- ID:
- ivo://CDS.VizieR/J/A+A/591/A145
- Title:
- VVV Survey outer bulge RRab stars
- Short Name:
- J/A+A/591/A145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VISTA Variables in the Via Lactea (VVV) is a near-IR time-domain survey of the Galactic bulge and southern plane. One of the main goals of this survey is to reveal the 3D structure of the Milky Way through their variable stars. In particular, enormous numbers of RR Lyrae stars have been discovered in the inner regions of the bulge (-8{deg}<~b<~-1{deg}) by optical surveys such as OGLE and MACHO, but leaving an unexplored window of more than ~47 sq deg (-10.0{deg}<~l<~+10.7{deg} and -10.3{deg}<~b<~-8.0{deg}) observed by the VVV Survey. Our goal is to characterize the RR Lyrae stars in the outer bulge in terms of their periods, amplitudes, Fourier coefficients, and distances in order to evaluate the 3D structure of the bulge in this area. The distance distribution of RR Lyrae stars will be compared to that of red clump stars, which is known to trace a X-shaped structure, in order to determine whether these two different stellar populations share the same Galactic distribution. A search for RR Lyrae stars was performed in more than ~47 sq deg at low Galactic latitudes (-10.3{deg}<~b<~-8.0{deg}). In the procedure the {chi}^2^ value and analysis of variance (AoV) statistic methods were used to determine the variability and periodic features of the light curves, respectively. To prevent misclassifications, the analysis was performed only on the fundamental mode RR Lyrae stars (RRab) owing to similarities found in the near-IR light curve shapes of contact eclipsing binaries (W UMa) and first overtone RR Lyrae stars (RRc). On the other hand, the red clump stars of the same analyzed tiles were selected, and cuts in the color-magnitude diagram were applied and the maximum distance restricted to ~20kpc in order to construct a similar catalog in terms of distances and covered area compared to the RR Lyrae stars. We report the detection of more than 1000 RR Lyrae ab-type stars in the VVV Survey located in the outskirts of the Galactic bulge. A few of them are possibly associated with the Sagittarius Dwarf Spheroidal Galaxy. We calculated colours, reddening, extinction, and distances of the detected RR Lyrae stars in order to determine the outer bulge 3D structure. Our main result is that, at the low galactic latitudes mapped here, the RR Lyrae stars trace a centrally concentrated spheroidal distribution. This is a noticeably different spatial distribution to the one traced by red clump stars known to follow a bar and X-shaped structure. We estimate the completeness of our sample at 80% for K_s_<=15mag.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/153/179
- Title:
- VVV Survey RR Lyr stars in Southern Galactic plane
- Short Name:
- J/AJ/153/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep near-IR images from the VISTA Variables in the Via Lactea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295{deg}<l<350{deg}, -2.24{deg}<b<-1.05{deg}). The sample's distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond l~340{deg}, and the sample's spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations.
21233. VY CMa ALMA NaCl images
- ID:
- ivo://CDS.VizieR/J/A+A/592/A76
- Title:
- VY CMa ALMA NaCl images
- Short Name:
- J/A+A/592/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- At the end of their lives, most stars lose a significant amount of mass through a stellar wind. The specific physical and chemical circumstances that lead to the onset of the stellar wind for cool luminous stars are not yet understood. Complex geometrical morphologies in the circumstellar envelopes prove that various dynamical and chemical processes are interlocked and that their relative contributions are not easy to disentangle. We aim to study the inner-wind structure (R<250R*) of the well-known red supergiant VY CMa, the archetype for the class of luminous red supergiant stars experiencing high mass loss. Specifically, the objective is to unravel the density structure in the inner envelope and to examine the chemical interaction between gas and dust species. We analyse high spatial resolution (~0.24"x0.13") ALMA Science Verification (SV) data in band 7, in which four thermal emission lines of gaseous sodium chloride (NaCl) are present at high signal-to-noise ratio.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/532
- Title:
- VY CMa molecular line spectra
- Short Name:
- J/MNRAS/437/532
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the far-infrared and submillimetre molecular emission-line spectrum of the luminous M-supergiant VY CMa, observed with the Spectral and Photometric Imaging Receiver (SPIRE) and Photodetector Array Camera and Spectrometer for Herschel spectrometers aboard the Herschel Space Observatory. Over 260 emission lines were detected in the 190-650{mu}m SPIRE Fourier Transform Spectrometer spectra, with one-third of the observed lines being attributable to H_2_O. Other detected species include CO, ^13^CO, H_2_O, SiO, HCN, SO, SO2, CS, H_2_S and NH_3_. Our model fits to the observed ^12^CO and ^13^CO line intensities yield a ^12^C/^13^C ratio of 5.6+/-1.8, consistent with measurements of this ratio for other M-supergiants, but significantly lower than previously estimated for VY CMa from observations of lower-J lines. The spectral line energy distribution for 20 SiO rotational lines shows two temperature components: a hot component at ~1000K, which we attribute to the stellar atmosphere and inner wind, plus a cooler ~200K component, which we attribute to an origin in the outer circumstellar envelope. We fit the line fluxes of ^12^CO, ^13^CO, H_2_O and SiO, using the smmol non-local thermodynamic equilibrium (LTE) line transfer code, with a mass-loss rate of 1.85x10^-4^M_{sun}_/yr between 9R* and 350R*. We also fit the observed line fluxes of ^12^CO, ^13^CO, H_2_O and SiO with smmol non-LTE line radiative transfer code, along with a mass-loss rate of 1.85x10^-4^M_{sun}_/yr. To fit the high rotational lines of CO and H_2_O, the model required a rather flat temperature distribution inside the dust condensation radius, attributed to the high H_2_O opacity. Beyond the dust condensation radius the gas temperature is fitted best by an r-0.5 radial dependence, consistent with the coolant lines becoming optically thin. Our H_2_O emission-line fits are consistent with an ortho:para ratio of 3 in the outflow.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A16
- Title:
- VY Scl reduced spectra & radial velocities
- Short Name:
- J/A+A/617/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the context of a large campaign to determine the system parameters of high mass transfer cataclysmic variables, we found VY Scl in a low state in 2008. Making use of this low state, we study the stellar components of the binary with little influence of the normally dominating accretion disc. Time-resolved spectroscopy and photometry of VY Scl taken during the low state are presented. We analysed the light-curve and radial velocity curve and use time-resolved spectroscopy to calculate Doppler maps of the dominant emission lines. The spectra show narrow emission lines of Halpha, Hbeta, HeI, NaI D, and FeII, as well as faint TiO absorption bands that trace the motion of the irradiated secondary star, and Halpha and HeI emission line wings that trace the motion of the white dwarf. From these radial velocities, we find an orbital period of 3.84h, and put constraints on binary parameters such as the mass ratio M2/M1 of 0.43 and the inclination of 15. With a secondary mass between 0.3 and 0.35M_{sun}_, we derive the mass for the white dwarf as M1=0.6-1.1M_{sun}_.
