- ID:
- ivo://CDS.VizieR/J/MNRAS/357/345
- Title:
- Pulsating pre-main-sequence stars in NGC6383
- Short Name:
- J/MNRAS/357/345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for pulsating pre-main-sequence (PMS) stars was performed in the young open cluster NGC 6383 using CCD time-series photometry in Johnson B and V filters. With an age of only ~1.7Myr all cluster members later than spectral type A0 have not reached the ZAMS yet, hence being ideal candidates for investigating PMS pulsation among A- and F-type stars. In total 286 stars have been analysed using classical Fourier techniques. From about a dozen stars within the boundaries of the classical instability strip, two stars were found to pulsate: NGC 6383 #170, with five frequencies simultaneously, and NGC 6383 #198, with a single frequency. In addition, NGC 6383 #152 is a suspected PMS variable star, but our data remain inconclusive. Linear, non-adiabatic models assuming PMS evolutionary phase and purely radial pulsation were calculated for the two new PMS pulsators. NGC 6383 #170 appears to pulsate radially in third and fifth overtones, while the other three frequencies seem to be of non-radial nature. NGC 6383 #198 pulsates mono-periodically, most probably in the third radial overtone. Magnitudes and BV colours were available in the literature for only one third of all stars and we used them for calibrating the remaining.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/356/331
- Title:
- QSO-candidates in OGLE-II Galactic bulge fields
- Short Name:
- J/MNRAS/356/331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 97 QSO candidates in 48 Galactic bulge fields of the Optical Gravitational Lensing Experiment II (OGLE-II) covering ~11deg^2^, which are selected via their variability. We extend light curves of variable objects which were detected in a 3-yr baseline in the OGLE-II variable star catalogue to fourth year. We search for objects that are faint (16<I_0_<18.5) and slowly variable over 4-yr in this catalogue by using the variogram/structure function. Finding the QSOs in such stellar-crowded and high extinction fields is challenging, but should be useful for the astrometric reference frame. Spectroscopic follow-up observations are required to confirm these QSO candidates. Follow-up observations are being prepared for four of these fields (BUL_SC1, 2, 32 and 45). Follow-up observations for other fields are strongly encouraged. The complete list and light curves of all 97 candidates are available in electronic format at http://www.astro.princeton.edu/sumi/QSO-OGLEII/ .
- ID:
- ivo://CDS.VizieR/J/ApJ/747/107
- Title:
- QSO Candidates in the MACHO LMC database
- Short Name:
- J/ApJ/747/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog the 2566 QSO candidates in the MACHO LMC database. In these catalogs, we complied number of properties of the objects including RA, Dec, crossmatched IDs with several catalogs, magnitudes, photometric redshifts, etc. See Kim et al. (2011ApJ...735...68K) for the SVM (a.k.a. Support Vector Machine, a supervised machine learning algorithm) QSO classification model based on the time variability of lightcurves. We used the model to select the 2566 QSO candidates. In this work, we employed multiple diagnostics such as X-ray flux, mid-IR color and AGN SED fitting in order to select 663 promising QSO candidates among the 2,566 candidates. These candidates are flagged in the catalog. We calibrated the MACHO RA and Dec of the candidates using the UCAC3 catalog and improved the average astrometric accuracy from ~3" to ~0.5".
