- ID:
- ivo://CDS.VizieR/J/AJ/144/4
- Title:
- Properties of dwarf galaxies in the Local Group
- Short Name:
- J/AJ/144/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Positional, structural, and dynamical parameters for all dwarf galaxies in and around the Local Group are presented, and various aspects of our observational understanding of this volume-limited sample are discussed. Over 100 nearby galaxies that have distance estimates reliably placing them within 3Mpc of the Sun are identified. This distance threshold samples dwarfs in a large range of environments, from the satellite systems of the MW and M31, to the quasi-isolated dwarfs in the outer regions of the Local Group, to the numerous isolated galaxies that are found in its surroundings. It extends to, but does not include, the galaxies associated with the next nearest groups, such as Maffei, Sculptor, and IC 342. Our basic knowledge of this important galactic subset and their resolved stellar populations will continue to improve dramatically over the coming years with existing and future observational capabilities, and they will continue to provide the most detailed information available on numerous aspects of dwarf galaxy formation and evolution. Basic observational parameters, such as distances, velocities, magnitudes, mean metallicities, as well as structural and dynamical characteristics, are collated, homogenized (as far as possible), and presented in tables that will be continually updated to provide a convenient and current online resource. As well as discussing the provenance of the tabulated values and possible uncertainties affecting their usage, the membership and spatial extent of the MW sub-group, M31 sub-group, and the Local Group are explored. The morphological diversity of the entire sample and notable sub-groups is discussed, and timescales are derived for the Local Group members in the context of their orbital/interaction histories. The scaling relations and mean stellar metallicity trends defined by the dwarfs are presented, and the origin of a possible "floor" in central surface brightness (and, more speculatively, stellar mean metallicity) at faint magnitudes is considered.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/817/79
- Title:
- Properties of emission-line galaxies
- Short Name:
- J/ApJ/817/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the physical and morphological properties of z~2 Ly{alpha} emitting galaxies (LAEs) identified in the HETDEX Pilot Survey and narrow band studies with those of z~2 optical emission line selected galaxies (oELGs) identified via HST WFC3 infrared grism spectroscopy. Both sets of galaxies extend over the same range in stellar mass (7.5<logM/M_{sun}_<10.5), size (0.5<R<3.0kpc), and star formation rate (~1<SFR<100M_{sun}_/yr). Remarkably, a comparison of the most commonly used physical and morphological parameters - stellar mass, half-light radius, UV slope, SFR, ellipticity, nearest neighbor distance, star formation surface density, specific SFR, [OIII] luminosity, and [OIII] equivalent width - reveals no statistically significant differences between the populations.
- ID:
- ivo://CDS.VizieR/J/AJ/143/31
- Title:
- Properties of fragile binary candidates in SDSS DR8
- Short Name:
- J/AJ/143/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 80 very wide fragile binary candidates (projected separations >10000AU) from the Sloan Digital Sky Survey Data Release Eight spectral archive. The pairs were selected based on proper motion, radial velocity, metallicity, and photometric parallax criteria. The angular separations of these pairs range from 3" to 250". The peak in the metallicity distribution of these pairs is about -0.5dex of solar metallicity. Space motions and reduced proper motion diagrams indicate that all these pairs are members of the disk. The chromospheric activity index S_HK_ of each component in 38 binary candidates having spectra of high signal-to-noise ratio and member stars of three open clusters (NGC 2420, M67, and NGC 6791) were measured. The S_HK_ versus color relation for these binary candidates is consistent with the trend seen in these open clusters. The ages implied by this relation suggest that fragile wide pairs can survive longer than 8Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/48
- Title:
- Properties of Galactic Be Supergiants. VI.
