- ID:
- ivo://CDS.VizieR/J/AJ/134/1890
- Title:
- Secondary standard stars in u'g'r'i'z'
- Short Name:
- J/AJ/134/1890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of secondary standard stars for the u'g'r'i'z' photometric system that has been established in selected open and globular star clusters. These standards are calibrated to the original standard system defined by Smith et al. with an accuracy of 1% or better, extend as faint as r'~20, and are concentrated in small regions of the sky. As a result, they can serve as viable calibrators of photometry obtained on some of the large-aperture, high-demand telescopes that employ the u'g'r'i'z' filter set.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/139/1438
- Title:
- SED and age estimates of 104 M31 globular clusters
- Short Name:
- J/AJ/139/1438
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of 104 M31 globular clusters (GCs) and GC candidates in 15 intermediate-band filters of the Beijing-Arizona-Taiwan-Connecticut photometric system. The GCs and GC candidates were selected from the Revised Bologna Catalog (v.3.5). We obtain the cluster ages by comparing the photometric data with up-to-date theoretical synthesis models. The photometric data used are Galaxy Evolution Explorer far- and near-ultraviolet and Two Micron All Sky Survey near-infrared JHKs magnitudes, combined with optical photometry. The ages of our sample clusters cover a large range, although most clusters are younger than 10Gyr. Combined with the ages obtained in our series of previous papers focusing on the M31 GC system, we present the full M31 GC age distribution.
- ID:
- ivo://CDS.VizieR/J/AJ/141/89
- Title:
- SEGUE stellar parameter pipeline. IV.
- Short Name:
- J/AJ/141/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic and photometric data for likely member stars of five Galactic globular clusters (M3, M53, M71, M92, and NGC 5053) and three open clusters (M35, NGC 2158, and NGC 6791) are processed by the current version of the SEGUE Stellar Parameter Pipeline (SSPP), in order to determine estimates of metallicities and radial velocities (RVs) for the clusters. These results are then compared to values from the literature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/1966
- Title:
- Segue 3 VI photometry
- Short Name:
- J/MNRAS/433/1966
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep Galileo (Telescopio Nazionale Galileo) B, V and I images of Segue 3, reaching V~25, reveal that it is the youngest globular cluster known so far in the Galaxy. A young age of 3.2Gyr is found, differently from a previous estimate of 12Gyr. It also appears to be moderately metal rich with [Fe/H]~-0.8, rather than [Fe/H]~-1.7, as previously suggested by Fadely et al. (2011AJ....142...88F, Cat. J/AJ/142/88). A main difference in the age derivation relative to Fadely et al. comes from the consideration of subgiant branch stars in the isochrone fitting. A deduced distance of d_{sun}_=29.1kpc is compatible with the outer halo location of other low luminosity globular clusters.
- ID:
- ivo://CDS.VizieR/J/A+AS/112/367
- Title:
- Selected Regions C and E in the LMC
- Short Name:
- J/A+AS/112/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD data of objects in the LMC selected regions C and E. These data include the young globular cluster NGC 1818, the association NGC 1948 and the intermediate age cluster NGC 1978. We discuss the calibration of the data and provide complete tables of the photometry and astrometry of all stars within our field of view.
