School2008

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Contents

Introduction

This is the wiki entry for the CARMA Summer School June 21-28, 2008. Individual talks will be posted here and you are free to post additional notes, comments etc. The participants in the 2008 Summer School are listed below.

For help on editting Wiki content, see the User's Guide.

Cast of Characters

http://carma.astro.umd.edu/carma/summerschool/2008/GroupPhotoThumb.jpg

Students

Katherine Lee (University of Illinois at Urbana-Champaign)
Joe Converse (University of California Berkeley)
Megan Roscioli (University of Chicago)
Nicole Hasler (University of Alabama)
Stephanie Cortes (University of Arizona)
Shane Bussman (University of Arizona)
Timothy Davis (Oxford)
Josh Goldstein (University of Maryland)
Sarah Graves (Cambridge)
Masayuki Fukuhara (University of Tokyo)
Mike Anderson (Cal Tech)
Jithin George (University of Maryland)
Reiko Momose (University of Tokyo)
Josep-Maria Masque (Barcelona)
Alvaro Sanchez-Monge (Barcelona)
Amanda Heiderman (University of Texas)
Timothy Morton (Cal Tech)
Dan Welty (University of Illinois at Urbana-Champaign)
David Hogg (Exeter)
Lei Zhu (Peking)

Instructors

Melvyn Wright (UCB)
Dick Plambeck (UCB)
Marc Pound (UMD)
Douglas Bock (OVRO)
Nikolaus Volgenau (OVRO)
Jin Koda (CIT)
John Carpenter (CIT)

Special Guest Stars

James Lamb (OVRO)
David Hawkins (OVRO)

Producers

Terry Sepsey (OVRO)
Cecil Patrick (OVRO)

Second Unit Directors

Colette Salyk (CIT)
Scott Schnee (CIT)

Travel Arrangements

Air and Land Directions to CARMA

For travel by air there are a number of options - Las Vegas; Los Angeles Area: LAX, Burbank, Ontario; Reno; Inyokern. Each of these requires a 4 to 5 hour drive to get to CARMA from the airport. The exception is Inyokern (airport code IYK) which is a small regional airport in the Owens Valley. However, only United flies to IYK (via LAX) and there are only 2 flights a day. From IYK, it is about a 2 hour drive to CARMA (rental cars available).

Detailed driving directions to OVRO and CARMA from Los Angeles, Reno, and Las Vegas are here.

What To Bring If You Are Camping

Since all meals will be at the control building, the only essential camping equipment is a sleeping bag. The sleeping bag need not be very warm, since nighttime temperatures will be above freezing. It would be helpful if students who are not flying would bring sleeping mat and tent if they have them. We will purchase enough tents and mats for others. We'll do a poll for who needs what once the accommodation choices are settled.

Other Things You May Want To Bring

Flashlight, bug spray, plastic coffee mug, sunglasses, windbreaker, sweater, rainjacket, binoculars for star gazing/ birdwatching, and good walking shoes.

Payment

We can only take cash or checks written in US dollars. Students can pay for food (and dorms/cottage if applicable) at the time or we will invoice them afterwards. Those staying in motels will pay the motels directly at the time of the visit.

Public Transit between Bishop and Reno

A bus runs Mon,Tue,Thu,Fri. The link to the schedule is below.

http://easternsierratransitauthority.com/wb/pages/bus-routes/bishop-reno.php

Shared Rides

Use this wiki to coordinate shared rides. Give your name, your flight details, how many you can accomodate, and special notes such as whether you will be toting camping gear.

(Note you need an initial space on the line to get the gray box).


Name         Airport          Arrival                 Departure        Renting     Notes                               If Camping...
                       Day    Flight   Time       Day   Flight Time     Car?                                          Can you bring:
                                                                                                                    Tent? (Y/N) Sleeping Mat(Y/N)?   
Marc Pound     IYK     6/22   UAL5434  11:55     6/28  UAL5434 12:15    Yes     Camping; not hiking on 6/28                Y      Y 

Tim Davis      LAS     6/21   KL6711   23:09     6/29  KL6776  13:55    Maybe   Hotel room booked in Las Vegas for 6/21, 
                                                                               travelling to CARMA 6/22.

