- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/869/106
- Title:
- SMARTS & Euler R-band monitoring of WFI J2033-4723
- Short Name:
- J/ApJ/869/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 13 seasons of R-band photometry of the quadruply lensed quasar WFI J2033-4723 from the 1.3m SMARTS telescope at CTIO and the 1.2m Euler Swiss Telescope at La Silla, in which we detect microlensing variability of ~0.2mag on a timescale of ~6yrs. Using a Bayesian Monte Carlo technique, we analyze the microlensing signal to obtain a measurement of the size of this system's accretion disk of log(r_s_/cm)=15.86_-0.27_^+0.25^ at {lambda}_rest_=2481{AA}, assuming a 60{deg} inclination angle. We confirm previous measurements of the BC and AB time delays, and we obtain a tentative measurement of the delay between the closely spaced A1 and A2 images of {Delta}t_A1A2_=t_A1_-t_A2_=-3.9_-2.2_^+3.4^d. We conclude with an update to the Quasar Accretion Disk Size-Black Hole Mass Relation, in which we confirm that the accretion disk size predictions from simple thin disk theory are too small.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A31
- Title:
- SMC blob N26 multiband photometry
- Short Name:
- J/A+A/564/A31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-excitation compact HII regions of the Magellanic Clouds are sites of recent massive star formation in low metallicity environments. Detailed study of these regions and their environments using high-spatial resolution observations is necessary to better understand massive star formation, which is still an unsolved problem. We aim at a detailed study of the Small Magellanic Cloud compact HII region N26, which is only ~4" in diameter. This study is based on high spatial resolution imaging (~0.1"-0.3") in JHKs and L' bands, using the VLT equipped with the NAOS adaptive optics system. A larger region (~50pcx76pc) was also imaged at medium spatial resolution, using the ESO 2.2m telescope in optical wavelengths. We also used the JHKs archival data from the IRSF survey and the Spitzer Space Telescope SAGE-SMC survey.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/893/67
- Title:
- Smoothed amplitudes from Kepler, K2 and TESS phot.
- Short Name:
- J/ApJ/893/67
- Date:
- 03 Dec 2021 00:35:27
- Publisher:
- CDS
- Description:
- We investigate starspot distributions consistent with space-based photometry of F, G, and K stars in six stellar associations ranging in age from 10Myr to 4Gyr. We show that a simple light-curve statistic called the "smoothed amplitude" is proportional to stellar age as t^-1/2^, following a Skumanich-like spin-down relation. We marginalize over the unknown stellar inclinations by forward modeling the ensemble of light curves for direct comparison with the Kepler, K2, and TESS photometry. We sample the posterior distributions for spot coverage with approximate Bayesian computation. We find typical spot coverages in the range 1%-10%, which decrease with increasing stellar age. The spot coverage is proportional to t^n^ where n=-0.37+/-0.16, also statistically consistent with a Skumanich-like t^-1/2^ decay of starspot coverage with age. We apply two techniques to estimate the spot coverage of young exoplanet-hosting stars likely to be targeted for transmission spectroscopy with the James Webb Space Telescope, and estimate the bias in exoplanet radius measurements due to varying starspot coverage.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/1
- Title:
- SMUDGes. I. First results in the Coma Cluster
- Short Name:
- J/ApJS/240/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a homogeneous catalog of 275 large (effective radius >~5.3") ultra-diffuse galaxy (UDG) candidates lying within an ~290deg^2^ region surrounding the Coma Cluster. The catalog results from our automated postprocessing of data from the Legacy Surveys, a three-band imaging survey covering 14000deg^2^ of the extragalactic sky. We describe a pipeline that identifies UDGs and provides their basic parameters. The survey is as complete in these large UDGs as previously published UDG surveys of the central region of the Coma Cluster. We conclude that the majority of our detections are at roughly the distance of the Coma Cluster, implying effective radii >=2.5kpc, and that our sample contains a significant number of analogs of DF44 (SMDG1300580+265835), where the effective radius exceeds 4kpc, both within the cluster and in the surrounding field. The g-z color of our UDGs spans a large range, suggesting that even large UDGs may reflect a range of formation histories. A majority of the UDGs are consistent with being lower stellar mass analogs of red sequence galaxies, but we find both red and blue UDG candidates in the vicinity of the Coma Cluster and a relative overabundance of blue UDG candidates in the lower-density environments and the field. Our eventual processing of the full Legacy Surveys data will produce the largest, most homogeneous sample of large UDGs.
