Visual construction of highly interactive applications

Esteban, Olivier; Chatty, Stéphane; Palanque, Philippe

doi:10.1007/978-0-387-34905-3_19

Cited by 8 publications

(18 citation statements)

References 9 publications

(7 reference statements)

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“…A similar velocity of +27 km s −1 was found from radio recombination lines by Lockman (1989). Esteban & Rosado (1995) concluded that photoionization is the main source of excitation of the inner ring, for which the WR star is mainly responsible. Following the classification by Chu (1991) for WR ring nebulae, they classified the inner nebula as R s type, because it does not present evidence of expansion and its morphology is shell-structured.…”

Section: Background Of CV Ser and Its Close Environssupporting

confidence: 73%

“…1.1, Gonzalez & Rosado (1984) and Esteban & Rosado (1995) (using optical lines), and Cappa et al (2002) (using radio continuum data) explained the inner optical bright filament and its radio counterparts as the result of action of the UV field and the strong stellar winds of the star WR 113. An alternative scenario can be proposed taking into account the kinematical properties of Cloud 3, and the location of the WR star and SerOB2-1, -2, -3, -63, and -64.…”

Section: Scenariomentioning

confidence: 96%

“…Gonzalez & Rosado (1984) discovered a double optical structure of 4 and 9 in radius around the WR star and suggested that the outer ring, which is poorly defined, was formed by the WR star or its massive progenitor and is presently being photoionized by the O5.5Vf star HD 168112 A&A 545, A89 (2012) (at RA, Dec(J2000) = (18 h 18 m 40.8 s , −12 • 06 23.4 ), also belonging to Ser OB2 and located to the southwest of the ring nebula. Esteban & Rosado (1995) observed the inner ring in [Nii] λλ6548, 6584, [Sii] λλ6717, 6731, Hα λ6563, and Hβ λ4861. They determined that the velocity of the ionized gas is in the range [∼+27, ∼+39] km s −1 , which corresponds to a kinematical distance of 2.0 ± 0.2 kpc, according to circular galactic rotation models (e.g.…”

Section: Background Of CV Ser and Its Close Environsmentioning

confidence: 99%

“…Adopting a distance of 2.0 ± 0.6 kpc, Cappa et al (2002) obtained ionized masses and electron densities of 20 ± 10 M and 180−500 cm −3 , respectively, for the inner shell, and 90 M and 40 cm −3 , respectively, for the outer shell. From the IR-radio Conti & Vacca (1990), (e) Esteban & Rosado (1995), ( f ) Nugis & Lamers (2000), (g) Leitherer et al (1997), (h) Lamontagne et al (1996), (i) Koesterke & Hamann (1995), ( j) Nugis et al (1998).…”

Section: Background Of CV Ser and Its Close Environsmentioning

confidence: 99%

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Molecular gas toward G18.8+1.8

Vasquez

Rubio

Cappa

et al. 2012

A&A

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Aims. This work aims at investigating the characteristics of the molecular gas associated with the nebula G18.8+1.8, which is linked to the Wolf-Rayet star HD 168206 (WR 113), and its relation to other components of its local interstellar medium. Methods. We carried out molecular observations of the 12 CO(J = 1−0) and (J = 2−1) lines with an angular resolution of 44 and 22 using the SEST telescope. Complementary NANTEN data of the 12 CO(1−0) line were also used. The dust emission was analyzed using Spitzer-IRAC images at 8.0 μm, and WISE data at 3.4 μm, 4.6 μm, and 12.0 μm. Results. The SEST data allowed us to identify a molecular component (Cloud 3) that has velocities in the interval from ∼+30 to +36 km s −1 and is most probably linked to the nebula. Morphological and kinematical properties suggest that Cloud 3 consists of a wind-blown molecular half-shell, which expands around WR 113. The ratio R 2−1/1−0 and excitation temperatures indicate that the molecular gas is being irradiated by strong UV radiation. The location of the inner optical ring in the outer edge of Cloud 3 suggests that the stars SerOB2-1, -2, -3, -63, and -64 are responsables for the ionization of Cloud 3 and the inner ring nebula. A comparison between the spatial distribution of the molecular gas and the PAH emission at 8 μm indicates the existence of a photodissociation region between the ionized and the molecular gas. A search for candidate young stellar objects (YSOs) in the region around G18.8+1.8 based on available 2MASS, MSX, IRAS, and Spitzer-IRAC catalogs resulted in the detection of about sixty sources, some of them projected onto Cloud 3. Two small spots of clustered candidate YSOs are projected near the outer border of Cloud 3, although a triggered stellar formation scenario is doubtful.

