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We provide an extensive set of theoretical spectral energy distributions of massive stars derived from our "combined stellar structure and atmosphere models". The calculations covering the entire main sequence evolution for initial masses…

Astrophysics · Physics 2016-08-30 Daniel Schaerer , Alex de Koter

Aims. We analyse the effects of a first generation of fast rotating massive stars on the dynamical and chemical properties of globular clusters. Methods. We use stellar models of fast rotating massive stars, losing mass through a slow…

Astrophysics · Physics 2009-11-13 T. Decressin , C. Charbonnel , G. Meynet

Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. Massive stars in low-metallicity environments in the local Universe are reminiscent of their high redshift…

Solar and Stellar Astrophysics · Physics 2014-11-26 F. Tramper , H. Sana , A. de Koter , L. Kaper , O. H. Ramirez-Agudelo

We present spectroscopy of MIR emission lines in twelve starburst regions, located in eleven starburst galaxies, for which a significant number of lines between 2.38 and 45micron were observed with the ISO Short Wavelength Spectrometer,…

We present first results of near-infrared integral field spectroscopy of the central 8''$\times$8'' of the Wolf-Rayet nucleus of the barred spiral galaxy NGC 6764. In addition to stellar CO and Na I absorption lines as well as recombination…

Astrophysics · Physics 2007-05-23 A. Eckart , E. Schinnerer

We present a new set of synthesis models for stellar populations obtained with Starburst99, which are based on new stellar evolutionary tracks with rotation. We discuss models with zero rotation velocity and with velocities of 40% of the…

Astrophysics of Galaxies · Physics 2015-06-19 Claus Leitherer , Sylvia Ekstrom , Georges Meynet , Daniel Schaerer , Katerina B. Agienko , Emily M. Levesque

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we…

We present high resolution spectrophotometric data for 34 galactic planetary nebulae with [WC] nuclei (WRPNe).The sample includes PNe with early and late [WC] stars and some WELS. Physical conditions and chemical abundances have been…

Astrophysics · Physics 2009-11-06 M. Pena , G. Stasinska , S. Medina

The suggestion that roughly half the mass of the galactic halo might be in the form of white dwarfs, together with the limits on the infrared background light and on the initial metallicity of the galactic disk, would set strong constraints…

Astrophysics · Physics 2009-10-30 R. Canal , J. Isern , P. Ruiz-Lapuente

We present results of the analysis of near infrared spectroscopic observations of 6 high-redshift quasars (z > 4), emphasizing the measurement of the ultraviolet FeII/MgII emission line strength in order to estimate the beginning of intense…

Astrophysics · Physics 2009-11-10 M. Dietrich , F. Hamann , I. Appenzeller , M. Vestergaard

Using cosmological simulations to make useful, scientifically relevant emission line predictions is a relatively new and rapidly evolving field. However, nebular emission lines have been particularly challenging to model because they are…

Astrophysics of Galaxies · Physics 2019-12-30 Kirk S. S. Barrow

We report the discovery of [NeV]3426 emission, in addition to HeII4686 emission, in six compact star-forming galaxies. These observations considerably increase the sample of eight such galaxies discovered earlier by our group. For four of…

Astrophysics of Galaxies · Physics 2021-10-19 Y. I. Izotov , T. X. Thuan , N. G. Guseva

A spectrophotometric model able to compute the integrated spectrum of a galaxy, including the contribution both of the stellar populations and of the ionized interstellar gas of the HII regions powered by young hot stars, has been used to…

Astrophysics · Physics 2009-08-17 G. Barbaro , B. M. Poggianti

We propose that the emission of the high excitation [OIV] line observed with ISO in NGC 5253 and II Zw 40 is due to the presence of hot Wolf-Rayet (WR) stars in these objects. We construct a consistent evolutionary synthesis and…

Astrophysics · Physics 2007-05-23 Daniel Schaerer , Grazyna Stasinska

We analyze the stellar and nebular energy distributions of starbursts using our evolutionary synthesis model PEGASE coupled to the photoionization code CLOUDY. The originality of this study is to relate the evolution and the metallicity of…

Astrophysics · Physics 2009-11-06 E. Moy , B. Rocca-Volmerange , M. Fioc

For most elements, the isotopic ratios seen in cosmic rays (CRs) are similar to those in the solar wind. The most important exception to this is $^{22}$Ne/$^{20}$Ne where the CR value is $\sim 5$ times that of the solar wind. According to…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Maria E Kalyashova , Andrei M Bykov , Sergei M Osipov , Donald C Ellison , Danir V Badmaev

We determine the spectroscopic properties of ~1000 ostensibly star-forming galaxies at redshifts (z=4-10) using prism spectroscopy from JWST/NIRSpec. With rest-wavelength coverage between Lya and [S II] in the optical, we stack spectra as a…

Stellar population synthesis models can now reproduce the photometry of old stellar systems (age $>$ 2 Gyr) in the near-infrared (NIR) bands at 3.4 and 4.6$\mu$m (WISE W1 $\&$ W2 or IRAC 1 $\&$ 2). In this paper we derive stellar…

In an effort to better calibrate the supernova rate of starburst galaxies as determined from near-IR [Fe II] features, we report on a [Fe II] 1.644 microns line-imaging survey of a sample of 42 optically-selected SNRs in M33. A wide range…

Astrophysics · Physics 2009-11-07 T. Morel , R. Doyon , N. St-Louis

Massive rotating single stars with an initial metal composition appropriate for the dwarf galaxy I Zw 18 ([Fe/H]=$-$1.7) are modelled during hydrogen burning for initial masses of 9-300 M$_{\odot}$ and rotational velocities of 0-900 km…

Solar and Stellar Astrophysics · Physics 2015-08-26 D. Szécsi , N. Langer , S. -C. Yoon , D. Sanyal , S. de Mink , C. J. Evans , T. Dermine