ASTM102_Gal_Morph_Lab_Online
pdf
keyboard_arrow_up
School
Community College of Baltimore County *
*We aren’t endorsed by this school
Course
102
Subject
Astronomy
Date
Dec 6, 2023
Type
Pages
5
Uploaded by JusticePrairieDog1938
1
Galaxy Morphology
Name
Objective:
To be able to employ the process for classifying galaxies and recognize
the difficulties associated with it.
Purpose:
Part of science is classifying objects into categories so that similar char-
acteristics of a group can be identified and used to gain further understanding
about the group. Galaxy classification is difficult for reasons that will be explored
in lab today. Astronomers often use citizen science projects to statistically get a
classification rather than relying on the judgement of just one person. The Galaxy
Zoo Project’s website has a series of questions to guide anyone through the process
of classifying a galaxy. Volunteers are able to classify the number of galaxies a lone
researcher would take years to do.
A spiral galaxy has a disk with spiral arms where star formation occurs. These arms
typically appear blue due to the brightness of large stars in them which overpower
the diversity of stars in the region. It also has a central bulge with old red stars.
Spiral galaxies are split into three categories where Sa has a large bulge and faint
arms and an Sc has a small bulge and bright arms. The Sb category falls in between.
An elliptical galaxy is very different from a spiral galaxy.
An elliptical galaxy
has no disk or spiral arms. It has little gas and dust and few bright stars. Elliptical
galaxies are classified by how elliptical they are. E0 is a galaxy that is spherical.
E7 is a squished, elongated galaxy.
Another way to identify elliptical galaxies is by using the formula:
10(
a
-
b
)
a
where a
is the longest part of the elliptical galaxy and b is the shortest part of the elliptical
galaxy.
Directions:
Use the linked images to answer the questions as outlined below.
Answer all questions using complete sentences in the Galaxy Morphology Answer
Sheet. Watch your spelling and grammar.
1
Question 1:
Identify
Image 1
,
Image 2
, and
Image 3
as Sa, Sb, or Sc spiral galax-
ies. Justify each classification with an explanation.
Question 2:
Identify
Image 4
,
Image 5
, and
Image 6
as E0-E7 elliptical galaxies
without using the formula. Justify each classification with an explanation.
Question 3:
Re-identify Images 4-6 as E0-E7 elliptical galaxies using the formula
and a ruler. Show all of your work. Here is a
video
with an example calculation.
2
Question 4:
Identify the galaxy in
Image 7
. What type of galaxy is it? Why is it
hard to tell? What is one difficulty in determining galaxy type?
Question 5:
Does the galaxy in
Image 8
look the same at different wavelengths?
What is another problem with determining galaxy type?
Question 6:
Image 9
is an image of a spiral galaxy. What color are the arms?
What color is the central bulge? What does that tell you about the age of those
regions?
Question 7:
Image 10
is an image of an elliptical galaxy. What color is the galaxy?
What does that tell you about the age of the stars in the galaxy?
3
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
Question 8:
Image 11
is an image of an irregular galaxy. What does an irregular
galaxy look like? How is it different from the other two types of galaxies?
Question 9:
Image 12
,
Image 13
, and
Image 14
are of galaxies that have experi-
enced collisions. For each image explain how you know that a collision occurred.
Question 10:
Image 15
is of the Milky Way galaxy at different wavelengths. Are
the colors in the image really how the Milky Way looks to the naked eye? Explain.
Question 11:
Image 16
is a face on image of the Milky Way galaxy. Is this an
actual image or an artist rendition? How do you know?
4
Question 12:
What type of galaxy is the Milky Way?
5