The Distance to SN 1999em in NGC 1637 from the Expanding Photosphere Method

By D. Leonard, A. Filippenko, E. Gates, Weidong Li, R. Eastman, A. Barth, S. Bus, Ryan Chornock, A. Coil, S. Frink and 6 more. 2001

256 citations recorded by the source corpus.

We present 30 optical spectra and 49 photometric epochs sampling the first 517 days after discovery of supernova (SN) 1999em and derive its distance through the expanding photosphere method (EPM). SN 1999em is shown to be a Type II‐plateau (II‐P) event, with a photometric plateau lasting until about 100 days after explosion. We identify the dominant ions responsible for most of the absorption features seen in the optical portion of the spectrum during the plateau phase. Using the weakest unblended absorption features to estimate photospheric velocity, we find the distance to SN 1999em to be D = 8.2 ± 0.6 Mpc, with an explosion date of HJD 2,451,475.6 ± 1.4, or 5.3 ± 1.4 days before discovery. We show that this distance estimate is about 10% closer than the distance that results if the strong Fe ii λλ4924, 5018, 5169 absorption features, which have often been used in previous EPM studies, are used to estimate photospheric velocity. We examine potential sources of systematic error in EPM‐derived distances and find the most significant to result from uncertainty in the theoretical modeling of the flux distribution emitted by the SN photosphere (i.e., the “flux dilution factor”). We compare previously derived EPM distances to eight SNe II in galaxies (or members of the same group) for which a recently revised Cepheid distance exists from the Hubble Space Telescope Key Project and find DCepheids/DEPM = 0.87 ± 0.06 (statistical); eliminating the three SNe II distances for which a Cepheid distance exists only to a group member, and not the host galaxy itself, yields DCepheids/DEPM = 0.96 ± 0.09. Additional direct comparisons, especially to spectroscopically and photometrically normal SNe II‐P, will certainly help to produce a more robust comparison. Finally, we investigate the possible use of SNe II‐P as standard candles and find that for eight photometrically confirmed SNe II‐P with previously derived EPM distances and SN 1999em, the mean plateau absolute brightness is MV(plateau) = -16.4 ± 0.6 mag, implying that distances good to ∼30% (1 σ) may be possible without the need for a complete EPM analysis. At MV(plateau) = -15.9 ± 0.2 mag, SN 1999em is somewhat fainter than the average SN II‐P. The general consistency of absolute SNe II‐P brightness during the plateau suggests that the standard candle assumption may allow SNe II‐P to be viable cosmological beacons at z>2.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c59e8b592a1bbd477d13a8ff8410468ecb9ce47c

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In Astronomy and Astrophysics