- ID:
- ivo://CDS.VizieR/J/other/PZ/29.2
- Title:
- SN 2008ax UBVRI light curves
- Short Name:
- J/other/PZ/29.2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD UBVRI photometry covering about 320 days is presented for the type IIb SN 2008ax. Its photometric behavior is typical of core-collapse SNe with low amount of hydrogen. The main photometric parameters are derived and a comparison with SNe of similar types is reported. Preliminary modeling is carried out, and the results are compared to the observed light curves. The main parameters of the hydrodynamical models are close to those used for SN IIb 1993J.
3328. SN 2020bqj ligth curves
- ID:
- ivo://CDS.VizieR/J/A+A/652/A136
- Title:
- SN 2020bqj ligth curves
- Short Name:
- J/A+A/652/A136
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Type Ibn supernovae are a rare class of stripped envelope supernovae interacting with a helium-rich CSM. The majority of the SNe Ibn reported display a surprising homogeneity in their fast lightcurves and starforming hosts. We present the discovery and study of SN 2020bqj (ZTF20aalrqbu), a SN Ibn with a long-duration peak plateau lasting 40 days and hosted by a faint low-mass galaxy. We aim to explain its peculiar properties using an extensive data set. We compare the evolution of SN 2020bqj with SNe Ibn from the literature. We fit the bolometric and multi-band lightcurves with different powering mechanism models. The risetime, peak magnitude and spectral features of SN 2020bqj are consistent with those of most SNe Ibn, but the SN is a clear outlier based on its bright, long-lasting peak plateau and low host mass. We show through modeling that the lightcurve can be powered predominantly by shock heating from the interaction of the SN ejecta and a dense CSM. The peculiar Type Ibn SN 2011hw is a close analog to SN 2020bqj, suggesting a similar progenitor and CSM scenario. In this scenario a very massive progenitor star in the transitional phase between a luminous blue variable and a compact Wolf-Rayet star undergoes core-collapse, embedded in a dense helium-rich CSM with an elevated opacity compared to normal SNe Ibn, due to the presence of residual hydrogen. This scenario is consistent with the observed properties of SN 2020bqj and the modeling results. SN 2020bqj is a compelling example of a transitional SN Ibn/IIn based on not only its spectral features, but also its lightcurve, host galaxy properties and the inferred progenitor properties. The strong similarity with SN 2011hw suggests this subclass may be the result of a progenitor in a stellar evolution phase that is distinct from those of progenitors of regular SNe Ibn.
- ID:
- ivo://CDS.VizieR/J/ApJ/908/232
- Title:
- SN 2020bvc optical and near-IR spectra
- Short Name:
- J/ApJ/908/232
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present near-IR (NIR) and optical observations of the Type Ic supernova (SN Ic) SN 2020oi in the galaxy M100 and the broad-lined SN Ic SN 2020bvc in UGC 9379, using Gemini, Las Cumbres Observatory, Southern Astrophysical Telescope, and other ground-based telescopes. The NIR spectrum of SN 2020oi at day 63 since the explosion shows strong CO emissions and a rising K-band continuum, which is the first unambiguous dust detection from an SN Ic. Non-LTE CO modeling shows that CO is still optically thick and that the lower limit to the CO mass is 10^-3^M_{sun}_. The dust temperature is 810 K, and the dust mass is ~10^-5^M_{sun}_. We explore the possibilities that the dust is freshly formed in the ejecta, heated dust in the preexisting circumstellar medium, and an infrared echo. The light curves of SN 2020oi are consistent with a STELLA model with canonical explosion energy, 0.07M_{sun}_ Ni mass, and 0.7M_{sun}_ ejecta mass. A model of high explosion energy of 10^52^erg, 0.4M_{sun}_ Ni mass, and 6.5M_{sun}_ ejecta mass with the circumstellar matter reproduces the double-peaked light curves of SN 2020bvc. We observe temporal changes of absorption features of the IR CaII triplet, SI at 1.043{mu}m, and FeII at 5169{AA}. The blueshifted lines indicate high velocities, up to 60000km/s for SN 2020bvc and 20000km/s for SN 2020oi, and the expansion velocity rapidly declines before the optical maximum. We present modeled spectral signatures and diagnostics of CO and SiO molecular bands between 1.4 and 10{mu}m.
- ID:
- ivo://CDS.VizieR/J/MNRAS/394/2266
- Title:
- SN 2005cs one-year photometry
- Short Name:
- J/MNRAS/394/2266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the one-year long observational campaign of the type II plateau SN 2005cs, which exploded in the nearby spiral galaxy M51 (the Whirlpool galaxy). This extensive data set makes SN 2005cs the best observed low-luminosity, ^56^Ni-poor type II plateau event so far and one of the best core-collapse supernovae ever.
