- ID:
- ivo://CDS.VizieR/J/MNRAS/384/1444
- Title:
- Vr light curves of NGC 5466 RR Lyrae
- Short Name:
- J/MNRAS/384/1444
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and r photometry of the globular cluster NGC 5466. The difference image analysis technique adopted in this work has resulted in accurate time series photometry even in crowded regions of the cluster enabling us to discover five probably semi-regular variables. We present new photometry of three previously known eclipsing binaries and six SX Phe stars. The light curves of the RR Lyrae stars have been decomposed in their Fourier harmonics and their fundamental physical parameters have been estimated using semi-empirical calibrations. The zero points of the metallicity, luminosity and temperature scales are discussed and our Fourier results are transformed accordingly. The average iron abundance and distance to the Sun derived from individual RR Lyrae stars, indicate values of [Fe/H]=-1.91+/-0.19 and D=16.0+/-0.6kpc, or a true distance modulus of 16.02+/-0.09mag, for the parent cluster. These values are respectively in the Zinn & West metallicity scale and in agreement with recent luminosity determinations for the RR Lyrae stars in the LMC. The M_V_-[Fe/H] relation has been recalibrated as M_V_=+(0.18+/-0.03)[Fe/H]+(0.85+/-0.05) using the mean values derived by the Fourier technique on RR Lyrae s tars in a family of clusters. This equation predicts M_V_=0.58mag for [Fe/H]=-1.5, in agreement with the average absolute magnitude of RR Lyrae stars calculated from several independent methods. The M_V-[Fe/H] relationship and the value of [Fe/H] have implications on the age of the globular clusters when determined from the magnitude difference between the horizontal branch and the turn off point (HB-TO method). The above results however would not imply a change in the age of NGC 5466, of 12.5+/-0.9Gyr, estimated from recent isochrone fitting.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/40.209
- Title:
- VR light curves of 15 RR Lyrae in NGC 4147
- Short Name:
- J/other/RMxAA/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and R photometry of the RR Lyrae stars known in NGC 4147. The periodicities of most variables are revised and new ephemerides are calculated. The Blazhko effect has been detected in V2 and V6. Three previously reported variables; V5, V9, and V15 are found to be non-variable. A new variable V18 was discovered with a period of 0.49205-days and an amplitude of 0.15mag. Using the approach of Fourier decomposition of the light curves, the physical parameters of the RRab and RRc variables were estimated. The cluster is of the Oosterhoff type I. With the newly values [Fe/H]=-1.22+/-0.31 and 16.8+/-1.3kpc, the cluster fits very well into the Oosterhoff type-metallicity and metallicity-temperature sequence found in globular clusters. A comparison with ZAHB models indicates that the RRab stars have not yet evolved off the horizontal branch, a result consistent with the mean period of the RRab variables and with the metallicity of the cluster derived in this work.
23193. VRO 42.05.01 CO datacubes
- ID:
- ivo://CDS.VizieR/J/A+A/627/A75
- Title:
- VRO 42.05.01 CO datacubes
- Short Name:
- J/A+A/627/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The environment of supernova remnants (SNRs) is a key factor in their evolution, particularly at later stages of their existence. Mixed-morphology (MM) SNRs have a peculiar centre-filled X-ray shape that remains enigmatic. It is often assumed that they evolve in very dense environments, and that the X-ray morphology is due to interactions between the SNRs and their surroundings. We aim to determine whether VRO 42.05.01 is embedded in, and interacting with, a dense molecular environment. We also aim to understand the multi-wavelength emission from the environment of this SNR, and whether the interstellar material can be responsible for the the MM nature of the source, and for its strange radio and optical shape. We used the IRAM telescope in Pico Veleta, Spain, to search for signs of interaction between the SNR and neighbouring molecular clouds. We observed a region of 260 140 towards the west of VRO 42.05.01 and a region of 80 40 towards the north of the remnant in the ^12^CO J=1-0, ^13^CO J=1-0, and ^12^CO J=2-1 transitions with the EMIR receiver. We made maps of the properties of the observed molecular clouds (peak temperatures, central velocities, velocity dispersions), as well as maps of column density along the line of sight, and ratio of the ^12^CO J=2-1 to ^12^CO J=1-0 transitions.We also analyse archival optical, infrared, and radio spectroscopic data for other hints on the nature of the medium. We do not find conclusive physical proof that the SNR is interacting with the few, clumpy molecular clouds that surround it in the region of our observations, although there is some suggestion of such interaction (in a region outside our map) from infrared emission. We find that there is a velocity gradient in one of the molecular clouds that is consistent with a stellar wind blown by a 12-14M_{sun}_ progenitor star.We reassess the literature distance to VRO 42.05.01, and propose that it has a local standard of rest velocity of ~6km/s, and that it is located 1.0+/-0.4kpc away (the earlier distance value was 4.5+/-1.5kpc).We find that a dust sheet intersects VRO 42.05.01 and is possibly related to its double shell-shaped morphology.
