Galaxy Rotation Curves: Impact of Angle on Velocity and Shape

  • Context: Graduate 
  • Thread starter Thread starter TrickyDicky
  • Start date Start date
  • Tags Tags
    Curves Galaxy Rotation
Click For Summary
SUMMARY

The discussion focuses on the influence of the angle between the line of sight and the galactic plane on the shape of galaxy rotation curves. It highlights that when a galaxy is viewed face-on (90 degrees), Doppler velocity measurements are ineffective due to the lack of observable motion against the cosmological redshift. The case of M33 is presented, where the rotation curve is not flat but steadily increases, suggesting a direct correlation between viewing angle and the observed rotation curve shape. The projected rotation velocity is defined as V_rot * sin(i), emphasizing the mathematical relationship involved.

PREREQUISITES
  • Understanding of Doppler effect in astronomy
  • Familiarity with galaxy rotation curves
  • Knowledge of cosmological redshift
  • Basic trigonometry related to angles and projections
NEXT STEPS
  • Research the mathematical modeling of galaxy rotation curves
  • Study the effects of viewing angles on spectral line measurements
  • Explore the properties of M33 and its rotation dynamics
  • Learn about the implications of projected velocities in astrophysics
USEFUL FOR

Astronomers, astrophysicists, and students studying galaxy dynamics and rotation curves will benefit from this discussion.

TrickyDicky
Messages
3,507
Reaction score
28
Usually spectral lines of spiral arms are corrected for the angle of the galaxy plane with respect to our line of sight to give a velocity curve. I guess this works except in the case when the galaxy is exactly "face-on" from our view (at 90 degrees angle from our line of sight) where no Doppler velocity can be measured overimposed to the cosmological redshift.
Does the angle between line of sight and galactic plane influence the shape of the curves?
For instance I have seen rotation curves of M33 which is not edge-on and the rotation curve is not flat in this case,but raises steadily. http://www.hep.shef.ac.uk/research/dm/images/rotationCurve.jpg
Anyone knows of some relation between galaxy angle wrt our line of sight and shape of the rotation curve?
 
Astronomy news on Phys.org
I think that what you get is the projected rotation velocity, V_rot *sin(i) .
 

Similar threads

Undergrad Rotation curve in spiral galaxy velocity and uniform velocity dispersion
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Question of accuracy of galactic collision simulations
  • · Replies 10 ·
Replies
10
Views
1K
Undergrad Explanation for Galaxy Rotation Curves
  • · Replies 12 ·
Replies
12
Views
2K
Graduate Flat galaxy rotation curves without dark matter
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Deur Gravitational self-interaction Doesn't Explain Galaxy Rotation Curves
  • · Replies 72 ·
3
Replies
72
Views
10K
Undergrad Can magnetic fields explain anomalous galaxy rotation curves?
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Hubble redshift and calculation of galactic rotation curves
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How to calculate kinematic distances in the Milky Way
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Rotation Curves and the Influence of Stellar Mass on Orbital Velocity
  • · Replies 21 ·
Replies
21
Views
5K
Graduate Naive Question regarding Galaxy Rotation Curves
  • · Replies 4 ·
Replies
4
Views
2K