BRIGHT SOURCE SUBTRACTION REQUIREMENTS FOR REDSHIFTED 21 cm MEASUREMENTS

By A. Datta, Judd D. Bowman, C. Carilli. 2010

227 citations recorded by the source corpus.

The H i 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection of this signal. This paper investigates the extragalactic point source contamination and how accurately bright sources (≳1 Jy) must be removed in order to detect 21 cm emission with upcoming radio telescopes such as the Murchison Widefield Array. We consider the residual contamination in 21 cm maps and power spectra due to position errors in the sky model for bright sources, as well as frequency-independent calibration errors. We find that a source position accuracy of 0.1 arcsec will suffice for detection of the H i power spectrum. For calibration errors, 0.05% accuracy in antenna gain amplitude is required in order to detect the cosmic signal. Both sources of subtraction error produce residuals that are localized to small angular scales, k⊥ ≳ 0.05 Mpc−1, in the two-dimensional power spectrum.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b3c8b77cadcd93911c4d49d8d8b9b0b80dfeb9cc

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Citations in the corpus

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 GMRT Epoch of Reionization experiment: a new upper limit on the neutral hydrogen power spectrum at z≈ 8.6 (2010, background): “Bright point sources may play a significant role (Datta et al. 2010; Liu et al. 2009; Di Matteo et al. 2004), but are not treated separately here.”
INTENSITY MAPPING WITH CARBON MONOXIDE EMISSION LINES AND THE REDSHIFTED 21 cm LINE (2011, background): “…observational challenges, especially systematic effects from strong galactic and extra-galactic foreground emission, coupled with instrumental effects from the beam, polarization response, and calibration errors (e.g. Liu et al. 2009, Datta et al. 2010, Harker et al. 2010, Petrovic & Oh 2010).”
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.”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, methodology): “…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).”
Calibration requirements for detecting the 21 cm epoch of reionization power spectrum and implications for the SKA (2016, background): “I M ] 7 J un 2 fuse structure scales (Mitchell et al. 2008), addition of polarized components (Mitchell et al. 2008), inclusion of small source position offsets (Ng & See 1996; Wijnholds & van der Veen 2009; Datta et al. 2009), and the imperfection of source models (Datta et al. 2009, 2010).”
FOUR FUNDAMENTAL FOREGROUND POWER SPECTRUM SHAPES FOR 21 cm COSMOLOGY OBSERVATIONS (2012, methodology): “For the random calibration errors on all baselines in Figure 11 of Datta et al. (2010), this produces a wedge of contamination below k|| Max with a functional form that follows the baseline distribution.”
WHAT NEXT-GENERATION 21 cm POWER SPECTRUM MEASUREMENTS CAN TEACH US ABOUT THE EPOCH OF REIONIZATION (2013, background): “…region in the 2D (k⊥, k‖) plane, with more k‖ modes free from foreground contamination on the shortest baselines (i.e. at the smallest k⊥ values) (Datta et al. 2010; Vedantham et al. 2012; Morales et al. 2012; Parsons et al. 2012b; Trott et al. 2012), as schematically diagrammed in Figure…”
Hydrogen Epoch of Reionization Array (HERA) (2016, background): “In simulations see Datta et al. (2010) and Hazelton et al. (2013), and for observations Pober et al. (2013a), and Parsons et al. (2014).”
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): “…mode-mixing 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.…”
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. 2016).”
PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM AT z = 8.4 (2015, unknown): “This relationship, known colloquially as “the wedge,” was derived analytically (P12b; Vedantham et al. 2012; Thyagarajan et al. 2013; Liu et al. 2014a,b), and has been confirmed in simulations (Datta et al. 2010; Hazelton et al. 2013) and observationally (Pober et al. 2013; Dillon et al. 2014).”
THE IMPACT OF POINT-SOURCE SUBTRACTION RESIDUALS ON 21 cm EPOCH OF REIONIZATION ESTIMATION (2012, background): “…be a limiting factor in statistical EoR estimation for proposed experiments with MWA and PAPER, contrary to the conclusions of previous analyses (Datta et al. 2010), which relied on assumed position errors that were independent of source strength; (2) frequency-channel covariance combined with…”