SPECTER: An Instrument Concept for CMB Spectral Distortion Measurements with Enhanced Sensitivity

Fuente: arXiv
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Autori principali: Sabyr, Alina, Sierra, Carlos, Hill, J. Colin, McMahon, Jeffrey J.
Natura: Preprint
Pubblicazione: 2024
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author Sabyr, Alina
Sierra, Carlos
Hill, J. Colin
McMahon, Jeffrey J.
author_facet Sabyr, Alina
Sierra, Carlos
Hill, J. Colin
McMahon, Jeffrey J.
contents Deviations of the cosmic microwave background (CMB) energy spectrum from a perfect blackbody uniquely probe a wide range of physics, ranging from fundamental physics in the primordial Universe ($μ$-distortion) to late-time baryonic feedback processes ($y$-distortion). While the $y$-distortion can be detected with a moderate increase in sensitivity over that of COBE/FIRAS, the $Λ$CDM-predicted $μ$-distortion is roughly two orders of magnitude smaller and requires substantial improvements, with foregrounds presenting a serious obstacle. Within the standard model, the dominant contribution to $μ$ arises from energy injected via Silk damping, yielding sensitivity to the primordial power spectrum at wavenumbers $k \approx 1-10^{4}$ Mpc$^{-1}$. Here, we present a new instrument concept, SPECTER, with the goal of robustly detecting $μ$. The instrument technology is similar to that of LiteBIRD, but with an absolute temperature calibration system. Using a Fisher approach, we optimize the instrument's configuration to target $μ$ while marginalizing over foreground contaminants. Unlike Fourier-transform-spectrometer-based designs, the specific bands and their individual sensitivities can be independently set in this instrument, allowing significant flexibility. We forecast SPECTER to observe the $Λ$CDM-predicted $μ$-distortion at $\approx 5σ$ (10$σ$) assuming an observation time of 1 (4) year(s) (corresponding to mission duration of 2 (8) years), after foreground marginalization. Our optimized configuration includes 16 bands spanning 1-2000 GHz with $\sim$degree-scale angular resolution at $\sim150$ GHz and 1100 total detectors. SPECTER will additionally measure the $y$-distortion at sub-percent precision and its relativistic correction at percent-level precision, yielding tight constraints on the total thermal energy and mean temperature of ionized gas.
format Preprint
id arxiv_https___arxiv_org_abs_2409_12188
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle SPECTER: An Instrument Concept for CMB Spectral Distortion Measurements with Enhanced Sensitivity
Sabyr, Alina
Sierra, Carlos
Hill, J. Colin
McMahon, Jeffrey J.
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
Deviations of the cosmic microwave background (CMB) energy spectrum from a perfect blackbody uniquely probe a wide range of physics, ranging from fundamental physics in the primordial Universe ($μ$-distortion) to late-time baryonic feedback processes ($y$-distortion). While the $y$-distortion can be detected with a moderate increase in sensitivity over that of COBE/FIRAS, the $Λ$CDM-predicted $μ$-distortion is roughly two orders of magnitude smaller and requires substantial improvements, with foregrounds presenting a serious obstacle. Within the standard model, the dominant contribution to $μ$ arises from energy injected via Silk damping, yielding sensitivity to the primordial power spectrum at wavenumbers $k \approx 1-10^{4}$ Mpc$^{-1}$. Here, we present a new instrument concept, SPECTER, with the goal of robustly detecting $μ$. The instrument technology is similar to that of LiteBIRD, but with an absolute temperature calibration system. Using a Fisher approach, we optimize the instrument's configuration to target $μ$ while marginalizing over foreground contaminants. Unlike Fourier-transform-spectrometer-based designs, the specific bands and their individual sensitivities can be independently set in this instrument, allowing significant flexibility. We forecast SPECTER to observe the $Λ$CDM-predicted $μ$-distortion at $\approx 5σ$ (10$σ$) assuming an observation time of 1 (4) year(s) (corresponding to mission duration of 2 (8) years), after foreground marginalization. Our optimized configuration includes 16 bands spanning 1-2000 GHz with $\sim$degree-scale angular resolution at $\sim150$ GHz and 1100 total detectors. SPECTER will additionally measure the $y$-distortion at sub-percent precision and its relativistic correction at percent-level precision, yielding tight constraints on the total thermal energy and mean temperature of ionized gas.
title SPECTER: An Instrument Concept for CMB Spectral Distortion Measurements with Enhanced Sensitivity
topic Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2409.12188