Forecast for FAST: from galaxies survey to intensity mapping

Abstract

The Five-Hundred-Meter Aperture Spherical Radio Telescope(FAST) is the largest singledish radio telescope in the world. In this paper, we make forecast on the FAST HI large scale structure survey by mock observations. We consider a drift scan survey with the L-band 19 beam receiver, which may be commensal with the pulsar search and Galactic HI survey. We also consider surveys at lower frequency, either using the current single feed wide band receiver, or a future multi-beam phased array feed (PAF) in the UHF band. We estimate the number density of detected HI galaxies and the measurement error in positions, the precision of the surveys are evaluated using both Fisher matrix and simulated observations. The measurement error in the HI galaxy power spectrum is estimated, and we find that the error is relatively large even at moderate redshifts, as the number of positively detected galaxies drops drastically with increasing redshift. However, good cosmological measurement could be obtained with the intensity mapping technique where the large scale HI distribution is measured without resolving individual galaxies. The figure of merit (FoM) for the dark energy equation of state with different observation times are estimated, we find that with the existing L-band multibeam receiver, a good measurement of low redshift large scale structure can be obtained, which complements the existing optical surveys. With a PAF in the UHF band, the constraint can be much stronger, reaching the level of a dark energy task force (DETF) stage IV experiment.

The atomic gas of star-forming galaxies atz∼ 0.05 as revealed by the Five-hundred-meter Aperture Spherical Radio Telescope

“…Higher redshift Hi studies have been available from damped Lyα absorbers (Neeleman et al 2016), or intensity mapping (e.g. Hu et al 2020). To detect the Hi emission line beyond z ∼ 0.1 is still a major challenge.…”

The atomic hydrogen content of galaxies as a function of group-centric radius

“…From the evidence presented here, it is possible to take our analysis a step further and quantify the H properties vs. group-centric radius relations at fixed stellar mass as a function of halo mass and density, only when a large enough galaxy sample can be accessed. Next-generation Square Kilometre Array (SKA) precursor facilities such as the Australian SKA Pathfinder (ASKAP) (Johnston et al 2008;Meyer 2009), MeerKAT (Holwerda et al 2012), Five-hundredmeter Aperture Spherical radio Telescope (FAST) (Nan et al 2011;Duffy et al 2008;Hu et al 2020b) and WSRT/Aperture Tile in Focus (APERTIF) (Oosterloo et al 2009) will enable large-area surveys to significant depths. It will very soon be possible to extend our measurements to significantly larger samples, making it feasible to further quantify the contribution of different mechanisms to the H content increasing trend on radius, and potentially extend this to higher redshift.…”

Prospects for Constraining Interacting Dark Energy Models with 21 cm Intensity Mapping Experiments

“…So far, there are many current and future HI IM experiments comprised of wide-field and high-sensitivity radio telescopes or interferometers. Here we consider several typical examples, namely, the Baryon acoustic oscillations In Neutral Gas Observations (BINGO) [6,[32][33][34], the Five-hundred-meter Aperture Spherical radio Telescope (FAST) [35][36][37][38][39][40], the Square Kilometre Array (SKA) [24,[41][42][43], and the Tianlai cylinder array [18,[44][45][46][47][48]. This work aims to forecast how future HI IM experiments, including BINGO, FAST, SKA Phase I midfrequency array (SKA1-MID), and Tianlai, can constrain the interacting dark energy (IDE) model.…”