Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2009-06-10
Astrophys.J.701:1015-1031,2009
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
Accepted for publication in the Astrophysical Journal
Scientific paper
10.1088/0004-637X/701/2/1015
We present a spectroscopic study of the stellar cluster population of M82, the archetype starburst galaxy, based primarily on new Gemini-North multi-object spectroscopy of 49 star clusters. These observations constitute the largest to date spectroscopic dataset of extragalactic young clusters, giving virtually continuous coverage across the galaxy; we use these data to deduce information about the clusters as well as the M82 post-starburst disk and nuclear starburst environments. Spectroscopic age-dating places clusters in the nucleus and disk between (7, 15) and (30, 270) Myr, with distribution peaks at ~10 and ~140 Myr respectively. We find cluster radial velocities in the range (-160, 220) km/s (wrt the galaxy centre) and line of sight Na I D interstellar absorption line velocities in (-75, 200) km/s, in many cases entirely decoupled from the clusters. As the disk cluster radial velocities lie on the flat part of the galaxy rotation curve, we conclude that they comprise a regularly orbiting system. Our observations suggest that the largest part of the population was created as a result of the close encounter with M81 ~220 Myr ago. Clusters in the nucleus are found in solid body rotation on the bar. The possible detection of WR features in their spectra indicates that cluster formation continues in the central starburst zone. We also report the potential discovery of two old populous clusters in the halo of M82, aged >8 Gyr. Using these measurements and simple dynamical considerations, we derive a toy model for the invisible physical structure of the galaxy, and confirm the existence of two dominant spiral arms.
Bastian Nate
Gallagher III S. . J.
Konstantopoulos Iraklis S.
Smith Lleweilun J.
Trancho Gelys
No associations
LandOfFree
A spectroscopic census of the M82 stellar cluster population 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 spectroscopic census of the M82 stellar cluster population, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A spectroscopic census of the M82 stellar cluster population will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-516038