a local filament segment, and find that this parameter is a
superior predictor of galactic gas supply and quenching. Our results indicate
that most galaxies are quenched and gas-poor near high-line density filaments
at z10.5 galaxies is mainly driven by
mass, while lower-mass galaxies are significantly affected by the filament line
density. In high-line density filaments, satellites are strongly quenched,
whereas centrals have reduced star formation, but not gas fraction, at z<=0.5.
We discuss the prospect of applying our new filament identification method to
galaxy surveys with SDSS, DESI, Subaru PFS, etc. to elucidate the effect of
large-scale structure on galaxy formation.Comment: Submitted to ApJ, comments welcome. Data available at
https://github.com/farhantasy/CosmicWeb-Galaxies
Geophysical Research Letters, Vol. 31, No. 10, L10806, Doi:10.1029/2004gl020028, 2004
This paper addresses the question of the effective collision frequency resulting from the ion-acoustic drift instability using a Vlasov simulation with realistic mass ratio mp/me = 1836 for these parameters: proton to electron temperature ratio Tp/Te = 0.5 and drift velocity between electrons and protons vd = 1.7v the (v the is the electron thermal velocity). Note, that we have chosen the same parameters as used by Watt et al. [2002]. The paper is organized as follows: First, in section 2 we present an overview of the linear and quasi-linear theory of ion-acoustic drift instability. Then, in section 3 we describe the simulation method and in section 4 we show results of the simulation and compare them with the theoretical predictions of section 2. Finally, in section 5 we discuss the result
Peptidomics of Circular Cysteine-Rich Plant Peptides: Analysis of the Diversity of Cyclotides from <i>Viola tricolor</i> by Transcriptome and Proteome Mining
Cyclotides are plant-derived mini proteins. They are genetically
encoded as precursor proteins that become post-translationally modified
to yield circular cystine-knotted molecules. Because of this structural
topology cyclotides resist enzymatic degradation in biological fluids,
and hence they are considered as promising lead molecules for pharmaceutical
applications. Despite ongoing efforts to discover novel cyclotides
and analyze their biodiversity, it is not clear how many individual
peptides a single plant specimen can express. Therefore, we investigated
the transcriptome and cyclotide peptidome of <i>Viola tricolor</i>. Transcriptome mining enabled the characterization of cyclotide
precursor architecture and processing sites important for biosynthesis
of mature peptides. The cyclotide peptidome was explored by mass spectrometry
and bottom-up proteomics using the extracted peptide sequences as
queries for database searching. In total 164 cyclotides were discovered
by nucleic acid and peptide analysis in <i>V. tricolor</i>. Therefore, violaceous plants at a global scale may be the source
to as many as 150 000 individual cyclotides. Encompassing the
diversity of <i>V. tricolor</i> as a combinatorial library
of bioactive peptides, this commercially available medicinal herb
may be a suitable starting point for future bioactivity-guided screening
studies
Peptidomics of Circular Cysteine-Rich Plant Peptides: Analysis of the Diversity of Cyclotides from <i>Viola tricolor</i> by Transcriptome and Proteome Mining
Cyclotides are plant-derived mini proteins. They are genetically
encoded as precursor proteins that become post-translationally modified
to yield circular cystine-knotted molecules. Because of this structural
topology cyclotides resist enzymatic degradation in biological fluids,
and hence they are considered as promising lead molecules for pharmaceutical
applications. Despite ongoing efforts to discover novel cyclotides
and analyze their biodiversity, it is not clear how many individual
peptides a single plant specimen can express. Therefore, we investigated
the transcriptome and cyclotide peptidome of <i>Viola tricolor</i>. Transcriptome mining enabled the characterization of cyclotide
precursor architecture and processing sites important for biosynthesis
of mature peptides. The cyclotide peptidome was explored by mass spectrometry
and bottom-up proteomics using the extracted peptide sequences as
queries for database searching. In total 164 cyclotides were discovered
by nucleic acid and peptide analysis in <i>V. tricolor</i>. Therefore, violaceous plants at a global scale may be the source
to as many as 150 000 individual cyclotides. Encompassing the
diversity of <i>V. tricolor</i> as a combinatorial library
of bioactive peptides, this commercially available medicinal herb
may be a suitable starting point for future bioactivity-guided screening
studies