DINGO early science with ASKAP-12

Transcription

1 DINGO early science with ASKAP-12, Martin Meyer DINGO team ASKAP early science workshop 8 October 2015

2 DINGO Science

3 DINGO Early Science Evolution of HI Across Cosmic Time Use HI stacking techniques to sample a cosmologically representative volume in HI emission to measure evolution in the neutral atomic hydrogen content of the Universe (ΩHI) over the past 4 Gyr HI and Environment Combine ASKAP and GAMA data to study the connection between HI content and environment for z<0.1. Angular Momentum Measure the specific stellar angular momentum j by combining HI linewidths from ASKAP with optical inclination and size measurements from GAMA. This will result in a wellcharacterized sample of galaxies with simultaneous measurements of stellar mass M and j.

4 Survey Speed SS = FoV eff x (A/T eff ) 2 FoVeff = Effective Field of View = (π/8)(1.3λ/d) 2 Teff = effective system temperature = Tsys/η FoV A Teff SS Parkes ~28 1 ATCA ~ JVLA ~ ASKAP ~ ASKAP ~80 11

5 Evolving HI Universe Measure ΩHI at different redshift intervals 30 deg 2 0<z< <z< <z< <z<0.4

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7 HI Scaling relations Delhaize et al.

8 HI stacking Extracting a statistical HI signal by co-adding the 21-cm line emission form multiple galaxies using their known positions and redshifts ASKAP: HI to z ~ 0.4 GAMA: optical spectra

9 HI stacking

10 GAMA Data Products

11 GAMA: 20-band Photometry

12 DINGO early science For ASKAP-12 we intend to use G23 DEC=-30 ASKAP-12 PSF DEC=0

13 GAMA23 field

14 GAMA23 field

15 GAMA23 field

16 HI predictions Either assume MHI* or use scaling relations. e.g. Cortese et al. 2011, Denes et al, 2014 Scaling relations from Denes et al. 2014

17 HI stack predictions ASKAP-12, 100 hours redshift z Frequency MHz Tsyseff (K) σ(500 km/s) mjy km/s Flux M*HI mjy km/s S/N (M*HI 500 km/s) ~20% ~90% ~40% ~40% ~20% RFI

18 log10(amp) (Jy) RFI VLA L-Band Spectra, 2012 June B-config Freq (MHz)

19 log10(amp) (Jy) RFI VLA L-Band Spectra, 2012 June B-config airplane gps radio Freq (MHz)

20 HI stack predictions G23 covers 2 ASKAP pointings All integration times are total times, including both pointing S/N calculations take into account RFI estimates. S/N estimates for 500 km/s spread over 3 bins z Freq MHz G-23 dn MHI* S/N 100 hrs MHI* S/N 200 hrs MHI_i S/N 100 hrs MHI_i S/N 200 hrs hours needed: improved statistics better resolved spectrum capability of making sub-samples push the high redshift bins (really novel)

21 HI and environment HI and Environment Combine ASKAP and GAMA data to study the connection between HI content and environment for z<0.1, specifically: Measure the dependence of HI content on geometric environment (in pair, group, filament, or void) and parent halo mass Determine the impact of star formation and AGN activity on the neutral ISM Explore the nature of HI-excess galaxies

22 Galaxy groups

23 Structure and environment

24 Gas fraction

25 Angular Momentum Measure the specific stellar angular momentum j by combining HI linewidths from ASKAP with optical inclination and size measurements from GAMA: the first measurement of the two-dimensional distribution in the (M, j)-plane of a sample with well-described completeness, the largest, systematic measurement of the relationship between M, j, and tertiary galaxy properties (morphology, gas fraction, depletion time), the most accurate measurement of the large-scale distribution, including environmentdependence, of angular momentum. Obreschkow & Glazebrook 2013

26 Angular Momentum Obreschkow & Glazebrook 2013

27 Tully-Fisher S. Meyer et al. subm.

28 Proposed observations 2 ASKAP pointings in the GAMA23 field 2x100 hrs MHz possibly commensal with WALLABY fields (similar technical requirements) 2x100 hrs MHz better stacking statistics push out to z~0.5 uniform sensitivity less RFI

29 Key data products # Product Qty Size per item (GB) Total size (GB) 1 Cleaned Stokes I cube at 30 resolution; size: ; pixel size: 7.5 ; data type: 32 bit floating-point; Daily cleaned Stokes I cube at 30 resolution; size: ; pixel size: 7.5 ; data type: 32 bit floatingpoint; assuming ~7 8 h sessions per field, 4 fields in total PSF images for 30 data cubes (twice the size on each spatial axis with adequate frequency resolution, eg. 1MHz, equivalent to 0.1% change in PSF); assuming 4 fields x 36 beams Sensitivity/weight cube for 30 data cubes; specifications as in #1 ~

30 Summary Possible to do great HI science with ASKAP-12 Evolution of neutral hydrogen using HI stacking 100 hours (per 300 MHz) in 2 fields gives ΩHI to z~0.5 More time/fields enables high-z HI scaling relations Studies of HI content in different environment Angular momentum studies GAMA ideal match for ASKAP pointings and bandwidth Richest multi-λ data on ASKAP scales Pre-eminent local survey for: environment, halo masses, pair studies, multi-λ coverage, structural analysis, etc.

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