IMPROVED DISTANCES TO TYPE Ia SUPERNOVAE WITH TWO SPECTROSCOPIC SUBCLASSES

By Xiaofeng Wang, A. Filippenko, M. Ganeshalingam, W. Li, J. Silverman, L. Wang, R.Chornock, R.J.Foley, E.L.Gates, B. Macomber and 7 more. 2009

199 citations recorded by the source corpus.

We study the observables of 158 relatively normal Type Ia supernovae (SNe Ia) by dividing them into two groups in terms of the expansion velocity inferred from the absorption minimum of the Si ii λ6355 line in their spectra near B-band maximum brightness. One group (“Normal”) consists of normal SNe Ia populating a narrow strip in the Si ii velocity distribution, with an average expansion velocity 〈v〉 = 10, 600 ± 400 km s−1 near B maximum; the other group (“HV”) consists of objects with higher velocities, v ≳  11, 800 km s−1. Compared with the Normal group, the HV one shows a narrower distribution in both the peak luminosity and the luminosity decline rate Δm15. In particular, their B−V colors at maximum brightness are found to be on average redder by ∼ 0.1 mag, suggesting that they either are associated with dusty environments or have intrinsically red B−V colors. The HV SNe Ia are also found to prefer a lower extinction ratio RV ≈ 1.6 (versus ∼  2.4 for the Normal ones). Applying such an absorption-correction dichotomy to SNe Ia of these two groups remarkably reduces the dispersion in their peak luminosity from 0.178 mag to only 0.125 mag.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d84acfe0c6e2763385e62797d4313bd9f4151ae2

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In Astronomy and Astrophysics

