Laura Wolz - Galaxy evolution with HI intensity Mapping

HI intensity mapping

Integrated line flux over entire HI mass function

Tomographic maps of the universe for 0<z<6

Observe large cosmological volumes for wide redshifts with high z and low spatial resolution

measurement of large scale tructure

Temperature power spectrum

Amplitude tests mean HI density and thus Omega_HI

Non-linear effects: environments and galaaxy formation

Experiment

GBT

Parkes

SKA

ASKAP

CHIME

Tianlai

MeerKAT

BINGO

Challenges

Receiver noise: amplitude comparable to signal - isotropic, manageable in power spectrum space

Instrumental errors: calibration uncertainties, beam and pointing errors, polarization leakage - simulations of instrument response

RFI : contaminates in spatial and frequency space - go to the desert

foreground contaminations: galactic emission and extra-glaactic point sources - avoidence and removal strategies

GBT X EBOSS data analysis

GBT updated intensty mapping data in 0.6<z<1

eBOSS ELGs: 0.7<z<1.1;LRGs:0.6<z<.9

Area overlap: 100 square degrees

Goal: etimate th HI content of eBOSS ELGs and LRGs via cross-correlation eith GBT HI intensity maps

Goal: constrain HI density and bias at z=0.8

Goal: compare different foreground removal methods

Neutral Hydrogen Evolution: HI auto-correlation

Require HI distribution to do correct cosmology

Measure HI evolution to discover connection to galaxy formation processes

SKA Low Intensity Mapping

SKA low observation between 200-350MHz - 3.05<z<6.1

Core and central configurations with 224/296 stations in 500m/1750m radius

Deep survey with 100sq deg with 5000hrs

Medium survey with 100 sq deg with 2500hrs

Instrumental Simulations

Meraxes galaxy formation model of the DRAGONS simulation including high particle and redshift resolution

Blitz-Rosolowsky HI partitioning scheme

z=5.0

OSKAR visibility simulatr for core and central areas of HI signal and diffuse foreground

fastICA: solving the coctail party problem

Independent component analysis (ICA) seperates a multicomponent signal into subcomponents such that components are statistically independent

Central limit theorum: PDF of a mixture of independent components is more gaussian than the PDF of any individual component

Components with gaussian PDFs can not be indentified

Galaxy Evolution: HI-galaxy cross-correlations

HI only detected for low redshift

String selection effects toward HI rich objects\

HI intensity maps are complete - Global HI density

HI-galaxy cross-correlations sensitive to galaxy properties

cross shot noise measures HII contents in galaxy samples

Poisson noise scales as HI brightness temperature of the optical galaxy sample

Maths

Hydro-simulations

Subgrid models include gas cooling and heating, feedback processes, star evolution etc

Neutral hydrogen partition

Phenomenological and theoretical partitioning models

Analytic models

Semi analytic and hydrodynamical models very complex

Computationally expensive for one cosmology

Analytic halo model framework based on I maass per halo

Predict observables such as power spectra, HI mass functions, column densities

Fit parameters of HI-halo-mass relation to observables

discrete model: HI associated to galaxy