Astronomy and Astrophysics – Astrophysics
Scientific paper
Mar 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997a%26a...319..450g&link_type=abstract
Astronomy and Astrophysics, v.319, p.450-458
Astronomy and Astrophysics
Astrophysics
8
Galaxies: Individual: Ngc 5907, Galaxies: Ism, Galaxies: Kinematics And Dynamics, Galaxies: Nuclei, Radio Lines: Galaxies
Scientific paper
We have studied with the IRAM interferometer the ^12^CO(1-0) emission around the nucleus of NGC 5907, an edge-on spiral at the center of which we had previously detected fast rotating molecular gas. The high angular resolution (3.1", or 160 pc along the major axis) allowed an accurate determination of NGC5907's kinematical center (α(J1950.0)= 15h14m35.5s, δ(J1950.0)=56d30'43.3"). Within +/-2" from the center, we detect molecular gas with velocities of +/-160km/s (relative to the source systemic velocity V_sys_=677km/s(LSR)), and, within +/-10" from the center, velocities of up to +/-180km/s. Part of the gas exhibits non-circular motions. We explain the gas kinematics by the presence of a stellar bar with an angular velocity ({OMEGA}_p_=70km/s/kpc and of an Outer Inner Linblad Resonance (oILR) at r=~14". The dynamical mass inside the R<300pc region, estimated from the steepness of the apparent rotation curve, is =~5x10^9^Msun_. It is comparable to the stellar mass derived from near IR photometry and >10 times larger than the mass of gas in the same region. The CO brightness distribution and, presumably, the molecular gas distribution are highly asymmetrical. The interferometer, which filters out the smooth disk emission detected by the 30-m telescope, reveals two narrow structures parallel to the major axis. We identify those with spiral arms. From their position and velocities, we determine an inclination i=86.5° of the plane of the galaxy. The thickness of the arms, perpendicularly to this plane, is found to be <=3" (<=150pc). The large mass concentration near the nucleus and the flat rotation curve of NGC 5907 are more typical of early or intermediate-type spirals than of late type spirals. Yet, the large CO and HI luminosties, the conspicuous molecular arms, and the absence of visible bulge on optical photographs are more characteristic of Sc-Sd galaxies. NGC 5907 may thus be at a critical stage of galactic evolution.
Garcia-Burillo Santiago
Guélin Michel
Neininger Nikolaus
No associations
LandOfFree
A high-resolution ^12^CO(1-0) study of the nucleus of NGC 5907. Observations and modelling. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A high-resolution ^12^CO(1-0) study of the nucleus of NGC 5907. Observations and modelling., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A high-resolution ^12^CO(1-0) study of the nucleus of NGC 5907. Observations and modelling. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1857827