Details

Autor(en) / Beteiligte

• Läsker, Ronald
• van den Bosch, Remco C. E
• van de Ven, Glenn
• Ferreras, Ignacio
• La Barbera, Francesco
• Vazdekis, Alexandre
• Falcón-Barroso, Jesús

Titel

Bottom-heavy initial mass function in a nearby compact L galaxy

Ist Teil von

• Monthly notices of the Royal Astronomical Society. Letters, 2013-09, Vol.434 (1), p.L31-L35

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We present orbit-based dynamical models and stellar population analysis of Sloan Digital Sky Survey J151741.75−004217.6, a low-redshift (z = 0.116) early-type galaxy (ETG) which, for its moderate luminosity, has an exceptionally high velocity dispersion. We aim to determine the central black hole (BH) mass (M *), the i-band stellar mass-to-light ratio ( * , i ) and the slope of the initial mass function (IMF). Combining constraints from Hubble Space Telescope imaging and long-slit kinematic data with those from fitting the spectrum with stellar populations models of varying IMFs, we show that this galaxy has a large fraction of low-mass stars, significantly higher than implied even by a Salpeter IMF. We exclude a Chabrier/Kroupa as well as a unimodal (i.e. single-segment) IMF, while a bimodal (low-mass tapered) shape is consistent with the dynamical constraints. Thereby, our study demonstrates that a very bottom-heavy IMF can exist even in an L* ETG. We place an upper limit of 1010.5 M on M *, which still leaves open the possibility of an extremely massive BH.