FOUR FUNDAMENTAL FOREGROUND POWER SPECTRUM SHAPES FOR 21 cm COSMOLOGY OBSERVATIONS

By Miguel F. Morales, Bryna J. Hazelton, I. Sullivan, A. Beardsley. 2012

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Contamination from instrumental effects interacting with bright astrophysical sources is the primary impediment to measuring Epoch of Reionization (EoR) and Baryon Acoustic Oscillations (BAO) 21 cm power spectra—an effect called mode mixing. In this paper, we identify four fundamental power spectrum shapes produced by mode mixing that will affect all upcoming observations. We are able, for the first time, to explain the wedge-like structure seen in advanced simulations and to forecast the shape of an “EoR window” that is mostly free of contamination. Understanding the origins of these contaminations also enables us to identify calibration and foreground subtraction errors below the imaging limit, providing a powerful new tool for precision observations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/c7bd93326046d4677317069ceefcda75b00f671c

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Citations in the corpus

A PER-BASELINE, DELAY-SPECTRUM TECHNIQUE FOR ACCESSING THE 21 cm COSMIC REIONIZATION SIGNATURE (2012, background): “Understanding the relationship between delay-space and k-space also provides a simple inter- pretation of the foreground “wedge” described in Datta et al. (2010) and Morales et al. (2012), and is seen in Figure 10.”
21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal (2015, background): “…across all frequencies, but instead localize the majority of the foreground noise into a foreground ‘wedge’ within cylindrical 2D k-space (Datta et al. 2010; Morales et al. 2012; Parsons et al. 2012b; Trott et al. 2012; Vedantham et al. 2012; Thyagarajan et al. 2013; Liu et al. 2014a,b).”
Calibration requirements for detecting the 21 cm epoch of reionization power spectrum and implications for the SKA (2016, unknown): “…“foreground wedge” due to the mode-mixing of power from small k‖ values into larger k‖ values as demonstrated in Figure 1 (Datta et al. 2010; Morales et al. 2012; Vedantham et al. 2012; Parsons et al. 2012b; Trott et al. 2012; Hazelton et al. 2013; Thyagarajan et al. 2013; Pober et al.…”
FIRST SEASON MWA EOR POWER SPECTRUM RESULTS AT REDSHIFT 7 (2016, background): “…et al. 2015a,b; Trott et al. 2012; Liu et al. 2014a,b; Hazelton et al. 2013; Pober et al. 2013; Thyagarajan et al. 2013; Vedantham et al. 2012; Morales et al. 2012; Datta et al. 2010), while others are investigating the spectral structure of point sources themselves (e.g. Offringa et al.…”
OPENING THE 21 cm EPOCH OF REIONIZATION WINDOW: MEASUREMENTS OF FOREGROUND ISOLATION WITH PAPER (2013, methodology): “These observations have confirmed general predictions presented in, e.g., Datta et al. (2010), Morales et al. (2012) and P12b: that foreground emission occupies a “wedge” in the 2D (k⊥, k‖) plane, leaving a window at higher k‖ values for 21cm EoR studies.”
WHAT NEXT-GENERATION 21 cm POWER SPECTRUM MEASUREMENTS CAN TEACH US ABOUT THE EPOCH OF REIONIZATION (2013, background): “These studies did not include the more sophisticated understanding of foreground emission that has arisen in the last few years, i.e., the division of 2D cylindrical k-space into the foreground-contaminated “wedge” and the relatively clean “EoR window” (Datta et al. 2010; Vedantham et al. 2012; Mora”
LATE-TIME COSMOLOGY WITH 21 cm INTENSITY MAPPING EXPERIMENTS (2014, background): “…them to such a level that the cosmological signal can be extracted in an unbiased way (Oh & Mack 2003; Barkana & Loeb 2005; Santos et al. 2005; Morales et al. 2006, 2012; Wang et al. 2006; Gleser et al. 2008; Jelić et al. 2008; Liu et al. 2009, 2014; Liu & Tegmark 2011; Petrovic & Oh 2011;…”
Hydrogen Epoch of Reionization Array (HERA) (2016, background): “Through theoretical and observational work (Datta et al. 2010; Morales et al. 2012; Parsons et al. 2012b; Vedantham et al. 2012; Thyagarajan et al. 2013; Hazelton et al. 2013; Pober et al. 2013a; Liu et al. 2014a,b), we have learned how the boundary between the wedge and the EoR window is…”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, background): “…instrument (in both the PSF and the primary beam), and chromatic calibration errors create additional ‘modemixing’ foreground contaminants which introduce spectral structure to the otherwise smooth foregrounds (Datta et al. 2010; Morales et al. 2012; Trott et al. 2012; Vedantham et al. 2012).”
Science with the Murchison Widefield Array (2012, background): “Many classes of errors and residuals re- maining in the maps after the foreground cleaning stages described above can be modeled given sufficient knowledge of the instrumental response (Morales et al. 2006; Bowman et al. 2009; Datta et al. 2010; Morales et al. 2012).”
THE IMPACT OF POINT-SOURCE SUBTRACTION RESIDUALS ON 21 cm EPOCH OF REIONIZATION ESTIMATION (2012, background): “In particular, the review of Morales et al. (2012) presents arguments for the origin of this feature due to point-source amplitude and position errors, gridding artifacts and calibration errors.”