Low-extinction windows in the inner Galactic Bulge

Dutra, Carlos Maximiliano; Santiago, B.; Bica, E.

doi:10.1051/0004-6361:20011541

Cited by 170 publications

(165 citation statements)

References 28 publications

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“…Photometric data were downloaded for objects of a field located in Baade's window, we extracted photometry for an area of Δα × Δδ ≈ 0.5 • × 1 • . Only stars fulfilling σ JHK < 0.05 mag were chosen, the correction for interstellar reddening was carried out according to the extinction values given by Dutra et al (2002). The 2MASS photometry had to be transformed to our Bessell system using the equations given in Carpenter (2001; see their Appendix A).…”

Section: Appendix A: Various Comparative Datamentioning

confidence: 99%

Synthetic photometry for carbon-rich giants

Nowotny¹,

Aringer²,

Höfner

et al. 2013

A&A

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Late-type giant stars in the evolutionary stage of the asymptotic giant branch increasingly lose mass via comparatively slow but dense stellar winds. Not only do these evolved red giants contribute in this way to the enrichment of the surrounding interstellar medium, but the outflows also have a substantial influence on the spectro-photometric appearance of such objects. In the case of carbon-rich atmospheric chemistries, the developing cool circumstellar envelopes contain dust grains mainly composed of amorphous carbon. With increasing mass-loss rates, this leads to more and more pronounced circumstellar reddening. With the help of model calculations we aim at reproducing the observational photometric findings for a large sample of well-characterised galactic C-type Mira variables losing mass at different rates. We used dynamic model atmospheres, describing the outer layers of C-rich Miras, which are severly affected by dynamic effects. Based on the resulting structures and under the assumptions of chemical equilibrium as well as LTE, we computed synthetic spectra and synthetic broad-band photometry (Johnson-Cousins-Glass BVRIJHKL M). A set of five representative models with different stellar parameters describes a sequence from less to more evolved objects with steadily increasing mass-loss rates. This allowed us to study the significant influence of circumstellar dust on the spectral energy distributions and the (amplitudes of) lightcurves in different filters. We tested the photometric properties (mean NIR magnitudes, colours, and amplitudes) and other characteristics of the models (mass-loss rates, periods, and bolometric corrections) by comparing these with the corresponding observational data adopted from the literature. Using different kinds of diagrams we illustrate where the models are located in a supposed evolutionary sequence defined by observed C-type Mira samples. Based on comparisons of galactic targets with empirical relations derived for C stars in the Large Magellanic Cloud we discuss the relevance of metallicity and excess carbon (C-O) for the development of dust-driven winds. Having investigated the dynamic model atmospheres from different (mainly photometric) perspectives, we conclude that our modelling approach (meaning the combination of numerical method and a suitable choice of model parameters) is able to describe C-rich long-period variables over a wide range of mass-loss rates, i.e., from moderately pulsating objects without any dusty wind to highly dust-enshrouded Carbon Miras. Thus, we can trace the observed sequence of C-type Miras, which is mainly determined by the mass loss.

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Section: Appendix A: Various Comparative Datamentioning

confidence: 99%

Synthetic photometry for carbon-rich giants

Nowotny¹,

Aringer²,

Höfner

et al. 2013

A&A

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“…The best fit isochrone then gives the value of apparent distance-modulus as 10.80.3 mag and 11.30.2 mag for NGC 110 and DOLIDZE 14, respectively. The reddening correction has been obtained by the absorption formula A H /A V = 0.176 as suggested by Dutra et al (2002). The distance of each cluster is then determined through the following relation:…”

Section: Colour-magnitude Diagrams: Distance Age and Colour-excessmentioning

confidence: 99%

Basic parameters of open star clusters DOLIDZE 14 and NGC 110 in infrared bands

Joshi

et al. 2015

New Astronomy

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The basic physical parameters of a poorly studied open cluster NGC 110 and an unstudied open cluster DOLIDZE 14 are estimated in the present study using the archival P P MXL and W ISE catalogues. The radius of both the clusters are estimated by fitting the modified King's empirical model on their stellar density profiles. The other basic parameters of the clusters such as distance, reddening, and age are obtained by visual fitting of the Marigo's solar metallicity isochrone on their IR colour-magnitude diagrams (CMDs). The mean-proper motion of the clusters are estimated through the individual proper motion of probable members identified through the dynamical and statistical methods. The archival catalogues (JHKW 1 W 2 ) are constructed for both the clusters by compiling the extracted data from the P P MXL and W ISE catalogues. The various colour-excesses, such as E(J −H), E(H −K) and E(W 1 − W 2 ), are estimated using the best fit theoretical isochrone on the (J − H) − H, (H − K) − H and (W 1 − W 2 ) − H CMDs, respectively. The ratios of various infrared colours of the clusters are obtained through their two-colour diagrams. We also identify the most probable members in these clusters by estimating spatial, kinematic and spatio-kinematic probabilities of stars within the cluster. A correlation between the E(H −K) and E(W 1 −W 2 ) is also established.

