scholarly journals The stellar population and initial mass function of NGC 1399 with MUSE

2018 ◽  
Vol 479 (2) ◽  
pp. 2443-2456 ◽  
Author(s):  
Sam P Vaughan ◽  
Roger L Davies ◽  
Simon Zieleniewski ◽  
Ryan C W Houghton
Keyword(s):  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass

scholarly journals Hα and FUV luminosities from a stochastically formed stellar population

2011 ◽  
Vol 7 (S284) ◽  
pp. 53-55
Author(s):  
Nidia Lugo Lopez L. ◽  
Gladis Magris C. ◽  
Antonio Parravano
Keyword(s):  
Power Law ◽  
Surface Brightness ◽  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

AbstractIt has been observed that the ratio of Hα to FUV luminosity (LHα/LFUV) is lower in low surface brightness galaxies. This behaviour has been attributed to systematic variations of the upper mass end and/or the slope of the Initial Mass Function (IMF) Meurer et al. (2009) and Lee et al. (2009)). However these hypotheses do not explain the observed scatter in luminosity ratio (LHα/LFUV). We present a model for the total LHα and LFUV luminosity arising from a randomly populated IMF following the Salpeter power law and the clustering law of Oey & Clarke (2007).

scholarly journals New indications on the Galactic bulge IMF by microlensing surveys

2007 ◽  
Vol 3 (S245) ◽  
pp. 367-368
Author(s):  
L. Mancini ◽  
S. Calchi Novati
Keyword(s):  
Mass Spectrum ◽  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Galactic Bulge

AbstractBasing on recent microlensing observations, we analyse the mass spectrum of the Galactic bulge stellar population and study the slope of the initial mass function.

scholarly journals The influence of star clusters on galactic disks: new insights in star-formation in galaxies

2008 ◽  
Vol 4 (S254) ◽  
pp. 209-220
Author(s):  
Pavel Kroupa
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Star Clusters ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Disk Galaxies ◽  
Galactic Disks

AbstractStars form in embedded star clusters which play a key role in determining the properties of a galaxy's stellar population. A large fraction of newly born massive stars are shot out from dynamically unstable embedded-cluster cores spreading them to large distances before they explode. Embedded clusters blow out their gas once the feedback energy from the new stellar population overcomes its binding energy, leading to cluster expansion and in many cases dissolution into the galaxy. Galactic disks may be thickened by such processes, and some thick disks may be the result of an early epoch of vigorous star-formation. Binary stellar systems are disrupted in clusters leading to a lower fraction of binaries in the field, while long-lived clusters harden degenerate-stellar binaries such that the SNIa rate may increase by orders of magnitude in those galaxies that were able to form long-lived clusters. The stellar initial mass function of the whole galaxy must be computed by adding the IMFs in the individual clusters. The resulting integrated galactic initial mass function (IGIMF) is top-light for SFRs < 10 M⊙/yr, and its slope and, more importantly, its upper stellar mass limit depend on the star-formation rate (SFR), explaining naturally the mass–metallicity relation of galaxies. Based on the IGIMF theory, the re-calibrated Hα-luminosity–SFR relation implies dwarf irregular galaxies to have the same gas-depletion time-scale as major disk galaxies, implying a major change of our concept of dwarf-galaxy evolution. A galaxy transforms about 0.3 per cent of its neutral gas mass every 10 Myr into stars. The IGIMF-theory also naturally leads to the observed radial Hα cutoff in disk galaxies without a radial star-formation cutoff. It emerges that the thorough understanding of the physics and distribution of star clusters may be leading to a major paradigm shift in our understanding of galaxy evolution.

scholarly journals CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS

2014 ◽  
Vol 792 (2) ◽  
pp. L37 ◽  
Author(s):  
Richard M. McDermid ◽  
Michele Cappellari ◽  
Katherine Alatalo ◽  
Estelle Bayet ◽  
Leo Blitz ◽  
...  
Keyword(s):  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Population Parameters

scholarly journals THE LOW-MASS STELLAR POPULATION IN L1641: EVIDENCE FOR ENVIRONMENTAL DEPENDENCE OF THE STELLAR INITIAL MASS FUNCTION

2012 ◽  
Vol 752 (1) ◽  
pp. 59 ◽  
Author(s):  
Wen-Hsin Hsu ◽  
Lee Hartmann ◽  
Lori Allen ◽  
Jesús Hernández ◽  
S. T. Megeath ◽  
...  
Keyword(s):  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Stellar Initial Mass Function ◽  
Low Mass ◽  
Environmental Dependence

scholarly journals What does the IMF really tell us about star formation?

