- ID:
- ivo://CDS.VizieR/J/A+A/634/A37
- Title:
- TURTLS Light curves of ^56^Ni distributions
- Short Name:
- J/A+A/634/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have shown how the distribution of ^56^Ni within the ejected material of type Ia supernovae can have profound consequences on the observed light curves. Observations at early times can therefore provide important details on the explosion physics in thermonuclear supernovae, which are poorly constrained. To this end, we present a series of radiative transfer calculations that explore variations in the ^56^Ni distribution. Our models also show the importance of the density profile in shaping the light curve, which is often neglected in the literature. Using our model set, we investigate the observations that are necessary to determine the 56Ni distribution as robustly as possible within the current model set. Additionally, we find that this includes observations beginning at least 14 days before B-band maximum, extending to approximately maximum light with a relatively high (<~3 day) cadence, and in at least one blue and one red band are required (such as B and R, or g and r). We compare a number of well-observed type Ia supernovae that meet these criteria to our models and find that the light curves of 70-80% of objects in our sample are consistent with being produced solely by variations in the ^56^Ni distributions. The remaining supernovae show an excess of flux at early times, indicating missing physics that is not accounted for within our model set, such as an interaction or the presence of short-lived radioactive isotopes. Comparing our model light curves and spectra to observations and delayed detonation models demonstrates that while a somewhat extended ^56^Ni distribution is necessary to reproduce the observed light curve shape, this does not negatively affect the spectra at maximum light. Investigating current explosion models shows that observations typically require a shallower decrease in the ^56^Ni mass towards the outer ejecta than is produced for models of a given ^56^Ni mass. Future models that test differences in the explosion physics and detonation criteria should be explored to determine the conditions necessary to reproduce the 56Ni distributions found here.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/589/A94
- Title:
- TU UMa light curves and maxima, CL Aur minima
- Short Name:
- J/A+A/589/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent statistical studies prove that the percentage of RR Lyrae pulsators that are located in binaries or multiple stellar systems is considerably lower than might be expected. This can be better understood from an in-depth analysis of individual candidates. We investigate in detail the light time effect of the most probable binary candidate TU UMa. This is complicated because the pulsation period shows secular variation. We model possible light time effect of TU UMa using a new code applied on previously available and newly determined maxima timings to confirm binarity and refine parameters of the orbit of the RRab component in the binary system. The binary hypothesis is also tested using radial velocity measurements. We used new approach to determine brightness maxima timings based on template fitting. This can also be used on sparse or scattered data. This approach was successfully applied on measurements from different sources. To determine the orbital parameters of the double star TU UMa, we developed a new code to analyse light time effect that also includes secular variation in the pulsation period. Its usability was successfully tested on CL Aur, an eclipsing binary with mass-transfer in a triple system that shows similar changes in the O-C diagram. Since orbital motion would cause systematic shifts in mean radial velocities (dominated by pulsations), we computed and compared our model with centre-of-mass velocities. They were determined using high-quality templates of radial velocity curves of RRab stars. Maxima timings adopted from the GEOS database (168) together with those newly determined from sky surveys and new measurements (85) were used to construct an O-C diagram spanning almost five proposed orbital cycles. This data set is three times larger than data sets used by previous authors. Modelling of the O-C dependence resulted in 23.3-year orbital period, which translates into a minimum mass of the second component of about 0.33Ms. Secular changes in the pulsation period of TU UMa over the whole O-C diagram were satisfactorily approximated by a parabolic trend with a rate of -2.2ms/yr. To confirm binarity, we used radial velocity measurements from nine independent sources. Although our results are convincing, additional long-term monitoring is necessary to unambiguously confirm the binarity of TU UMa.
