The BINGO Project IV: Simulations for mission performance assessment and preliminary component separation steps

Abstract

Aims. The large-scale distribution of neutral hydrogen (Hi) in the Universe is luminous through its 21-cm emission. The goal of the Baryon Acoustic Oscillations from Integrated Neutral Gas Observations -BINGO radio telescope is to detect Baryon Acoustic Oscillations (BAO) at radio frequencies through 21-cm Intensity Mapping (IM). The telescope will span the redshift range 0.127 < z < 0.449 with an instantaneous field-of-view of 14.75 • × 6.0 • . Methods. In this work, we investigate different constructive and operational scenarios of the instrument by generating sky maps as they should be produced by the instrument. In doing this we use a set of end-to-end IM mission simulations. The maps will additionally also be used to evaluate the efficiency of a component separation method (GNILC). Results. We have simulated the kind of data that would be produced in a single-dish IM experiment like BINGO. According to the results obtained we have optimized the focal plane design of the telescope. In addition, the application of the GNILC method on simulated data shows that it is feasible to extract the cosmological signal across a wide range of multipoles and redshifts. The results are comparable with the standard PCA method.

The BINGO project

“…Following previous BINGO papers by Fornazier et al (2021) and Liccardo et al (2021), our simulations included the contribution of seven foreground components, including Galactic synchrotron, free-free, thermal dust, and anomalous microwave (AME) emissions, extragalactic thermal and kinetic Sunyaev-Zel'dovich (SZ) effects, and unresolved radio point sources, all generated using a recent version of the Planck Sky Model software (PSM; Delabrouille et al 2013). The specific configuration of the PSM code that was used to generate our foreground emissions is as described bellow.…”

“…A population of sources below the detection threshold was simulated on the basis of theoretical number counts. A more complete discussion of the foreground simulation for the BINGO frequency can be found in Fornazier et al (2021) and Liccardo et al (2021).…”

“…We also took the expected thermal (white) noise level per pixel into account by employing a system temperature of 70 K. This level was estimated considering 28 horns, each of them observing at a constant elevation, achieving a survey area of 5324 deg 2 (a sky fraction of f sky ∼ 0.13). We assumed five years of observation and the horn arrangement designed for the Phase 1 of observations, as discussed in previous BINGO publications (Wuensche et al 2021;Abdalla et al 2021b;Liccardo et al 2021). For a good sampling of the map in declination, the position of the horns will be shifted to displace their pointing on the sky by a fraction of a beam width in elevation.…”

“…In this work, we used the GNILC method (Remazeilles et al 2011), a nonparametric component separation technique, to perform the foreground cleaning process. This method has been tested in previous work and showed an excellent performance when applied to 21 cm IM observations (Olivari et al 2016) and, more specifically, to the BINGO-simulated data (see Liccardo et al 2021;Fornazier et al 2021;Mericia et al 2022).…”

“…We find that in general, both cases lead to results comparable to those from Tables 2 and 3, although each redshift range and clustering estimator has its own most advantageous configuration. In this sense, for simplicity, and because previous BINGO papers employ a redshift binning linear in frequency (Liccardo et al 2021;Fornazier et al 2021;Costa et al 2021), we continued to use z-bins with δν = 9.33 MHz width and the BAO fitting process considering three sets of N z = 10 z-bin for both estimators.…”