- ID:
- ivo://CDS.VizieR/J/PASP/122/347
- Title:
- Chinese Small Telescope ARray (CSTAR)
- Short Name:
- J/PASP/122/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In 2008 January the twenty-fourth Chinese expedition team successfully deployed the Chinese Small Telescope ARray (CSTAR) to Dome A, the highest point on the Antarctic plateau. CSTAR consists of four 14.5cm optical telescopes, each with a different filter (g,r,i, and open) and has a 4.5{deg}x4.5{deg} field of view (FOV). It operates robotically as part of the Plateau Observatory, PLATO, with each telescope taking an image every ~30s throughout the year whenever it is dark. During 2008, CSTAR 1 performed almost flawlessly, acquiring more than 0.3 million -band images for a total integration time of 1728hr during 158 days of observations. For each image taken under good sky conditions, more than 10,000 sources down to magnitude could be detected. We performed aperture photometry on all the sources in the field to create the catalog described herein. Since CSTAR has a fixed pointing centered on the south celestial pole (Dec=-90{deg}), all the sources within the FOV of CSTAR were monitored continuously for several months. The photometric catalog can be used for studying any variability in these sources, and for the discovery of transient sources such as supernovae, gamma-ray bursts, and minor planets.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/135/966
- Title:
- Circumstellar disk evolution in NGC 2068/71
- Short Name:
- J/AJ/135/966
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the disk and accretion properties of young stars in the NGC 2068 and NGC 2071 clusters. Using low-resolution optical spectra, we define a membership sample and determine an age for the region of ~2Myr. Using high-resolution spectra of the H{alpha} line we study the accretion activity of these likely members and also examine the disk properties of the likely members using IRAC and MIPS mid-infrared photometry. A substantial fraction (79%) of the 67 members have an infrared excess while all of the stars with significant infrared excess show evidence for active accretion. We find three populations of evolved disks (IRAC weak, MIPS weak, and transition disks) all of which show decreased accretion activity in addition to the evidence for evolution in the dust disk.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/1873
- Title:
- Classification of LAMOST DR4 galaxies
- Short Name:
- J/MNRAS/474/1873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the classification and composite spectra of galaxies in the fourth data release (DR4) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST). We select 40182 spectra of galaxies from LAMOST DR4, which have photometric information but no spectroscopic observations in the Sloan Digital Sky Survey (SDSS). These newly observed spectra are recalibrated and classified into six classes - passive, H{alpha}-weak, star-forming, composite, LINER and Seyfert - using the line intensity (H{beta}, [OIII] 5007, H{alpha} and [NII] 6585). We also study the correlation between spectral class and morphological type through three parameters: concentration index, (u-r) colour and D4000n index. We calculate composite spectra of high signal-to-noise ratio (S/N) for six spectral classes and, using these composites, we pick out some features that can differentiate the classes effectively, including H{beta}, Fe5015, H{gamma}A, HK and the Mg2 band. In addition, we compare our composite spectra with the SDSS ones and analyse their differences. A galaxy catalogue of 40182 newly observed spectra (36601 targets) and the composite spectra of the six classes are available online (http://sciwiki.lamost.org/downloads/wll).
- ID:
- ivo://CDS.VizieR/J/AJ/131/1674
- Title:
- Close binary systems from SDSS DR4
- Short Name:
- J/AJ/131/1674
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic sample of 746 detached close binary systems from the Sloan Digital Sky Survey (SDSS) Fourth Data Release (2006ApJS..162...38A). The majority of these binaries consist of a white dwarf primary and a low-mass secondary (typically M dwarf) companion. We have determined the temperature and gravity for 496 of the white dwarf primaries and the spectral type and magnetic activity properties for 661 of the low-mass secondaries. We have estimated the distances for each of the white dwarf-main-sequence star binaries and use white dwarf evolutionary grids to establish the age of each binary system from the white dwarf cooling times.
- ID:
- ivo://CDS.VizieR/J/ApJS/199/34
- Title:
- Clusters of galaxies in SDSS-III
- Short Name:
- J/ApJS/199/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the photometric redshifts of galaxies from the Sloan Digital Sky Survey III (SDSS-III), we identify 132684 clusters in the redshift range of 0.05<=z<0.8. Monte Carlo simulations show that the false detection rate is less than 6% for the whole sample. The completeness is more than 95% for clusters with a mass of M_200_>1.0x10^14^M_{sun}_ in the redshift range of 0.05<=z<0.42, while clusters of z>0.42 are less complete and have a biased smaller richness than the real one due to incompleteness of member galaxies. We compare our sample with other cluster samples, and find that more than 90% of previously known rich clusters of 0.05<=z<0.42 are matched with clusters in our sample. Richer clusters tend to have more luminous brightest cluster galaxies (BCGs). Correlating with X-ray and the Planck data, we show that the cluster richness is closely related to the X-ray luminosity, temperature, and Sunyaev-Zel'dovich measurements. Comparison of the BCGs with the SDSS luminous red galaxy (LRG) sample shows that 25% of LRGs are BCGs of our clusters and 36% of LRGs are cluster member galaxies. In our cluster sample, 63% of BCGs of r_petro_<19.5 satisfy the SDSS LRG selection criteria.
