scholarly journals Synthetic high-resolution line spectra of star-forming galaxies below 1200 Å, based on FUSE spectral libraries of hot stars

2003 ◽  
Vol 212 ◽  
pp. 744-746
Author(s):  
Carmelle Robert ◽  
Anne Pellerin ◽  
Alessandra Aloisi ◽  
Claus Leitherer ◽  
Charles G. Hoopes ◽  
...  
Keyword(s):  
Stellar Population ◽  
Magellanic Clouds ◽  
Population Synthesis ◽  
Hot Stars ◽  
Star Forming ◽  
Synthetic Spectra ◽  
Stellar Population Synthesis ◽  
The Galaxy ◽  
Wind Profiles ◽  
Spectral Libraries

We have generated far-UV stellar libraries using spectra of hot stars in the Galaxy and the Large and Small Magellanic Clouds. These libraries were implemented into the stellar population synthesis codes starburst99 and lavalsb and used to compute synthetic spectra of star-forming galaxies. Model spectra for galaxies are presented and variations of the hot star photospheric and wind profiles are discussed. This poster summarizes the work of Robert et al. (2002).

scholarly journals On the apparent lack of Be X-ray binaries with black holes in the galaxy and in the Magellanic Clouds

2010 ◽  
Vol 6 (S275) ◽  
pp. 329-330
Author(s):  
Janusz Ziółkowski ◽  
Krzysztof Belczyński
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Stellar Population ◽  
Magellanic Clouds ◽  
Population Synthesis ◽  
X Ray ◽  
Stellar Population Synthesis ◽  
The Galaxy ◽  
X Ray Binaries

AbstractIn the Galaxy there are 67 Be X-ray binaries known to-date. Out of those, 45 host a neutron star, and for the reminder the nature of a companion is not known. None, so far, is known to host a black hole. This disparity is referred to as a missing Be – black hole X-ray binary problem. The stellar population synthesis calculations following the formation of Be X-ray binaries (Belczyński & Ziółkowski 2009) predict that the ratio of the binaries with neutron stars to the ones with black holes is rather high FNS/BH ~ 30–50. A comparison of this ratio with the number of confirmed Be – neutron star X-ray binaries (45) indicates that the expected number of Be – black hole X-ray binaries is of the order of only ~0–2. This is entirely consistent with the observed Galactic sample. Therefore, there is no problem of the missing Be+BH X-Ray Binaries for the GalaxyIn the Magellanic Clouds there are 94 Be X-ray binaries known to-date. Out of those, 60 host a neutron star. Again, none hosts a black hole. The stellar population synthesis calculations carried out specifically for the Magellanic Clouds (Ziółkowski & Belczyński 2010) predict that the ratio of the Be X-ray binaries with neutron stars to the ones with black holes is only FNS/BH ~ 10. This value is rather too low, as it implies the expected number of Be+BH X-ray binaries of the order of ~6, while none is observed. We found, that to remove the discrepancy, one has to take into account a different history of the star formation rate in the Magellanic Clouds, with the respect to the Galaxy. New stellar population synthesis calculations are currently being carried out.

scholarly journals The Missing Population of Be+Black Hole X-Ray Binaries

2008 ◽  
Vol 4 (S252) ◽  
pp. 399-403
Author(s):  
Aleksander Sadowski ◽  
J. Ziółkowski ◽  
K. Belczyński ◽  
T. Bulik
Keyword(s):  
Black Hole ◽  
Stellar Population ◽  
Magellanic Clouds ◽  
Population Synthesis ◽  
Period Range ◽  
X Ray ◽  
Stellar Population Synthesis ◽  
The Galaxy ◽  
Orbital Periods ◽  
X Ray Binaries

AbstractAt present, 117 Be/neutron star (Be/NS) X-ray binaries (XRBs) are known in the Galaxy and the Magellanic Clouds, but not a single Be/black hole (Be/BH) binary was found so far. We carried out the calculations of stellar population synthesis to investigate the case of the apparently missing population of Be/BH XRBs. According to our calculations, the main reason of this disparity is the fact that within the orbital period range where Be XRBs are found (~10 to ~300 days), these systems are formed predominantly with a NS component. The systems with a BH component are formed predominantly with much longer orbital periods and they are not easy to detect.

scholarly journals Ultraviolet spectral libraries of massive stars at low metallicity

1999 ◽  
Vol 193 ◽  
pp. 616-617
Author(s):  
Carmelle Robert
Keyword(s):  
Stellar Population ◽  
Massive Stars ◽  
Magellanic Clouds ◽  
Solar Neighbourhood ◽  
Hot Stars ◽  
Star Forming ◽  
Distant Star ◽  
Medium Resolution ◽  
Low Metallicity ◽  
Spectral Libraries

Three new ultraviolet spectral libraries of massive, hot stars using high and medium resolution spectra of objects located in the solar neighbourhood and the Magellanic Clouds are presented. Massive stars display unique wind signatures which are relatively easy to study in the ultraviolet. These libraries are crucial tools when investigating the massive stellar population of distant star-forming galaxies.

scholarly journals Population Synthesis: Challenges for the Next Decade

2009 ◽  
Vol 5 (S262) ◽  
pp. 55-64
Author(s):  
Gustavo Bruzual A.
Keyword(s):  
Stellar Evolution ◽  
Stellar Population ◽  
Stellar Model ◽  
Data Sets ◽  
Population Synthesis ◽  
Current Interest ◽  
Recent Advances ◽  
Stellar Population Synthesis ◽  
Spectral Libraries

