Table of Contents
What kind of cluster is the Bullet Cluster?
The massive galaxy cluster, 1E 0657-56, discovered by Tucker et al. (1998) consists of two colliding galaxy clusters at z = 0.296. In this distinct merging system, a sub-cluster, the “bullet” has collided with the main cluster, approximately in the plane of the sky (Barrena et al. 2002).
What is so special about the Bullet Cluster quizlet?
The Bullet cluster is actually two separate galaxy clusters that have collided, stripping out hot gas in the process. Careful measurements show that the hot, X-ray-emitting gas in the Bullet Cluster contains about 7 times as much total mass as all the stars in the cluster’s galaxies combined.
What is so special about the Bullet Cluster?
The “Bullet Cluster” is an extremely important object for astrophysical research including studies of dark matter. This cluster was formed after the violent collision of two large clusters of galaxies moving at great speeds. The Bullet Cluster is located about 3.8 billion light years from Earth.
Why does the Bullet Cluster provide evidence for dark matter?
When space is warped by dark matter’s gravity, the light of distant galaxies appears distorted. Multi-wavelength observations of the Bullet Cluster provided the first strong observational evidence that dark matter does not interact with normal matter, or with itself, and holds the majority of mass in a galaxy cluster.
What is the Bullet Cluster experiment?
The Bullet Cluster (1E 0657-56) consists of two colliding clusters of galaxies. Gravitational lensing studies of the Bullet Cluster are claimed to provide the best evidence to date for the existence of dark matter. Observations of other galaxy cluster collisions, such as MACS J0025.
When was the Bullet Cluster discovered?
The Bullet Cluster,discovered in 1998, is the prototypical example of galaxy mergers.
Why does a cluster of galaxies act like a lens?
A gravitational lens can occur when a huge amount of matter, like a cluster of galaxies, creates a gravitational field that distorts and magnifies the light from distant galaxies that are behind it but in the same line of sight. The effect is like looking through a giant magnifying glass.
What is the mass to light ratio of the solar system?
The ratio of the mass of an object to its total luminosity. The mass and luminosity are usually measured in terms of solar mass and solar luminosity; hence the mass-to-light ratio of the Sun is 1.
How does gravitational lensing tell us about the mass of a galaxy cluster?
Newton’s universal law of gravitation predicts how mass can distort light, so we can apply Newton’s law to determine the mass of the cluster. The lensing allows us to determine the orbital speeds of galaxies in the cluster, so that we can determine the mass of the cluster from the orbital velocity law.
Can Mond explain the bullet cluster?
A famous example is the Bullet Cluster, which consists of two such colliding clusters. Observations suggest that dark matter follows the stars in these events, which have a lower total mass than the gas cloud. MOND cannot explain why that is.
How far away is the bullet cluster?
3.721 billion light years.
Where is the dark matter?
The first variety is about 4.5 percent of the universe and is made of the familiar baryons (i.e., protons, neutrons, and atomic nuclei), which also make up the luminous stars and galaxies. Most of this baryonic dark matter is expected to exist in the form of gas in and between the galaxies.
What is the evidence for dark matter?
Primary evidence for dark matter comes from calculations showing that many galaxies would fly apart, or that they would not have formed or would not move as they do, if they did not contain a large amount of unseen matter.
What is the best evidence for dark energy?
The most direct and strongest evidence for the accelerating universe with dark energy is provided by the distance measurements using type Ia supernovae (SN Ia) for the galaxies at high redshift.
What evidence tells us that at least some dark matter consists of objects that astronomers call MACHOs?
What evidence tells us that at least some dark matter consists of objects that astronomers call MACHOs (massive compact halo objects)? We have detected gravitational lensing of distant objects that appears to be caused by compact but unseen objects in the halo of our galaxy.
What are WIMPs made of?
WIMPs are Weakly Interacting Massive Particles, hypothetical particles which may be the main (or only) component of Dark Matter, a form of matter which emits and absorbs no light and which comprises approx 75% of all mass in the observable universe.
What is the general distribution of galaxy colors?
We found that the galaxy distribution is bimodal in all colors in all redshift bins, from which we can classify galaxies into red and blue types. Further, this bimodal distribution has become redder towards present, which suggests the aging of galaxies.
Is gravitational lensing real?
As the light emitted by distant galaxies passes by massive objects in the universe, the gravitational pull from these objects can distort or bend the light. Strong gravitational lensing can actually result in such strongly bent light that multiple images of the light-emitting galaxy are formed. Nov 20, 2017.
How Vera Rubin discovered dark matter?
In the 1960s and ’70s, Rubin’s observations of stars whirling around within galaxies revealed the gravitational tug of invisible “dark matter.” Although astronomers had detected hints of this enigmatic substance for decades, Rubin’s data helped finally convince a skeptical scientific community that dark matter exists ( Aug 17, 2021.
Are there galaxies with no dark matter?
DF2 isn’t the only galaxy devoid of dark matter. Shany Danieli of the Institute for Advanced Study in Princeton, New Jersey, used Hubble in 2020 to obtain an accurate distance to another ghostly galaxy, called NGC 1052-DF4 (or simply DF4), which apparently lacks dark matter, too.
How does dark energy affect the expansion of the universe?
Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart. One explanation for dark energy is that it is a property of space. As a result, this form of energy would cause the universe to expand faster and faster.
