- ID:
- ivo://CDS.VizieR/J/PASP/117/227
- Title:
- Properties of 101 galaxies from the NFGS
- Short Name:
- J/PASP/117/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 101 galaxies selected from the Nearby Field Galaxy Survey to investigate the effect of aperture size on the star formation rate, metallicity, and reddening determinations for galaxies. Our sample includes galaxies of all Hubble types except ellipticals with global star formation rates (SFRs) ranging from 0.01 to 100M_{sun}_/yr, metallicities in the range 7.9<~log(O/H)+12<~9.0, and reddening of 0<~A(V)<~3.3. We compare the SFR, metallicity, and reddening derived from nuclear spectra to those derived from integrated spectra.
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- ID:
- ivo://CDS.VizieR/J/AJ/144/129
- Title:
- Properties of 83 known stellar SiO maser sources
- Short Name:
- J/AJ/144/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out simultaneous observations of four maser lines, SiO v=1,2, ^29^SiO v=0,J=1-0, and H_2_O 6_16_-5_23_, toward 83 known SiO maser sources without H_2_O maser detections using the Korean VLBI Network single dish telescopes. Both SiO and H_2_O masers were detected from 14 sources, resulting in a detection rate of 16.9%. H_2_O maser emission without SiO maser emission was detected from one source. Therefore, H_2_O maser emission was newly detected from 15 sources. SiO maser emission without H_2_O detection was detected from 55 sources, which gives a total SiO maser detection rate of 83.1% when including sources that have both SiO and H_2_O maser emission detected. SiO v=2 maser emission was detected from nine sources without v=1 maser detection. The SiO v=2 maser sources without the v=1 maser detections need to be investigated, with a large number of v=2 only maser sources related to the development of dust shells and their evolutionary sequence from asymptotic giant branch (AGB) to post-AGB stars. The average values of the peak and integrated antenna temperature ratios of H_2_O to SiO masers are 0.44 and 0.28 in the 14 sources that have both SiO and H_2_O detections. Observational characteristics of several individual sources are noted and the dependence of the different maser intensity ratios on the stellar phase is discussed. In addition, the observational results of SiO and H_2_O masers are discussed in IRAS two-color diagrams.
- ID:
- ivo://CDS.VizieR/J/ApJ/852/49
- Title:
- Properties of metal-poor stars in APOGEE DR13
- Short Name:
- J/ApJ/852/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We find two chemically distinct populations separated relatively cleanly in the [Fe/H]-[Mg/Fe] plane, but also distinguished in other chemical planes, among metal-poor stars (primarily with metallicities [Fe/H]<-0.9) observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and analyzed for Data Release 13 (DR13) of the Sloan Digital Sky Survey. These two stellar populations show the most significant differences in their [X/Fe] ratios for the {alpha}-elements, C+N, Al, and Ni. In addition to these populations having differing chemistry, the low metallicity high-Mg population (which we denote "the HMg population") exhibits a significant net Galactic rotation, whereas the low-Mg population (or "the LMg population") has halo-like kinematics with little to no net rotation. Based on its properties, the origin of the LMg population is likely an accreted population of stars. The HMg population shows chemistry (and to an extent kinematics) similar to the thick disk, and is likely associated with in situ formation. The distinction between the LMg and HMg populations mimics the differences between the populations of low- and high-{alpha} halo stars found in previous studies, suggesting that these are samples of the same two populations.
