4 research outputs found
PRIYA: A New Suite of Lyman-alpha Forest Simulations for Cosmology
We present the PRIYA suite of cosmological simulations, based on the code and
hydrodynamic model of the ASTRID simulation, and designed for cosmological
analyses of the Lyman- forest. Our simulation suite spans a
-dimensional parameter space, including cosmological parameters and
astrophysical/thermal parameters. We have run low fidelity simulations
with particles in a Mpc/h box and high fidelity simulations
with particles in a Mpc/h box. All our simulations include a
full physics model for galaxy formation, including supernova and AGN feedback,
and thus also contain a realistic population of DLAs. We advance on earlier
simulations suites by larger particle loads, by incorporating new physical
models for patchy hydrogen and helium reionization, and by self-consistently
incorporating a model for AGN feedback. We show that patchy helium reionization
imprints an excess in the 1D flux power spectrum on large scales, which may
allow future measurements of helium reionization bubble sizes. Simulation
parameters are chosen based on a Latin hypercube design and a Gaussian process
is used to interpolate to arbitrary parameter combinations. We build a
multi-fidelity emulator for the 1D flux power spectrum and the mean IGM
temperature. We show that our final interpolation error is and that our
simulations produce a flux power spectrum converged at the percent level for
- . Our simulation suite will be used to interpret Lyman-
forest 1D flux power spectra from SDSS and future DESI data releases.Comment: 24 pages, 11 figures, submitted to JCA
Boosting Line Intensity Map Signal-to-Noise with the Ly- Forest Cross-Correlation
We forecast the prospects for cross-correlating future line intensity mapping
(LIM) surveys with the current and future Ly- forest data. We use large
cosmological hydrodynamic simulations to model the expected emission signal for
the CO rotational transition in the COMAP LIM experiment at the 5-year
benchmark and the Ly- forest absorption signal for various surveys,
including eBOSS, DESI, and PFS. We show that COLy- forest can
significantly enhance the detection signal-to-noise ratio of CO, with a
to improvement when cross-correlated with the forest observed in the
Prime Focus Spectrograph (PFS) survey and a to enhancement for the
currently available eBOSS or the upcoming DESI observations. We compare to the
signal-to-noise improvements expected for a galaxy survey and show that
COLy- is competitive with even a spectroscopic galaxy survey in
raw signal-to-noise. Furthermore, our study suggests that the clustering of CO
emission is tightly constrained by COLy- forest, due to the
increased signal-to-noise ratio and the simplicity of Ly- absorption
power spectrum modeling. Any foreground contamination or systematics are
expected not to be shared between LIM surveys and Ly- forest
observations; this provides an unbiased inference. Our findings highlight the
potential benefits of utilizing the Ly- forest to aid in the initial
detection of signals in line intensity experiments. For example, we also
estimate that [CII]Ly- forest measurements from EXCLAIM and
DESI/eBOSS, respectively, should have a larger signal-to-noise ratio than
planned [CII]quasar observations by about an order of magnitude. Our
results can be readily applied to actual data thanks to the observed quasar
spectra in eBOSS Stripe 82, which overlaps with several LIM surveys.Comment: Codes and the produced data are available at
https://github.com/qezlou/lal
Recommended from our members
Cosmic Noon at 3D
Cosmic Noon in 3D:Lyman-alpha forest has emerged as a potent observational tool for probing the gas dynamics within the Intergalactic Medium (IGM) during cosmic noon. Surveys such as BOSS and DESI, which analyze the forest within the spectra of background quasars, have recently provided unique insights into cosmology and relevant astrophysical processes, including HeII reionization. Conversely, Lyman-alpha tomography surveys enhance the density of background sources by observing the more abundant Lyman Break Galaxies (LBGs), furnishing a 3D map of neutral hydrogen at redshifts around z ~2-3 with exceptional spatial resolution of approximately 2 cMpc/h. Furthermore, Line Intensity Mapping (LIM) represents a novel technique aimed at detecting the collective emission from all galaxies across the sky. In my thesis, I will delve into the indispensable role of state-of-the-art cosmological hydrodynamic simulations in modeling these observations, constraining cosmology and elucidating the intricate connection between galaxies and their gaseous environment on IGM scales
Characterizing Protoclusters and Protogroups at z 2.5 Using Ly Tomography
Ly- tomography surveys have begun to produce three-dimensional (3D)
maps of the intergalactic medium (IGM) opacity at with Mpc
resolution. These surveys provide an exciting new way to discover and
characterize high-redshift overdensities, including the progenitors of today's
massive groups and clusters of galaxies, known as protogroups and
protoclusters. We use the IllustrisTNG- hydrodynamical simulation to build
mock maps that realistically mimic those observed in the Ly-
Tomographic IMACS Survey (LATIS). We introduce a novel method for delineating
the boundaries of structures detected in 3D Ly- flux maps by applying
the watershed algorithm. We provide estimators for the dark matter masses of
these structures (at ), their descendant halo masses at , and
the corresponding uncertainties. We also investigate the completeness of this
method for the detection of protogroups and protoclusters. Compared to earlier
work, we apply and characterize our method over a wider mass range that extends
to massive protogroups. We also assess the widely used fluctuating
Gunn-Peterson approximation (FGPA) applied to dark-matter-only simulations; we
conclude while it is adequate for estimating the Ly- absorption signal
from moderate-to-massive protoclusters (), it
artificially merges a minority of lower-mass structures with more massive
neighbors. Our methods will be applied to current and future
Ly-~tomography surveys to create catalogs of overdensities and study
environment-dependent galaxy evolution in the Cosmic~Noon~era.Comment: 18 pages, 18 figures, codes available at
https://github.com/mahdiqezlou/LyTomo-Watershe