Determining the Type, Redshift, and Age of a Supernova Spectrum

Blondin, S.; Tonry, J.

doi:10.1086/520494

Cited by 453 publications

(549 citation statements)

References 116 publications

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“…We find that, regardless of subtype or which of the two wavelength ranges is used, SNID capably classifies events in the presence of strong reddening (E(B − V ) ∼ 2.0 mag and R V = 3.1), so long as the spectra exhibit a S/N 1-3. This is to be expected, as SNID divides input spectra by a pseudo-continuum fit and discards the spectral color information before performing crosscorrelation (Blondin & Tonry 2007). In contrast, classifications performed via visual comparison may be prone to error when strong reddening is present.…”

Section: Classification Methodsmentioning

confidence: 99%

Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions

Shivvers

Modjaz

Zheng

et al. 2017

PASP

141

130

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We re-examine the classifications of supernovae (SNe) presented in the Lick Observatory Supernova Search (LOSS) volume-limited sample with a focus on the stripped-envelope SNe. The LOSS volumelimited sample, presented by Leaman et al. (2011) andLi et al. (2011b), was calibrated to provide meaningful measurements of SN rates in the local universe; the results presented therein continue to be used for comparisons to theoretical and modeling efforts. Many of the objects from the LOSS sample were originally classified based upon only a small subset of the data now available, however, and recent studies have both updated some subtype distinctions and improved our ability to perform robust classifications, especially for stripped-envelope SNe. We re-examine the spectroscopic classifications of all events in the LOSS volume-limited sample (180 SNe and SN impostors) and update them if necessary. We discuss the populations of rare objects in our sample including broad-lined Type Ic SNe, Ca-rich SNe, SN 1987A-like events (we identify SN 2005io as SN 1987A-like here for the first time), and peculiar subtypes. The relative fractions of Type Ia SNe, Type II SNe, and stripped-envelope SNe in the local universe are not affected, but those of some subtypes are. Most significantly, after discussing the often unclear boundary between SNe Ib and Ic when only noisy spectra are available, we find a higher SN Ib fraction and a lower SN Ic fraction than calculated by Li et al. (2011b): spectroscopically normal SNe Ib occur in the local universe 1.7 ± 0.9 times more often than do normal SNe Ic.

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Section: Classification Methodsmentioning

confidence: 99%

Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions

Shivvers

Modjaz

Zheng

et al. 2017

PASP

141

130

View full text Add to dashboard Cite

show abstract

“…Using the Supernova Identification tool, SNID (Blondin & Tonry 2007), and pseudo equivalent measurements of several spectral features, Liu et al 2015 classify SN2007kj as a SNIb. Modjaz et al (2014) previously used SNID to classify SN 2007kj as a SNIb as well.…”

Section: "Sn Ib" 2007kjmentioning

confidence: 99%

LINE IDENTIFICATIONS OF TYPE I SUPERNOVAE: ON THE DETECTION OF Si II FOR THESE HYDROGEN-POOR EVENTS

Parrent

Milisavljević

Söderberg

et al. 2016

ApJ

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Here we revisit line identifications of type I supernovae (SNe I) and highlight trace amounts of unburned hydrogen as an important free parameter for the composition of the progenitor. Most one-dimensional stripped-envelope models of supernovae indicate that observed features near 6000-6400 Å in typeI spectra are due to more than Si IIλ6355. However, while an interpretation of conspicuous Si IIλ6355 can approximate 6150 Å absorption features for all SNe Ia during the first month of free expansion, similar identifications applied to 6250 Å features of SNe Ib and Ic have not been as successful. When the corresponding synthetic spectra are compared with highquality timeseries observations, the computed spectra are frequently too blue in wavelength. Some improvement can be achieved with Fe II lines that contribute redward of 6150 Å; however, the computed spectra either remain too blue or the spectrum only reaches a fair agreement when the rise-time to peak brightness of the model conflicts with observations by a factor of two. This degree of disagreement brings into question the proposed explosion scenario. Similarly, a detection of strong Si IIλ6355 in the spectra of broadlined Ic and super-luminous events of type I/R is less convincing despite numerous model spectra used to show otherwise. Alternatively, we suggest 6000-6400 Å features are possibly influenced by either trace amounts of hydrogen or blueshifted absorption and emission in Hα, the latter being an effect which is frequently observed in the spectra of hydrogen-rich, SNe II.

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“…For this object we have observations with both the WFC3 G102 and G141 grisms. Fitting the composite spectrum with the SuperNova IDentification (SNID) software (Blondin & Tonry 2007), we find the best template match is a Type Ia SN at z = 1.59. Once again we find that the STARDUST photometric classification agrees well with this spectroscopic information: an SN Ia light curve at z ∼ 1.6 provides the best available light curve template.…”

Section: Grism Spectroscopymentioning

confidence: 99%

TYPE Ia SUPERNOVA RATE MEASUREMENTS TO REDSHIFT 2.5 FROM CANDELS: SEARCHING FOR PROMPT EXPLOSIONS IN THE EARLY UNIVERSE

et al. 2014

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The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ∼0.25 deg 2 with ∼900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ∼ 2.5. We classify ∼24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ∼3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f P = 0.53 ±0.09 stat0.10 ±0.10 sys0.26 , consistent with a delay time distribution that follows a simple t −1 power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions-though further analysis and larger samples will be needed to examine that suggestion.

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Determining the Type, Redshift, and Age of a Supernova Spectrum

Cited by 453 publications

References 116 publications

Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions

Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions

LINE IDENTIFICATIONS OF TYPE I SUPERNOVAE: ON THE DETECTION OF Si II FOR THESE HYDROGEN-POOR EVENTS

TYPE Ia SUPERNOVA RATE MEASUREMENTS TO REDSHIFT 2.5 FROM CANDELS: SEARCHING FOR PROMPT EXPLOSIONS IN THE EARLY UNIVERSE

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