N A W G
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NRAO Algorithms Working Group Meeting - PRELIMINARY AGENDA
Date: 2006-03-08 (Wednesday)
Time: 1300 MST = 1500 EST
Video Hub: CV-conf (others call in)
Rooms: SOC317/CV311/GB241/TUCN525
Audio Toll-Free number (in US): 866-791-0515
Participant Passcode: 4329509
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The NAWG:
I would like to invite you to attend and participate in the eleventh NRAO
Algorithms Working Group (NAWG) meeting on Wednesday 8 March 2006.
The goal of these meetings is to have a general forum to discuss
data-processing algorithms related issues of interest to scientists and
software folks alike (independent of development platform or package). This
is in response to the pressures of planning for the EVLA hard problems like
wide-field/wide-band imaging as well as thinking about problems for ALMA and
GBT. It is meant to be as observatory-wide as possible and I'm trying to
solicit some participants from the various sites.
These meetings are meant to be mostly informal discussion with some scheduled
presentations ("Main Events") on algorithmic research and/or implementation
topics. If you wish to participate and also want to speak on a topic let me
know (or just show up either in person or via video/audio)!
These meetings are scheduled for the 2nd Wednesday each month (in the NAUG
meeting slot in the calendar).
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Agenda:
Send items for inclusion to smyers
1. Organizational issues
o request for contributed talks for future meetings!
2. Project-related (ALMA, EVLA, GBT, VLBA, &c.) issues
o EVLA Memo 102 (02/2006)
"Monte Carlo Methods for Bayesian Image Reconstruction and
Analysis in Radio Astronomy"
Urvashi R. V. & T.J. Cornwell
http://www.aoc.nrao.edu/evla/geninfo/memoseries/evlamemo102.pdf
3. ***Main Event*** - Presentations and Discussion Items
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A pair of short talks by Gianfranco Gentile and Joe Hembold (UNM)
on the use of spherical harmonic transforms in interferometry
for ultra-wide-field imaging.
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"Spherical harmonics and wide field imaging"
Gianfranco Gentile, Joe Helmboldt, Sudhakar Prasad (UNM)
Abstract: I will introduce the approach of representing the sky
brightness in terms of spherical harmonics and how this can be in
principle used to create images from interferometric
measurements. This could be an alternative approach to other
wide-field imaging techniques such as faceting and the
w-projection method.
PPT and PDF available at:
ftp://neoastro.phys.unm.edu/pub/ggentile/
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"Spherical Harmonic Interferometric Imaging: Implementation"
Joe Helmboldt, Gianfraco Gentile, and Sudhakar Prasad (UNM)
Abstract: By representing the surface brightness of the sky in
terms of spherical harmonics, one can arrive at a relation
between the spatial coherence function measured by an
interferometer and the spherical harmonic transform of the
brightness distribution. However, there are several practical
concerns one must address in order to use this to produce images
using actual interferometric data. These involve 1) the
determination of the largest value of l for which one needs to
compute the spherical harmonic transform of the brightness
distribution, 2) the computation of spherical harmonics for large
(up to 100,000) values of l, and 3) the optimal technique to use
to convert visibilities into values of the spherical harmonic
transform for pairs of l and m values. These issues and our
current efforts to address them will be discussed.
PDF will be available before the talk at:
http://astronomy.nmsu.edu/helmbold/sh_imaging.pdf
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4. Future events (please sign up!)
o Convolutional mosaicing (Myers, Golap, Bhatnagar)
5. Relevant reading:
o Links to Jan 2006 URSI talks:
Session J2 Friday Jan 6 2006
New Interferometric Calibration Techniques
Organizer: M. Wright
- Mark Holdaway's talk on fast-switching for ALMA
http://www.aoc.nrao.edu/~smyers/aips++/talks/HoldawayURSI06jan06.pdf
Session J3 Friday Jan 6 2006
Challenges and New Algorithms for Interferometric Imaging
Organizer: S. Myers
- Sanjay's talk on high-dynamic range imaging
http://www.aoc.nrao.edu/~smyers/aips++/talks/BhatnagarURSI06jan06.pdf
- Urvashi's talk on wide-band continuum imaging (see below)
http://www.aoc.nrao.edu/~smyers/aips++/talks/UrvashiURSI06jan06.pdf
- Crystal's talk on submillimeter imaging (SMA & ALMA)
http://www.aoc.nrao.edu/~smyers/aips++/talks/BroganURSI06jan06.pdf
o Online Conference Proceedings:
- "SKA Wide-Field Imaging Workshop", Dwingeloo, NL, 22-24 June 2005
http://www.skatelescope.org/pages/news/Wrksp20220605.htm
- "ALMA and SZ", Paris, 7-8 April 2005
http://www.dstu.univ-montp2.fr/alma/sz.html
- "First RadioNET Software Forum", Jodrell Bank, 1-3 March 2005
http://www.radionet-eu.org/rnwiki/ProceedingsFirstSoftwareForumMeeting
o Paper & Memos:
- Beyond the isoplanatic patch in the VLA Low-frequency Sky Survey
(W.D. Cotton et al.)
Abstract: http://link.aip.org/link/%3FPSISDG/5489/180/1
- Solving for the Antenna Based Pointing Errors (Bhatnagar, Cornwell &
Golap)
http://www.aoc.nrao.edu/evla/geninfo/memoseries/evlamemo84.pdf
- EVLA and SKA Computing Costs for Wide Field Imaging (Cornwell)
http://www.aoc.nrao.edu/evla/geninfo/memoseries/evlamemo77.pdf
- W Projection: A New Algorithm for Non-Coplanar Baselines (Cornwell,
Golap, Bhatnagar)
http://www.aoc.nrao.edu/evla/geninfo/memoseries/evlamemo67.pdf
- W-projection paper draft:
http://www.atnf.csiro.au/people/tim.cornwell/wproj-paper.pdf
- Effects of Atmospheric Emission Fluctuations and Gain Fluctuations on
Continuum Total Power Observations with ALMA (Holdaway)
http://www.mma.nrao.edu/memos/html-memos/abstracts/abs490.html
http://www.mma.nrao.edu/memos/html-memos/alma490/memo490.pdf
o Algorithms etc.
FFTs:
http://www.fftw.org/links.html
FFTs on the Sphere:
http://www.cs.dartmouth.edu/~rockmore/fft.html
http://www.cs.dartmouth.edu/~geelong/sphere/
HEALPIX:
http://healpix.jpl.nasa.gov/
Fast convolution on the sphere:
http://arxiv.org/abs/astro-ph/0008227
o Post-processing requirements:
- ALMA Offline Data Processing Requirements
http://www.alma.nrao.edu/development/computing/docs/joint/0018/ALMAoffline-sw-18.pdf
- EVLA Offline Data Processing Requirements
http://www.aoc.nrao.edu/~smyers/evla/evla_offline.pdf
o GBT:
- GBT Software Review Agenda & Presentations
http://wiki.gb.nrao.edu/bin/view/Software/ReviewAgenda2004
- GBT Standard Observing Modes
http://wiki.gb.nrao.edu/bin/view/Observing/StandardObservingModes
6. Upcoming meetings and deadlines:
o 2006 Jan 4-7 URSI Meeting (w/Algorithms session), Boulder, CO
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o NAWG Website: http://www.aoc.nrao.edu/~smyers/nawg/
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