The Luminosity of SN 1999by in NGC 2841 and the Nature of “Peculiar” Type Ia Supernovae

By P. Garnavich, Alceste Z. Bonanos, K. Krisciunas, S. Jha, R. Kirshner, E. Schlegel, P. Challis, Lucas Macri, K. Hatano, D. Branch and 2 more. 2001

155 citations recorded by the source corpus.

We present UBVRIJHK photometry and optical spectroscopy of the so-called peculiar Type Ia supernova 1999by in NGC 2841. The observations began 1 week before visual maximum light, which is well defined by daily observations. The light curves and spectra are similar to those of the prototypical subluminous event SN 1991bg. We find that maximum light in B occurred on 1999 May 10.3 UT (JD 2,451,308.8 ± 0.3) with B = 13.66 ± 0.02 and a color of Bmax - Vmax = 0.51 ± 0.03. The late-time color implies minimal dust extinction from the host galaxy. Our photometry, when combined with the recent Cepheid distance to NGC 2841, gives a peak absolute magnitude of MB = -17.15 ± 0.23, making SN 1999by one of the least luminous Type Ia events ever observed. We estimate a decline rate parameter of Δm15(B) = 1.90 mag, versus 1.93 for SN 1991bg, for which 1.10 is typical for so-called normal events. We compare SN 1999by with other subluminous events and find that the Bmax - Vmax color correlates strongly with the decline rate and may be a more sensitive indicator of luminosity than the fading rate for these objects. We find a good correlation between luminosity and the depth of the spectral feature at 580 nm, which had been attributed solely to Si II. We show that in cooler photospheres the 580 nm feature is dominated by Ti II, which provides a simple physical explanation for the correlation. Using only subluminous Type Ia supernovae, we derive a Hubble parameter of H0 = 75 km s-1 Mpc-1, consistent with values found from brighter events.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Geophysics

View Paper: https://www.semanticscholar.org/paper/b54e2cc679941ad273ff0414dc3ed53fb9b9645f

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In Astronomy and Astrophysics

1. A. Filippenko
2. K. Luhman
3. S. Smartt
4. A. Riess
5. S. Jha
6. R. Kirshner
7. N. Smith
8. Weidong Li

In Electrical and Electronic Engineering

1. A. Riess
2. A. Filippenko
3. S. Jha
4. A. Gal-yam
5. S. Smartt
6. Ryan Chornock
7. Weidong Li
8. J. Prieto

In Geophysics

1. Jason Eastman
2. D. Kasen

Citations in the corpus

• Sub-Chandrasekhar-mass White Dwarf Detonations Revisited (2017, background): “Also overlaid for comparison in gray are three well-observed SNe Ia: the subluminous 1991bg-like SN 1999by (Garnavich et al. 2004; Stritzinger 2005; Ganeshalingam et al. 2010), the normal SN 2011fe (Munari et al. 2013; Pereira et al. 2013; Tsvetkov et al. 2013), and the over-luminous 1991T-like SN…”
• The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations? (2006, methodology): “Finally, the absolute magnitudes 2007 PASP, 119:360–387 of SN 1999by were calculated from the photometry of Garnavich et al. (2004) and the Cepheid distance modulus of Macri et al. (2001).”
• High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios (2010, unknown): “…m15(B) = 1.02], 2001el [Krisciunas et al. 2003, m15(B) = 1.13] and 2004eo [Pastorello et al. 2007b, m15(B) = 1.46], the subluminous SN Ia 1999by [Garnavich et al. 2004, m15(B) = 1.90], the superluminous SN Ia 2007if [Scalzo et al. 2010, m15(B) = 0.71] and the Type Ic hypernova 1998bw (Galama et…”
• DOUBLE-DETONATION SUB-CHANDRASEKHAR SUPERNOVAE: SYNTHETIC OBSERVABLES FOR MINIMUM HELIUM SHELL MASS MODELS (2010, background): “However, observationally these events are characterized by a fast decline (Δm15(B) ∼ 1.9; e.g., Garnavich et al. 2004; Taubenberger et al. 2008).”
• Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete Sample (2010, result): “…are the light curves of SN 1991T (dash-dotted line, from Lira et al. 1998) and the well-observed SN 1991bg-like object SN 1999by (dashed line, from Garnavich et al. 2004), arbitrarily shifted to absolute magnitudes of −19.5 and −17.5, respectively.2 The published light curves of SNe 1991T and…”
• The Diversity of Type Ia Supernovae: Evidence for Systematics? (2004, methodology): “Alternatively, Garnavich et al. (2004), using synthetic spectra, tentatively suggest that in SN 1999by and, in general, in SNe Ia with ∆m15(B)> 1.2 the 5800 Å feature is mostly due to TiII transitions rather than to SiII.”
• UBVRI Light Curves of 44 Type Ia Supernovae (2005, background): “The relationship betweenB−V andsV shown in the lower panel is in good accord with the results presented by Phillips et al. (1999) and Garnavich et al. (2004).”
• Comparative Direct Analysis of Type Ia Supernova Spectra. I. SN 1994D (2005, background): “The spectrum of the extreme CL SN 1999by, a SN 1991bg-like (Garnavich et al. 2004), is more highly evolved than the others of the 1 week postmaximum sample; in fact it has more in common with the 3 week postmaximum spectra of the CNs than with their 1 week postmaximum spectra.”
• Massive stars exploding in a He-rich circumstellar medium. I. Type Ibn (SN 2006jc-like) events (2008, background): “Using a relationship between colour and decline rate for underluminous 1991bg-like SNe Ia (see also Garnavich et al. 2004), van den Bergh (2002) obtained a value of∆m15(B) = 2.21 mag, which is not only inconsistent with that of a normal SN Ia, but also much higher than any 1991bg-like event…”
• THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE (2000, background): “Spectra of individual SN Ia have been published in several papers (SN 1998aq, Branch et al. 2003; SN 1998bu, Jha et al. 1999b; SN 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;…”
• The dependence of Type Ia Supernovae luminosities on their host galaxies (2010, background): “Trends do exist between other colours and stretch and at other lightcurve phases (e.g. Phillips et al. 1999; Nobili & Goobar 2008) and for sub-luminous SN1991bg-like very low-s SNe Ia (Garnavich et al. 2004; Jha et al. 2006), but these are excluded from our analysis by the s > 0.8 requirement.”
• THE CARNEGIE SUPERNOVA PROJECT: ANALYSIS OF THE FIRST SAMPLE OF LOW-REDSHIFT TYPE-Ia SUPERNOVAE (2009, background): “Garnavich et al. (2004) studied a small sample of fast-declining SNe Ia and found that they followed the Lira relationship fairly well, but SN 2006mr suggests that there may be exceptions.”