- ID:
- ivo://CDS.VizieR/J/A+A/555/A36
- Title:
- VrI light curves of NGC7099 variables
- Short Name:
- J/A+A/555/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derive an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]_ZW_=-2.01+/-0.04, or [Fe/H]_UVES_=-2.11+/-0.06, and a distance of 8.32+/-0.20kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35+/-0.42kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0+/-1.0Gyr for M 30.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/528/A42
- Title:
- VRi light curves of the lensed QSO HE 0435-1223
- Short Name:
- J/A+A/528/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VRi photometric observations of the quadruply imaged quasar HE0435-1223, carried out with the Danish 1.54m telescope at the La Silla Observatory. Our aim was to monitor and study the magnitudes and colors of each lensed component as a function of time.
- ID:
- ivo://CDS.VizieR/J/ApJ/783/35
- Title:
- VRI light curves of TT Her
- Short Name:
- J/ApJ/783/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocities and photometry of the short-period Algol TT Herculis. Previous attempts to model the light curves of the system have met with limited success, primarily because of the lack of a reliable mass ratio. Our spectroscopic observations are the first to result in radial velocities for the secondary star, and thus provide a spectroscopic mass ratio. Simultaneous analysis of the radial velocities and new photometry shows that the system is a double contact binary, with a rapidly rotating primary that fills its limiting lobe.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/21
- Title:
- VRI monitoring of the QSO 3C 273 in 2005-2016
- Short Name:
- J/ApJS/229/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have monitored the quasar 3C 273 in the optical V, R, and I bands from 2005 to 2016. Intraday variability (IDV) is detected on seven nights. The variability amplitudes on most of the nights are less than 10%, and on four nights, more than 20%. When considering the nights with time spans >4hr, the duty cycle (DC) is 14.17%. Over the 12yrs, the overall magnitude and color index variabilities are {Delta}I=0.67, {Delta}R=0.72, {Delta}V=0.68, and {Delta}(V-R)=0.25, respectively. The largest clear IDV has an amplitude of 42% over just 5.8 minutes, and the weakest detected IDV is 5.4% over 175 minutes. The BWB (bluer when brighter) chromatic trend is dominant for 3C 273 and appears at different flux levels on intraday timescales. The BWB trend exists for short-term timescales and intermediate-term timescales but different timescales have different correlations. There is no BWB trend for our whole time-series data sets. A significant anticorrelation between the BWB trend and length of timescales is found. Combining with V-band data from previous works, we find a possible quasi-periodicity of P=3918+/-1112 days. The possible explanations for the observed variability, BWB chromatic trend, and periodicity are discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/128/846
- Title:
- VRI observations of CE Leonis
- Short Name:
- J/AJ/128/846
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present complete VRI light curves of the contact binary CE Leo and provide detailed photometric solutions, as well as an analysis of its period variation. A total of 73 times of minima over 50years, including our observations, were used for the period study.
- ID:
- ivo://CDS.VizieR/J/AZh/84/885
- Title:
- VRI observations of radio source S5 0716+71
- Short Name:
- J/AZh/84/885
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of VRI photometry of the gravitationally lensed system Q2237+0305 carried out on the 1.5-m telescope of Maidanak observatory in 2004-2005 are presented. The distance between the components is of the order of 1".
- ID:
- ivo://CDS.VizieR/J/ApJ/669/525
- Title:
- VRI photometric standards for NGC 6946
- Short Name:
- J/ApJ/669/525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, very late time optical photometry and spectroscopy of the interesting Type II-P supernova SN 2002hh, in NGC 6946. Gemini/GMOS-N has been used to acquire visible spectra at six epochs between 2004 August and 2006 July, following the evolution of the SN from age 661 to 1358-days. Few optical spectra of Type II supernovae with ages greater than 1yr exist. In addition, g', r', and i' images were acquired at all six epochs. The spectral and photometric evolution of SN 2002hh has been very unusual. Measures of the brightness of this SN, both in the R and I bands, as well as in the Halpha emission flux, show no significant fading over an interval of nearly 2-years.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/262
- Title:
- VRI photometry and theta values in open clusters
- Short Name:
- J/ApJS/176/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, new Cousins VRI data are presented for NGC 752 and Praesepe, and new and extant data are combined into an augmented database for M67. For those three clusters, catalogs containing Cousins VRI photometry, reddening-corrected values of (V-K)J, and temperatures are produced. The same is done for Coma by using both previously published and newly derived Cousins photometry. An extant set of catalogs for the Hyades is updated to include V magnitudes and values of (R-I)C that were published after the original catalogs appeared. Finally, M67 V magnitudes published previously by Sandquist are corrected for an effect that depends on location on the face of the cluster. The corrected data and values of (V-I)C given by Sandquist are then set out in a supplementary catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/149/200
- Title:
- VRI photometry in NGC 7129
- Short Name:
- J/AJ/149/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC7129 is a bright reflection nebula located in the molecular cloud complex near l=105.4{deg}, b=+9.9{deg}, about 1.15kpc distant. Embedded within the reflection nebula is a young cluster dominated by a compact grouping of four early-type stars: BD+65{deg}1638 (B3V), BD+65{deg}1637 (B3e), SVS 13 (B5e), and LkH{alpha} 234 (B8e). About 80 H{alpha} emission sources brighter than V~23 are identified in the region, many of which are presumably T Tauri star members of the cluster. We also present deep (V~23), optical (VR_C_I_C_) photometry of a field centered on the reflection nebula and spectral types for more than 130 sources determined from low dispersion, optical spectroscopy. The narrow pre-main sequence evident in the color-magnitude diagram suggests that star formation was rapid and coeval. A median age of about 1.8Myr is inferred for the H{alpha} and literature-identified X-ray emission sources having established spectral types, using pre-main sequence evolutionary models. Our interpretation of the structure of the molecular cloud and the distribution of young stellar objects is that BD+65{deg}1638 is primarily responsible for evacuating the blister-like cavity within the molecular cloud. LkH{alpha} 234 and several embedded sources evident in near-infrared adaptive optics imaging have formed recently within the ridge of compressed molecular gas. The compact cluster of low-mass stars formed concurrently with the early-type members, concentrated within a central radius of ~0.7pc. Star formation is simultaneously occurring in a semi-circular arc some ~3pc in radius that outlines remaining dense regions of molecular gas. High dispersion, optical spectra are presented for BD+65{deg}1638, BD+65{deg}1637, SVS 13, LkH{alpha} 234, and V350 Cep. These spectra are discussed in the context of the circumstellar environments inferred for these stars.
- ID:
- ivo://CDS.VizieR/J/A+A/430/19
- Title:
- VRI photometry of Abell 3921 galaxies
- Short Name:
- J/A+A/430/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis and results of a new VRI photometric and spectroscopic survey of the central ~1.8x1.2Mpc^2^ region of the galaxy cluster A3921 (z=0.094). We detect the presence of two dominant clumps of galaxies with a mass ratio of ~5: a main cluster centred on the Brightest Cluster Galaxy (BCG) (A3921-A), and an NW sub-cluster (A3921-B) hosting the second brightest cluster galaxy. The distorted morphology of the two sub-clusters suggests that they are interacting, while the velocity distribution of 104 confirmed cluster members does not reveal strong signatures of merging.
