Sheet1Your NameSection #Part IIYourColor# ofGalaxyGalaxyObserved.docx

Sheet1Your Name:Section #:Part IIYourColor#
ofGalaxyGalaxyObservedIndexemissionNameTypeColorB
(B_T)V (V_T)(B - V)Spectra?linesDescription of
spectraExample:NGC 3310spiralblue &
orange11.1510.80.35Yes44241.6 to 5103.6 A, 4 -5 emission
lines and 2 absorption linesNGC 224NGC 598NGC 5194NGC
4579NGC 4303NGC 5055NGC 4826NGC 3623NGC 3627NGC
2300NGC 4261NGC 4881NGC 3377UGC 145UGC 206NGC
147UGC 387NGC 185NGC 227UGC 579NGC 315UGC 610NGC
430NGC 507UGC 973NGC 533Part IIIQuestions from "Appleby
Galaxy Zoo Lab Project v.July 2010.doc"#1.Average color
index of spirals:Average color index of ellipticals:#2.A color
index of less than 0.45 is considered red.A color index greater
than 0.45 is considered blue.Which are redder: spirals or
ellipticals?:(#3.)Choose one of your galaxies above and copy-
paste its spectrum to a word document.Use circles to identify at
least 5 absorption lines ("dips").Use circles to identify at least 1
emission line ("peak").Hint: See "NGC 3310 Example
spectra.doc"#4.How do elliptical and spiral spectra
differ?:#5.How do the quantity of emission lines differ between
galaxy types?:#6.Object ID 587731520668631247Galaxy
type:Reason for classification
type:http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=58773
1520668631247
Sheet2
Sheet3
Our Expanding Universe

Description:
In the early 20th century, astronomers made an amazing
discovery that changed everything they thought they understood
about the universe. The discovery made was that almost every
galaxy is moving away from us. Before this discovery,
astronomers knew that the universe was full of stars and
nebulae, but they had no idea that some of the nebulae were
actually other galaxies, or that these galaxies were moving away
from us.
When Hubble and Humason first made this discovery, they
plotted the distance to the galaxies on one axis versus the
recessional speed of the galaxies on the other axis and found
that they were correlated. The tight correlation implied a
fundamental relationship, which led to the calculation of what is
now known as the Hubble constant. The relationship is known
as Hubble’s Law. As any law in science, it merely describes the
way the data behave and does not explain why. The explanation
for why galaxies appear to be moving away from us at faster
rates the farther they are away from us comes from the Big
Bang theory. Theories seek to explain why, while laws simply
describe repeated observable behavior.
According to the Big Bang theory, the Hubble constant
describes the rate at which the universe is expanding. Hubble
first determined the value of this constant to be 500 km/s/Mpc.
This value means that for each Megaparsec of distance from us
an object is, its distance from us is increasing by 500 km every
second (or, conversely, a Megaparsec (3.086 x 1019 km) of
space is increasing in size by 500 km every second). This
exercise will give students a chance to understand how these
measurements are made. In addition, students will calculate the
value of the Hubble constant based on real data.

Introduction:
Determining the rate of expansion of the universe is an
endeavor that astronomers have undertaken for almost a
century. For decades, there were two conflicting values for this
number. Only recently have astronomers begun to come to
agreement about the value of the Hubble constant, but it is not
through the measurements of recessional speeds of galaxies. As
will be evident with this experiment, there is good reason to be
skeptical of the determination of Hubble’s constant through a
correlation of recessional speeds with distance.
First, you will acquire a galaxy spectrum, identify an absorption
line and measure the redshift of the galaxy. Next, you will use a
simple equation to determine the recessional speed of the galaxy
and then compare your answer with the accepted value for
recessional speed for that galaxy.
Finally, you will use NED (the NASA/IPAC Extragalactic
Database) to acquire recessional speeds and distances for
several (at least 10) galaxies of your choice. Using these data,
you will determine the value for the Hubble constant and
compare this value with Hubble’s original value (500
km/s/Mpc) and the current accepted value (72 km/s/Mpc).
1. Get the spectrum of a galaxy. Go to
http://nedwww.ipac.caltech.edu/ and select “Spectra” under the
heading “Data”. Once there, enter “NGC1050” for the “object
name” and click on the “submit query” button. The second
spectrum that appears is one for the galaxy NGC 1050 and
shows data for the wavelengths from 5445 to 7899 Angstroms.
(This information appears in the far right column of the table.)
2. Determine the wavelength of the tallest peak in the spectrum.
Launch the Specview Applet by clicking on the word
“Specview” below the spectrum for NGC 1050.This applet will

