4.1.2 Intrinsic colors and visual absolute magnitudes (calibration of the MK system)

Schmidt-Kaler, Th.

doi:10.1007/10201975_2

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…In order to construct analytical approximations which will describe stellar absorption indices as functions of T eff and log g, we need to transform the observed (B − V, M V ) of the groups (from O'Connell 1976;Schmidt-Kaler 1982;Humphreys & McElroy 1984) into the theoretical (T eff , log g). This is done by superimposing isochrones on the colour magnitude diagram of stellar groups (Fig.…”

Section: Derivation Of Stellar Parameters T Eff and Log Gmentioning

confidence: 99%

Absorption line indices in theUV

Maraston¹,

Colmenárez

Bender

et al. 2008

A&A

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Aims. Stellar absorption lines in the optical (e.g. the Lick system) have been extensively studied and constitute an important stellar population diagnostic for galaxies in the local universe and up to moderate redshifts. Proceeding towards higher look-back times, galaxies are younger and the ultraviolet becomes the relevant spectral region where the dominant stellar populations shine. A comprehensive study of ultraviolet absorption lines of stellar population models is however still lacking. With this in mind, we study absorption line indices in the far and mid-ultraviolet in order to determine age and metallicity indicators for UV-bright stellar populations in the local universe as well as at high redshift. Methods. We explore empirical and theoretical spectral libraries and use evolutionary population synthesis to compute synthetic line indices of stellar population models. From the empirical side, we exploit the IUE-low resolution library of stellar spectra and system of absorption lines, from which we derive analytical functions (fitting functions) describing the strength of stellar line indices as a function of gravity, temperature and metallicity. The fitting functions are entered into an evolutionary population synthesis code in order to compute the integrated line indices of stellar populations models. The same line indices are also directly evaluated on theoretical spectral energy distributions of stellar population models based on Kurucz high-resolution synthetic spectra, In order to select indices that can be used as age and/or metallicity indicators for distant galaxies and globular clusters, we compare the models to data of template globular clusters from the Magellanic Clouds with independently known ages and metallicities. Results. We provide synthetic line indices in the wavelength range ∼1200 Å to ∼3000 Å for stellar populations of various ages and metallicities.This adds several new indices to the already well-studied CIV and SiIV absorptions. Based on the comparison with globular cluster data, we select a set of 11 indices blueward of the 2000 Å rest-frame that allows us to recover well the ages and the metallicities of the clusters. These indices are ideal to study ages and metallicities of young galaxies at high redshift. We also provide the synthetic high-resolution stellar population SEDs.

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Section: Derivation Of Stellar Parameters T Eff and Log Gmentioning

confidence: 99%

Absorption line indices in theUV

Maraston¹,

Colmenárez

Bender

et al. 2008

A&A

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“…3. The vertical curve represents the location of MS stars from spectral types B0 to M4 (Schmidt-Kaler 1982;Ducati et al 2001), corrected for a foreground extinction of A V = 2 mag and a distance of 450 pc; the arrows correspond to reddening vectors of A V = 20 mag. While a few objects experience an extinction of up to A V = 45 mag, most of them have 5 < A V < 25 without any obvious distinction between OMC 2 and 3, as visible from Fig.…”

Section: Excess Regionmentioning

confidence: 99%

The stellar content of OMC 2/3

Nielbock

Chini

Muller

2003

A&A

103

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Abstract. We have revisited the stellar content of OMC 2 and OMC 3 by means of MIR imaging and NIR photometry; in addition, we have extended the existing (sub)mm maps by a huge 1200 µm map obtained with SIMBA showing new sources and filamentary features for the first time at that wavelength. The MIR data reveal 43 new sources at N and Q which are partly associated with dense condensations at millimetre wavelengths. Six close binary sources could be resolved at locations where existing (sub)mm maps only show single emission peaks; three of them are classified as early (B-type) systems, one of them is compatible with type K while the remaining two seem to be T Tauri stars. Furthermore, the MIR images indicate the existence of separate circumstellar discs in the K-binary system. NIR colour-colour and colour-magnitude diagrams obtained from 2MASS data are examined to explore the physical properties of the sources and to derive the distribution of J luminosities. There is a clear decrease in luminosity and thus in stellar mass when going from South to North. Likewise, there is an anti-correlation between Class I and II objects in both regions: while OMC 2 contains twice as much Class II objects compared to Class I, the situation is reversed in OMC 3.

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“…We can also use the derived spectral type to estimate the distance to the source. K4III stars have a characteristic V-band absolute magnitude M V = 0.0 (Schmidt-Kaler 1982). This is equivalent to M K = −3.3 considering the known intrinsic (V − K) int colour for a K4III star (e.g.…”

Section: Igr J17445−2747: a Bursting Neutron Star With A Giant Companionmentioning

confidence: 99%

The Swift Bulge Survey: optical and near-IR follow-up featuring a likely symbiotic X-ray binary and a focused wind CV

Shaw

Heinke

Maccarone

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The nature of very faint X-ray transients (VFXTs) -transient X-ray sources that peak at luminosities L X 10 36 erg s −1 -is poorly understood. The faint and often shortlived outbursts make characterising VFXTs and their multi-wavelength counterparts difficult. In 2017 April we initiated the Swift Bulge Survey, a shallow X-ray survey of ∼16 square degrees around the Galactic centre with the Neil Gehrels Swift Observatory. The survey has been designed to detect new and known VFXTs, with follow-up programmes arranged to study their multi-wavelength counterparts. Here we detail the optical and near-infrared follow-up of four sources detected in the first year of the Swift Bulge Survey. The known neutron star binary IGR J17445-2747 has a K4III donor, indicating a potential symbiotic X-ray binary nature and the first such source to show X-ray bursts. We also find one nearby M-dwarf (1SXPS J174215.0-291453) and one system without a clear near-IR counterpart (Swift J175233.9-290952). Finally, 3XMM J174417.2-293944 has a subgiant donor, an 8.7 d orbital period, and a likely white dwarf accretor; we argue that this is the first detection of a white dwarf accreting from a gravitationally focused wind. A key finding of our follow-up campaign is that binaries containing (sub)giant stars may make a substantial contribution to the VFXT population.

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4.1.2 Intrinsic colors and visual absolute magnitudes (calibration of the MK system)

Cited by 9 publications

References 21 publications

Absorption line indices in theUV

Absorption line indices in theUV

The stellar content of OMC 2/3

The Swift Bulge Survey: optical and near-IR follow-up featuring a likely symbiotic X-ray binary and a focused wind CV

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