Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSupernovae and their host galaxies -- VI. Normal Type Ia and 91bg-like supernovae in ellipticals
172
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
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 favor SN Ia progenitor models such as He-ignited violent mergers that have the potential to explain the observed SN/host properties.
rate research
Read More
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, 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.
We compare the host galaxies of 902 supernovae, including SNe Ia, SNe II and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the SDSS Data Release 7. We further selected 213 galaxies by requiring the light fraction of spectral observations $>$15%, which could represent well the global properties of the galaxies. Among them, 135 galaxies appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of star-forming, AGNs (including composites, LINERs and Seyfert 2s) and Absorp (their related emission-lines are weak or non-existence) galaxies. The diagrams related to parameters D$_n$(4000), H$delta_A$, stellar masses, SFRs and specific SFRs for the SNe hosts show that almost all SNe II and most of SNe Ibc occur in SF galaxies, which have a wide range of stellar mass and low D$_n$(4000). The SNe Ia hosts as SF galaxies follow similar trends. A significant fraction of SNe Ia occurs in AGNs and Absorp galaxies, which are massive and have high D$_n$(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased towards higher 12+log(O/H) ($sim$0.1dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.
Using a sample of nearby spiral galaxies hosting 185 supernovae (SNe) Ia, we perform a comparative analysis of the locations and light curve decline rates $(Delta m_{15})$ of normal and peculiar SNe Ia in the star formation deserts (SFDs) and beyond. To accomplish this, we present a simple visual classification approach based on the UV/H$alpha$ images of the discs of host galaxies. We demonstrate that, from the perspective of the dynamical timescale of the SFD, where the star formation (SF) is suppressed by the bar evolution, the $Delta m_{15}$ of SN Ia and progenitor age can be related. The SFD phenomenon gives an excellent possibility to separate a subpopulation of SN Ia progenitors with the ages older than a few Gyr. We show, for the first time, that the SFDs contain mostly faster declining SNe Ia $(Delta m_{15} > 1.25)$. For the galaxies without SFDs, the region within the bar radius, and outer disc contain mostly slower declining SNe Ia. To better constrain the delay times of SNe Ia, we encourage new studies (e.g. integral field observations) using the SFD phenomenon on larger and more robust datasets of SNe Ia and their host galaxies.
Recent studies find that some early-type galaxies host Type II or Ibc supernovae (SNe II, Ibc). This may imply recent star-formation activities in these SNe host galaxies, but a massive star origin of the SNe Ib so far observed in early-type galaxies has been questioned because of their intrinsic faintness and unusually strong Ca lines shown in the nebular phase. To address the issue, we investigate the properties of early-type SNe host galaxies using the data with Galaxy Evolution Explore(GALEX) ultraviolet photometry, and the Sloan Digital Sky Survey (SDSS) optical data. Our sample includes eight SNe II and one peculiar SN Ib (SN 2000ds) host galaxies as well as 32 SN Ia host galaxies. The host galaxy of SN 2005cz, another peculiar SN Ib, is also analysed using the GALEX data and the NASA/IPAC Extragalactic Database (NED) optical data. We find that the NUV-optical colors of SN II/Ib host galaxies are systematically bluer than those of SN Ia host galaxies, and some SN II/Ib host galaxies with NUV-r colors markedly bluer than the others exhibit strong radio emission. We perform a stellar population synthesis analysis and find a clear signature of recent star-formation activities in most of the SN II/Ib host galaxies. Our results generally support the association of the SNe II/Ib hosted in early-type galaxies with core-collapse of massive stars. We briefly discuss implications for the progenitors of the peculiar SNe Ib 2000ds and 2005cz.
The sample of 137 low-redshift type Ia supernovae with 0.05 < z < 0.3 obtained from the SDSS-II Supernova Survey for the southern equatorial stripe of 300 square degrees is used to derive the luminosity functions of type Ia supernovae and of their host galaxies in the gri passbands. We show that the luminosity function of type Ia supernova host galaxies matches well with that of galaxies in the general field, suggesting that the occurrence of type Ia supernovae does not favour a particular type of galaxies but is predominantly proportional to the luminosity of galaxies. The only evidence that points to possible correlation between the supernova rate and star formation activity is that the supernova rate in late-type galaxies is higher than that in early-type galaxies by 31+/-35%. The sample contains 8 type Ia supernovae whose host galaxies were not identified, but it is shown that their occurrence is consistent with them occurred in low luminous galaxies beyond the survey. The luminosity function of type Ia supernovae is approximately Gaussian with the full-width half maximum being a factor of 1.4 in luminosity. The Gaussian distribution becomes tighter if the ratio of extinction to reddening, R_V, is lower than the characteristic value for the Milky Way and if luminosity is corrected for the light curve shape. The colour excess is ~0.07 mag which is significantly smaller than reddening expected for field galaxies. This colour excess does not vary with the distance of the supernovae from the centre of the host galaxy to 15 kpc. This suggests that the major part of the colour excess appears to be either intrinsic or reddening that arises in the immediate environment of supernova, rather than interstellar reddening in host galaxies.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
