scholarly journals STELLAR POPULATIONS IN THE CENTRAL 0.5 pc OF THE GALAXY. II. THE INITIAL MASS FUNCTION

2013 ◽  
Vol 764 (2) ◽  
pp. 155 ◽  
Author(s):  
J. R. Lu ◽  
T. Do ◽  
A. M. Ghez ◽  
M. R. Morris ◽  
S. Yelda ◽  
...  
Keyword(s):  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
The Galaxy

scholarly journals Simple interpolation functions for the galaxy-wide stellar initial mass function and its effects in early-type galaxies

2019 ◽  
Vol 490 (1) ◽  
pp. 848-867 ◽  
Author(s):  
J Dabringhausen
Keyword(s):  
Formation Rate ◽  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
The Galaxy ◽  
Stellar Initial Mass Function ◽  
Stellar Masses ◽  
Interpolation Functions

ABSTRACT The galaxy-wide stellar initial mass function (IGIMF) of a galaxy is thought to depend on its star formation rate (SFR). Using a catalogue of observational properties of early-type galaxies (ETGs) and a relation that correlates the formation time-scales of ETGs with their stellar masses, the dependencies of the IGIMF on the SFR are translated into dependencies on more intuitive parameters like present-day luminosities in different passbands. It is found that up to a luminosity of approximately 109 L⊙ (quite independent of the considered passband), the total masses of the stellar populations of ETGs are slightly lower than expected from the canonical stellar initial mass function (IMF). However, the actual mass of the stellar populations of the most luminous ETGs may be up to two times higher than expected from a simple stellar population model with the canonical IMF. The variation of the IGIMF with the mass of ETGs is presented here also as convenient functions of the luminosity in various passbands.

scholarly journals Chandra Study of the Cepheus B Star‐forming Region: Stellar Populations and the Initial Mass Function

2006 ◽  
Vol 163 (2) ◽  
pp. 306-334 ◽  
Author(s):  
Konstantin V. Getman ◽  
Eric D. Feigelson ◽  
Leisa Townsley ◽  
Patrick Broos ◽  
Gordon Garmire ◽  
...  
Keyword(s):  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Star Forming

scholarly journals The Initial Mass Function of Young Open Clusters in the Galaxy: A Preliminary Result

2015 ◽  
Vol 12 (S316) ◽  
pp. 357-358
Author(s):  
Beomdu Lim ◽  
Hwankyung Sung ◽  
Hyeonoh Hur ◽  
Byeong-Gon Park
Keyword(s):  
Star Formation ◽  
Environmental Conditions ◽  
Mass Function ◽  
Open Clusters ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Formation Processes ◽  
Global Properties ◽  
Wide Range ◽  
The Galaxy

AbstractThe initial mass function (IMF) is an essential tool with which to study star formation processes. We have initiated the photometric survey of young open clusters in the Galaxy, from which the stellar IMFs are obtained in a homogeneous way. A total of 16 famous young open clusters have preferentially been studied up to now. These clusters have a wide range of surface densities (log σ = −1 to 3 [stars pc−2] for stars with mass larger than 5M⊙) and cluster masses (Mcl = 165 to 50, 000M⊙), and also are distributed in five different spiral arms in the Galaxy. It is possible to test the dependence of star formation processes on the global properties of individual clusters or environmental conditions. We present a preliminary result on the variation of the IMF in this paper.

scholarly journals IMF variations in unresolved stellar populations: Challenges

2015 ◽  
Vol 11 (A29B) ◽  
pp. 193-194
Author(s):  
Ignacio Ferreras ◽  
Francesco La Barbera ◽  
Alexandre Vazdekis
Keyword(s):  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Spectral Features ◽  
Early Type ◽  
Stellar Initial Mass Function

AbstractThis talk focuses on the challenges facing the recent discovery of variations of the stellar initial mass function in massive early-type galaxies, with special emphasis on the constraints via gravity-sensitive spectral features.