- ID:
- ivo://CDS.VizieR/J/AJ/142/126
- Title:
- CN and CH in SDSS Galactic globular clusters
- Short Name:
- J/AJ/142/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a homogeneous survey of the CN and CH band strengths in eight Galactic globular clusters observed during the course of the Sloan Extension for Galactic Understanding and Exploration sub-survey (SEGUE) of the Sloan Digital Sky Survey. We confirm the existence of a bimodal CN distribution among red giant branch (RGB) stars in all of the clusters with metallicity greater than [Fe/H]=-1.7; the lowest metallicity cluster with an observed CN bimodality is M53, with [Fe/H]~=-2.1. There is also some evidence for individual CN groups on the subgiant branches of M92, M2, and M13, and on the RGBs of M92 and NGC 5053. Finally, we quantify the correlation between overall cluster metallicity and the slope of the CN band strength-luminosity plot as a means of further demonstrating the level of CN enrichment in cluster giants. Our results agree well with previous studies reported in the literature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/408/181
- Title:
- CN2002ch UBVRI and ugriz light curves
- Short Name:
- J/MNRAS/408/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric and spectroscopic observations of an unusual luminous blue variable (LBV) in NGC 3432, covering three major outbursts in 2008 October, 2009 April and 2009 November. Previously, this star experienced an outburst also in 2000 (known as SN 2000ch). During outbursts the star reached an absolute magnitude between -12.1 and -12.8. Its spectrum showed H, HeI and FeII lines with P-Cygni profiles during and soon after the eruptive phases, while only intermediate-width lines in pure emission (including HeII {lambda}4686) were visible during quiescence. The fast-evolving light curve soon after the outbursts, the quasi-modulated light curve, the peak magnitude and the overall spectral properties are consistent with multiple episodes of variability of an extremely active LBV. However, the widths of the spectral lines indicate unusually high wind velocities (1500-2800km/s), similar to those observed in Wolf-Rayet stars. Although modulated light curves are typical of LBVs during the S-Dor variability phase, the luminous maxima and the high frequency of outbursts are unexpected in S-Dor variables.
- ID:
- ivo://CDS.VizieR/J/ApJ/766/109
- Title:
- Color/age/metallicity gradients of E galaxies
- Short Name:
- J/ApJ/766/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to understand the past merging history of elliptical galaxies, we studied the optical-near-infrared (NIR) color gradients of 204 elliptical galaxies. These galaxies are selected from the overlap region of the Sloan Digital Sky Survey (SDSS) Stripe 82 and the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The use of optical and NIR data (g, r, and K) provides large wavelength baselines, and breaks the age-metallicity degeneracy, allowing us to derive age and metallicity gradients. The use of the deep SDSS Stripe 82 images makes it possible for us to examine how the color/age/metallicity gradients are related to merging features. We find that the optical-NIR color and the age/metallicity gradients of elliptical galaxies with tidal features are consistent with those of relaxed ellipticals, suggesting that the two populations underwent a similar merging history on average and that mixing of stars was more or less completed before the tidal features disappeared. Elliptical galaxies with dust features have steeper color gradients than the other two types, even after masking out dust features during the analysis, which can be due to a process involving wet merging. More importantly, we find that the scatter in the color/age/metallicity gradients of the relaxed and merging feature types decreases as their luminosities (or masses) increase at M>10^11.4^M_{sun}_ but stays large at lower luminosities. Mean metallicity gradients appear nearly constant over the explored mass range, but a possible flattening is observed at the massive end.
- ID:
- ivo://CDS.VizieR/J/A+A/423/755
- Title:
- Color-Induced Displacement double stars in SDSS
- Short Name:
- J/A+A/423/755
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first successful application of the astrometric color-induced displacement technique (CID, the displacement of the photocenter between different band-passes dur to a varying contribution of differently colored components to the total light), originally proposed by Wielen (1996A&A...314..679W) for discovering unresolved binary stars.
- ID:
- ivo://CDS.VizieR/J/AJ/139/1808
- Title:
- Colors and kinematics of SDSS L dwarfs
- Short Name:
- J/AJ/139/1808
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 484 L dwarfs, 210 of which are newly discovered from the Sloan Digital Sky Survey (SDSS) Data Release 7 spectroscopic database. We combine this sample with known L dwarfs to investigate their izJHKS colors. We present photometric distance relations based on i-z and i-J colors and derive distances to our L dwarf sample. We combine the distances with SDSS/2MASS proper motions in order to examine the tangential velocities.