Steph Cortes   LAX     6/22   SW3232   10:20a    6/29  SW3337  18:40    Yes     Camping and hiking                         Y      Y 
Shane Bussmann LAX     6/20   AB3530   15:40     7/03  USAir207      16:35    No   Camping and hiking                      N    N
Jithin George  LAS     6/21   UAL1549  10:20a    6/29  UAL1565 7:15a    Yes     Hotel room booked in Las Vegas for 6/21, 
                                                                               travelling to CARMA 6/22.
Alvaro Sanchez LAS     6/20   AA 0135  18:30     7/03  AA 0134 20:30    Yes    Hiking on 6/28.
                                                                               We will book a hotel in LA for 6/20 and
                                                                               6/21.
Josep-Maria Masque LAS  6/20  AA 0135  18:30     7/03  AA 0134 20:30    Yes    Hiking on 6/28.
                                                                               The same as Alvaro Sanchez.
Dan Welty      RNO     6/22   AA 1331  12:00     6/28  AA 1750 13:10    Yes    not hiking on 6/28
Masayuki Fukuhara  LAX 6/17   UA 6479  21:05     7/01  UA 891 12:59    Maybe No  Camping and hiking                         N      N
Rieko Momose       LAX  6/17  UA 6479  21:05       7/01 UA 891 12:59    No        Camping and hiking
Katherine Lee      LAS  6/21  AA 1417  16:30     6/28  AA 2040 12:40    Yes     not hiking on 6/28
Amanda Heiderman   RNO  06/19    US526    18:31   07/10   UA1462  11:10    Yes    hiking on 06/28
David Hogg         LAX  6/21  BD3981   19:30     7/10  BD4052  10:49    No     Observing the week after the school, hiking
Sarah Graves       LAX  6/18  UA0935   13:38     7/2   UA0934  13:11    No     I'm going to be in SF before and after, the summer
                                                                                school. Getting a lift to/from the CARMA from 
                                                                               Berkeley.
Lei Zhu            LAS  6/21  Jetblue  17:22    6/29   Jetblue 23:25    No     Camping&Hiking                              N      Y
                              B6-0285                  B6-0684
Nicole Hasler       LAS  6/21  DL65     18:40    6/29   UA1486  15:48    Yes     Hiking on 6/28

Computers

You are encouraged to bring your own laptop; a few desktops will be available for student use. Wireless access will be available; if you require a cable ethernet connection please let Marc Pound know. We will have a switch with 6 ports and 6 ethernet cables. If more than six people need cable ethernet, you'll have to share! MIRIAD is the data reduction and analysis environment. You should try to install it before arriving at the school. It can be installed on Linux and Mac. Sorry, we don't support cygwin. See the Miriad wiki page for details on installing; if you have questions contact Peter Teuben (teuben@astro.umd.edu). He is also maintaining a Miriad2008 todo list where you can find out what the status of the summer school software is.

Electricity

Electricity will be supplied at 120V, 60 Hz, using outlets accepting "American-style" parallel flat-pronged plugs.

Entering your Project Information

To run an observing script, the project first needs to have an entry in the project database. This entry is created via the CARMA proposal system. We have created a special version of the proposal system just for summer school students.

Create yourself a login and enter the basic information for your project here, including a few sentence abstract. When you submit this info, the proposal system will give you back a project code, e.g. cs017. Remember this code, as you will use it in your observing script.

Observing Scripts

An example CARMA observing script is shown cs016_orion.obs. These scripts will observe your science target and all of the calibrators.

The script is organized into parts. The first part of the script contains options that you can edit according to your science program. The second part of the script begins after the line "Main part of the script", and executes the commands to observe your calibrators and science target. This part of the script should not be edited unless you need to customize your observing program.

The observing scripts can be created using the CARMA script writer. During the summer school, we will explain each part of the observing script.

Lectures and Handouts

Proposed Schedule for the Week

  INTRODUCTION to Millimeter Wavelength Interferometry

9-10 am Introduction. (Melvyn)
. Course outline

Day 1: Basics to get you going.

Day 2-4:
  Radio antennas, arrays, aperture synthesis, receivers and correlators.
  Observing techniques, scheduling, calibration, data inspection, imaging

Day 5:  Data analysis, Future developments, VLBI.


. Source characteristics, instrumentation, and observing techniques
  together define a matched filter to  possible observations with
  millimeter wavelength interferometers.