scholarly journals Star Formation in Cooling Flows

1987 ◽  
Vol 127 ◽  
pp. 167-177
Author(s):  
R. W. O'Connell
Keyword(s):  
Star Formation ◽  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Flow Forming ◽  
Cooling Flows ◽  
Cd Galaxies ◽  
Ngc 1275 ◽  
The Imf

Star formation, probably with an abnormal initial mass function, represents the most plausible sink for the large amounts of material being accreted by cD galaxies from cooling flows. There are three prominent cases (NGC 1275, PKS 0745-191, and Abell 1795) where cooling flows have apparently induced unusual stellar populations. Recent studies show that about 50% of other accreting cD's have significant ultraviolet excesses. It therefore appears that detectable accretion populations are frequently associated with cooling flows. The questions of the form of the IMF, the fraction of the flow forming stars, and the lifetime of the flow remain open.

Effect of the Initial Mass Function of Primaries on Binary Stellar Populations

2005 ◽  
Vol 22 (4) ◽  
pp. 1018-1021
Author(s):  
Zhang Feng-Hui ◽  
Han Zhan-Wen ◽  
Li Li-Fang
Keyword(s):  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass

scholarly journals Impact of metallicity and star formation rate on the time-dependent, galaxy-wide stellar initial mass function

2018 ◽  
Vol 620 ◽  
pp. A39 ◽  
Author(s):  
T. Jeřábková ◽  
A. Hasani Zonoozi ◽  
P. Kroupa ◽  
G. Beccari ◽  
Z. Yan ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Probability Density Distribution ◽  
Star Forming ◽  
The Galaxy ◽  
Stellar Initial Mass Function ◽  
Stellar Masses

The stellar initial mass function (IMF) is commonly assumed to be an invariant probability density distribution function of initial stellar masses. These initial stellar masses are generally represented by the canonical IMF, which is defined as the result of one star formation event in an embedded cluster. As a consequence, the galaxy-wide IMF (gwIMF) should also be invariant and of the same form as the canonical IMF; gwIMF is defined as the sum of the IMFs of all star-forming regions in which embedded clusters form and spawn the galactic field population of the galaxy. Recent observational and theoretical results challenge the hypothesis that the gwIMF is invariant. In order to study the possible reasons for this variation, it is useful to relate the observed IMF to the gwIMF. Starting with the IMF determined in resolved star clusters, we apply the IGIMF-theory to calculate a comprehensive grid of gwIMF models for metallicities, [Fe/H] ∈ (−3, 1), and galaxy-wide star formation rates (SFRs), SFR ∈ (10−5, 105) M⊙ yr−1. For a galaxy with metallicity [Fe/H] < 0 and SFR > 1 M⊙ yr−1, which is a common condition in the early Universe, we find that the gwIMF is both bottom light (relatively fewer low-mass stars) and top heavy (more massive stars), when compared to the canonical IMF. For a SFR < 1 M⊙ yr−1 the gwIMF becomes top light regardless of the metallicity. For metallicities [Fe/H] > 0 the gwIMF can become bottom heavy regardless of the SFR. The IGIMF models predict that massive elliptical galaxies should have formed with a gwIMF that is top heavy within the first few hundred Myr of the life of the galaxy and that it evolves into a bottom heavy gwIMF in the metal-enriched galactic centre. Using the gwIMF grids, we study the SFR−Hα relation and its dependency on metallicity and the SFR. We also study the correction factors to the Kennicutt SFRK − Hα relation and provide new fitting functions. Late-type dwarf galaxies show significantly higher SFRs with respect to Kennicutt SFRs, while star-forming massive galaxies have significantly lower SFRs than hitherto thought. This has implications for gas-consumption timescales and for the main sequence of galaxies. We explicitly discuss Leo P and ultra-faint dwarf galaxies.

scholarly journals The galaxy-wide initial mass function of dwarf late-type to massive early-type galaxies

2013 ◽  
Vol 436 (4) ◽  
pp. 3309-3320 ◽  
Author(s):  
C. Weidner ◽  
P. Kroupa ◽  
J. Pflamm-Altenburg ◽  
A. Vazdekis
Keyword(s):  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
Late Type ◽  
The Galaxy
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