The Missing Baryon Problem & Baryonic Tuller-Fisher

[Saul]

I believe people when they read the title of this thread will not understand the nuances of the problem. The fact that 99% of the baryons are missing from satellite dwarf galaxies while most of the baryons are found in clusters may seem insignificant. When you read about this anomaly I would assume you are thinking where did the baryons go and where are they hiding. The point is the baryons should have been part of the initial universe based on the Standard model and should therefore be found in galaxies, dwarf galaxies, and clusters based on formation models for those astronomical objects.

The mystery deepens as the amount of missing matter changes as if it is control by an unknown parameter in spiral galaxies. I will start a separate thread to discuss Disney et al's paper on spiral galaxies.

Comment:
As the properties of a spiral galaxy should be controlled by multiple independent parameters (Initial gas cloud mass and velocity, relative torque of adjacent gas clouds, dark matter cloud concentration, initial spin, merger history and so on.) based on the hierarchical dark matter model, one would not expect the spiral and disk galaxy parameters to be tightly controlled and linked to one another.

The observational point is the missing baryonic matter is not random but is again tightly controlled. Why?

In clusters there is more baryonic mass about the galaxies. What is the source of that matter? Why does it not form galaxies? (A basic calculation that is included in my copy of Introduction to Intergalactic Astronomy and Cosmology by Peter Schneider shows that cluster gas should have collapsed to form stars. There are for the cluster gas three puzzles. Why some much more gas, why is the gas so hot, and what keeps the gas from collapsing to form stars.)http://arxiv.org/abs/0911.2700v1

The Baryon Content of Cosmic Structures

We make an inventory of the baryonic and gravitating mass in structures ranging from the smallest galaxies to rich clusters of galaxies. We find that the fraction of baryons converted to stars reaches a maximum between M500 = 10^12 to 10^13 solar mass, suggesting that star formation is most efficient in bright galaxies in groups. The fraction of baryons detected in all forms deviates monotonically from the cosmic baryon fraction as a function of mass. On the largest scales of clusters , most of the expected baryons are detected, while in the smallest dwarf galaxies, fewer than 1% are detected. Where these missing baryons reside is unclear.

The Baryonic Tully-Fisher relation for rotating disks shown in Fig. 1 extends over five decades in baryonic mass, a considerable improvement over the two decades typically considered. Before considering how the baryonic mass relates to the total mass, we first invest gate whether this relation can be extended still further. Rotationally supported systems cover the range 20 < Vc < 300 kms−1, but there are both smaller and larger pressure supported systems.

This is a talk by Bergman where he states the puzzle as to why the amount of missing galaxy mass is tightly controlled.http://www.sron.nl/files/HEA/XRAY2010/talks/9/bregman.pdf

How Did Galaxies Get So Smart?
• Precise depletion of baryons (McGaugh data)
– rms is 20%, mostly obs• Galaxies know to lose
precise fraction of baryons
– e.g., Vf = 90 km/sec, 95% lost, 5% retained
– not 93% or 97%
• “Engineered” mass loss precision
– Regardless of star/gas ratio
– Regardless of BH mass

 

[Saul]

I am not sure people will understand why this observation is interesting.

The ratio of the BH hole's mass to the ratio of BH hole's Host galaxy get less with redshift by a factor of 7 from z=0 to z=3. Gets less by a factor of 7. Gets less by a factor of 7.

Either the BH has lost mass which is assumed to be impossible or the galaxies have gained mass or BH mass formation was more efficient at Z=3 than Z=0 in a manner that changes with in a straight line with redshift.

I am placing this observation in this thread because it concerns an anomaly concerning mass. Specific astronomical objects have more or less gas. Gas is mass.

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7790506

Co-Evolution of Supermassive Black Holes and Their Host Galaxies


We study the evolution of the MBH/Mhost relation up to z = 3 for a sample of 96 quasars with known host galaxy luminosities. Black hole masses are estimated assuming virial equilibrium in the broad-line regions, while the host galaxy masses are inferred from their luminosities. With this data, we are able to pin down the evolution of the MBH/Mhost relation over 85% of the age of the universe. While the MBH/Lhost relation remains nearly unchanged, taking into account the aging of the stellar population, we find that the MBH/Mhost ratio (Γ) increases by a factor ~ 7 from z = 0 to z = 3. We show that the evolution of Γ is independent of radio loudness and quasar luminosity. We propose that the most massive black holes, in their quasar phase at high-redshift, become extremely rare objects in host galaxies of similar mass in the local universe.

This is a public link to the same paper.

http://arxiv.org/PS_cache/arxiv/pdf/0911/0911.2988v1.pdf

The quasar MBH–Mhost relation through Cosmic Time
II – Evidence for evolution from z = 3 to the present age

In Figure 2 MBH, Mhost and their ratio Γ are plotted all together as a function of redshift. The linear best fit of log Γ is: log Γ = (0.28 ± 0.06) z − (2.91 ± 0.06) suggesting that galaxies with similar stellar masses harbour BHs approx. 7 times more massive at z = 3 than galaxies at z = 0.