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Section: Background Of CV Ser and Its Close Environssupporting

confidence: 73%

Section: Scenariomentioning

confidence: 96%

Section: Background Of CV Ser and Its Close Environsmentioning

confidence: 99%

Section: Background Of CV Ser and Its Close Environsmentioning

confidence: 99%

See 2 more Smart Citations

Molecular gas toward G18.8+1.8

Vasquez

Rubio

Cappa

et al. 2012

A&A

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“…Cases in which inconsistent distances have been reported in the literature are discussed further in Appendix B. Tuthill et al (2008), (5) Hillenbrand et al (1993), (6) Djurašević et al (2001), (7)Smith (2006), (8) Hur, Sung & Bessell (2012), (9) Davies et al (2012a), (10) Cappa et al (2010), (11) Lundström & Stenholm (1984), (12) Vazquez et al (1995), (13) Kothes & Dougherty (2007), (14) Koumpia & Bonanos (2012), (15) Martín, Cappa & Testori (2007), (20) Esteban & Rosado (1995), (21) Schweickhardt et al (1999). Distance references (1-22 as in Table 1): (23) Arnal et al (1999), (24)Crowther, Smith & Hillier (1995b), (25) Tovmassian, Navarro & Cardona (1996), (26) Howarth & Schmutz (1995), (27) Cappa et al (1999), (28) , (29) Garmany & Stencel (1992), (30) Bohannan & Crowther (1999).…”

Section: Calibration Samplementioning

confidence: 99%

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Rosslowe

Crowther

2015

Monthly Notices of the Royal Astronomical Society

123

143

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We construct revised near-infrared absolute magnitude calibrations for 126 Galactic Wolf-Rayet (WR) stars at known distances, based in part upon recent large scale spectroscopic surveys. Application to 246 WR stars located in the field, permits us to map their Galactic distribution. As anticipated, WR stars generally lie in the thin disk (∼40 pc half width at half maximum) between Galactocentric radii 3.5-10 kpc, in accordance with other star formation tracers. We highlight 12 WR stars located at vertical distances of 300 pc from the midplane. Analysis of the radial variation in WR subtypes exposes a ubiquitously higher N W C /N W N ratio than predicted by stellar evolutionary models accounting for stellar rotation. Models for non-rotating stars or accounting for close binary evolution are more consistent with observations. We consolidate information acquired about the known WR content of the Milky Way to build a simple model of the complete population. We derive observable quantities over a range of wavelengths, allowing us to estimate a total number of 1200 +300 −100 Galactic WR stars, implying an average duration of ∼ 0.25 Myr for the WR phase at the current Milky Way star formation rate. Of relevance to future spectroscopic surveys, we use this model WR population to predict follow-up spectroscopy to K S ≃ 13 mag will be necessary to identify 95% of Galactic WR stars. We anticipate that ESA's Gaia mission will make few additional WR star discoveries via low-resolution spectroscopy, though will significantly refine existing distance determinations. Appendix A provides a complete inventory of 322 Galactic WR stars discovered since the VIIth catalogue (313 including Annex), including a revised nomenclature scheme.

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Deep high spectral resolution spectroscopy and chemical composition of ionized nebulae

et al. 2014

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High spectral resolution spectroscopy has proved to be very useful for the advancement of chemical abundances studies in photoionized nebulae, such as H II regions and planetary nebulae (PNe). Classical analyses make use of the intensity of bright collisionally excited lines (CELs), which have a strong dependence on the electron temperature and density. By using high resolution spectrophotometric data, our group has led the determination of chemical abundances of some heavy element ions, mainly O ++ , O + and C ++ from faint recombination lines (RLs), allowing us to deblend them from other nearby emission lines or sky features. The importance of these lines is that their emissivity depends weakly on the temperature and density structure of the gas. The unresolved issue in this field is that recombination lines of heavy element ions give abundances that are about 2-3 times higher than those derived from CELs −in H II regions− for the same ion, and can even be a factor of 70 times higher in some PNe. This uncertainty puts into doubt the validity of face values of metallicity that we use as representative not only for ionized nebulae in the Local Universe, but also for star-forming dwarf and spiral galaxies at different redshifts. Additionally, high-resolution data can allow us to detect and deblend faint lines of neutron capture element ions in PNe. This information would introduce further restrictions to evolution models of AGBs and would help to quantify the chemical enrichment in s-elements produced by low and intermediate mass stars. The availability of an echelle spectrograph at the E-ELT will be of paramount interest to: (a) extend the studies of heavyelement recombination lines to low metallicity objects, (b) to extend abundance determinations of s-elements to planetary nebulae in the extragalactic domain and to bright Galactic and extragalactic H II regions. . However, high spectral resolution spectroscopy permits to obtain proper measurements of very faint lines of much interest for abundance studies due to their closeness to other lines or telluric emission features, specially in the reddest part of the op-⋆ Corresponding author. e-mail: cel@iac.es tical range or the near infrared (NIR). In most PNe, high spectral resolution is necessary in order to resolve their usually complex velocity structure, where velocity splitting of the order of few to several tens of km s −1 is the common rule. Since the velocity structure of H II regions is normally much simpler, spectral resolutions of about R∼10,000 are necessary to resolve their line widths and thus optimize the contrast of the faint lines with respect to the underlying continuum. The continuum may be very intense in the case of the spectra of extragalactic H II regions, where most of the contribution comes from the stellar underlying population we are including in our observing area and may even contain absorption features. Moreover, there are also important bright collisionally excited emission lines that need the use of high spectral resolution −R∼3000 ...

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Visual construction of highly interactive applications

Cited by 8 publications

References 9 publications

Molecular gas toward G18.8+1.8

Molecular gas toward G18.8+1.8

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

Deep high spectral resolution spectroscopy and chemical composition of ionized nebulae

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