94 research outputs found
A Forecast for Large Scale Structure Constraints on Horndeski Gravity with Line Intensity Mapping
We consider the potential for line intensity mapping (LIM) of the rotational
CO(1-0), CO(2-1) and CO(3-2) transitions to detect deviations from General
Relativity from within the framework of a very general class of
modified gravity models, called Horndeski theories. Our forecast assumes a
multi-tracer analysis separately obtaining information from the matter power
spectrum and the first two multipoles of the redshift space distortion power
spectrum. To achieve level constraints on the slope of the kinetic
gravity braiding and Planck mass evolution parameters, a mm-wave LIM experiment
would need to accumulate spectrometer hours, feasible with
instruments that could be deployed in the 2030s. Such a measurement would
constrain large portions of the remaining parameter space available to
Scalar-Tensor modified gravity theories. Our modeling code is publicly
available.Comment: 13 pages, 5 figures; to be submitted to Monthly Notices of the Royal
Astronomical Societ
Report of the Topical Group on Cosmic Frontier 5 Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before for Snowmass 2021
This report summarizes the envisioned research activities as gathered from
the Snowmass 2021 CF5 working group concerning Dark Energy and Cosmic
Acceleration: Cosmic Dawn and Before. The scientific goals are to study
inflation and to search for new physics through precision measurements of relic
radiation from the early universe. The envisioned research activities for this
decade (2025-35) are constructing and operating major facilities and developing
critical enabling capabilities. The major facilities for this decade are the
CMB-S4 project, a new Stage-V spectroscopic survey facility, and existing
gravitational wave observatories. Enabling capabilities include aligning and
investing in theory, computation and model building, and investing in new
technologies needed for early universe studies in the following decade (2035+).Comment: contribution to Snowmass 202
Characterization of MKIDs for CMB observation at 220 GHz with the South Pole Telescope
We present an updated design of the 220 GHz microwave kinetic inductance
detector (MKID) pixel for SPT-3G+, the next-generation camera for the South
Pole Telescope. We show results of the dark testing of a 63-pixel array with
mean inductor quality factor , aluminum inductor
transition temperature K, and kinetic inductance fraction
. We optically characterize both the microstrip-coupled and
CPW-coupled resonators, and find both have a spectral response close to
prediction with an optical efficiency of . However, we find
slightly lower optical response on the lower edge of the band than predicted,
with neighboring dark detectors showing more response in this region, though at
level consistent with less than 5\% frequency shift relative to the optical
detectors. The detectors show polarized response consistent with expectations,
with a cross-polar response of for both detector orientations.Comment: 6 pages, 5 figures, ASC 2022 proceeding
SuperSpec: On-chip spectrometer design, characterization, and performance
SuperSpec is an integrated, on-chip spectrometer for millimeter and sub-millimeter astronomy. SuperSpec is demonstrating a proof-of-principle multi-beam spectrometer on the sky at the Large Millimeter Telescope (LMT) in Mexico covering the 200 - 300 GHz frequency range with moderate resolution (R ~ 270 - 290). The dual-polarization, three-pixel instrument will consist of 6 SuperSpec spectrometer chips. We present the design and characterization of the devices being used in the first SuperSpec demonstration along with lab testing of the instrument performance
Mapping Cosmic Dawn and Reionization: Challenges and Synergies
Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored
observational eras in cosmology: a time at which the first galaxies and
supermassive black holes formed and reionized the cold, neutral Universe of the
post-recombination era. With current instruments, only a handful of the
brightest galaxies and quasars from that time are detectable as individual
objects, due to their extreme distances. Fortunately, a multitude of
multi-wavelength intensity mapping measurements, ranging from the redshifted 21
cm background in the radio to the unresolved X-ray background, contain a
plethora of synergistic information about this elusive era. The coming decade
will likely see direct detections of inhomogenous reionization with CMB and 21
cm observations, and a slew of other probes covering overlapping areas and
complementary physical processes will provide crucial additional information
and cross-validation. To maximize scientific discovery and return on
investment, coordinated survey planning and joint data analysis should be a
high priority, closely coupled to computational models and theoretical
predictions.Comment: 5 pages, 1 figure, submitted to the Astro2020 Decadal Survey Science
White Paper cal
Cosmology with the Highly Redshifted 21cm Line
In addition to being a probe of Cosmic Dawn and Epoch of Reionization
astrophysics, the 21cm line at is also a powerful way to constrain
cosmology. Its power derives from several unique capabilities. First, the 21cm
line is sensitive to energy injections into the intergalactic medium at high
redshifts. It also increases the number of measurable modes compared to
existing cosmological probes by orders of magnitude. Many of these modes are on
smaller scales than are accessible via the CMB, and moreover have the advantage
of being firmly in the linear regime (making them easy to model theoretically).
Finally, the 21cm line provides access to redshifts prior to the formation of
luminous objects. Together, these features of 21cm cosmology at provide
multiple pathways toward precise cosmological constraints. These include the
"marginalizing out" of astrophysical effects, the utilization of redshift space
distortions, the breaking of CMB degeneracies, the identification of signatures
of relative velocities between baryons and dark matter, and the discovery of
unexpected signs of physics beyond the CDM paradigm at high redshifts.Comment: Science white paper submitted to Decadal 2020 surve
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