19543. TV Boo V light curve
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/1442
- Title:
- TV Boo V light curve
- Short Name:
- J/MNRAS/428/1442
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study investigates periodic modulation of the light curve of the RRc star TV Boo and its physical parameters based on photometric data. This phenomenon, known as the Blazhko effect, is quite rare among RRc stars. The frequency analysis based on the data gathered at the Masaryk University Observatory (MUO) and also using SuperWASP data revealed symmetrically structured peaks around the main pulsation frequency and its harmonics, which indicate two modulation components of the Blazhko period. The main modulation periodicity was found to be 9.7374+/-0.0054d. This is one of the shortest known Blazhko periods among RRc stars. The second modulation period (21.5+/-0.2d) causes changes of the Blazhko effect itself. Some indices show that TV Boo could be affected by long-term changes of the order of years. Basic physical parameters were estimated via an MUO V light-curve solution using Fourier parameters. TV Boo seems to be a low-metallicity star with [Fe/H]=-1.89.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A49
- Title:
- TW Hya CO (2-1), CN (2-1) and CS (5-4) data cubes
- Short Name:
- J/A+A/592/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to obtain a spatially resolved measurement of velocity dispersions in the disk of TW Hya. We obtained images with high spatial and spectral resolution of the CO J=2-1, CN N=2-1 and CS J=5-4 emission with ALMA in Cycle 2. The radial distribution of the turbulent broadening was derived with two direct methods and one modelling approach. The first method requires a single transition and derives T_ex_ directly from the line profile, yielding a v_turb_. The second method assumes that two different molecules are co-spatial, which allows using their relative line widths for calculating T_kin_ and v_turb_. Finally we fitted a parametric disk model in which the physical properties of the disk are described by power laws, to compare our direct methods with previous values.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A46
- Title:
- TW Hydrae association with X-shooter
- Short Name:
- J/A+A/632/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of the protoplanetary disk frequency in young star clusters of different ages indicate disk lifetimes <10Myr. However, our current knowledge of how mass accretion in young stars evolves over the lifespans of disks is subject to many uncertainties, especially at the lower stellar masses. In this study, we investigate ongoing accretion activity in the TW Hydrae association (TWA), the closest association of pre-main sequence stars with active disks. The age (8-10Myr) and the proximity of the TWA render it an ideal target to probe the final stages of disk accretion down to brown dwarf masses. The study is based on homogeneous spectroscopic data from 300nm to 2500nm, obtained synoptically with X-shooter, which allows simultaneous derivation of individual extinction, stellar parameters, and accretion parameters for each star. The continuum excess emission diagnostics is used to estimate the accretion luminosities and mass accretion rates of our disk-bearing targets, and the shape and intensity of permitted and forbidden emission lines are analyzed to probe the physics of the star-disk interaction environment.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/4073
- Title:
- Two catalogues of superclusters
- Short Name:
- J/MNRAS/445/4073
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two new catalogues of superclusters of galaxies out to a redshift of z=0.15, based on the Abell/ACO cluster redshift compilation maintained by one of us (HA). The first of these catalogues, the all-sky Main SuperCluster Catalogue (MSCC), is based on only the rich (A-) Abell clusters, and the second one, the Southern SuperCluster Catalogue (SSCC), covers declinations {delta}<-17{deg} and includes the supplementary Abell S-clusters. A tunable Friends-of-Friends algorithm was used to account for the cluster density decreasing with redshift and for different selection functions in distinct areas of the sky. We present the full list of Abell clusters used, together with their redshifts and supercluster memberships and including the isolated clusters. The SSCC contains about twice the number of superclusters than MSCC for {delta}<-17{deg}, which we found to be due to (1) new superclusters formed by A-clusters in their cores and surrounded by S-clusters (50%), (2) new superclusters formed by S-clusters only (40%), (3) redistribution of member clusters by fragmentation of rich (multiplicity m>15) superclusters (8%), and (4) new superclusters formed by the connection of A-clusters through bridges of S-clusters (2%). Power-law fits to the cumulative supercluster multiplicity function yield slopes of {alpha}=-2.0 and {alpha}=-1.9 for MSCC and SSCC, respectively. This power-law behaviour is in agreement with the findings for other observational samples of superclusters, but not with that of catalogues based on cosmological simulations.