- ID:
- ivo://CDS.VizieR/J/AJ/156/213
- Title:
- Properties of N2K stars & new gas giant companions
- Short Name:
- J/AJ/156/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce the discovery of six new gas giant exoplanets: a double-planet system orbiting HD 148164 (Msini of 1.23 and 5.16 M_JUP_) and single planet detections around HD 55696 (Msini=3.87 M_JUP_), HD 98736 (Msini=2.33 M_JUP_), HD 203473 (Msini=7.8 M_JUP_), and HD 211810 (Msini=0.67 M_JUP_). These gas giant companions have orbital semimajor axes between 1.0 and 6.2 au and eccentricities ranging from 0.13 to 0.71. We also report evidence for three gravitationally bound companions with Msini between 20 and 30 M_JUP_, placing them in the mass range of brown dwarfs, around HD 148284, HD 214823, and HD 217850, and four low-mass stellar companions orbiting HD 3404, HD 24505, HD 98630, and HD 103459. In addition, we present updated orbital parameters for 42 previously announced planets. We also report a nondetection of the putative companion HD 73256 b. Finally, we highlight the most promising candidates for direct imaging and astrometric detection, and we find that many hot Jupiters from our sample could be detectable by state-of-the-art telescopes such as Gaia.
- ID:
- ivo://CDS.VizieR/J/ApJ/496/39
- Title:
- Properties of poor groups of galaxies. I.
- Short Name:
- J/ApJ/496/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use multifiber spectroscopy of 12 poor groups of galaxies to address (1) whether the groups are bound systems or chance projections of galaxies along the line of sight; (2) why the members of each group have not already merged to form a single galaxy, despite the groups' high galaxy densities, short crossing times, and likely environments for galaxy-galaxy mergers; and (3) how galaxies might evolve in these groups, where the collisional effects of the intragroup gas and the tidal influences of the global potential are weaker than in rich clusters. Each of the 12 groups has fewer than about five cataloged members in the literature. Our sample consists of 1002 galaxy velocities, 280 of which are group members. The groups have mean recessional velocities between 1600 and 7600km/s. Nine groups, including three Hickson compact groups, have the extended X-ray emission characteristic of an intragroup medium (see Paper II, 1998ApJ...496...73M).
- ID:
- ivo://CDS.VizieR/J/ApJ/539/136
- Title:
- Properties of poor groups of galaxies. III.
- Short Name:
- J/ApJ/539/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The form of the galaxy luminosity function (GLF) in poor groups - regions of intermediate galaxy density that are common environments for galaxies - is not well understood. Multiobject spectroscopy and wide-field CCD imaging now allow us to measure the GLF of bound group members directly (i.e., without statistical background subtraction) and to compare the group GLF with the GLFs of the field and of rich clusters. We use R-band images in 1.5x1.5degree^2^ mosaics to obtain photometry for galaxies in the fields of six nearby (2800<cz<7700km/s) poor groups for which we have extensive spectroscopic data, including 328 new galaxy velocities.
1257. Properties of Sgr Stars
- ID:
- ivo://CDS.VizieR/J/ApJ/889/63
- Title:
- Properties of Sgr Stars
- Short Name:
- J/ApJ/889/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using 3D positions and kinematics of stars relative to the Sagittarius (Sgr) orbital plane and angular momentum, we identify 166 Sgr stream members observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) that also have Gaia DR2 astrometry. This sample of 63/103 stars in the Sgr trailing/leading arm is combined with an APOGEE sample of 710 members of the Sgr dwarf spheroidal core (385 of them newly presented here) to establish differences of 0.6dex in median metallicity and 0.1dex in [{alpha}/Fe] between our Sgr core and dynamically older stream samples. Mild chemical gradients are found internally along each arm, but these steepen when anchored by core stars. With a model of Sgr tidal disruption providing estimated dynamical ages (i.e., stripping times) for each stream star, we find a mean metallicity gradient of 0.12+/-0.03dex/Gyr for stars stripped from Sgr over time. For the first time, an [{alpha}/Fe] gradient is also measured within the stream, at 0.02_/-0.01dex/Gyr using magnesium abundances and at 0.04+/-0.01dex/Gyr^ using silicon, which imply that the Sgr progenitor had significant radial abundance gradients. We discuss the magnitude of those inferred gradients and their implication for the nature of the Sgr progenitor within the context of the current family of Milky Way satellite galaxies, and we suggest that more sophisticated Sgr models are needed to properly interpret the growing chemodynamical detail we have on the Sgr system.