allow you to display the data using any units, to display
reference lines and to measure the wavelength of the emission
lines shown. You may have to change the units.
3. Calculate the redshift of the galaxy. Usually the laboratory
wavelength of the tallest peak in the spectrum is 6562.8
Angstroms. The redshift of the galaxy is equal to the observed
wavelength (what you measure) minus the laboratory
wavelength, divided by the laboratory wavelength. The number
you get should be a number between zero and 1, closer to zero.
Round off your answer to the nearest 1000th.
4. Calculate the recessional speed of the galaxy. The recessional
speed of the galaxy is the redshift, times the speed of light. Use
the speed of light in km/s, so that your answer will be in km/s.
Check the answer you get against the value on NED. To check
the value on NED, go to the website above and click on
“Redshift” under the heading of “Data”. Once there, enter
“NGC 1050” for the “object name” and click on the “redshift”
button. Scroll down to find the recessional speed, which will be
labeled “Velocity” or “Helio. Radial Velocity”. Ask your
instructor which value you should use if the values are very
different from one another.
5. Look up the luminosity distance for the galaxy. Go back to
the website and look up the galaxy using the “by name” option
under the “objects” heading. At the very bottom of the page,
there is a section called “Cosmology-Corrected Quantities”.
There should be at least three different distances listed. Use the
“Luminosity Distance”. This distance is calculated using the
luminosity and apparent brightness of the galaxy. This distance
does not depend on the motion of the galaxy, so it is what we
will use as an independent measure of distance.
6. Determine the value of the Hubble constant. Repeat steps 1
through 5 to get the heliocentric radial velocities and luminosity

distances for at least nine other galaxies from the list found in
Appendix A. Make sure the velocities are all greater than 1000
km/s. (This is because the motions of galaxies that are moving
at slower speeds is not dominated by the expansion of the
universe.) To determine the value of the Hubble constant, plot
the data you collected on a graph using Excel. Put the speed on
the y-axis and the distance on the x-axis. Make sure speed is in
units of km/s and distance is in Mpc. The slope of the line that
fits these data points is the Hubble constant.
7. Compare the value of the Hubble constant you determined to
the current accepted value (72 km/s/Mpc) and to Hubble’s
original value (500 km/s/Mpc). Determine the percent
difference between your value and the other two values. (The
formula for percent difference can be found in Appendix B.)
The Hubble constant can also be used to calculate the age of the
universe, assuming a constant rate of expansion. To perform
this calculation, all you have to do is divide the number of km
in a Mpc by the Hubble constant value, then divide it by the
number of seconds in a year. That will give you the age of the
universe in years. Use your textbook or the internet to find
these conversion values.
OPTIONAL STEP 8. For the final product of this exercise, write
a report in the style of a scientific publication. You should have
an abstract explaining the goal of the experiment and a brief
description of the experiment and the results. The introduction
should describe the history behind the experiment and
methodology. Use your textbook and reliable internet resources
(like NASA websites) as resources for this part. Be sure to
address why one should be skeptical of the determination of
Hubble’s constant through a correlation of recessional speeds
with distance. The next section would be the Data and
Observations section where you describe how you acquired the
data for this experiment and what methods you used to acquire
it. Here, you should explain what types of spectra you used to