1. A. Filippenko
2. A. Riess
3. S. Smartt
4. R. Kirshner
5. S. Jha
6. N. Smith
7. E. Berger
8. D. Maoz

In Instrumentation

1. N. Smith
2. A. Filippenko
3. L. Hernquist
4. J. Silverman
5. Weidong Li
6. Luis C. Ho
7. D. Schneider
8. A. Riess

Citations in the corpus

• Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples (2014, background): “…ii) the existence of several subclasses of SNe Ia with different intrinsic colors as identified by their correlation with spectral indicators (Wang et al. 2009, 2013; Nordin et al. 2011; Foley et al. 2011); iii) a potential evolution of the effective dust extinction law due to a mixture of…”
• Observational Clues to the Progenitors of Type Ia Supernovae (2013, background): “…steady burning, and WD mass growth, but again that a hot helium layer ignites at some point, possibly ejecting much of the accumulated mass. Alternatively, the donor may be a helium-rich star, avoiding the challenges involved in mass gain through hydrogen-rich accretion (see Wang et al. 2009a).”
• THE CARNEGIE SUPERNOVA PROJECT: ANALYSIS OF THE FIRST SAMPLE OF LOW-REDSHIFT TYPE-Ia SUPERNOVAE (2009, background): “Wang et al. (2009) have recently pointed out that both SNe 2005A and 2006X belong to the group of high-velocity SNe Ia, and that this group shows systematically different reddening properties (with lower RV values) than normal SNe Ia, probably due to a circumstellar dust component or to intrinsic…”
• Berkeley Supernova Ia Program – I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae (2012, background): “Wang et al. (2009) obtained an additional improvement by separating their sample of SNe Ia into two groups based on the ejecta velocity near maximum brightness; they suggested different reddening laws for these two samples.”
• TYPE Ia SUPERNOVA LIGHT CURVE INFERENCE: HIERARCHICAL MODELS IN THE OPTICAL AND NEAR-INFRARED (2010, background): “These studies assumed that a universal color or dust absorption profile applied to all SNe Ia. Recently, Wang et al. (2009a) separately fit RV ≈ 1.6 for a subset of SNe Ia with high ejecta velocities, and RV ≈ 2.4 for a subset with normal ejecta velocities.”
• High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios (2010, background): “…Extragalactic Database (http://nedwww.ipac.caltech.edu/) 2 Adopting a lower value for the host-galaxy reddening of e.g. RV = 2.36 as suggested by Wang et al. (2009a) for normal SNe Ia would reduce the inferred extinction in V (and hence the peak luminosity calculated in Section 3.2) by ∼7 per…”
• RESULTS OF THE LICK OBSERVATORY SUPERNOVA SEARCH FOLLOW-UP PHOTOMETRY PROGRAM: BVRI LIGHT CURVES OF 165 TYPE Ia SUPERNOVAE (2010, methodology): “SN 2005cf data taken with KAIT were reduced independently by Wang et al. (2009b).”
• COSMOLOGICAL CONSTRAINTS FROM MEASUREMENTS OF TYPE Ia SUPERNOVAE DISCOVERED DURING THE FIRST 1.5 yr OF THE Pan-STARRS1 SURVEY (2013, background): “Candidates are, for example, ejecta velocity (Wang et al. 2009; Foley & Kasen 2011; Foley et al. 2011), other spectral features (Foley et al. 2008; Bailey et al. 2009; Blondin et al. 2011; Silverman et al. 2012b; Foley & Kirshner 2013), and host galaxy properties (Kelly et al. 2010; Lampeitl et al.…”
• Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete Sample (2010, background): “…subclasses: normal SNe Ia with normal expansion velocities (“IaN” in Table 3 and hereafter), normal SNe Ia with high expansion velocities (“IaHV,” see Wang et al. 2009 for our definition of this subclass), SN 1991bg-like objects (“Ia-91bg”; Filippenko et al. 1992b; Leibundgut et al. 1993), SN…”
• THE EFFECT OF HOST GALAXIES ON TYPE Ia SUPERNOVAE IN THE SDSS-II SUPERNOVA SURVEY (2010, background): “Such correlations would have important consequences for supernova surveys and could improve the use of SNe Ia as “standard candles” (Wang et al. 2009; Sullivan et al. 2010).”
• The Carnegie Supernova Project. I. Third Photometry Data Release of Low-redshift Type Ia Supernovae and Other White Dwarf Explosions (2017, methodology): “Also given are classifications in the Branch et al. (2006) and Wang et al. (2009) schemes using the same criteria as Folatelli et al. (2013).”
• Fourteen months of observations of the possible super-Chandrasekhar mass Type Ia Supernova 2009dc (2010, methodology): “This is similar to the EW of the same line in SN 2006gz at similar epochs (Hicken et al. 2007), and both are well below the average Si II EW for normal SNe Ia (though they are comparable to the overluminous SN 1991T-like SNe Ia; e.g. Hachinger, Mazzali & Benetti 2006; Wang et al. 2009a).”
• An Open Catalog for Supernova Data (2016, background): “…seemingly different supernova types, to generating mean spectra and exploring spectroscopic diversity (Benetti et al. 2005; Branch et al. 2005, 2006, 2007, 2008, 2009; Wang et al. 2009; Blondin et al. 2012; Folatelli et al. 2013; Maguire et al. 2014; Sasdelli et al. 2015, 2016; Kromer et al. 2016).”
• Nearby supernova rates from the Lick Observatory Supernova Search – I. The methods and data base (2010, background): “…grouped into the following subclasses: (a) normal objects (e.g., Branch & Tammann 1992), (b) high expansion velocity objects (Benetti et al. 2005; Wang et al. 2009), (c) SN 1991T-like objects (Filippenko et al. 1992a; Phillips et al. 1992), (d) SN 1991bg-like objects (Filippenko et al. 1992b;…”
• THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE (2000, methodology): “…1999by, Garnavich et al. 2004; SN 2001ay, Krisciunas et al. 2011a; SN 2001eh and SN 2001ep, Sauer et al. 2008; SN 2002cx, Li et al. 2003; SN 2005cf, Wang et al. 2009b; SN 2006bt, Foley et al. 2010; SN 2006gz, Hicken et al. 2007a), including the large sample of 432 spectra of 32 SN Ia (including SN…”
• TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1 (2014, unknown): “However, the presence of significant scatter around the SN IIP decline rate–peak magnitude relation presented here suggests additional correlations with secondary factors, as have emerged among SNe Ia (Wang et al. 2009; Foley et al. 2011).”