NGC 6503 : a case study of dark matter

The galaxy NGC 6503 is not a very bright or massive or big galaxy as they come, however it is relatively isolated in space and thus not expected to have been perturbed by companions. This simplifies studying the gasflow in the galaxy in order to say something sensible about the dark matter contents in a galaxy. Otherwise one could be worried about companions perturbing the dynamics of the gas or stars in this galaxy.

You can clearly see that the immediate neighborhood of NGC 6503 is void of any other galaxies. Most of the visible objects in this picture are stars of our milky way (two are labeled) and a few are fuzzy objects in the far universe catalogues by an Infra Red and Ultra Violet telescope.

• BD = Bonner Durchmusterung [bright stars]
• HD = H. Draper [bright stars]
• 2MASX = 2Micron All-Sky Survey, Extended source catalogue
• GALEXASC = GALEX All-Sky Survey Source Catalog
• NGC = New General Catalog (of Nebulae and Clusters of Stars) wikipedia

See http://cds.u-strasbg.fr/cgi-bin/Dic-Simbad for a service if you ever need to know what that strange astronomy acronym in a source name means...

References for N6503 velocity field

The following papers discuss this work in more detail:

• Analysis of high-resolution velocity fields - NGC 6503 (van Moorsel, 1985)

• Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick H I Disks (Greisen, 2009)

• Searching for non-axisymmetries in NGC 6503: a weak end-on bar (Kuzio de Naray, 2012)

• Data on Eric Greisen's website: ftp://ftp.aoc.nrao.edu/staff/egreisen/

Notebooks

We have the following notebooks:

• spectra : Spectra in M31 - a tribute to Vera Rubin's work
• cubes : Spectral Line Data Cubes in Astronomy - Part 1
• orbits: Gas Streaming in Disks: circular orbit approach

We will not cover:

• Spectral Line Data Cubes in Astronomy - Part 2
• Non-circular orbits : orbit integrations using scipy.integrate.odeint
• Rotation Curves from Velocity Fields or Cubes: forwards and backwards modeling(MIRIAD/NEMO)

Related material you can read up on, but not covered here.

• Dark matter and Dark energy are not the accepted theory. Here is a very recent story: http://www.sciencealert.com/a-controversial-new-gravity-hypothesis-has-passed-its-first-test
• A notebook developed to show the discovery of the merging binary black hole: https://losc.ligo.org/s/events/GW150914/GW150914_tutorial.html