Number of results to display per page
Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/AN/325/705
- Title:
- RIJHKs of low-mass stars in sigma Ori
- Short Name:
- J/AN/325/705
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an RI photometric survey covering an area of 430 arcmin^2^ around the multiple star sigma Orionis. The observations were conducted with the 0.8m IAC-80 Telescope at the Teide Observatory. The survey limiting R and I magnitudes are 22.5 and 21, and completeness magnitudes 21 and 20, respectively. We have selected 53 candidates from the I vs. R-I colour-magnitude diagram (I=14-20) that follow the previously known photometric sequence of the cluster. Adopting an age of 2-4 Myr for the cluster, we find that these objects span a mass range from 0.35M_{sun}_ to 0.015M_{sun}_. We have performed J-band photometry of 52 candidates and K_s photometry for 12 of them, with the result that 50 follow the expected infrared sequence for the cluster, thus confirming with great confidence that the majority of the candidates are bona fide members. JHK_s photometry from the Two Micron All Sky Survey (2MASS, Cat. <II/246>) is available for 50 of the candidates and are in good agreement with our data. Out of 48 candidates, which have photometric accuracies better than 0.1mag in all bands, only three appear to show near-infrared excesses.
- ID:
- ivo://CDS.VizieR/J/A+A/418/33
- Title:
- RI photometry of C stars in NGC 147
- Short Name:
- J/A+A/418/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged a 42'x28' field centered on the spheroidal galaxy NGC 147 to study its AGB population and determine the main structural properties of this M31 companion. This field was observed through two broadband (R and I) and two narrowband (CN and TiO) filters, following the standard approach of our systematic survey of C stars in nearby galaxies. We identified 288 C stars in NGC 147. The average I-magnitude of such sample of C stars is <I>=20.31 with {sigma}=0.40. If we adopt a distance modulus {mu}0=24.39, derived from the luminosity of both the tip of the red giant branch (TRGB) and the horizontal branch (HB) by Han et al. (1997, Cat. <J/AJ/113/1001>, we conclude that the average absolute I-magnitude of C stars is <M_I_>=-4.39, thus slightly under luminous with respect to what was found for other galaxies in our survey.
- ID:
- ivo://CDS.VizieR/J/A+A/417/479
- Title:
- RI photometry of NGC 185 carbon stars
- Short Name:
- J/A+A/417/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the CFH12K wide field camera to survey the carbon star population of NGC 185 using the CN-TiO technique. 145 C stars are identified with a mean <I>=19.99+/-0.05, corresponding to <M_I_>=-4.41+/-0.05, a mean luminosity similar to what was recently found for the C star population of NGC 147. The stellar surface density profile of NGC 185 follows a power law with an exponential scale length of 2.53+/-0.07'. The surface density of C stars follows also a power law but with a smaller scale length, 1.56+/-0.06, demonstrating that the intermediate-age population of NGC 185 is more concentrated than its old population. A tidal radius, r_t_=22.5+/-2.2' is determined from red giant star counts. The C/M ratio of NGC 185 is 0.17+/-0.02 with no apparent sign of a radial gradient. We compare the carbon star populations of NGC 185 and NGC 147 to conclude that it is unlikely that they form a close pair.