- ID:
- ivo://CDS.VizieR/III/13
- Title:
- Vyssotsky's Catalogues 1950.0
- Short Name:
- III/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog includes the results of a complete survey of the McCormick objective prism plates for M dwarf stars. catalog.dat includes identifications, magnitudes, proper motions in RA and Dec, spectral types and parallaxes.
- ID:
- ivo://CDS.VizieR/J/A+A/577/A127
- Title:
- W49A JCMT Spectral Legacy Survey spectroscopy
- Short Name:
- J/A+A/577/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The massive and luminous star-forming region W49A is a well-known Galactic candidate to probe the physical conditions and chemistry similar to those expected in external starburst galaxies. We aim to probe the physical and chemical structure of W49A on a spatial scale of ~0.8pc based on the JCMT Spectral Legacy Survey, which covers the frequency range between 330 and 373GHz. The wide 2x2-arcmin field and the high spectral resolution of the HARP instrument on JCMT provides information on the spatial structure and kinematics of the cloud traced by the observed molecular lines. For species where multiple transitions are available, we estimate excitation temperatures and column densities using a population diagram method that takes beam dilution and optical depth corrections into account. We detected 255 transitions corresponding to 63 species in the 330-373GHz range at the center position of W49A. Excitation conditions can be probed for 14 molecules, including the complex organic molecules CH_3_CCH, CH_3_CN, and CH_3_OH. The chemical composition suggests the importance of shock, photon-dominated region (PDR), and hot core chemistry. Many molecular lines show a significant spatial extent across the maps including CO and its isotopologues, high density tracers (e.g., HCN, HNC, CS, HCO^+^), and tracers of UV irradiation (e.g., CN and C_2_H). The spatially extended species reveal a complex velocity-structure of W49A with possible infall and outflow motions. Large variations are seen between the subregions with mostly blue-shifted emission toward the eastern tail, mostly red-shifted emission toward the northern clump, and emission peaking around the expected source velocity toward the southwest clump. A comparison of column density ratios of characteristic species observed toward W49A to Galactic PDRs suggests that while the chemistry toward the W49A center is driven by a combination of UV irradiation and shocks, UV irradiation dominates for the northern clump, eastern tail, and southwest clump regions. A comparison to a starburst galaxy and an active galactic nucleus suggests similar C_2_H, CN, and H_2_CO abundances (with respect to the dense gas tracer ^34^CS) between the ~0.8pc scale probed for W49A and the >1kpc regions in external galaxies with global star formation.
- ID:
- ivo://CDS.VizieR/J/A+A/216/44
- Title:
- Walraven photometry in Sco-Cen association
- Short Name:
- J/A+A/216/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Walraven photometry is presented of established and probable members of the Scorpio-Centaurus OB association. For each star, effective temperature and surface gravity are derived using Kurucz atmosphere models (1979ApJS...40....1K). From the Straizys and Kuriliene (1981Ap&SS..80..353S) tables, absolute magnitudes are calculated. Distance moduli and visual extinctions are determined for all stars. From a comparison of the HR-diagrams of the stars in each subgroup with theoretical isochrones, the ages of the three subgroups are derived. The distances to the three subgroups are shown to be different; there is a general trend (also within each subgroup) for the distances to be larger at higher galactic longitudes. The visual extinction in the youngest subgroup Upper-Scorpius, is well correlated with the IRAS 100-micron map. The distance toward the Ophiuchus dark clouds is found to be 125 pc, based on the photometric distances to the stars. Most of the early-type stars in Upper-Scorpius are located at the far side of the dark clouds.
- ID:
- ivo://CDS.VizieR/J/A+AS/98/505
- Title:
- Walraven photometry near AG Car
- Short Name:
- J/A+AS/98/505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Walraven-photometric data of 114 stars of 5.9<V<14.7 within 17 arcmin of the Luminous Blue Variable AG Car (HD 94910). The results are expressed in terms of V-magnitude in the Johnson system and in observed and extinction-free colours in the Walraven system. For a description of the Walraven photometric system, see e.g. <GCPD/11>
- ID:
- ivo://CDS.VizieR/J/A+AS/101/87
- Title:
- Walraven photometry of 8 Cataclysmic variables
- Short Name:
- J/A+AS/101/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The files contain the results of the photometry observations obtained during July/August 1988 with the Walraven photometer on the 90cm telescope at ESO (La Silla). The brightness measurements are collected simultaneously in the 5 passbands VBLUW (544, 430, 384, 362 and 324nm) with integration times of 16s.