AbstractIn this paper I present a brief summary of recent advances in the fields of stellar evolution, stellar model atmospheres, and stellar spectral libraries, which allow us to build more realistic stellar population synthesis models than those available up to now. Applications of these models to problems of current interest are discussed. Problems that need to be understood and data sets that need to be collected in order to solve issues present in these models are listed.

scholarly journals Resolved maps of stellar mass and SED of galaxies from optical/NIR imaging and SPS models

2009 ◽  
Vol 5 (S262) ◽  
pp. 89-92 ◽  
Author(s):  
Stefano Zibetti ◽  
Stéphane Charlot ◽  
Hans-Walter Rix
Keyword(s):  
Monte Carlo ◽  
Pilot Study ◽  
Stellar Population ◽  
Mass Density ◽  
Stellar Mass ◽  
Population Synthesis ◽  
Surface Mass ◽  
Nir Imaging ◽  
Stellar Population Synthesis ◽  
The Galaxy

AbstractWe report on the method developed by Zibetti, Charlot & Rix (2009) to construct resolved stellar mass maps of galaxies from optical and NIR imaging. Accurate pixel-by-pixel colour information (specifically g – i and i – H) is converted into stellar mass-to-light ratios with typical accuracy of 30%, based on median likelihoods derived from a Monte Carlo library of 50,000 stellar population synthesis models that include dust and updated TP-AGB phase prescriptions. Hence, surface mass densities are computed. In a pilot study, we analyze 9 galaxies spanning a broad range of morphologies. Among the main results, we find that: i) galaxies appear much smoother in stellar mass maps than at any optical or NIR wavelength; ii) total stellar mass estimates based on unresolved photometry are biased low with respect to the integral of resolved stellar mass maps, by up to 40%, due to dust obscured regions being under-represented in global colours; iii) within a galaxy, on local scales colours correlate with surface stellar mass density; iv) the slope and tightness of this correlation reflect/depend on the morphology of the galaxy.

scholarly journals Stellar Population Synthesis of Star-forming Clumps in Galaxy Pairs and Non-interacting Spiral Galaxies

2018 ◽  
Vol 234 (2) ◽  
pp. 35 ◽  
Author(s):  
Javier Zaragoza-Cardiel ◽  
Beverly J. Smith ◽  
Margarita Rosado ◽  
John E. Beckman ◽  
Theodoros Bitsakis ◽  
...  
Keyword(s):  
Stellar Population ◽  
Spiral Galaxies ◽  
Population Synthesis ◽  
Star Forming ◽  
Stellar Population Synthesis

scholarly journals A stellar population synthesis model for the study of ultraviolet star counts of the Galaxy

2014 ◽  
Vol 565 ◽  
pp. A33 ◽  
Author(s):  
Ananta C. Pradhan ◽  
Devendra K. Ojha ◽  
Annie C. Robin ◽  
Swarna K. Ghosh ◽  
John J. Vickers
Keyword(s):  
Stellar Population ◽  
Population Synthesis ◽  
Stellar Population Synthesis ◽  
The Galaxy

scholarly journals Quantifying correlations between galaxy emission lines and stellar continua using a PCA-based technique

2014 ◽  
Vol 10 (S306) ◽  
pp. 301-303
Author(s):  
Róbert Beck ◽  
László Dobos ◽  
István Csabai
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Active Galaxies ◽  
Emission Lines ◽  
Theoretical Modelling ◽  
Support Vector ◽  
Population Synthesis ◽  
Star Forming ◽  
Stellar Population Synthesis ◽  
Empirical Curve

AbstractWe analyse the correlations between continuum properties and emission line equivalent widths of star-forming and narrow-line active galaxies from SDSS. We show that emission line strengths can be predicted reasonably well from PCA coefficients of the stellar continuum using local multiple linear regression. Since upcoming sky surveys will make broadband observations only, theoretical modelling of spectra will be essential to estimate physical properties of galaxies. Combined with stellar population synthesis models, our technique will help generate more accurate model spectra and mock catalogues of galaxies to be used to fit data from new surveys. We also show that, by combining PCA coefficients from the pure continuum and the emission lines, a plausible distinction can be made between weak AGNs and quiescent star-forming galaxies. Our method uses a support vector machine, and allows a more refined separation of active and star-forming galaxies than the empirical curve of Kauffmann et al. (2003).

scholarly journals Wolf–Rayet stars in the Antennae unveiled by MUSE

2020 ◽  
Vol 500 (2) ◽  
pp. 2076-2095
Author(s):  
V M A Gómez-González ◽  
Y D Mayya ◽  
J A Toalá ◽  
S J Arthur ◽  
J Zaragoza-Cardiel ◽  
...  
Keyword(s):  
Stellar Population ◽  
Young Star ◽  
Interacting Galaxies ◽  
Population Synthesis ◽  
Large Telescope ◽  
Single Star ◽  
Star Forming ◽  
Evolutionary Scenario ◽  
Very Large Telescope ◽  
Stellar Population Synthesis

ABSTRACT We present the analysis of archival Very Large Telescope (VLT) Multi-Unit Spectroscopic Explorer (MUSE) observations of the interacting galaxies NGC 4038/39 (a.k.a. the Antennae) at a distance of 18.1 Mpc. Up to 38 young star-forming complexes with evident contribution from Wolf–Rayet (WR) stars are unveiled. We use publicly available templates of Galactic WR stars in conjunction with available photometric extinction measurements to quantify and classify the WR population in each star-forming region, on the basis of its nearly Solar oxygen abundance. The total estimated number of WR stars in the Antennae is 4053 ± 84, of which there are 2021 ± 60 WNL and 2032 ± 59 WC-types. Our analysis suggests a global WC to WN-type ratio of 1.01 ± 0.04, which is consistent with the predictions of the single star evolutionary scenario in the most recent bpass stellar population synthesis models.

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