Request for Expertise: Observational Hypotheses Concerning Disk Galaxies

 Hello. I am an amateur astronomer interested in the large-scale kinematics of disk galaxies.

While analyzing publicly available observational data and scientific publications, I have formulated a set of what I believe are relatively straightforward and operationally testable hypotheses concerning the connection between the internal dynamics of galaxies and the formation of their spiral structure and gas kinematics.

• Запрос экспертизы по наблюдательным гипотезам дисковых галактик

Below is a brief list of the hypotheses.

The connection between bar strength and spiral arm pitch angle

Hypothesis: In disk galaxies with a pronounced bar, the pitch angle of the spiral arms statistically correlates with the bar's parameters (length, ellipticity).

How to test: Photometry (S4G, SDSS) and morphological classification; correlation analysis of bar parameters and pitch angle.

Gas kinematic asymmetry in a dense environment

Hypothesis: For galaxies in clusters, the asymmetry in gas velocities is more pronounced than for field galaxies of comparable mass.

How to test: IFU data (MaNGA, CALIFA) taking into account environmental parameters; comparison of gas and stellar velocity maps.

Counter-rotating components as an indicator of recent accretion

Hypothesis: The presence of counter-rotating gas or stellar components is related to signs of recent external matter inflow.

How to test: IFU spectroscopy — searching for opposite signs of angular momentum and correlating it with morphological disturbances.

The connection between spiral arm regularity and the disk's resonant structure

Hypothesis: Galaxies with long, symmetric spiral arms more frequently show signs of stable resonances (ILR/OLR) than systems with fragmented spiral structure.

How to test: Comparing morphology with dynamic rotation models; frequency analysis of available rotation curves.

Magneto-kinematic correlation in spiral galaxies

Hypothesis: The orientation of large-scale magnetic fields correlates with the direction of gas flows in spiral arms.

How to test: Radio observations (polarization, Faraday rotation) combined with HI/CO maps; comparing the directions of the magnetic field and velocity gradients.

I would be grateful if you could assess the feasibility of such tests or indicate which of these questions have already been covered in detail in the literature.

Sincerely,

Boris D. Yarovoy