- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1390
- Title:
- Properties of 102 SNe and their 100 hosts
- Short Name:
- J/MNRAS/471/1390
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the height distributions of the different types of supernovae (SNe) from the plane of their host galaxies. We use a well-defined sample of 102 nearby SNe appearing inside high-inclined (i>=85{deg}), morphologically non-disturbed S0-Sd host galaxies from the Sloan Digital Sky Survey. For the first time, we show that in all the subsamples of spirals, the vertical distribution of core-collapse (CC) SNe is about twice closer to the plane of the host disc than the distribution of SNe Ia. In Sb-Sc hosts, the exponential scale height of CC SNe is consistent with those of the younger stellar population in the Milky Way (MW) thin disc, while the scale height of SNe Ia is consistent with those of the old population in the MW thick disc. We show that the ratio of scale lengths to scale heights of the distribution of CC SNe is consistent with those of the resolved young stars with ages from ~10 up to ~100Myr in nearby edge-on galaxies and the unresolved stellar population of extragalactic thin discs. The corresponding ratio for SNe Ia is consistent with the same ratios of the two populations of resolved stars with ages from a few 100Myr up to a few Gyr and from a few Gyr up to ~10Gyr, as well as with the unresolved population of the thick disc. These results can be explained considering the age-scale height relation of the distribution of stellar population and the mean age difference between Type Ia and CC SNe progenitors.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/490/718
- Title:
- Properties of 109 SNe and their 104 hosts
- Short Name:
- J/MNRAS/490/718
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the galactocentric distributions of the 'normal' and peculiar '91bg-like' subclasses of 109 supernovae (SNe) Ia, and study the global parameters of their elliptical hosts. The galactocentric distributions of the SN subclasses are consistent with each other and with the radial light distribution of host stellar populations, when excluding bias against central SNe. Among the global parameters, only the distributions of u - r colours and ages are inconsistent significantly between the ellipticals of different SN Ia subclasses: the normal SN hosts are on average bluer/younger than those of 91bg-like SNe. In the colour-mass diagram, the tail of colour distribution of normal SN hosts stretches into the Green Valley - transitional state of galaxy evolution, while the same tail of 91bg-like SN hosts barely reaches that region. Therefore, the bluer/younger ellipticals might have more residual star formation that gives rise to younger 'prompt' progenitors, resulting in normal SNe Ia with shorter delay times. The redder and older ellipticals that already exhausted their gas for star formation may produce significantly less normal SNe with shorter delay times, outnumbered by 'delayed' 91bg-like events. The host ages (lower age limit of the delay times) of 91bg-like SNe does not extend down to the stellar ages that produce significant u-band fluxes - the 91bg-like events have no prompt progenitors. Our results favour SN Ia progenitor models such as He-ignited violent mergers that have the potential to explain the observed SN/host properties.
- 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/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.
- ID:
- ivo://CDS.VizieR/J/AJ/155/183
- Title:
- Properties of variables in the NGC 1846 field
- Short Name:
- J/AJ/155/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Intermediate-age (IA) star clusters in the Large Magellanic Cloud (LMC) present extended main-sequence turn-offs (MSTO) that have been attributed to either multiple stellar populations or an effect of stellar rotation. Recently it has been proposed that these extended main sequences can also be produced by ill-characterized stellar variability. Here we present Gemini-S/Gemini Multi-Object Spectrometer (GMOS) time series observations of the IA cluster NGC 1846. Using differential image analysis, we identified 73 new variable stars, with 55 of those being of the Delta Scuti type, that is, pulsating variables close the MSTO for the cluster age. Considering completeness and background contamination effects, we estimate the number of {delta} Sct belonging to the cluster between 40 and 60 members, although this number is based on the detection of a single {delta} Sct within the cluster half-light radius. This amount of variable stars at the MSTO level will not produce significant broadening of the MSTO, albeit higher-resolution imaging will be needed to rule out variable stars as a major contributor to the extended MSTO phenomenon. Though modest, this amount of {delta} Sct makes NGC 1846 the star cluster with the highest number of these variables ever discovered. Lastly, our results present a cautionary tale about the adequacy of shallow variability surveys in the LMC (like OGLE) to derive properties of its {delta} Sct population.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A127
- Title:
- Properties of X-ray selected AGNs
- Short Name:
- J/A+A/525/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is mounting evidence that active galactic nuclei (AGN) selected through optical emission lines or radio luminosities comprise two distinct AGN populations, whose activity is triggered by different processes. In two previous papers, we studied the host galaxies and environment of radio-loud AGN. In this third paper we study the properties of a sample of Type-2 AGN that were selected on the basis of their [2-10]keV X-ray luminosity. We find that the X-ray luminosity function is in good agreement with previous studies and that the fraction of galaxies hosting an X-ray AGN is a strong function of the stellar mass of the host galaxy. The shape of this fraction-mass relation is similar to the fraction of galaxies that are emission-line AGN, while it differs significantly from the relation observed for radio-selected AGN. The AGN in our sample tend to be located in underdense environments where galaxy mergers and interactions are likely to occur. For all host galaxy masses, the Type-2 AGN display a strong infrared excess at short (~3.5um) wavelengths, suggesting the presence of hot dust possibly associated with a hot dusty torus. These results add weight to the belief that the X-ray selection criteria identifies a population of AGN similar to the emission-line selected population but distinct from the radio population at high masses.