DAY 1: Mon 23 June

9-10am
.  Astronomy from comets to cosmology
. emission mechanisms: thermal and non-thermal
-- source selection: astronomy, frequency, size, brightness sensitivity

. Atmospheric windows at optical, IR, and radio frequencies

. CARMA site characteristics

10-11 am  APERTURE SYNTHESIS BASICS (Melvyn)

. Radio antennas: collecting area and resolution
. Aperture arrays
. response of a 2-element interferometer to point source.
. coordinate systems: (u,v,w), u,v tracks for different arrays.
. CARMA array characteristics. antennas, Rx bands, correlator.
. Aperture Synthesis Imaging.
. Mapping extended sources. resolving out extended structures
. Calibration, Imaging and Deconvolution.

11-12 am. Antenna tour (James Lamb; Dick)

.  Visit to telescopes. Intro to antenna hardware.
-- antenna structure
--  drive system
--  manual, computer control
--  limits and switches
--  cable wraps

12am - 1pm  Lunch.


1-1:30 pm  Intro to CARMA computers. (Marc)

. computers. data flow. archiving
- control computer: roadmap of machines, disks, directories and
    subdirectories
. school data reduction and analysis space. login, passwords.
. basic observing procedures, on-line monitors and data inspection
- key programs:

1:30-2:30 pm    Basic demos (students guided by Jin)
  -- observe a point source (maser or quasar) and a planet.
  -- plot amplitude and phase vs. uvdistance
  -- constant amplitude for point source, Bessel function (with
     phase flips) for planet
  -- set up correlator in various modes, take spectra of Orion

2:30-3:30 pm  OBSERVING PROCEDURES (Melvyn)

. Calibrations:
  -- gain(t,f,p) - gain, bandpass, polarization, pointing.
. calibration intervals.  V' = gain(t,f,p) x V + noise
. Observing scripts
. selecting suitable observations for the target sources.
  -- sensitivity
  -- source size; mosaicing.
. DEMO: CARMA sensitivity calculator

. CARMA correlator capabilities; selecting a correlator settup.
. choosing calibrators for gain, bandpass, flux and pointing.

3:30-5:00 pm  group discussion selecting student projects. (Douglas)
   More students this year -- pair off on projects.
   After discussion period, each group should
      - email one paragraph about project to memo organizer (Marc)
      - insert project via proposal web page

5-6 pm Intro to preparing CARMA observing scripts (John)

6 pm Dinner at the CARMA site.

Student projects observed on CARMA array overnight.


DAY 2: Tues 24 June

9-9:45 am DATA INSPECTION AND ANALYSIS (Melvyn)

. overview of data reduction procedure
. introduction to MIRIAD data reduction package.
. basic Miriad data format: header, history, uvdata, gains, bandpass
. inspecting uvdata: uvindex, uvlist, uvplt, uvspec
. selecting uvdata: keywords select= and line=
. flagging bad data with uvflag
. antenna based calibration; selfcal and mfcal. gpplt. gains bandpass polcal
. rewriting edited data sets with uvaver, uvcat, uvcal

9:45-10:15  ASSESSING DATA QUALITY (Nikolaus)

ONGOING: Students submit their proposal cover sheets by noon today.

10:15-11:15 Create draft observing schedule for the week  (Jin with students)

11:15-noon IMAGING (Melvyn)

. Review of basic math: brightness distribution is FT of visibility data.
. FFT requires convolving onto a grid; choosing the pixel and image size.
  -- mosaicing
. invert; choice of natural, uniform, robust weighting, effect on the
    synthesized beam
. deconvolution algorithms: clean, maxen, mossdi, mosmem, restor

12 - 1 pm Lunch at the CARMA site

1-2 pm. CARMA hardware - I.  Receivers and Calibration (Dick)
- introduce system block diagram; receiver, cal load, local osc,
    phaselocks, fiber, downconverter, correlator
- compute energy collected if observing 20 Jy source for 1 yr;
    would need to observe for 10^5 yrs to heat 1 drop of water by 1 C
- receiver types:
    - bolometers: not suitable for interferometry because they
        don't preserve phase
    - HEMT amplifiers: not yet competitive at 1mm
    - heterodyne rcvr: downconvert to lower freq in a nonlinear device
- SIS mixers: photon-assisted tunneling; not a Josephson effect
- cryogenics; closed-cycle refrigerators, compressors
- local oscillator: Gunn oscillator
    - must be synchronized between all antennas; discuss in lecture 2
    - both USB and LSB are downconverted to IF; can be separated
        with 90 degree phase switch; also defer to lecture 2
- combining LO and signal: mylar beamsplitter
- receiver and system temperature
- calibration:
    - ideally, calibrate on loads outside the earth's atmosphere
    - the chopper wheel method

2-2:30 pm. Correlator Tour (Dave Hawkins)

2:30-3:15pm  Troubleshooting on a real observing script (Jithin, Josh, John C., Dick, Marc)

4-5 pm Example data reduction using student data.