- ID:
- ivo://CDS.VizieR/J/ApJ/851/L27
- Title:
- Two dips in the LC of 3XMMJ004232.1+411314
- Short Name:
- J/ApJ/851/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed a search for eclipsing and dipping sources in the archive of the EXTraS project-a systematic characterization of the temporal behavior of XMM-Newton point sources. We discovered dips in the X-ray light curve of 3XMM J004232.1+411314, which has been recently associated with the hard X-ray source dominating the emission of M31. A systematic analysis of XMM-Newton observations revealed 13 dips in 40 observations (total exposure time of ~0.8Ms). Among them, four observations show two dips, separated by ~4.01hr. Dip depths and durations are variable. The dips occur only during low-luminosity states (L_0.2-12_<1x10^38^erg/s), while the source reaches L_0.2-12_~2.8x10^38^erg/s. We propose that this system is a new dipping low-mass X-ray binary in M31 seen at high inclination (60{deg}-80{deg}); the observed dipping periodicity is the orbital period of the system. A blue HST source within the Chandra error circle is the most likely optical counterpart of the accretion disk. The high luminosity of the system makes it the most luminous (not ULX) dipper known to date.
- ID:
- ivo://CDS.VizieR/J/MNRAS/339/913
- Title:
- Two distant massive clusters of galaxies
- Short Name:
- J/MNRAS/339/913
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the radio, optical, and X-ray properties of two newly discovered, very X-ray luminous, distant clusters of galaxies. Both systems were noted as cluster candidates in a cross-correlation of data from the WENSS (<VIII/162>) radio survey and the ROSAT All-Sky Survey (<IX/10>). Follow-up observations performed by us and the Massive Cluster Survey (MACS) team confirmed both sources as distant galaxy clusters. The first cluster, MACS J0717.5+3745 at a redshift of z=0.5548, contains a very extended, steep-spectrum radio source offset from the cluster core, making it the most distant radio relic known. The second cluster, MACS J1621.3+3810 at z=0.465, is a strong cooling flow with a relatively weak central radio source. We present results from ROSAT High-Resolution Imager (HRI, Cat. <IX/28>) observations of both clusters as well as from optical imaging and VLA radio interferometry observations. Our discoveries demonstrate that distant clusters can be efficiently identified in a relatively shallow X-ray survey, that radio/X-ray selection is efficient, and that both cooling flow and non-cooling flow clusters are selected.
- ID:
- ivo://CDS.VizieR/II/108
- Title:
- Two-Micron Sky Survey, Nearest SAO Stars on POSS
- Short Name:
- II/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog is a list of potential guide stars developed for a program to obtain more precise positions of objects in the IRC Two-Micron Sky Survey of Neguebauer and Leighton (1969). For each IRC source (col. 1), it gives: (col. 2) the identification of the star in the SAO catalog which is nearest, (col. 3) the great circle arc distance (in seconds) between the SAO star and the IRC source, (col. 4) the position angle (in degrees) of the IRC source relative to the SAO star, (col. 5) the plate number(s) of the POSS on which the IRC source appears, (col. 6,7) the approximate rectangular coordinates (in mm) of the IRC source on the POSS print area with respect to the Southwest corner, and (col. 8) the modified Luyten Palomar number. The POSS plate numbers given are for the red plates.
19550. Two-Micron Sky Survey (TMSS)
- ID:
- ivo://CDS.VizieR/II/2B
- Title:
- Two-Micron Sky Survey (TMSS)
- Short Name:
- II/2B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog, giving sources of emission in the 2.2-micrometer region for more than 5000 stars, represents a systematic survey of the Northern Hemisphere for stars brighter than third magnitude. The survey was carried out with a telescope at Mount Wilson, California, having a 62-inch diameter and an f/l aluminized epoxy mirror mounted equatorially. Radiation at an effective wavelength of 2.2 micrometers was detected by a lead sulfide photoconductive cell cooled by liquid nitrogen. In addition to the 2.2-micrometer detector array, radiation at an effective wavelength of 0.84 micrometers was detected by a simple silicon photovoltaic cell. The catalog includes right ascension and declination (B1950.0), K and I magnitudes, number of measurements, V magnitude, spectral types, cross identifications to the numbering systems of the General Catalogue, the Durchmusterung catalogs, the Bright Star Catalogue, and star names.