- ID:
- ivo://CDS.VizieR/J/AJ/152/129
- Title:
- VR photometry for 914 stars in NGC 188
- Short Name:
- J/AJ/152/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the newly commissioned 50cm Binocular Network telescope at Qinghai Station of Purple Mountain Observatory (Chinese Academy of Sciences) to observe the old open cluster NGC188 in V and R as part of a search for variable objects. Our time-series data span a total of 36 days. Radial velocity and proper-motion selection resulted in a sample of 532 genuine cluster members. Isochrone fitting was applied to the cleaned cluster sequence, yielding a distance modulus of (m-M)_V_^0^=11.35+/-0.10mag and a total foreground reddening of E(V-R)=0.062+/-0.002mag. Light-curve solutions were obtained for eight W Ursae Majoris eclipsing binary systems (W UMas), and their orbital parameters were estimated. Using the latter parameters, we estimate a distance to the W UMas that is independent of the host cluster's physical properties. Based on combined fits to six of the W UMas (EP Cep, EQ Cep, ES Cep, V369 Cep, and-for the first time-V370 Cep and V782 Cep), we obtain an average distance modulus of (m-M)_V_^0^=11.31+/-0.08mag, which is comparable to that resulting from our isochrone fits. These six W UMas exhibit an obvious period-luminosity relation. We derive more accurate physical parameters for the W UMa systems and discuss their initial masses and ages. The former show that these W UMa systems have likely undergone angular momentum evolution within a convective envelope (W-type evolution). The ages of the W UMa systems agree well with the cluster's age.
- ID:
- ivo://CDS.VizieR/J/A+AS/119/329
- Title:
- VR photometry in the Shapley Supercluster
- Short Name:
- J/A+AS/119/329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V and R CCD photometric sequences of stars and galaxies for calibrating ESO/SERC (R) survey plates in the region of the Shapley supercluster of galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/122/714
- Title:
- VR photometry of Century Survey galaxies
- Short Name:
- J/AJ/122/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 64{deg}^2^ of deep V and R CCD images to measure the local V- and R-band luminosity functions of galaxies. The V_0_<16.7 and R_0_<16.2 redshift samples contain 1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1748
- Title:
- VR photometry of type II Cepheids
- Short Name:
- J/AJ/128/1748
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 1256 new photometric observations of 36 Cepheids with periods longer than 8 days. The majority are likely type II Cepheids, but we have included about a dozen classical Cepheids for comparison purposes, a few stars of uncertain type, and one putative RV Tauri star. We discuss the appearance of the light curves, the Fourier parameters, and the light-curve stability in terms of differentiation between type I and type II Cepheids. Although we encounter the same difficulties as previous investigators in using these parameters for this purpose, we are able to identify some stars of particular interest, including several likely type I Cepheids at large distances from the Galactic plane. Six stars with especially large period changes are identified and discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/130/832
- Title:
- VR photometry of type II Cepheids. III
- Short Name:
- J/AJ/130/832
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 741 new photometric observations for 22 Cepheids with periods between 3 and 8 days. Many of the stars are probable type II Cepheids, but we have included some type I Cepheids for comparison.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A53
- Title:
- VR + velocity variations of IRAS 11472-0800
- Short Name:
- J/A+A/542/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We focus here on one particular and poorly studied object, IRAS 11472-0800. It is a highly evolved post-asymptotic giant branch (post-AGB) star of spectral type F, with a large infrared excess produced by thermal emission of circumstellar dust. We deployed a multi-wavelength study that includes the analyses of optical and IR spectra as well as a variability study based on photometric and spectroscopic time-series.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A77
- Title:
- V426 Sagittae (HBHA 1704-05) light curves
- Short Name:
- J/A+A/636/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star V426 Sge (HBHA 1704-05), originally classified as an emission-line object and a semi-regular variable, brightened at the beginning of August 2018, showing signatures of a symbiotic star outburst. We aim to confirm the nature of V426 Sge as a classical symbiotic star, determine the photometric ephemeris of the light minima, and suggest the path from its 1968 symbiotic nova outburst to the following 2018 Z And-type outburst. We re-constructed an historical light curve (LC) of V426 Sge from approximately the year 1900, and used original low- (R~500-1500; 330-880nm) and high-resolution (R~11000-34000; 360-760nm) spectroscopy complemented with Swift-XRT and UVOT, optical UBVR_C_I_C_ and near-infrared $JHKL$ photometry obtained during the 2018 outburst and the following quiescence. The historical LC reveals no symbiotic-like activity from ~1900 to 1967. In 1968, V426 Sge experienced a symbiotic nova outburst that ceased around 1990. From approximately 1972, a wave-like orbitally related variation with a period of 493.4+/-0.7-days developed in the LC. This was interrupted by a Z And-type outburst from the beginning of August 2018 to the middle of February 2019. At the maximum of the 2018 outburst, the burning white dwarf (WD) increased its temperature to >~2x10^5^K, generated a luminosity of ~7x10^37^(d/3.3kpc}^2^erg/s, and blew a wind at the rate of ~3x10^-6^M_{sun}_/yr. Our spectral energy distribution models from the current quiescent phase reveal that the donor is a normal M4-5 III giant characterised with Teff~3400K, R_G_~106(d/3.3kpc})R_{sun}_ and L_G_~1350(d/3.3kpc})^2^L_{sun}_ and the accretor is a low-mass ~0.5M_{sun}_ WD. During the transition from the symbiotic nova outburst to the quiescent phase, a pronounced sinusoidal variation along the orbit develops in the LC of most symbiotic novae. The following eventual outburst is of Z And-type, when the accretion by the WD temporarily exceeds the upper limit of the stable burning. At this point the system becomes a classical symbiotic star.