- ID:
- ivo://CDS.VizieR/J/AJ/155/207
- Title:
- Properties of yellow supergiant stars in the SMC
- Short Name:
- J/AJ/155/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We recently discovered a yellow supergiant (YSG) in the Small Magellanic Cloud (SMC) with a heliocentric radial velocity of ~300 km/s, which is much larger than expected for a star at its location in the SMC. This is the first runaway YSG ever discovered and only the second evolved runaway star discovered in a galaxy other than the Milky Way. We classify the star as G5-8 I and use de-reddened broad-band colors with model atmospheres to determine an effective temperature of 4700+/-250 K, consistent with what is expected from its spectral type. The star's luminosity is then log L/L_{sun}_~4.2~0.1, consistent with it being a ~30 Myr 9 M_{sun}_ star according to the Geneva evolution models. The star is currently located in the outer portion of the SMC's body, but if the star's transverse peculiar velocity is similar to its peculiar radial velocity, in 10 Myr the star would have moved 1.6{deg} across the disk of the SMC and could easily have been born in one of the SMC's star-forming regions. Based on its large radial velocity, we suggest it originated in a binary system where the primary exploded as a supernovae, thus flinging the runaway star out into space. Such stars may provide an important mechanism for the dispersal of heavier elements in galaxies given the large percentage of massive stars that are runaways. In the future, we hope to look into additional evolved runaway stars that were discovered as part of our other past surveys.
2928. PSCz catalog
- ID:
- ivo://CDS.VizieR/VII/221
- Title:
- PSCz catalog
- Short Name:
- VII/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The PSCz survey consists of redshifts, infra-red and optical photometry, and assorted other information for 18351 IRAS sources, mostly selected from the Point Source Catalog. The survey was designed to select almost all galaxies with flux brighter than 0.595Jy at 60 microns, over the 84% of the sky with extinction small enough that reliable and complete optical identification and spectroscopy was possible. Some of the sources are not galaxies and some are multiple entries for the same galaxy as described below. There are in total 15411 galaxies or possible galaxies, for which redshifts are available for 14677. The galaxies without redshift are mostly distant or at low latitude, as described below. Many of these galaxies have now been observed as part of the BTP project (Saunders et al 1999, astro-ph/9909174 "The Behind the Plane Survey"), and their redshifts will be included in future revisions of the catalogue. The main catalogue is "pscz.dat". There is also a short version of the catalogue, "psczvs.dat", containing sufficient information for most studies. They correspond to the version 2.2.
- ID:
- ivo://CDS.VizieR/J/AJ/159/25
- Title:
- PS1 light curves and rotation periods of new asteroids
- Short Name:
- J/AJ/159/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intranight trajectories of asteroids can be approximated by straight lines, and so are their intranight detections. Therefore, the Hough transform, a line detecting algorithm, can be used to connect the line-up detections to find asteroids. We applied this algorithm to a high-cadence Pan-STARRS 1 (PS1) observation, which was originally designed to collect asteroid light curves for rotation period measurements. The algorithm recovered most of the known asteroids in the observing fields and, moreover, discovered 3574 new asteroids with magnitude mainly of 21.5<w_p1_<22.5mag. This magnitude range is equivalent to subkilometer main-belt asteroids (MBAs), which usually lack rotation period measurements due to their faintness. Using the light curves of the 3574 new asteroids, we obtained 122 reliable rotation periods, of which 13 are super-fast rotators (SRFs; i.e., rotation period of <2hr). The required cohesion to survive these SFRs range from tens to thousands of Pa, a value consistent with the known SFRs and the regolith on the Moon and Mars. The higher chance of discovering SFRs here suggests that subkilometer MBAs probably harbor more SFRs.
- ID:
- ivo://CDS.VizieR/J/AJ/162/21
- Title:
- PS1 photometry of 2863 ICRF3 quasars
- Short Name:
- J/AJ/162/21
- Date:
- 14 Mar 2022 06:53:33
- Publisher:
- CDS
- Description:
- We make use of individual (epoch) detection data from the Pan-STARRS "3{pi}" survey for 2863 optical ICRF3 counterparts in the five wavelength bands g, r, i, z, and y, published as part of the Data Release 2. A dedicated method based on the Functional Principal Component Analysis is developed for these sparse and irregularly sampled data. With certain regularization and normalization constraints, it allows us to obtain uniform and compatible estimates of the variability amplitudes and average magnitudes between the passbands and objects. We find that the starting assumption of affinity of the light curves for a given object at different wavelengths is violated for several percent of the sample. The distributions of rms variability amplitudes are strongly skewed toward small values, peaking at ~0.1mag with tails stretching to 2mag. Statistically, the lowest variability is found for the r band and the largest for the reddest y band. A small "brighter-redder" effect is present, with amplitudes in y greater than amplitudes in g in 57% of the sample. The variability versus redshift dependence shows a strong decline with z toward redshift 3, which we interpret as the time dilation of the dominant time frequencies. The colors of radio-loud ICRF3 quasars are correlated with redshift in a complicated, wavy pattern governed by the emergence of brightest emission lines within the five passbands.