- Short Name:
- J/ApJ/897/48
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We report the results of long-term spectroscopic monitoring of the A-type supergiant with the B[e] phenomenon 3Pup=HD62623. We confirm earlier findings that it is a binary system. The orbital parameters were derived using cross-correlation of the spectra in a range of 4460-4632{AA}, which contains over 30 absorption lines. The orbit was found to be circular with a period of 137.4{+/-}0.1days, radial velocity semiamplitude K1=5.0{+/-}0.8km/s, systemic radial velocity {gamma}=26.4{+/-}2.0km/s, and mass function f(m)=(1.81_-0.76_^+0.97^)x10^-3^M{sun}. The object may have evolved from a pair with initial masses of ~6.0M{odot} and ~3.6M{sun} with an initial orbital period of ~5days. Based on the fundamental parameters of the A-supergiant (luminosity log L/L{sun}=4.1{+/-}0.1 and effective temperature Teff=8500{+/-}500K) and evolutionary tracks of mass-transferring binaries, we found current masses of the gainer M2=8.8{+/-}0.5M{sun} and donor M1=0.75{+/-}0.25M{sun}. We also modeled the object's IR-excess and derived a dust mass of ~5x10^-5^M{sun} in the optically thin dusty disk. The orbital parameters and properties of the H{alpha} line profile suggest that the circumstellar gaseous disk is predominantly circumbinary. The relatively low mass of the gainer led us to a suggestion that 3 Pup should be excluded from the B[e] supergiant group and moved to the FSCMa group. Overall these results further support our original suggestion that FSCMa objects are binary systems, where an earlier mass transfer caused formation of the circumstellar envelope.
- 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/AJ/155/44
- Title:
- Properties of PMS stars in young cluster Berkeley 59
- Short Name:
- J/AJ/155/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Berkeley 59 is a nearby (~1 kpc) young cluster associated with the Sh2-171 H II region. We present deep optical observations of the central ~2.5x2.5 pc^2^ area of the cluster, obtained with the 3.58 m Telescopio Nazionale Galileo. The V/(V-I) color-magnitude diagram manifests a clear pre-main-sequence (PMS) population down to ~0.2 M_{sun}_. Using the near-infrared and optical colors of the low-mass PMS members, we derive a global extinction of A_V_=4 mag and a mean age of ~1.8 Myr, respectively, for the cluster. We constructed the initial mass function and found that its global slopes in the mass ranges of 0.2-28 M_{sun}_ and 0.2-1.5 M_{sun}_ are -1.33 and -1.23, respectively, in good agreement with the Salpeter value in the solar neighborhood. We looked for the radial variation of the mass function and found that the slope is flatter in the inner region than in the outer region, indicating mass segregation. The dynamical status of the cluster suggests that the mass segregation is likely primordial. The age distribution of the PMS sources reveals that the younger sources appear to concentrate close to the inner region compared to the outer region of the cluster, a phenomenon possibly linked to the time evolution of star-forming clouds. Within the observed area, we derive a total mass of ~10^3^ M_{sun}_ for the cluster. Comparing the properties of Berkeley 59 with other young clusters, we suggest it resembles more closely the Trapezium cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/644
- Title:
- Properties of SDSS QSOs in the ChaMP
- Short Name:
- J/ApJ/690/644
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project. Our highest-confidence matched sample includes 1135 X-ray detected quasars in the redshift range 0.2<z<5.4, representing some 36Msec of effective exposure. We provide catalogs of QSO properties, and describe our novel method of calculating X-ray flux upper limits and effective sky coverage. Spectroscopic redshifts are available for about 1/3 of the detected sample; elsewhere, redshifts are estimated photometrically. We detect 56 QSOs with redshift z>3, substantially expanding the known sample. We find no evidence for evolution out to z~5 for either the X-ray photon index {Gamma} or for the ratio of optical/UV to X-ray flux {alpha}_ox_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/2848
- Title:
- Properties of 500 SNe and their 419 hosts
- Short Name:
- J/MNRAS/456/2848