get your recessional speeds; also, you should describe the
process you used to extract the data for NGC 1050. The next
section is the Analysis section. Here you present the graph you
made of the data you collected and describe the analysis you did
to extract the Hubble constant. Your comparison to the
currently accepted and original values should be included in this
section, as well as your calculations of the age of the universe.
Finally, the Conclusions section will summarize the experiment
and list the conclusions you drew from your data and your
analysis. Don’t forget to include a References section and list
all resources you used for this experiment.
Sum 10Name: ________________________________
Lab Report for Lab #12:Our Expanding Universe
1. Get the spectrum of a galaxy. Go to
http://nedwww.ipac.caltech.edu/ and select “Spectra” under the
heading “Data”. Once there, enter “NGC1050” for the “object
name” and click on the “submit query” button. The second
spectrum that appears is one for the galaxy NGC 1050 and
shows data for the wavelengths from 5445 to 7899 Angstroms.
(This information appears in the far right column of the table.)
2. Determine the wavelength of the tallest peak in the spectrum.
Launch the Specview Applet by clicking on the word
“Specview” below the spectrum for NGC 1050.This applet will
allow you to display the data using any units, to display
reference lines and to measure the wavelength of the emission
lines shown. You may have to change the units.
[Type answer here]
3. Calculate the redshift of the galaxy. Usually the laboratory
wavelength of the tallest peak in the spectrum is 6562.8
Angstroms. The redshift of the galaxy is equal to the observed

wavelength (what you measure) minus the laboratory
wavelength, divided by the laboratory wavelength. The number
you get should be a number between zero and 1, closer to zero.
Round off your answer to the nearest 1000th.
[Type answer here]
4. Calculate the recessional speed of the galaxy. The recessional
speed of the galaxy is the redshift, times the speed of light. Use
the speed of light in km/s, so that your answer will be in km/s.
Check the answer you get against the value on NED. To check
the value on NED, go to the website above and click on
“Redshift” under the heading of “Data”. Once there, enter
“NGC 1050” for the “object name” and click on the “redshift”
button. Scroll down to find the recessional speed, which will be
labeled “Velocity” or “Helio. Radial Velocity”. Ask your
instructor which value you should use if the values are very
different from one another.
[Type answers here]
5. Look up the luminosity distance for the galaxy. Go back to
the website and look up the galaxy using the “by name” option
under the “objects” heading. At the very bottom of the page,
there is a section called “Cosmology-Corrected Quantities”.
There should be at least three different distances listed. Use the
“Luminosity Distance”. This distance is calculated using the
luminosity and apparent brightness of the galaxy. This distance
does not depend on the motion of the galaxy, so it is what we
will use as an independent measure of distance.
[Type answer here]
6. Determine the value of the Hubble constant. Repeat steps 1
through 5 to get the heliocentric radial velocities and luminosity
distances for at least nine other galaxies from the list found at
the end of this lab. Make sure the velocities are all greater than
1000 km/s. (This is because the motions of galaxies that are
moving at slower speeds is not dominated by the expansion of

the universe.) To determine the value of the Hubble constant,
plot the data you collected on a graph using Excel. Put the
speed on the y-axis and the distance on the x-axis. Make sure
speed is in units of km/s and distance is in Mpc. The slope of
the line that fits these data points is the Hubble constant.
[Type answers here]
7. Compare the value of the Hubble constant you determined to
the current accepted value (72 km/s/Mpc) and to Hubble’s
original value (500 km/s/Mpc). Determine the percent
difference (accuracy) between your value and the other two
values above, and the percent error (precision) between your
value and the currently accepted value. (The formulas can be
found at the end of this lab, below the listing of galaxies.) The
Hubble constant can also be used to calculate the age of the
universe, assuming a constant rate of expansion. To perform
this calculation, all you have to do is divide the number of km
in a Mpc by the Hubble constant value, then divide it by the
number of seconds in a year. That will give you the age of the
universe in years. Use your textbook or the internet to find
these conversion values.
[Type answers here]
OPTIONAL STEP 8. For the final product of this exercise, write
a report in the style of a scientific publication. You should have
an abstract explaining the goal of the experiment and a brief
description of the experiment and the results. The introduction
should describe the history behind the experiment and
methodology. Use your textbook and reliable internet resources
(like NASA websites) as resources for this part. Be sure to
address why one should be skeptical of the determination of
Hubble’s constant through a correlation of recessional speeds
with distance. The next section would be the Data and
Observations section where you describe how you acquired the
data for this experiment and what methods you used to acquire
it. Here, you should explain what types of spectra you used to