- ID:
- ivo://CDS.VizieR/J/A+A/462/107
- Title:
- Simulations of metal-poor star clusters
- Short Name:
- J/A+A/462/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intrinsic uncertainty (due to statistical effects) affecting the integrated colours and mass-to-light ratios as a function of the cluster's integrated visual magnitude (M_V^tot^_) is studied. We investigate the case of metal-poor, single-burst stellar populations with age from a few million years to a likely upper value for the Galactic globular cluster ages. Monte Carlo techniques are used for randomly generating stars distributed according to the cluster's mass function. Integrated colours and mass-to-light ratios in different photometric bands are presented as a function of age for different assumptions on the cluster total V magnitude and they are checked for good agreement with the observational values of low-metallicity Galactic clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/2625
- Title:
- SLUGGS Globular Cluster CaT and [Z/H]
- Short Name:
- J/MNRAS/451/2625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The outer halo regions of early-type galaxies carry key information about their past accretion history. However, spectroscopically probing the stellar component at such galactocentric radii is still challenging. Using the DEep Imaging Multi-Object Spectrograph on the Keck, we have been able to measure the metallicities of the stellar and globular cluster components in 12 early-type galaxies out to more than 10Re.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/389
- Title:
- SLUGGS globular clusters in early-type galaxies
- Short Name:
- J/MNRAS/428/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectrophotometric survey of 2522 extragalactic globular clusters (GCs) around 12 early-type galaxies, nine of which have not been published previously. Combining space-based and multicolour wide-field ground-based imaging, with spectra from the Keck/DEep Imaging Multi-Object Spectrograph (DEIMOS) instrument, we obtain an average of 160 GC radial velocities per galaxy, with a high-velocity precision of ~15km/s per GC. After studying the photometric properties of the GC systems, such as their spatial and colour distributions, we focus on the kinematics of metal-poor (blue) and metal-rich (red) GC subpopulations to an average distance of ~8 effective radii from the galaxy centre.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/105
- Title:
- SLUGGS NGC 3607 and 3608 globular clusters
- Short Name:
- J/MNRAS/458/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an investigation of the globular cluster (GC) systems of NGC 3607 and NGC 3608 as part of the ongoing SLUGGS (SAGES Legacy Unifying Globulars and GalaxieS) survey. We use wide-field imaging data from the Subaru telescope in the g, r and i filters to analyse the radial density, colour and azimuthal distributions of both GC systems. With the complementary kinematic data obtained from the Keck II telescope, we measure the radial velocities of a total of 81 GCs. Our results show that the GC systems of NGC 3607 and NGC 3608 have a detectable spatial extent of ~15 and 13 galaxy effective radii, respectively. Both GC systems show a clear bimodal colour distribution. We detect a significant radial colour gradient for the GC subpopulations in both galaxies. NGC 3607 exhibits an overabundance of red GCs on the galaxy minor axis and NGC 3608 shows a misalignment in the GC subpopulation position angles with respect to the galaxy stellar component. With the aid of literature data, we discuss several relationships between the properties of GC systems and their host galaxies. A one-to-one relation between the ellipticities of red GCs and the galaxy stellar light emphasizes the evolutionary similarities between them. In our sample of four slowly rotating galaxies with kinematically decoupled cores, we observe a higher ellipticity for the blue GC subpopulation than their red counterparts. Also, we notice the flattening of negative colour gradients for the blue GC subpopulations with increasing galaxy stellar mass. Finally, we discuss the formation scenarios associated with the blue GC subpopulation.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A11
- Title:
- SMC BV photometry of 9 star cluster fields
- Short Name:
- J/A+A/591/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution and structure of the Magellanic Clouds is currently under debate. The classical scenario in which both the Large and Small Magellanic Clouds (LMC, SMC) are orbiting the Milky Way has been challenged by an alternative in which the LMC and SMC are in their first close passage to our Galaxy. The clouds are close enough to us to allow spatially resolved observation of their stars, and detailed studies of stellar populations in the galaxies are expected to be able to constrain the proposed scenarios. In particular, the west halo (WH) of the SMC was recently characterized with radial trends in age and metallicity that indicate tidal disruption. We intend to increase the sample of star clusters in the west halo of the SMC with homogeneous age, metallicity, and distance derivations to allow a better determination of age and metallicity gradients in this region. Distances and positions are compared with the orbital plane of the SMC depending on the scenario adopted. Comparisons of observed and synthetic V(B-V) colour-magnitude diagrams were used to derive age, metallicity, distance, and reddening for star clusters in the SMC west halo. Observations were carried out using the 4.1m SOAR telescope. Photometric completeness was determined through artificial star tests, and the members were selected by statistical comparison with a control field. We derived an age of 1.23+/-0.07Gyr and [Fe/H]=-0.87+/-0.07 for the reference cluster NGC 152, compatible with literature parameters. Age and metallicity gradients are confirmed in the WH: 2.6+/-0.6Gyr/{deg} and -0.19+/-0.09dex/{deg}, respectively. The age-metallicity relation for the WH has a low dispersion in metallicity and is compatible with a burst model of chemical enrichment. All WH clusters seem to follow the same stellar distribution predicted by dynamical models, with the exception of AM-3, which should belong to the counter-bridge. Bruck 6 is the youngest cluster in our sample. It is only 130+/-40Myr old and may have been formed during the tidal interaction of SMC-LMC that created the WH and the Magellanic bridge. We suggest that it is crucial to split the SMC cluster population into groups: main body, wing and bridge, counter-bridge, and WH. This is the way to analyse the complex star formation and dynamical history of our neighbour. In particular, we show that the WH has clear age and metallicity gradients and an age-metallicity relation that is also compatible with the dynamical model that claims a tidal influence of the LMC on the SMC.
