Definition of Volume Limited Sample for Sky Surveys

  • Thread starter Zaphodx57x
  • Start date
  • Tags
    Volume
In summary, a volume limited sample is a type of survey used in sky surveys to catalog galaxies. It specifically focuses on galaxies within a certain redshift range and filters out fainter galaxies as redshift increases. This results in only galaxies of a finite brightness range being considered at relevant redshifts. However, there is no precise definition for this term and confusion arises as to whether it refers to absolute or apparent brightness.
  • #1
Zaphodx57x
31
0
Does anybody have a link to a precise definition of a "volume limited sample." This pertains especially to sky surveys that catalog galaxies. Due to limited precision, surveys tend to miss fainter galaxies as redshift increases. Thus, very loosely, I think, a volume limited sample filters out certain galaxies so that only galaxies of a finite brightness range are considered at all pertinent redshifts. However, I am looking for a precise definition, but can't seem to find one.
 
Astronomy news on Phys.org
  • #2
A volume limited sample just takes galaxies within a certain redshift range.

Zaphodx57x said:
Thus, very loosely, I think, a volume limited sample filters out certain galaxies so that only galaxies of a finite brightness range are considered at all pertinent redshifts.

Do you mean absolute or apparent brightness? If the latter, this is not a volume limited sample.
 

What is the definition of volume limited sample for sky surveys?

A volume limited sample for sky surveys is a subset of a larger population of celestial objects that is defined by a specific range of distances. These objects are selected based on their observed brightness and are assumed to have similar intrinsic properties.

Why is a volume limited sample important for sky surveys?

A volume limited sample allows researchers to study a specific subset of celestial objects within a defined volume of space. This allows for more accurate statistical analyses and can provide insights into the distribution and properties of objects within a particular region of the sky.

How is a volume limited sample selected for a sky survey?

A volume limited sample is typically selected by setting a minimum and maximum distance range and then identifying objects within that range based on their observed brightness. This can be done using telescopes or satellite observatories.

What are the limitations of using a volume limited sample for sky surveys?

One limitation of using a volume limited sample is that it may not be representative of the entire population of celestial objects. This is because the selection method is based on brightness, which can be affected by factors such as dust or gas obscuration. Additionally, the distance range chosen may inadvertently exclude certain types of objects or favor others.

How does a volume limited sample differ from other sampling methods used in astronomy?

A volume limited sample differs from other sampling methods, such as flux limited or magnitude limited samples, because it takes into account the distance of objects in addition to their observed brightness. This allows for a more precise selection of objects and reduces the bias towards brighter objects that can occur with other sampling methods.

Similar threads

Modern Digital Audio: Understanding Dither and Oversampling in Hi-Res Age"
    • Computing and Technology
Replies
9
Views
1K
Are Quasars and Galaxies Redshifts Truly Quantized?
    • Astronomy and Astrophysics
3
Replies
80
Views
24K
Structure of the Galaxy: 6 Questions Confirmed
    • Sci-Fi Writing and World Building
Replies
31
Views
2K
I Rovelli on Quantum Gravity
    • Beyond the Standard Models
4
Replies
105
Views
10K
How Do Large Galaxy Fluctuations Challenge Standard Cosmological Models?
    • Cosmology
Replies
12
Views
4K
I Exploring ΛCDM Model: Cosmology Intertwined in 4 Pre-Prints
    • Cosmology
Replies
1
Views
1K
I Some questions about Cosmic Microwave Background radiation
    • Cosmology
Replies
13
Views
2K
Ultra Deep Field raises questions
    • Astronomy and Astrophysics
Replies
6
Views
3K
Precise (Or Epsilon-Delta) Definition of a Limit
    • Calculus
Replies
8
Views
3K
Much of our understanding of the physics of AGN
    • Astronomy and Astrophysics
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top