Science Lab - $20

Observing Project Lab: GalaxyZoo.org Project

YOU MUST COMPLETE THIS OBSERVING PROJECT BY THE START

OF CLASS ON: __________________________.

This project consists of three parts:

1.) Classify at least 250 galaxies as either spiral or elliptical.

2.) Pick 30 galaxies (15 elliptical, 15 spiral) and for each:

a.) Find its color

b.) Examine its spectrum.

Please read all of the instructions below before you start. It really will make your job

easier. Note: due to ongoing website changes, some instructions may not be exact

Overview

Part I: Galaxy Classification

In this part of the activity you will do useful science for research astronomers while also learning about galaxies. Your task is to examine 250 galaxies and classify each as either spiral or elliptical. To do this part:

1.) Go to http://www.zooniverse.org/ and register (the register button is in the upper

right corner of the screen titled “My Account” or “Log In”).

2.) After you register, click on Galaxy Zoo Hubble on the right and do the tutorial “How to Take Part”. (Tutorial is found under “Quick Links” at the bottom.)

3.) After you are done with the tutorial start classifying galaxies!

4.) If you log out and then back in to the site, you get back to the galaxy

classification screen from the link “Classify Galaxies” on the right.

5.) You must classify at least 400 galaxies for full credit (400 = A, 250 = D) on

this part. (This is really not so bad. Once you get started it won’t take much

more than 1.5 hours. DO NOT spend more than ~15 seconds per object.)

Part II: Galaxy Properties (found on “Galaxy Zoo Parts II & III objects Data Sheet.xls”)

In this part you will look for differences between galaxies other than shape.

1.) Choose 30 of the galaxies from the “Galaxy Zoo Parts II & III objects Data Sheet.xls”, 15 spiral and 15 elliptical, many of which have spectral information. Record the galaxy type in the data table for this project; more detailed instructions are found

under “For more detailed instructions.”

2.) For each galaxy:

a.) Record its BT and VT magnitudes, and calculate the color, B-V. This is pretty

easy to do if you have made a spreadsheet (See “For more detailed instructions.”)

b.) Count the number of emission lines in the spectrum.

Part III: Answer questions (found on “Galaxy Zoo Parts II & III objects Data Sheet.xls”)

1.) What is the average color of the spiral galaxies in your sample?

What about the ellipticals?

2.) Which are redder, the ellipticals or spirals?

3.) For one of your galaxies, print out its spectrum and indicate on the graph at

least 5 absorption lines ("dips") and at least one emission line (peak).

4.) What differences do you see in the spectra of the ellipticals and spirals?

5.) What differences do you notice in the number of emission lines in the spectra

of ellipticals and spirals?

6.) Explore object ID 587731520668631247. Classify this object as either

elliptical or spiral and give a short explanation (a couple sentences long)

describing why you made the choice you did. Your choice should address

shape, color, and spectrum.

The easy way to see the data on this galaxy is to follow this link:

http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587731520668631247

What to turn in:

o Copy-Paste of your “My Galaxies” page (link on right) into word document.

o Data sheet (your spreadsheet)

o Typed answers to the questions in Part III above found on Data Sheet

Basic GalaxyZoo Navigation:

For more detailed instructions:

* Go to NED at: http://nedwww.ipac.caltech.edu/forms/byname.html

* Type in the object name, either an NGC (New General Catalog) number or a UGC (Uppsala General Catalog) number, and push the “Enter” key on your keyboard or click “Submit query.” * Click on the Images link and look for a color image taken in an optical band or one in the range of 4000 Å to 7000 Å (400 nm – 700 nm). (If a color image does not exist, write NA on your data sheet.)

* Go back to the previous page/tab and click on the blue image next to the Images link.

* Scroll down and look for the BT and VT magnitudes (labeled as B (B_T) and V (V_T), respectively). Record these in the data sheet.

* Go back to the previous page/tab and click on the Spectra link next to the blue image.

* Analyze spectra and record data in data sheet.

* For question 3 Part III: Right-click on a spectra and choose “copy.” Paste it to a word document. Place circles (100% transparent, no fill) around emission and absorption lines.

Images link “blue image” Spectra link