Top Banner
Robbie Auld 1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Simulated HI observations Robbie Auld Cardiff University collaborating with Oxford SKADS team
10

Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Jan 14, 2016

Download

Documents

Susan Robertson
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 1Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Simulated HI observationsSimulated HI observations

Robbie AuldCardiff University

collaborating with Oxford SKADS team

Page 2: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 2Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

OutlineOutline

• Description of the data pipeline

• Sky simulation (SEX)

• Telescope Simulation

• Detection Technique

• Comparisons: HIPASS vs. SEX

• dN/dz – SEX vs. SAX

• Future THINGS: IC 2574

Page 3: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 3Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Data PipelineData Pipeline

Cleaned datacube

Web query

Sky model

SKA simulatorParselTongue script (HRK) that uses AIPS routines. Includes: antenna Tsys, antenna layout, gain factors, integration time per visibility, total observation time

Corrupted cube

Source Finder

S3 simulation (RW & FL) Query generated via the web interface, source list and datacube generated locally with S3 Tools.

Duchamp source finder package (ATNF)

Page 4: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 4Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Resulting datacubeResulting datacube

Filled UV plane!

Page 5: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 5Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Source detector: DuchampSource detector: DuchampLocates sets of contiguous voxels (3D pixels) above some threshold.

Threshold determination:

Manual (absolute value / S/N value)

Automatic (False Discovery Rate method)

Enhancement

Spectral smoothing (Hanning)

Spatial smoothing (Gaussian convolution)

A trous (wavelet procedure)

Voxels above threshold are flagged, merging algorithm rejects multiple detections

Page 6: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 6Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Duchamp outputDuchamp output

Postscript file of all detections

VO compatible catalogue file

Page 7: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 7Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Comparisons with HIPASSComparisons with HIPASS

Page 8: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 8Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

SEX shortcomingsSEX shortcomings

• HIMF (0 < z < 0.1)

Wilman et al. 2008

Page 9: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 9Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

SEX vs. SAX: dn/dz SEX vs. SAX: dn/dz

Abdalla & Rawlings (2005)

Diamonds – SAXStars – SEXSEX differential number counts too low.

Page 10: Robbie Auld1 Simulated HI Observations 4 th SKADS Workshop, Lisbon, 2-3 October 2008 Simulated HI observations Robbie Auld Cardiff University collaborating.

Robbie Auld 10Simulated HI Observations4th SKADS Workshop, Lisbon, 2-3 October 2008

Future THINGS: IC 2574Future THINGS: IC 2574Integrated intensity Velocity Field

Explore effects of different array configurations with the galaxy in the local neighbourhood and then try moving it further away.