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“…The main photometrical parameters (age, distance, and reddening) are determined for our clusters by fitting the 2MASS ZAMS solar metallicity isochrones of Marigo et al (2008) The observed data has been corrected for interstellar reddening using the coefficients ratios AJ AV = 0.276 and AH AV = 0.176, which were derived from absorption rations of Schlegel et al (1998), while the ratio AK s AV = 0.118 was derived from Dutra et al (2002). 1.…”

Section: Colour-magnitude Diagramsmentioning

confidence: 99%

“…The main photometrical parameters (age, distance, and reddening) are determined for our clusters by fitting the 2MASS ZAMS solar metallicity isochrones of The observed data has been corrected for interstellar reddening using the coefficients ratios AJ AV = 0.276 and AH AV = 0.176, which were derived from absorption rations of Schlegel et al (1998), while the ratio AK s AV = 0.118 was derived from Dutra et al (2002). Once the cluster's distance R ⊙ is estimated, then the distance from the galactic centre (R G ) and the projected distances on the galactic plane from the Sun (X ⊙ & Y ⊙ ) and the distance from galactic plane (Z ⊙ ) can be determined, (for more details about the distances calculations, see Tadross 2011).…”

Section: Colour-magnitude Diagramsmentioning

confidence: 99%

PPMXL photometric analysis of three open cluster candidates

Tadross¹

2012

New Astronomy

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We present here the astrophysical parameters of three stellar open cluster candidates using PPMXL 1 database. In this study, the main photometric, astrometry and statistical parameters of Ruprecht 13, Ruprecht 16 and Ruprecht 24 are estimated for the first time.Keywords: open clusters and associations -individual: Ruprecht (13, 16, 24) -astrometry -Stars -astronomical databases: catalogues. PACS: 91.10. Lh, 95.80.+p, 95.85.Jq, 97.10.Zr, 98.20.Di Open star clusters (OCs) play an important role in studying the formation and evolution of the Galactic disk and the stellar evolution as well. The fundamental physical parameters of OCs, e.g. distance, reddening, age, and metallicity are necessary for studying the Galactic disk. The strong interest of OCs results come from their fundamental properties. Among the 1787 currently OCs, more than half of them have been poorly studied or even unstudied up to now, Piatti et al. (2011). Thus the current paper is a part of our continuation series whose goal is to obtain the main astrophysical properties of previously unstudied OCs using modern databases. The most important thing for using PPMXL database lies in containing the positions, proper motions of USNO-B1.0 2 and the Near Infrared (NIR) photometry of the Two Micron All Sky Survey (2MASS) 3 , which let it be the powerful detection of the star clusters behind the hydrogen thick clouds on the Galactic plane.Our candidates are selected from among the unstudied OCs of Ruprecht catalogue (hereafter, Ru 13, Ru 16, and Ru 24). They are lying in the third quarter of Galactic longitude and close to the Galactic plane. The only available information about these clusters are the coordinates and the apparent diame- * Tel/Fax: +202 25560645/ +202 25548020 Table 1. The quality of the data is taken into account and the physical properties of each cluster are estimated by applying the same methodology. This paper is organized as follows. PPMXL data extraction and preparation are presented in Section 2, while the data analysis and parameters estimations are described in Sections 3. Finally, the conclusion is devoted to Section 4. PPMXL Data Extraction and preparationThe astrophysical parameters of the investigated cluster have been estimated using the PPMXL Catalogue of Roeser et al. (2010). It is combining the USNO-B1.0 proper motion of Monet et al. (2003) and NIR JHK s pass-band of 2MASS Point Sources of Cutri et al. (2003). USNO-B1.0 is a very useful catalogue, which gives us an opportunity to distinguish between the members and background/field stars. While, NIR 2MASS photometry provides J (1.25µm), H (1.65µm), and K s (2.17µm) band photometry for millions of galaxies and nearly a half-billion stars (Carpenter, 2001). This survey has proven to be a powerful tool in the analysis of the structure and stellar content of open clusters . The photometric uncertainty of the 2MASS data is less than 0.155 at K s ∼ 16.5 magnitude which is the photometric completeness for stars with |b| > 25 o , Skrutskie et al. (2006).It is noted th...

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Low-extinction windows in the inner Galactic Bulge

Cited by 170 publications

References 28 publications

Synthetic photometry for carbon-rich giants

Synthetic photometry for carbon-rich giants

Basic parameters of open star clusters DOLIDZE 14 and NGC 110 in infrared bands

PPMXL photometric analysis of three open cluster candidates

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