- ID:
- ivo://CDS.VizieR/J/ApJ/891/28
- Title:
- N-rich field stars from LAMOST and APOGEE data
- Short Name:
- J/ApJ/891/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Interesting chemically peculiar field stars may reflect their stellar evolution history and their possible origin in a different environment from where they are found now; this is one of the most important research fields in Galactic archeology. To explore this further, we have used the CN-CH bands around 4000{AA} to identify N-rich metal-poor field stars in LAMOST DR3. Here we expand our N-rich, metal-poor field star sample to ~100 stars in LAMOST DR5, where 53 of them are newly found in this work. We investigate light elements of common stars between our sample and APOGEE DR14. While Mg, Al, and Si abundances generally agree with the hypothesis that N-rich metal-poor field stars come from enriched populations in globular clusters, it is still inconclusive for C, N, and O. After integrating the orbits of our N-rich field stars and a control sample of normal metal-poor field stars, we find that N-rich field stars have different orbital parameter distributions compared to the control sample-specifically, apocentric distances, maximum vertical amplitude (Zmax), orbital energy, and z-direction angular momentum (Lz). The orbital parameters of N-rich field stars indicate that most of them are inner-halo stars. The kinematics of N-rich field stars support their possible GC origin. The spatial and velocity distributions of our bona fide N-rich field star sample are important observational evidence to constrain simulations of the origin of these interesting objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/127/105
- Title:
- Nuclear star clusters in late-type spiral galaxies
- Short Name:
- J/AJ/127/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the structural properties of nuclear star clusters in late-type spiral galaxies. More specifically, we fit analytical models to Hubble Space Telescope images of 39 nuclear clusters in order to determine their effective radii after correction for the instrumental point-spread function. We use the results of this analysis to compare the luminosities and sizes of nuclear star clusters to those of other ellipsoidal stellar systems, in particular the Milky Way globular clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/702/441
- Title:
- Obscured active galaxies
- Short Name:
- J/ApJ/702/441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Obscured or narrow-line active galaxies offer an unobstructed view of the quasar environment in the presence of a luminous and vigorously accreting black hole (BH). We exploit the large new sample of optically selected luminous narrow-line active galaxies from the Sloan Digital Sky Survey at redshifts 0.1<z<0.45, in conjunction with follow-up observations with the Low Dispersion Survey Spectrograph (LDSS3) at Magellan, to study the distributions of BH mass and host galaxy properties in these extreme objects.
- ID:
- ivo://CDS.VizieR/J/A+A/437/705
- Title:
- Observations of PHEMU97 and PHEMU03 at Ukkel
- Short Name:
- J/A+A/437/705
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we describe the observations of the mutual phenomena of the Galilean Satellites of Jupiter performed at the Royal Observatory of Belgium, as part of the PHEMU97 and PHEMU03 campaigns. The paper describes the observational technique, the data reduction and summarises the results obtained.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/1691
- Title:
- Observations of the distant Kuiper belt
- Short Name:
- J/ApJ/720/1691
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field survey using the 1.2m Samuel Oschin Telescope at Palomar Observatory. This survey was designed to find the most distant members of the Kuiper Belt and beyond. We searched ~12000deg^2^ down to a mean limiting magnitude of 21.3 in R. A total number of 52 Kuiper Belt objects and Centaurs have been detected, 25 of which were discovered in this survey. Except for the redetection of Sedna, no additional Sedna-like bodies with perihelia greater than 45AU were detected despite sensitivity out to distances of 1000AU. We discuss the implications for a distant Sedna-like population beyond the Kuiper Belt, focusing on the constraints we can place on the embedded stellar cluster environment the early Sun may be have been born in, where the location and distribution of Sedna-like orbits sculpted by multiple stellar encounters is indicative of the birth cluster size. We also report our observed latitude distribution and implications for the size of the plutino population.
