Լիլիթ Բարխուդարյանի հրապարակումները

Դասավորել ըստ
Տարի
Publication year (field_publication_year)

Հոդված

Supernovae and their host galaxies - III. The impact of bars and bulges on the radial distribution of supernovae in disc galaxies
Monthly Notices of the Royal Astronomical Society

Հատոր. 456 No. 3 Էջ. 2848-2860 (2016)

URL: https://arxiv.org/abs/1511.08896

DOI: https://doi.org/10.1093/mnras/stv2853

Նկարագրություն: We present an analysis of the impact of bars and bulges on the radial distributions of the different types of supernovae (SNe) in the stellar discs of host galaxies with various morphologies. We use a well-defined sample of 500 nearby (≤100 Mpc) SNe and their low-inclined (i ≤ 60°) and morphologically non-disturbed S0-Sm host galaxies from the Sloan Digital Sky Survey. We find that in Sa-Sm galaxies, all core-collapse (CC) and vast majority of SNe Ia belong to the disc, rather than the bulge component. The radial distribution of SNe Ia in S0-S0/a galaxies is inconsistent with their distribution in Sa-Sm hosts, which is probably due to the contribution of the outer bulge SNe Ia in S0-S0/a galaxies. In Sa-Sbc galaxies, the radial distribution of CC SNe in barred hosts is inconsistent with that in unbarred ones, while the distributions of SNe Ia are not significantly different. At the same time, the radial distributions of both types of SNe in Sc-Sm galaxies are not affected by bars. We propose that the additional mechanism shaping the distributions of Type Ia and CC SNe can be explained within the framework of substantial suppression of massive star formation in the radial range swept by strong bars, particularly in early-type spirals. The radial distribution of CC SNe in unbarred Sa-Sbc galaxies is more centrally peaked and inconsistent with that in unbarred Sc-Sm hosts, while the distribution of SNe Ia in unbarred galaxies is not affected by host morphology. These results can be explained by the distinct distributions of massive stars in the discs of early- and late-type spirals.


Supernovae and their host galaxies - V. The vertical distribution of supernovae in disc galaxies
Monthly Notices of the Royal Astronomical Society

Հատոր. 471 No. 2 Էջ. 1390-1400 (2017)

URL: https://arxiv.org/abs/1705.09626

DOI: https://doi.org/10.1093/mnras/stx1608

Նկարագրություն: 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°), 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 ∼100 Myr 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 100 Myr up to a few Gyr and from a few Gyr up to ∼10 Gyr, 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.


The impact of spiral density waves on the star formation distribution: a view from core-collapse supernovae

Հատոր. 65 No. 2 Էջ. 379-384 (2018)

URL: https://arxiv.org/abs/1811.12001

DOI: https://doi.org/10.52526/25792776-2018.2.2-379

Նկարագրություն: We present an analysis of the impact of spiral density waves (DWs) on the radial and surface density distributions of core-collapse (CC) supernovae (SNe) in host galaxies with different arm classes. For the first time, we show that the corotation radius normalized surface density distribution of CC SNe (tracers of massive star formation) indicates a dip at corotation in long-armed grand-design (LGD) galaxies. The high SNe surface density just inside and outside corotation may be the sign of triggered massive star formation by the DWs. Our results may support the large-scale shock scenario induced by spiral DWs in LGD galaxies, which predicts a higher star formation efficiency around the shock fronts, avoiding the corotation region.


