Spectroscopy of superluminous supernova host galaxies. A preference of hydrogen-poor events for extreme emission line galaxies
G. Leloudas, S. Schulze, T. Kruehler, J. Gorosabel, L. Christensen, A. Mehner, A. de Ugarte Postigo, R. Amorin, C. C. Thoene, J. P. Anderson, F. E. Bauer, A. Ga… 展开作者
G. Leloudas, S. Schulze, T. Kruehler, J. Gorosabel, L. Christensen, A. Mehner, A. de Ugarte Postigo, R. Amorin, C. C. Thoene, J. P. Anderson, F. E. Bauer, A. Gallazzi, K. G. Helminiak, J. Hjorth, E. Ibar, D. Malesani, N. Morrell, J. Vinko, J. C. Wheeler
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Published version, matches proofs. Accepted 2015 February 13. 23 pages, 8 figures, 4 tables. Minor changes with respect to previous version
Superluminous supernovae (SLSNe) are very bright explosions that were only discovered recently and that show a preference for occurring in faint dwarf galaxies. Understanding why stellar evolution yields different types of stellar explosions in these environments is fundamental in order to both uncover the elusive progenitors of SLSNe and to study star formation in dwarf galaxies. In this paper, we present the first results of our project to study SUperluminous Supernova Host galaxIES, focusing on the sample for which we have obtained spectroscopy. We show that SLSNe-I and SLSNe-R (hydrogen-poor) often (~50% in our sample) occur in a class of galaxies that is known as Extreme Emission Line Galaxies (EELGs). The probability of this happening by chance is negligible and we therefore conclude that the extreme environmental conditions and the SLSN phenomenon are related. In contrast, SLSNe-II (hydrogen-rich) occur in more massive, more metal-rich galaxies with softer radiation fields. Therefore, if SLSNe-II constitute a uniform class, their progenitor systems are likely different from those of H-poor SLSNe. Gamma-ray bursts (GRBs) are, on average, not found in as extreme environments as H-poor SLSNe. We propose that H-poor SLSNe result from the very first stars exploding in a starburst, even earlier than GRBs. This might indicate a bottom-light initial mass function in these systems. SLSNe present a novel method of selecting candidate EELGs independent of their luminosity.
Obscured Star Formation in the Host Galaxies of Superluminous Supernovae
本文介绍了在$0.1 < z < 0.3$上用Karl G. Jansky甚大阵。观测到四个主星系，其中两个主星系具有很高的恒星形成速率（SFR $>$ 20 $M_{\odot}$ yr $^{-1}$），是SLSN主星系中恒星形成最强烈的主星系。我们比较了射电SFR和光学SFR，发现三个宿主星系的射电SFR超过了$>$ 2倍，这表明存在尘埃遮蔽的恒星形成，这是无法跟踪的光学研究。根据光学SFR，三个宿主星系中有两个位于星系主序星，根据射电SFR，它们位于主序星之上。这表明SLSN宿主中星暴星系的比例比以前的研究估计的要高。通过射电SFR与尘埃未校正光学SFR的比值计算消光系数，发现宿主星系的消光系数随金属丰度的增加而增加，这与本星系的消光系数关系一致。我们还将一个约束脉冲星驱动的SN模型，预测准稳态同步辐射无线电发射。
A Hubble Space Telescope Survey of the Host Galaxies of Superluminous Supernovae
我们目前的哈勃太空望远镜（HST）的WFC 3紫外和近红外（nIR）成像的21个超亮超新星（SLSNe）的主机星系，提供了一个敏感的探头的恒星形成和恒星质量的主机。通过与核塌缩超新星（CCSNe）和长时伽马射线暴（LGRB）的光度和形态特征比较，我们发现SLSN宿主星系在紫外和近红外波段都更暗、更致密，在某些情况下我们几乎不能恢复MV ~-14附近的绝对星等。此外，地面光学观测和档案的结果，我们产生的光谱能量分布（SED）适合这些主机，并表明SLSN主机具有较低的恒星质量和恒星形成率。这在缺乏氢的I型SLSN宿主星系中最为明显，尽管II型富氢SLSN宿主星系与CCSNe的主体星系仍然不同，跨越了非常宽的绝对星等范围，其中约30%的SLSNe-II来自比Mn I R ~-14更暗的星系。我们最微弱的SLSN主机的检测增加的信心，SLSNe-I主机是不同的LGRB的恒星形成率和恒星质量，并表明，金属丰度的明显相似性可能是由于有限的部分主机的发射线金属丰度测量是可行的。SLSN-II宿主的广泛光度范围很难通过金属丰度削减来描述，并且与任何合理的紫外加权光度函数的预期不匹配，这表明可能需要额外的环境限制来产生富含氢的SLSNe。
