Spectral Synthesis of Spectral Populations using Balmer Lines

Cananzi, K.; Augarde, R.; Lequeux, J.

doi:10.1007/978-94-011-1080-8_8

Cited by 12 publications

(15 citation statements)

References 3 publications

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“…To correct for the underlying stellar absorption, some authors (McCall, Rybski, & Shields 1985;Skillman & Kennicutt 1993) adopt a constant equivalent width (1.5-2 Å ) for all the hydrogen absorption lines. However, the actual value of their equivalent width is uncertain and depends on the age of the star formation burst (Díaz 1988;Cananzi, Augarde, & Lequeux 1993;Olofsson 1995). Thus we preferred to leave it as a free parameter, which was determined as follows.…”

Section: Long-slit Spectroscopymentioning

confidence: 99%

Spectrophotometric Observations of Blue Compact Dwarf Galaxies: Markarian 370

Cairós¹,

Caon²,

García-Lorenzo³

et al. 2002

ApJ

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We present results from a detailed spectrophotometric analysis of the blue compact dwarf galaxy (BCD) Mrk 370, based on deep UBVRI broadband and H narrowband observations, and on long-slit and twodimensional spectroscopy of its brightest knots. The spectroscopic data are used to derive the internal extinction and to compute metallicities, electronic density, and temperature in the knots. By subtracting the contribution of the underlying older stellar population, modeled by an exponential function, removing the contribution from emission lines, and correcting for extinction, we can measure the true colors of the young star-forming knots. We show that the colors obtained this way differ significantly from those derived without the above corrections and lead to different estimates of the ages and star-forming history of the knots. Using predictions of evolutionary synthesis models, we estimate the ages of both the starburst regions and the underlying stellar component. We found that we can reproduce the colors of all the knots with an instantaneous burst of star formation and the Salpeter initial mass function (IMF) with an upper mass limit of 100 M . The resulting ages range between 3 and 6 Myr. The colors of the low surface brightness component are consistent with ages larger than 5 Gyr. The kinematic results suggest ordered motion around the major axis of the galaxy.

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Section: Long-slit Spectroscopymentioning

confidence: 99%

Spectrophotometric Observations of Blue Compact Dwarf Galaxies: Markarian 370

Cairós¹,

Caon²,

García-Lorenzo³

et al. 2002

ApJ

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“…In Table 2 we give the tabulated spectral types of each star taken from the literature (Humphreys 1978;Garmany & Stencel 1992;Bouw 1981;Fernie 1983;Stothers 1991;Kaltcheva & Georgiev 1994;Cananzi et al 1993 Table 3. We summarize in Table 4 the information available for each star as well as the instrumental set-up (telescope+spectrograph) used to obtain the data and the Julian date of the observations.…”

Section: The Program Starsmentioning

confidence: 99%

Understanding A-type supergiants

Verdugo¹,

Talavera²,

Castro³

1999

Astron. Astrophys. Suppl. Ser.

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Abstract. This paper is the first of a series whose aim is to perform a systematic study of A-type supergiant atmospheres and winds. Here we present a spectral atlas of 41 A-supergiants observed by us in high and medium resolution in the visible and ultraviolet. The atlas consists of profiles of the Hα, Hβ, Hγ, Hδ, H , Ca II (H and K), Na I (D1 and D2), Mg II 4481 , Mg II [uv1] and Fe II [uv1, uv2, uv3, uv62, uv63, uv161] lines for 41 stars with spectral types ranging from B9 to A9 and luminosity classes Ia, Iab and Ib, and provides the basic data for a thoughtful study of these stars. The overall characteristics of the sample as well as the data reduction procedures are described. We also present some examples of spectral variability.

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“…Spectra have been taken in the blue spectral region, between 4000 Å and 4500 Å with a dispersion of 33 Å/mm (resolution R = 2000). The slit width was 2.5 , to allow a correct comparison of the spectrum with the spectra of a number of stars of different types, which were taken previously for calibrating the Balmer absorption line equivalent widths (Cananzi et al 1993). …”

Section: The Observationsmentioning

confidence: 99%

“…This will use spectral syntheses based on the models of Mas-Hesse (Mas-Hesse & Cerviño 1994). For absorption lines we will use a library of stellar spectra obtained especially for this purpose with the same instrument as the present one (Cananzi et al 1993). …”

Section: Introductionmentioning

confidence: 99%

H$_\gamma$ and H$_\delta$ absorption lines and the Initial Mass Function in extragalactic star forming regions

Sinanian

Kunth

Lequeux

et al. 2002

A&A

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Abstract. High-dispersion, long-slit spectroscopic observations of 13 extragalactic star-forming regions were obtained for two Blue Compact Dwarf galaxies (IZw18, IZw36) and for bright star-formation regions in the spiral galaxies M 101 and M 51 and in the irregular starburst galaxies Mrk 171 and NGC 4449. The H γ and/or H δ absorption lines have been observed in 11 star forming regions and will be used to constrain the Initial Mass Function and age of the young stellar populations. In this paper we present the results of the observations and the measurements of the absorption and emission lines. The astrophysical discussion is deferred to a forthcoming paper.

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Spectral Synthesis of Spectral Populations using Balmer Lines

Cited by 12 publications

References 3 publications

Spectrophotometric Observations of Blue Compact Dwarf Galaxies: Markarian 370

Spectrophotometric Observations of Blue Compact Dwarf Galaxies: Markarian 370

Understanding A-type supergiants

H$_\gamma$ and H$_\delta$ absorption lines and the Initial Mass Function in extragalactic star forming regions

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