5-6 pm students prepare observing scripts, analyze data.

Dinner at the CARMA site.

Student projects observed on CARMA array overnight.


DAY 3: Wed 25 June

9-10 am CALIBRATION (Melvyn)

. Calibrations - gain, bandpass, polarization, pointing.
. Antenna based calibrations: amplitude and phase closure
. Atmospheric and instrumental phase characteristics
. Tsys and Jy/K
. Pointing
. correlator calibration techniques.

10-12 am calibration and analysis of student projects (all)

12 - 1 pm Lunch at the CARMA site

1-2 pm  special topics in mapping (Melvyn)
- the missing short spacing problem; importance for getting correct
    answers for spectral index, etc; negative sidelobes due
    to extended structure; filling in missing spacings with
    larger single dish or Ekers-Rots scheme
- mosaicing: setting up grid files, linear and nonlinear
    mosaicing schemes
- heterogeneous  array imaging

2-4pm L
    Laptop tutorial data reduction and analysis of student data
    Students prepare observing scripts, and analyze data.


4-5 pm  Singledish observing of IRC+10216 and discussion of singledish techniques (Marc) 

5-6 pm 
    Laptop tutorial data reduction and analysis of student data
    Students prepare observing scripts, and analyze data.

Dinner at the CARMA site.

Student projects observed on CARMA array overnight.

DAY 4: Thurs 26 June

9-10 am CARMA hardware lecture 2 - local oscillators, phaselocks (Dick)
- review system block diagram, heterodyne system, local oscillator
- independent oscillators, 100 GHz, synchronized to fraction of
     one cycle over periods of hours (sounds hard)
- basic phaselock: mix with reference, low pass filter, generate
     correction voltage; keeps phase relationship fixed
- CARMA phaselock chain; synthesizer, YIG, Gunn, 10 MHz, 50 MHz
- numerical example: synth = xxx, YIG = yyy, LO = zzz
- fiber system; linelength correction
- lobe rotation
    - compute differential doppler shift due to earth's rotation 
      for 100 GHz signal incident on 2 antennas 10-m apart: 0.24 Hz
    - lobe rotators
- interferometer response for a double sideband conversion system
- need to offset freq of 1st LO as well as insert delays;
    can be understood as removing differential doppler shift
    due to earth's rotation
- phaselocks; the LO system
- cable length measurement system
- phase switching; Walsh functions
- sideband separation by phase switching; note that only signals
    common to an antenna pair can be separated; noise appears
    in both sidebands
- fiber optic hardware

10-11 am calibration (Dick)
- converting to flux density; aperture efficiency; source
    flux table
 
 12 - 1 pm  Lunch at the CARMA site

  1 - 2 pm  Combining Single dish and interferometric data (Melvyn) 

  2 - 3 pm  Interpreting Errors in images (Douglas) 

Dinner at the CARMA site.

Student projects observed on CARMA array overnight.


DAY 5: Fri 27 June

9-10 am CARMA hardware lecture 3 - correlator; software control (Dick)
- review system block diagram
- correlator is detector and spectrometer for the array
- XF vs FX
- delays, 2nd LO lobe rotation, sideband separation
- correlator modes
- FPGA's
- noise source
- basic architecture of computer control system, CAN nodes

10-10:30 observer's everyday responsibilities (John)
- creating and running the master master schedule
- deciding whether to do 1mm or 3mm
- data quality reports
- data archiving and disk management

10:30-12  Student presentations

 12 - 1 pm Lunch at the CARMA site

1-2 pm
- moving the antennas and calibrating a new array configuration (John, Jin)
- changing IFLO connections in the pits
- running tilt, shimming the antennas
- entering new station coordinates
- finding pointing offsets.
- finding the delay centers
- TV and radio pointing
- finding a baseline
- entering new pointing offsets or baselines

2-4 pm Student Presentations



4-5 pm
CARMA future plans (Douglas)
- A-configuration
- Carlstrom's 1 cm system
- wideband receivers
- 23-antenna CARMA array


. analysis of student data


Dinner at the CARMA site.

Student projects observed on CARMA array overnight.

DAY 6: Sat 28 June

hike.

Student projects observed on CARMA array overnight.
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