The impact of spiral density waves on the distribution of supernovae
Monthly Notices of the Royal Astronomical Society

Հատոր. 481 No. 1 Էջ. 566-577 (2018)

URL: https://arxiv.org/abs/1808.03099

DOI: https://doi.org/10.1093/mnras/sty2291

Նկարագրություն: We present an analysis of the impact of spiral density waves (DWs) on the radial and surface density distributions of supernovae (SNe) in host galaxies with different arm classes. We use a well-defined sample of 269 relatively nearby, low-inclination, morphologically non-disturbed and unbarred Sa-Sc galaxies from the Sloan Digital Sky Survey, hosting 333 SNe. Only for core-collapse (CC) SNe, a significant difference appears when comparing their R25-normalized radial distributions in long-armed grand-design (LGD) versus non-GD (NGD) hosts, with that in LGD galaxies being marginally inconsistent with an exponential profile, while SNe Ia exhibit exponential surface density profiles regardless of the arm class. Using a smaller sample of LGD galaxies with estimated corotation radii (Rc), we show that the Rc-normalized surface density distribution of CC SNe indicates a dip at corotation. Although not statistically significant, the high CC SNe surface density just inside and outside corotation may be the sign of triggered massive star formation by the DWs. Our results may, if confirmed with larger samples, support the large-scale shock scenario induced by spiral DWs in LGD galaxies, which predicts a higher star formation efficiency around the shock fronts, avoiding the corotation region.


Supernovae and their host galaxies - VI. Normal Type Ia and 91bg-like supernovae in ellipticals
Monthly Notices of the Royal Astronomical Society

Հատոր. 490 No. 1 Էջ. 718-732 (2019)

URL: https://arxiv.org/abs/1906.10501

DOI: https://doi.org/10.1093/mnras/stz2585

Նկարագրություն: 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.


Supernovae and their host galaxies - VII. The diversity of Type Ia supernova progenitors
Monthly Notices of the Royal Astronomical Society

Հատոր. 499 No. 1 Էջ. 1424-1440 (2020)

URL: https://arxiv.org/abs/2009.02135

DOI: https://doi.org/10.1093/mnras/staa2940

Նկարագրություն: We present an analysis of the light curve (LC) decline rates (Δm15) 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 Δm15 of normal SNe Ia and global ages (morphologies, colours, and 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 Δm15 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 Δm15 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.


Type Ia supernovae in the star formation deserts of spiral host galaxies
Monthly Notices of the Royal Astronomical Society

Հատոր. 505 No. 1 Էջ. L52-L57 (2021)

URL: https://arxiv.org/abs/2103.02970

DOI: https://doi.org/10.1093/mnrasl/slab048

Նկարագրություն: 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 (Δm15) 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/Hα images of the discs of host galaxies. We demonstrate that, from the perspective of the dynamical time-scale of the SFD, where the star formation is suppressed by the bar evolution, the Δm15 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 ages older than a few Gyr. We show, for the first time, that the SFDs contain mostly faster declining SNe Ia (Δm15 > 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.


Constraining Type Ia supernovae through their heights in edge-on galaxies
Monthly Notices of the Royal Astronomical Society

Հատոր. 520 No. 1 Էջ. L21-L27 (2023)

URL: https://arxiv.org/abs/2210.13249

DOI: https://doi.org/10.1093/mnrasl/slac163

Նկարագրություն: In this Letter, using classified 197 supernovae (SNe) Ia, we perform an analysis of their height distributions from the disc in edge-on spirals and investigate their light-curve (LC) decline rates (Δm15). We demonstrate, for the first time, that 91T- and 91bg-like subclasses of SNe Ia are distributed differently toward the plane of their host disc. The average height from the disc and its comparison with scales of thin/thick disc components gives a possibility to roughly estimate the SNe Ia progenitor ages: 91T-like events, being at the smallest heights, originate from relatively younger progenitors with ages of about several 100 Myr, 91bg-like SNe, having the highest distribution, arise from progenitors with significantly older ages ~10 Gyr, and normal SNe Ia, which distributed between those of the two others, are from progenitors of about one up to ~10 Gyr. We find a correlation between LC decline rates and SN Ia heights, which is explained by the vertical age gradient of the stellar population in discs and a sub-Chandrasekhar mass white dwarf explosion models, where the Δm15 parameter is a progenitor age indicator.