2009 ◽  
Vol 5 (S262) ◽  
pp. 368-369
Author(s):  
M. B. N. Kouwenhoven ◽  
S. P. Goodwin
Keyword(s):  
Star Formation ◽  
Formation Process ◽  
Stellar Population ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Detailed Knowledge ◽  
Mass Ratio ◽  
Ratio Distribution ◽  
The Imf

AbstractObtaining accurate measurements of the initial mass function (IMF) is often considered to be the key to understanding star formation, and a universal IMF is often assumed to imply a universal star formation process. Here, we illustrate that different modes of star formation can result in the same IMF, and that, in order to truly understand star formation, a deeper understanding of the primordial binary population is necessary. Detailed knowledge on the binary fraction, mass ratio distribution, and other binary parameters, as a function of mass, is a requirement for recovering the star formation process from stellar population measurements.

scholarly journals Galaxy properties as revealed by MaNGA – II. Differences in stellar populations of slow and fast rotator ellipticals and dependence on environment

2019 ◽  
Vol 489 (4) ◽  
pp. 5633-5652 ◽  
Author(s):  
M Bernardi ◽  
H Domínguez Sánchez ◽  
J R Brownstein ◽  
N Drory ◽  
R K Sheth
Keyword(s):  
Stellar Population ◽  
Velocity Dispersion ◽  
Stellar Populations ◽  
Mass Function ◽  
Elliptical Galaxies ◽  
Mass Scale ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Scaling Relations ◽  
Compact Galaxies

ABSTRACT We present estimates of stellar population (SP) gradients from stacked spectra of slow rotator (SR) and fast rotator (SR) elliptical galaxies from the MaNGA-DR15 survey. We find that (1) FRs are ∼5 Gyr younger, more metal rich, less α-enhanced and smaller than SRs of the same luminosity Lr and central velocity dispersion σ0. This explains why when one combines SRs and FRs, objects which are small for their Lr and σ0 tend to be younger. Their SP gradients are also different. (2) Ignoring the FR/SR dichotomy leads one to conclude that compact galaxies are older than their larger counterparts of the same mass, even though almost the opposite is true for FRs and SRs individually. (3) SRs with σ0 ≤ 250 km s−1 are remarkably homogeneous within ∼Re: they are old, α-enhanced, and only slightly supersolar in metallicity. These SRs show no gradients in age and M*/Lr, negative gradients in metallicity, and slightly positive gradients in [α/Fe] (the latter are model dependent). SRs with σ0 ≥ 250 km s−1 are slightly younger and more metal rich, contradicting previous work suggesting that age increases with σ0. They also show larger M*/Lr gradients. (4) Self-consistently accounting for M*/L gradients yields Mdyn ≈ M* because gradients reduce Mdyn by ∼0.2 dex while only slightly increasing the M* inferred using a Kroupa (not Salpeter) initial mass function. (5) The SR population starts to dominate the counts above $M_*\ge 3\times 10^{11}\, \mathrm{M}_\odot$; this is the same scale at which the size–mass correlation and other scaling relations change. Our results support the finding that this is an important mass scale that correlates with the environment and above which mergers matter.

scholarly journals Hubble Space Telescope observations of Baade's window

1993 ◽  
Vol 153 ◽  
pp. 289-290
Author(s):  
W. A. Baum ◽  
R. M. Light ◽  
J. Holtzman ◽  
D. Hunter ◽  
T. Kreidl ◽  
...  
Keyword(s):  
Stellar Population ◽  
Hubble Space Telescope ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Status Report ◽  
Wide Field ◽  
Galactic Bulge ◽  
Space Telescope ◽  
The Mean

This is a status report on a continuing program using the Hubble Space Telescope (HST) Wide–Field Camera (WFC) to probe the stellar population of the Galactic bulge to fainter magnitudes. We seek the mean age of the stars and the initial mass function (IMF). Galactic bulge stars offer the only opportunity to investigate the IMF of a super metal–rich population. They are 100 times closer than the next nearest sample.

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