get your recessional speeds; also, you should describe the
process you used to extract the data for NGC 1050. The next
section is the Analysis section. Here you present the graph you
made of the data you collected and describe the analysis you did
to extract the Hubble constant. Your comparison to the
currently accepted and original values should be included in this
section, as well as your calculations of the age of the universe.
Finally, the Conclusions section will summarize the experiment
and list the conclusions you drew from your data and your
analysis. Don’t forget to include a References section and list
all resources you used for this experiment.
List of Galaxies:
· M58
NGC 4579
· M61
NGC 4303
· M88

NGC 4501
· M77
NGC 1068
· M99
NGC 4254
· M100
NGC 4321
· M104: The Sombrero Galaxy
NGC 4594

· M109
NGC 3992
· M84
· M60
NGC 4649
· M87: Virgo A, central galaxy in the Virgo cluster
NGC 4486
% Difference = Difference in values × 100%
Average in values 1
% Error = Difference in values × 100%
Accepted value 1
Page 1 of 1
Page 2 of 3
SuII 10

Name: ________________________________
The Galaxy Zoo
Description:
Astronomy has not yet revealed much about the nature of
galaxies. For the most part, astronomers know that they are
composed of stars, gas and dust. They appear to have different
star formation histories, and differing amounts of the
aforementioned constituents, but little is known about how
galaxies get to be the way they are.
In order to better understand galaxies, however, astronomers
have attempted to divide them into groups by their appearances.
It is possible that the appearances of galaxies may be related to
their history or evolutionary track. Although, as yet, there is not
enough evidence to support this hypothesis, the first step in any
endeavor to understand something scientifically, is to classify
and compare.
In this exercise, students will look at a number of galaxies and
divide them into categories that they determine. Following this,
students will compare how their classification scheme compares
with the astronomy one.
Introduction:
Galaxies are large groups of gravitationally bound stars, with
gas and dust clouds intermingled. In this exercise, you will use
the World Wide Telescope to observe several galaxies. You will
then divide these galaxies into at least two groups based on
their shape and appearance. You will determine the nature of
the categories that you develop. At the end of the exercise, you
will compare the groupings that you made to those of

astronomers and discuss whether grouping galaxies in either
way is helpful to understanding the nature of galaxies.
1. Use the World Wide Telescope to observe the galaxies listed
in the table at the end of this exercise. Make sure that you look
at each galaxy carefully. You can decide how to categorize the
galaxies at any point during these observations, but you must
designate a category for every galaxy in the table. Your
categories can be broad or narrow. You must have at least 2,
you should not have more than 10.
[Type answer here – list categories and their abbreviations if
any, along with a brief description of each.]
2. Write a description of how you classified the galaxies you
observed.
What features did you consider in classifying these galaxies?
What features did you ignore?
Did you develop a symbol or designation for your
classifications?
What do your symbols or designations mean?
[Type answers here]
3. Now go back and use the Research button for each galaxy to
determine the astronomical classification of each galaxy. The
designations should be S for spiral, SB for barred spiral, E for
elliptical, I for irregular and pec for peculiar. If you are unsure
how to interpret the classification for each galaxy, ask for help
from your instructor.
[Type answer here]
4. Now compare your classification scheme with the
astronomical one.
(a) Does either lend any insight into the nature of a galaxy?
(b) Is one better than the other?
[Type answers here]
OPTIONAL STEP 5:Read a textbook or other reliable
information source to learn more about the morphological
classification of galaxies. Write a paper about the insight that

has been gained from these designations, if any.
List of Galaxies
NGC 628
NGC 4486
NGC 1300
IC 1623B
NGC 5194
NGC 300
NGC 393
NGC 7331
NGC 3031
NGC 205
NGC 523
NGC 5457
NGC 4472
NGC 1566
NGC 1316
NGC 4594