- ID:
- ivo://CDS.VizieR/J/AJ/157/235
- Title:
- Observations of the Kepler field with TESS
- Short Name:
- J/AJ/157/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the ability of the Transiting Exoplanet Survey Satellite (TESS) to detect and improve our understanding of planetary systems in the Kepler field. By modeling the expected transits of all confirmed and candidate planets detected by Kepler as expected to be observed by TESS, we provide a probabilistic forecast of the detection of each Kepler planet in TESS data. We find that TESS has a greater than 50% chance of detecting 260 of these planets at the 3{sigma} level in one sector of observations and an additional 120 planets in two sectors. Most of these are large planets in short orbits around their host stars, although a small number of rocky planets are expected to be recovered. Most of these systems have only one known transiting planet; in only ~5% of known multiply transiting systems do we anticipate more than one planet to be recovered. When these planets are recovered, we expect TESS to be a powerful tool to characterize transit timing variations. Using Kepler-88 (KOI-142) as an example, we show that TESS will improve measurements of planet-star mass ratios and orbital parameters, and significantly reduce the transit timing uncertainty in future years. Because TESS will be most sensitive to hot Jupiters, we research whether TESS will be able to detect tidal orbital decay in these systems. We find two confirmed planetary systems (Kepler-2 b and Kepler-13 b) and five candidate systems that will be good candidates to detect tidal decay.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/72
- Title:
- Observed sample of z~0.7 massive galaxies
- Short Name:
- J/ApJ/788/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed studies of the stellar populations of intermediate-redshift galaxies can shed light onto the processes responsible for the growth of the massive galaxy population in the last 8 billion years. We here take a step toward this goal by means of deep, multiobject rest-frame optical spectroscopy, performed with the Inamori Magellan Areal Camera and Spectrograph on the Magellan telescope, of a sample of ~70 galaxies in the Extended Chandra Deep Field South survey with redshift 0.65<=z<=0.75, apparent R>22.7 mag_Vega_, and stellar mass >10^10^ M_{sun}_. We measure velocity dispersion and stellar absorption features for individual sources. We interpret them by means of a large Monte Carlo library of star formation histories, following the Bayesian approach adopted for previous low redshift studies, and derive constraints on the stellar mass, mean stellar age, and stellar metallicity of these galaxies. We characterize for the first time the relations between stellar age and stellar mass and between stellar metallicity and stellar mass at z~0.7 for the galaxy population as a whole and for quiescent and star-forming galaxies separately. These relations of increasing age and metallicity with galaxy mass for the galaxy population as a whole have a similar shape as the z~0.1 analog derived for Sloan Digital Sky Survey galaxies but are shifted by -0.28 dex in age and by -0.13 dex in metallicity, at odds with simple passive evolution. Considering z=0.7 quiescent galaxies alone, we find that no additional star formation and chemical enrichment are required for them to evolve into the present-day quiescent population. However, other observations require the quiescent population to grow from z=0.7 to the present day. This growth could be supplied by the quenching of a fraction of z=0.7 M_{sstarf}_>10^11^ M_{sun}_ star-forming galaxies with metallicities already comparable to those of quiescent galaxies, thus leading to the observed increase of the scatter in age without affecting the metallicity distribution. However, rapid quenching of the entire population of massive star-forming galaxies at z=0.7 would be inconsistent with the age- and metallicity-mass relations for the population as a whole and with the metallicity distribution of star-forming galaxies only, which are, on average, 0.12 dex less metal rich than their local counterparts. This indicates chemical enrichment until the present in at least a fraction of the z=0.7 star-forming galaxies in our sample.
- ID:
- ivo://CDS.VizieR/J/AcA/65/39
- Title:
- OGLE Galactic Bulge ultra-short-period binaries
- Short Name:
- J/AcA/65/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 242 ultra-short-period (Porb<0.22d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve morphology, we divide the sample into candidates for contact binaries and non-contact binaries. In the latter group we distinguish binary systems consisting of a cool main-sequence star and a B-type subdwarf (HW Vir stars) and candidates for cataclysmic variables, including five eclipsing dwarf novae. One of the detected eclipsing binary systems - OGLE-BLG-ECL-000066 - with the orbital period below 0.1d, likely consists of M dwarfs in a nearly contact configuration. If confirmed, this would be the shortest-period M-dwarf binary system currently known. We discuss possible evolutionary mechanisms that could lead to the orbital period below 0.1d in an M-dwarf binary.
- ID:
- ivo://CDS.VizieR/J/AcA/63/115
- Title:
- OGLE-III Galactic disk eclipsing binaries
- Short Name:
- J/AcA/63/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of 11589 eclipsing binary stars identified in twenty-one OGLE-III Galactic disk fields toward constellations of Carina, Centaurus, and Musca. All eclipsing binaries but 402 objects are new discoveries. The binaries have out-of-eclipse brightness between I=12.5mag and I=21mag. The completeness of the catalog is estimated at a level of about 75%. Comparison of the orbital period distribution for the OGLE-III disk binaries with systems detected in other recent large-scale Galactic surveys shows the maximum around 0.40d and an almost flat distribution between 0.5d and 2.5d, independent of population. Ten doubly eclipsing systems and one eclipsing-ellipsoidal object were found among thousands of variables. Nine of them are candidates for quadruple systems. We also identify ten eclipsing subdwarf-B type binary stars and numerous eclipsing RS CVn type variables. All objects reported in this paper are part of the OGLE-III Catalog of Variable Stars.
- ID:
- ivo://CDS.VizieR/J/AcA/56/219
- Title:
- OGLE variable stars in NGC 6259
- Short Name:
- J/AcA/56/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for variable stars in the field of NGC6259. Altogether 85 variable stars have been discovered. 36 of them are eclipsing systems. This group contains 13 EA, 2 EB and 21 EW-type stars. Light curves of two variable stars resemble those of Miras. The remaining 47 variable stars detected in the field of this open cluster are most probably highly obscured red giants (OSARG, irregular). For all detected variable stars we provide their light curves, preliminary classification, discussion on the possible cluster membership, equatorial coordinates, finding charts and periods when possible.