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the impact of bars and bulges on the radial distributions of the different types of supernovae (SNe) in the stellar discs of host galaxies with various morphologies. We use a well-defined sample of 500 nearby (<=100Mpc) SNe and their low-inclined (i<=60deg) and morphologically non-disturbed S0-Sm host galaxies from the Sloan Digital Sky Survey. We find that in Sa-Sm galaxies, all core-collapse (CC) and vast majority of SNe Ia belong to the disc, rather than the bulge component. The radial distribution of SNe Ia in S0-S0/a galaxies is inconsistent with their distribution in Sa-Sm hosts, which is probably due to the contribution of the outer bulge SNe Ia in S0-S0/a galaxies. In Sa-Sbc galaxies, the radial distribution of CC SNe in barred hosts is inconsistent with that in unbarred ones, while the distributions of SNe Ia are not significantly different. At the same time, the radial distributions of both types of SNe in Sc-Sm galaxies are not affected by bars. We propose that the additional mechanism shaping the distributions of Type Ia and CC SNe can be explained within the framework of substantial suppression of massive star formation in the radial range swept by strong bars, particularly in early-type spirals. The radial distribution of CC SNe in unbarred Sa-Sbc galaxies is more centrally peaked and inconsistent with that in unbarred Sc-Sm hosts, while the distribution of SNe Ia in unbarred galaxies is not affected by host morphology. These results can be explained by the distinct distributions of massive stars in the discs of early- and late-type spirals.
- ID:
- ivo://CDS.VizieR/J/MNRAS/499/1424
- Title:
- Properties of 407 SNe and their 394 hosts
- Short Name:
- J/MNRAS/499/1424
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the light curve (LC) decline rates ({DELTA}m_15_) of 407 normal and peculiar supernovae (SNe) Ia and global parameters of their host galaxies. As previously known, there is a significant correlation between the {DELTA}m_15_ of normal SNe Ia and global ages (morphologies, colours, and masses) of their hosts. On average, those normal SNe Ia that are in galaxies from the Red Sequence (early-type, massive, old hosts) have faster declining LCs in comparison with those from the Blue Cloud (late-type, less massive, younger hosts) of the colour-mass diagram. The observed correlations between the {DELTA}m_15_ of normal SNe Ia and hosts' parameters appear to be due to the superposition of at least two distinct populations of faster and slower declining normal SNe Ia from older and younger stellar components. We show, for the first time, that the {DELTA}m_15_ of 91bg- and 91T-like SNe is independent of host morphology and colour. The distribution of hosts on the colour-mass diagram confirms the known tendency for 91bg-like SNe to occur in globally red/old galaxies, while 91T-like events prefer blue/younger hosts. On average, the youngest global ages of 02cx-like SNe hosts and their positions in the colour-mass diagram hint that these events likely originate from young population, but they differ from 91T-like events in the LC decline rate. Finally, we discuss the possible explosion channels and present our favoured SN Ia models that have the potential to explain the observed SN-host relations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/481/566
- Title:
- Properties of 333 SNe and their 269 hosts
- Short Name:
- J/MNRAS/481/566
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the impact of spiral density waves (DWs) on the radial and surface density distributions of supernovae (SNe) in host galaxies with different arm classes. We use a well-defined sample of 269 relatively nearby, low-inclination, morphologically non-disturbed and unbarred Sa-Sc galaxies from the Sloan Digital Sky Survey, hosting 333 SNe. Only for core-collapse (CC) SNe, a significant difference appears when comparing their R_25_-normalized radial distributions in long-armed grand-design (LGD) versus non-GD (NGD) hosts, with that in LGD galaxies being marginally inconsistent with an exponential profile, while SNe Ia exhibit exponential surface density profiles regardless of the arm class. Using a smaller sample of LGD galaxies with estimated corotation radii (R_C_), we show that the R_C_-normalized surface density distribution of CC SNe indicates a dip at corotation. Although not statistically significant, the high CC SNe surface density just inside and outside corotation may be the sign of triggered massive star formation by the DWs. Our results may, if confirmed with larger samples, support the large-scale shock scenario induced by spiral DWs in LGD galaxies, which predicts a higher star formation efficiency around the shock fronts, avoiding the corotation region.