NGC 221
NGC 536
NGC 620
ESO 286-19
Instructor’s Notes:
It would be best to do this exercise, before discussing galaxy
morphology. This will give the students the freedom to choose
designations that represent their own way of classifying.
The galaxy morphological classifications of these galaxies can
be found using NED and looking for “Basic Data”. In this
section, galaxy classification is listed, but classifications will
be in designation form, so this will need to be explained to
students. The initial information is included in the exercise, but
some students will wonder about the numbers following the
letter designations. For students who are really getting in to this
exercise, there are other, interesting areas to “play” with.
Students could be challenged to find an irregular galaxy or a
peculiar galaxy that is not interacting, for example.
v. 15Jan2011
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=587731520
668631247

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
Page 3 of 3
NGC 3310 – spiral galaxy
Emission lines (3)
Absorption lines (5)
Directions:
Right-click on the circle below, choose ‘copy’, and paste it on
your spectra as many times as needed. To move it, place your
arrow/curser over it until a four-way arrow appears. Left-click
and hold while the four-way arrow is visible and drag it to
where you want it.

Copy (
Or, you may print out the spectra, draw circles by hand, and
send a scanned copy.
The NED website entry page: http://nedwww.ipac.caltech.edu/
Choose “By Name” under “Objects” and this screen pulls-up:
Type in the object name, as listed in the date sheet (e.g. NGC
3310), and click “Submit query.” As an example, I have typed
in LMC (Large Magellanic Cloud). The screen will look like:
Notice the blue box along the bottom of the above screen shot.
To the left of it is a small image with the “Images” link
underneath. Click on the link; this will open-up a new
window/tab that will look something like this:
Scroll down and look at the thumbnail images along the left.
Find one that is in color. If you find one, check the 5th column
(Band, Wavelength) to see if the color on the image corresponds
to visible light or if it is representative.
For example, sometimes an image is in color, but the color
corresponds to the intensity of the light, or to different
wavelengths outside of the visible light spectrum. Some color
images are from the 2MASS, which stands for the 2 micron all-
sky survey. The visible light we see has a wavelength of
roughly 400 to 700 nanometers, or billionths of a meter. A
micron is a millionth of a meter, or a thousand times larger in

wavelength than visible light. This puts it in the infrared part of
the spectrum. So the color in the 2MASS images are referring to
differing infrared wavelengths.
Thus, when you find an image that appears to be in color, look
in the 5th column, labeled “Band, Wavelength.” If there is a V
with a number either between roughly 400 nm to 700 nm, OR
4000 Å to 7000 Å (Å = angstroms, or 1/10 nm), then it is within
the visible part of the spectrum and can be used.
If there is a color image for the object, describe in the data
sheet what colors you see in the column labeled “Your observed
color”. If there is no image available, write “NA” on your data
sheet.
Even if there is no color image, do look at the images of the
galaxy. By looking at it, determine what type of galaxy you
think it is: elliptical or spiral. Write that answer in the “Galaxy
Type” column of your data sheet.
You are now done with this screen/page/tab/window and may
navigate away from it by either closing it or just switching back
to the previous screen shown on page 3.
Referring to the screen on page 3, notice the blue box along the
bottom towards center. Click on that blue box. This will either
open a new window/tab (if you closed the previous one) or
change the “images” screen (if you only navigated away from it
without closing it) found on page 4.
<scroll down to the next page>
This tab/window will look something like the one below:
Scroll down and you will see something like this:
In the 2nd column (Observed Passband), look for the BT and VT
magnitudes (labeled as B (B_T) and V (V_T), respectively).
Record these in the data sheet. (As an example, B (B_T) is in

the 5th row.) Switch back to the first tab/window (on pg. 3) and
click on “spectra (to the right of the blue box).
VERY strange that the LMC has no spectra!! Some of the
objects on the data sheet may not, either. But those that do,
record the number of emission lines you see and a short
description of it. You may want to include the wavelength range
(listed along the x-axis). Also, under the “Spectra?” column on
the data sheet, type “yes” if it does have a spectra and “no” if it
does not.
PAGE
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