- ID:
- ivo://CDS.VizieR/J/A+A/265/32
- Title:
- Radial structure of the galactic disc
- Short Name:
- J/A+A/265/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/454/788
- Title:
- Radial velocities and BV photometry of NGC 3201
- Short Name:
- J/ApJ/454/788
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BV CCD frames have been used to derive surface brightness profiles for NGC 3201 which extend out to ~18'. A total of 857 radial velocities with median precision ~1km/s for 399 member giants have been used to trace the velocity dispersion profile out to 32.1' (the approximate tidal radius determined from fits of single-mass, isotropic King-Michie models to the cluster surface brightness profiles). The median difference in radial velocity for stars on either side of an imaginary axis stepped through the cluster in 1 deg increments shows a statistically significant maximum amplitude of 1.22+/-0.25km/s. We discuss several possible explanations of this result, including (1) cluster rotation, (2) preferential stripping of stars on prograde orbits near the limiting radius, (3) the projection of the cluster space velocity onto the plane of the sky, and (4) a slight drift in the velocity zero point. It is difficult to unambiguously identify the primary cause of the observed structure in the velocity field, however, and we suspect that all of the above processes may play a role. The BV surface brightness profiles and radial velocities have been modeled with both single- and multimass King-Michie models and nonparametric techniques. The corresponding density profiles and M/L profiles show good agreement over the interval 1.5<~R<~10pc, and both approaches suggest a steady rise in M/L with distance from the cluster center. Due to the low cluster luminosity we are unable to place useful constraints on the anisotropy of M/L_B~M/L_V~2.0+/-0.2 for the multimass and nonparametric models, compared to ~1.65+/-0.15 for models having equal-mass stars. Our best-fit, multimass models have mass function slopes of x~0.75+/-0.25, consistent with recent findings that the form of the mass function depends on the position relative to the potential of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/376/561
- Title:
- Rc light curves of 7 variables in M37
- Short Name:
- J/A+A/376/561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD photometric study of the dense galactic open cluster M 37 is discussed. The majority of the analysed data have been obtained through an R_C_ filter in order to collect time-series measurements. The observations were carried out on seven nights between December 1999 and February 2000, and have led to the discovery of 7 new variable stars in the field. Three of them have been unambiguously identified as W UMa-type eclipsing binaries, while two more are monoperiodic pulsating stars, most probably high-amplitude {delta} Scuti-type variables. Two stars seem to be long-period eclipsing binaries without firm period determination. The individual light curve data are presented here.
- ID:
- ivo://CDS.VizieR/J/AJ/125/2307
- Title:
- Rc photometry of ENEAR survey galaxies
- Short Name:
- J/AJ/125/2307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present R-band CCD photometry for 1332 early-type galaxies, observed as part of the Early-type NEARby galaxies (ENEAR) survey of peculiar motions using early-type galaxies in the nearby universe. Circular apertures are used to trace the surface brightness profiles, which are then fitted by a two-component bulge-disk model. From the fits, we obtain the structural parameters required to estimate galaxy distances using the Dn-{sigma} and fundamental plane relations. The photometric data reported here represent one of the largest high-quality and uniform all-sky samples currently available for early-type galaxies in the nearby universe, especially suitable for peculiar motion studies.
- ID:
- ivo://CDS.VizieR/J/AN/333/242
- Title:
- Recent photometry of symbiotic stars
- Short Name:
- J/AN/333/242
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new multicolour (U,B,V,Rc,Ic) photometric observations of classical symbiotic stars, EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, Draco C1, AG Peg and AX Per, carried out between 2007.1 and 2011.9. The aim of this paper is to present new data of our monitoring programme, to describe the main features of their light curves (LC) and to point problems for their future investigation. The data were obtained by the method of the classical photoelectric and CCD photometry.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2867
- Title:
- Red supergiants in Magellanic Clouds
- Short Name:
- J/AJ/126/2867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the red supergiant (RSG) content of the SMC and LMC using multiobject spectroscopy on a sample of red stars previously identified by BVR CCD photometry. We obtained high-accuracy (<1km/s) radial velocities for 118 red stars seen toward the SMC and 167 red stars seen toward the LMC, confirming most of these (89% and 95%, respectively) as red supergiants. Spectral types were also determined for most of these RSGs.
- ID:
- ivo://CDS.VizieR/J/A+A/447/473
- Title:
- R I CN TiO photometry of DDO190 carbon stars
- Short Name:
- J/A+A/447/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out deep R, I, CN, TiO observations of the dwarf irregular galaxy DDO 190. We confirm the existence intermediate-age population around this galaxy. The identification of 47 carbon stars seen up to 5 arcmin from the centre of the galaxy implies that the population distribution of DDO 190 is similar to those found in some other Local Group dIrr galaxies. An estimate of the metallicity, [Fe/H]=-1.55+/-0.12, is obtained based on the observed C/M ratio. From the analysis of star counts, corrected for the radial variation of the incompleteness level, we determine a scale-length {alpha}=40+/-5", in agreement with the recent literature.