- ID:
- ivo://CDS.VizieR/J/AJ/142/185
- Title:
- Properties of the eclipsing binary stars HY Vir
- Short Name:
- J/AJ/142/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HY Vir is found to be a double-lined F0m+F5 binary star with relatively shallow (0.3mag) partial eclipses. Previous studies of the system are improved with 7509 differential photometric observations from the URSA WebScope and 8862 from the NFO (New Forest Observatory) WebScope, and 68 high-resolution spectroscopic observations from the Tennessee State University 2m automatic spectroscopic telescope, and the 1m coude-feed spectrometer at Kitt Peak National Observatory (KPNO). Very accurate (better than 0.5%) masses and radii are determined from analysis of the new light curves and radial velocity curves. Theoretical models match the absolute properties of the stars at an age of about 1.35Gy.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/L8
- Title:
- Properties of TriAnd stars
- Short Name:
- J/ApJ/859/L8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nature of the Triangulum-Andromeda (TriAnd) system has been debated since the discovery of this distant, low-latitude Milky Way (MW) overdensity more than a decade ago. Explanations for its origin are either as a halo substructure from the disruption of a dwarf galaxy, or a distant extension of the Galactic disk. We test these hypotheses using the chemical abundances of a dozen TriAnd members from the Sloan Digital Sky Survey-IV's (SDSS-IV's) 14th Data Release (DR14) of Apache Point Observatory Galactic Evolution Experiment (APOGEE) data to compare to APOGEE abundances of stars with similar metallicity from both the Sagittarius (Sgr) dSph and the outer MW disk. We find that TriAnd stars are chemically distinct from Sgr across a variety of elements, (C+N), Mg, K, Ca, Mn, and Ni, with a separation in [X/Fe] of about 0.1 to 0.4dex depending on the element. Instead, the TriAnd stars, with a median metallicity of about -0.8, exhibit chemical abundance ratios similar to those of the lowest metallicity ([Fe/H]~-0.7) stars in the outer Galactic disk, and are consistent with expectations of extrapolated chemical gradients in the outer disk of the MW. These results suggest that TriAnd is associated with the MW disk, and, therefore, that the disk extends to this overdensity-i.e., past a Galactocentric radius of 24kpc-albeit vertically perturbed about 7kpc below the nominal disk midplane in this region of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/34
- Title:
- Properties of UCD candidates in M87/M49/M60 regions
- Short Name:
- J/ApJ/812/34
- Date:
- 14 Jan 2022 08:28:26
- Publisher:
- CDS
- Description:
- We use imaging from the Next Generation Virgo cluster Survey (NGVS) to present a comparative study of ultra-compact dwarf (UCD) galaxies associated with three prominent Virgo sub-clusters: those centered on the massive red-sequence galaxies M87, M49, and M60. We show how UCDs can be selected with high completeness using a combination of half-light radius and location in color-color diagrams (u*iK_s_ or u*gz). Although the central galaxies in each of these sub-clusters have nearly identical luminosities and stellar masses, we find large differences in the sizes of their UCD populations, with M87 containing ~3.5 and 7.8 times more UCDs than M49 and M60, respectively. The relative abundance of UCDs in the three regions scales in proportion to sub-cluster mass, as traced by X-ray gas mass, total gravitating mass, number of globular clusters (GCs), and number of nearby galaxies. We find that the UCDs are predominantly blue in color, with ~85% of the UCDs having colors similar to blue GCs and stellar nuclei of dwarf galaxies. We present evidence that UCDs surrounding M87 and M49 may follow a morphological sequence ordered by the prominence of their outer, low surface brightness envelope, ultimately merging with the sequence of nucleated low-mass galaxies, and that envelope prominence correlates with distance from either galaxy. Our analysis provides evidence that tidal stripping of nucleated galaxies is an important process in the formation of UCDs.
