- ID:
- ivo://CDS.VizieR/J/AJ/153/57
- Title:
- Shape parameters for 154 Galactic open clusters
- Short Name:
- J/AJ/153/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Galactic characteristics of 154 open clusters using the stellar statistics method with data from the WEBDA database. We find that all clusters in our sample are elongated in shape, which indicates that the spherical clusters are stretched out to be ellipsoid as a function of age (log(age/year)=6.64{--}9.7). By dividing a cluster into a central core and an outer part, we have computed the apparent ellipticities of these two parts respectively. The scale relations between ellipticities and age indicate that the outer parts of open clusters become more elliptical while the central cores remain circular. We suppose that the outer parts become more elliptical because they are more subjected to the external forces, e.g., Galactic differential rotation, while the central cores form a circular shape under the domination of stellar dynamics. We have also performed an analysis of the crucial influence of cluster mass and location on its shape.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/454/507
- Title:
- Short-period var. stars OmegaWhite survey
- Short Name:
- J/MNRAS/454/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the goals, strategy and first results of the OmegaWhite survey: a wide-field high-cadence g-band synoptic survey which aims to unveil the Galactic population of short-period variable stars (with periods <80min), including ultracompact binary star systems and stellar pulsators. The ultimate goal of OmegaWhite is to cover 400deg^2^ along the Galactic plane reaching a depth of g=21.5mag (10{sigma}), using OmegaCam on the VLT Survey Telescope (VST). The fields are selected to overlap with surveys such as the Galactic Bulge Survey and the VST Photometric H{alpha} Survey of the Southern Galactic Plane for multiband colour information. Each field is observed using 38 exposures of 39s each, with a median cadence of ~2.7min for a total duration of two hours. Within an initial 26deg^2^, we have extracted the light curves of 1.6 million stars, and have identified 613 variable candidates which satisfy our selection criteria. Furthermore, we present the light curves and statistical properties of 20 sources which have the highest likelihood of being variable stars. One of these candidates exhibits the colours and light-curve properties typically associated with ultracompact AM CVn binaries, although its spectrum exhibits weak Balmer absorption lines and is thus not likely to be such a binary system. We also present follow-up spectroscopy of five other variable candidates, which identifies them as likely low-amplitude {delta} Sct pulsating stars.
- ID:
- ivo://CDS.VizieR/J/AJ/151/143
- Title:
- Silicon depletion in the interstellar medium
- Short Name:
- J/AJ/151/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report interstellar silicon (Si) depletion and dust-phase column densities of Si along 131 Galactic sight lines using archival observations. The data were corrected for differences in the assumed oscillator strength. This is a much larger sample than previous studies but confirms the majority of results, which state that the depletion of Si is correlated with the average density of hydrogen along the line of sight (<n(H)>) as well as the fraction of hydrogen in molecular form (f(H_2_)). We also find that the linear part of the extinction curve is independent of Si depletion. Si depletion is correlated with the bump strength (c_3_/R_V_) and the FUV curvature (c_4_/R_V_) suggesting that silicon plays a significant role in both the 2175{AA} bump and the FUV rise.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/323
- Title:
- Simulated UVEX colors with reddening
- Short Name:
- J/MNRAS/399/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The UV-Excess survey of the northern Galactic plane images a 10{deg}x185{deg} wide band, centred on the Galactic equator using the 2.5-m Isaac Newton Telescope in four bands (U, g, r, HeI 5875) down to ~21-22mag (~20 in HeI 5875). The setup and data reduction procedures are described. Simulations of the colours of main-sequence stars, giant, supergiants, DA and DB white dwarfs and AM Canum Venaticorum stars are made, including the effects of reddening. A first look at the data of the survey (currently 30 per cent complete) is given.
- ID:
- ivo://CDS.VizieR/J/PASJ/62/525
- Title:
- SiO maser survey off the Galactic Plane
- Short Name:
- J/PASJ/62/525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A group of Mira variables in the solar neighborhood shows unusual spatial motion in the Galaxy. To study this motion on a much larger scale in the Galaxy, we newly surveyed 134 evolved stars off the Galactic plane by SiO maser lines, obtaining accurate radial velocities of 84 detected stars. Together with the past data of SiO maser sources, we analyzed the radial-velocity data of a large sample of sources distributed in a distance range of about 0.3-6kpc in the first Galactic quadrant. At Galactic longitudes between 20{deg} and 40{deg}, we found a group of stars with large negative radial velocities, which deviate by more than 100km/s from the Galactic rotation. We show that these deviant motions of maser stars are created by periodic gravitational perturbation of the Bulge bar, and that the effect appears most strongly at radii between corotation and outer Lindblad resonances. The resonance effect can explain the displacement of positions from the Galactic plane as well.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A76
- Title:
- Six infrared dark clouds multi-wavelength obs.