1. A. Filippenko
2. S. Smartt
3. E. Berger
4. N. Smith
5. Ryan Chornock
6. A. Riess
7. Weidong Li
8. S. Jha

In Nuclear and High Energy Physics

1. S. Smartt
2. A. Filippenko
3. E. Berger
4. Weidong Li
5. Ryan Chornock
6. S. Jha
7. R. Kirshner
8. A. Gal-yam

Citations in the corpus

• CHARACTERIZING THE V-BAND LIGHT-CURVES OF HYDROGEN-RICH TYPE II SUPERNOVAE (2014, background): “…with sufficient data to observe the initial maximum and decline from maximum (see e.g. SN 1999em photometry published in Hamuy et al. 2001 and Leonard et al. 2002), the initials1 decline rate has attracted little attention in SN II discussion (although its presence was indeed noted in the…”
• Type II-Plateau supernova radiation: dependences on progenitor and explosion properties (2013, methodology): “Third, the nebular phase spectra of Dessart & Hillier (2011) systematically predict no Hα emission although a strong line is observed (in, e.g., SN 1999em; Leonard et al. 2002).”
• Photometric and spectroscopic evolution of the Type IIP supernova SN 2004et (2006, methodology): “…V light curve of SN 2004et with those of other SNe IIP, namely, SN 1999em (Hamuy et al. 2001; Leonard et al. 2002a; Elmhamdi et al. 2003b), SN 1999gi (Leonard et al. 2002b), SN 1997D (Benetti et al. 2001 and references therein), SN 1990E (Schmidt et al. 1993) and SN 1987A (Hamuy et al. 1988).”
• A PANCHROMATIC VIEW OF THE RESTLESS SN 2009ip REVEALS THE EXPLOSIVE EJECTION OF A MASSIVE STAR ENVELOPE (2013, background): “Prieto et al. 2007, Fassia et al. 2000) and in SNe IIP as well (e.g. SN 1999em, with a plateau at ∼ 5000 K; Leonard et al. 2002).”
• The diversity of Type II supernova versus the similarity in their progenitors (2016, unknown): “2015; Gall et al. 2015; Pastorello et al. 2009; Inserra et al. 2013; Leonard et al. 2002a).”
• SN 2005cs in M51 – II. Complete evolution in the optical and the near-infrared (2009, background): “The line velocities of these SNe are systematically smallerby a factor ∼ 2 (see Figure 12) with respect to the normal SN IIP 1999em (Hamuy et al. 2001; Leonard et al. 2002b; Elmhamdi et al. 2003a).”
• Low‐luminosity Type II supernovae: spectroscopic and photometric evolution (2003, background): “This might be the case of SN 1999em (Baron et al. 2000; Leonard et al. 2002a; Pooley et al. 2002; Hamuy et al. 2001; Elmhamdi et al. 2003) for which recent Cepheid distance measurements Leonard et al. (2003) suggest that the host galaxy distance was previously underestimated and, consequently, the…”
• THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT (2013, background): “This is true for objects ranging from normal SNe II (e.g., Leonard et al. 2002) and Ib/c (Soderberg et al. 2008; Modjaz et al. 2009) to the SN IIn 2007pk (Pritchard et al. 2012) and even SLSNe (Miller et al. 2009; Gezari et al. 2009a; Quimby et al. 2011; Chomiuk et al. 2011; Lunnan et al. 2013;…”
• Twenty-Three High-Redshift Supernovae from the Institute for Astronomy Deep Survey: Doubling the Supernova Sample at z > 0.7 (2004, methodology): “We have selected single spectroscopic observations of SN 1998S (Lentz et al. 2001; Leonard et al. 2000) and SN 1999em (Baron et al. 2000; Leonard et al. 2002) to serve as our templates.”
• The first month of evolution of the slow-rising Type IIP SN 2013ej in M74 (2013, background): “Leonard et al. (2002) identified this absorption at early phases as Si II, while Baron et al. (2000) favoured an HV hydrogen interpretation.”
• An Hα Imaging Survey of Galaxies in the Local 11 Mpc Volume (2004, methodology): “Four galaxies with flowcorrected estimated distances of <11 Mpc were removed based on Cepheid distances: NGC 2090 and NGC 2541 (11.75 Mpc and 11.22 Mpc, respectively; Freedman et al. 2001), NGC 2841 (14.1 Mpc; Macri et al. 2001), and NGC 1637 (11.7 Mpc; Leonard et al. 2002).”
• The progenitor mass of the Type IIP supernova SN 2004et from late-time spectral modeling (2012, unknown): “…are for SN 1990E (Schmidt et al. 1993; Gomez & Lopez 1993; Benetti et al. 1994), SN 1999em (Leonard et al. 2002a; Elmhamdi et al. 2003), SN 1999gi (Leonard et al. 2002b), SN 2002hh (Pozzo et al. 2006), SN 2004dj (Chugai et al. 2005), SN 2004et (Sahu et al. 2006, M10), SN 2005cs (e.g. Pastorello…”
• Distance determinations using Type II supernovae and the expanding photosphere method (2005, methodology): “The EPM works fine for the LMC (using SN1987A, Eastman & Kirshner 1989) but predicts a distance to NGC 1637 50% smaller (using SN1999em, Leonard et al. 2002) than found using Cepheids (Leonard et al. 2003).”
• TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1 (2014, methodology): “…insensitive to selection against high extinction ob- 19 We convert our griz photometry to the Landolt and Vega systems using a color-based S correction obtained by integrating over the temporally nearest available UVOIR spectrum of SN 1999em, the ∼ +37 day spectrum from Leonard et al. (2002).”