Kavli Affiliate: Jeffrey J. McMahon
| First 5 Authors: Alina Sabyr, Carlos Sierra, J. Colin Hill, Jeffrey J. McMahon,
| Summary:
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 ($mu$-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
$Lambda$CDM-predicted $mu$-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 $mu$
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 $mu$. 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 $mu$ while robustly
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
$Lambda$CDM-predicted $mu$-distortion at $approx 5sigma$ (10$sigma$)
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 degree-scale angular
resolution at 150 GHz and 1046 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.
| Search Query: ArXiv Query: search_query=au:”Jeffrey J. McMahon”&id_list=&start=0&max_results=3