- Short Name:
- J/A+A/598/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared dark clouds (IRDCs) are ubiquitous in the Milky Way, yet they play a crucial role in breeding newly-formed stars. In order to further understand the dynamics, chemistry, and evolution of IRDCs, we carried out multi-wavelength observations towards a small sample. We performed new observations with the IRAM 30m and CSO 10.4m telescopes, with tracers HCO^+^, HCN, N_2_H^+^, C^18^O, DCO^+^, SiO, and DCN towards six IRDCs G031.97+00.07, G033.69-00.01, G034.43+00.24, G035.39-00.33, G038.95-00.47, and G053.11+00.05.
- ID:
- ivo://CDS.VizieR/J/ApJS/74/181
- Title:
- Small-diameter radiosources catalogue
- Short Name:
- J/ApJS/74/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey of the Galactic plane in the longitude range -20deg=<l<=120deg for Galactic latitudes |b|=<0.8deg has been carried out at 1400MHz using the VLA in the B configuration. We present here a catalog of the 1992 discrete sources detected in this survey which is ~75% complete to a limiting peak flux density of 25mJy for sources smaller than ~20" in diameter, although sources as faint as 8mJy and as large as 90" are also included. The catalog includes for each entry a position accurate to ~<3", peak and integrated flux densities, source extent, and information on counterparts both from earlier radio surveys of the plane (for which a comprehensive bibliography is included) and from the IRAS point source catalog. An extensive analysis of the integrity and completeness of the survey is presented here: in separate publications, we discuss the source content of the survey as derived from statistical analysis of the spatial distribution of the sources and from radio, optical and infrared follow up observations .
- ID:
- ivo://CDS.VizieR/J/PASP/126/219
- Title:
- Southern Galactic Be star candidates
- Short Name:
- J/PASP/126/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the result of a search for southern Galactic Be star candidates within the group of miscellaneous variables of the ASAS-2 catalog of variable stars, using statistical, morphological, photometric, and color criteria. This search lead us to obtain a catalog of 213 new Be star candidates. The I-band light curves of these candidates show outbursts (Type-1 stars) only in 9% of the sample, and stochastic variations (Type-4 stars) in 91% of the sample. We do not find stars showing clear high and low states (Type-2 stars) or showing outbursts and high and low states simultaneously (Type-1/Type-2 stars). Our sample of southern Galactic Be star candidates provide valuable new bright targets for high resolution spectroscopic studies with small/medium size telescopes.
- ID:
- ivo://CDS.VizieR/J/AJ/154/23
- Title:
- Southern H II Region Discovery Survey: pilot survey
- Short Name:
- J/AJ/154/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Southern H II Region Discovery Survey is a survey of the third and fourth quadrants of the Galactic plane that will detect radio recombination line (RRL) and continuum emission at cm-wavelengths from several hundred H II region candidates using the Australia Telescope Compact Array. The targets for this survey come from the WISE Catalog of Galactic H II Regions (Anderson et al. 2014, J/ApJS/212/1) and were identified based on mid-infrared and radio continuum emission. In this pilot project, two different configurations of the Compact Array Broad Band receiver and spectrometer system were used for short test observations. The pilot surveys detected RRL emission from 36 of 53 H II region candidates, as well as seven known H II regions that were included for calibration. These 36 recombination line detections confirm that the candidates are true H II regions and allow us to estimate their distances.
- ID:
- ivo://CDS.VizieR/VII/218
- Title:
- Southern Stars embedded in nebulosity
- Short Name:
- VII/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey of the Milky Way southward of the Palomar Sky Survey for the identification of reflection nebulae was carried out at the Cerro Tololo Inter-American Observatory in Chile. Plates in blue light were obtained at the Curtis Schmidt telescope covering a strip of plus or minus six degrees of the galactic equator. Red sensitive plates for comparison were also obtained with the same telescope covering the same area near the galactic plane. Observatory staff members and some students of the University of Toronto, Canada assisted in identifying stars embedded in nebulosity as shown by the plates. Although this catalogue roughly complements the Catalogue of Reflection Nebulae of van den Berg (1966AJ.....71..990V, Cat. <VII/21>), the region here surveyed is more narrowly confined to the galactic equator.
