Type II Supernovae

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Mario Hamuy - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of the optical light curves of hydrogen-rich and hydrogen-poor Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: P. J. Pessi, Joseph P. Anderson, Mario Hamuy, Christopher R. Burns, C. Contreras, G. Folatelli, S. Davis, M. Bersten, B. Englert, Eric Hsiao
    Abstract:

    Type II Supernovae (SNe II) show strong hydrogen features in their spectra throughout their whole evolution while Type IIb Supernovae (SNe IIb) spectra evolve from dominant hydrogen lines at early times to increasingly strong helium features later on. However, it is currently unclear whether the progenitors of these supernova (SN) Types form a continuum in pre-SN hydrogen mass or whether they are physically distinct. SN light-curve morphology directly relates to progenitor and explosion properties such as the amount of hydrogen in the envelope, the pre-SN radius, the explosion energy and the synthesized mass of radioactive material. In this work we study the morphology of the optical-wavelength light curves of hydrogen-rich SNe II and hydrogen-poor SNe IIb to test whether an observational continuum exists between the two. Using a sample of 95 SNe (73 SNe II and 22 SNe IIb), we define a range of key observational parameters and present a comparative analysis between both Types. We find a lack of events that bridge the observed properties of SNe II and SNe IIb. Light curve parameters such as rise times and post-maximum decline rates and curvatures clearly separate both SN Types and we therefore conclude that there is no continuum, with the two SN Types forming two observationally distinct families. In the V-band a rise time of 17 days (SNe II lower, SNe IIb higher), and a magnitude difference between 30 and 40 days post explosion of 0.4 mag (SNe II lower, SNe IIb higher) serve as approximate thresholds to differentiate both Types.

  • Type II Supernovae as distance indicators at near-IR wavelengths
    Monthly Notices of the Royal Astronomical Society, 2018
    Co-Authors: O. Rodriguez, Mario Hamuy, Nidia Morrell, Mark M. Phillips, Kevin Krisciunas, Alejandro Clocchiatti, Giuliano Pignata, G. Folatelli, M. Roth, S. Castellon
    Abstract:

    Motivated by the advantages of observing at near-IR wavelengths, we investigate Type II Supernovae (SNe II) as distance indicators at those wavelengths through the Photospheric Magnitude Method (PMM). For the analysis, we use $BVIJH$ photometry and optical spectroscopy of 24 SNe II during the photospheric phase. To correct photometry for extinction and redshift effects, we compute total-to-selective broadband extinction ratios and $K$-corrections up to $z=0.032$. To estimate host galaxy colour excesses, we use the colour-colour curve method with the $V\!-\!I$ versus $B\!-\!V$ as colour combination. We calibrate the PMM using four SNe II in galaxies having Tip of the Red Giant Branch distances. Among our 24 SNe II, nine are at $cz>2000$ km s$^{-1}$, which we use to construct Hubble diagrams (HDs). To further explore the PMM distance precision, we include into HDs the four SNe used for calibration and other two in galaxies with Cepheid and SN Ia distances. With a set of 15 SNe II we obtain a HD rms of 0.13 mag for the $J$-band, which compares to the rms of 0.15-0.26 mag for optical bands. This reflects the benefits of measuring PMM distances with near-IR instead of optical photometry. With the evidence we have, we can set the PMM distance precision with $J$-band below 10 per cent with a confidence level of 99 per cent.

  • UBVRIz Light Curves of 51 Type II Supernovae
    The Astronomical Journal, 2016
    Co-Authors: Lluís Galbany, Mario Hamuy, Santiago González-gaitán, Mark M. Phillips, Nicholas B. Suntzeff, Jose Maza, Thomas De Jaeger, Tania Moraga, Kevin Krisciunas, Nidia Morrell
    Abstract:

    We present a compilation of UBV RIz light curves of 51 Type II Supernovae discovered during the course of four different surveys during 1986 to 2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being thus shorter (longer) for larger (smaller) s values.

  • ubvriz light curves of 51 Type II Supernovae
    The Astronomical Journal, 2016
    Co-Authors: Lluís Galbany, Mario Hamuy, Nicholas B. Suntzeff, Jose Maza, S Gonzalezgaitan, M M Phillips, Thomas De Jaeger, Tania Moraga, Kevin Krisciunas
    Abstract:

    Author(s): Galbany, L; Hamuy, M; Phillips, MM; Suntzeff, NB; Maza, J; Jaeger, TD; Moraga, T; Gonzalez-Gaitan, S; Krisciunas, K; Morrell, NI; Thomas-Osip, J; Krzeminski, W; Gonzalez, L; Antezana, R; Wishnjewski, M; McCarthy, P; Anderson, JP; Gutierrez, CP; Stritzinger, M; Folatelli, G; Anguita, C; Galaz, G; Green, EM; Impey, C; Kim, YC; Kirhakos, S; Malkan, MA; Mulchaey, JS; Phillips, AC; Pizzella, A; Prosser, CF; Schmidt, BP; Schommer, RA; Sherry, W; Strolger, LG; Wells, LA; Williger, GM | Abstract: © 2016. The American Astronomical Society. All rights reserved. We present a compilation of UBVRIz light curves of 51 Type II Supernovae discovered during the course of four different surveys during 1986-2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (CaT), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.

  • A HUBBLE DIAGRAM from Type II Supernovae BASED SOLELY on PHOTOMETRY: The PHOTOMETRIC COLOR METHOD
    The Astrophysical Journal, 2015
    Co-Authors: T. De Jaeger, Claudia P. Gutiérrez, Joseph P. Anderson, Mario Hamuy, Santiago González-gaitán, Maximilian Stritzinger, Mark M. Phillips, Luis Bolt, Lluís Galbany, Christopher R. Burns
    Abstract:

    We present a Hubble diagram of Type II Supernovae using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I (CSP) for which optical and near-infrared light-curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a colour term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) colour and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric colour method (PCM) with the standardised candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag which compares with 0.43 mag from the PCM, for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of Supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow-up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data. Subject headings: cosmology: distance scale – galaxies: distances and redshifts – Stars: Supernovae: general

Santiago González-gaitán - One of the best experts on this subject based on the ideXlab platform.

  • Progenitor properties of Type II Supernovae: fitting to hydrodynamical models using Markov chain Monte Carlo methods
    Astronomy & Astrophysics, 2020
    Co-Authors: Laureano Martinez, Joseph P. Anderson, Santiago González-gaitán, Francisco Förster, Melina C. Bersten, Gastón Folatelli
    Abstract:

    The progenitor and explosion properties of Type II Supernovae (SNe II) are fundamental to understand the evolution of massive stars. Special interest has been given to the range of initial masses of their progenitors, but despite the efforts made, it is still uncertain. Direct imaging of progenitors in pre-explosion images point out an upper initial mass cutoff of $\sim$18$M_{\odot}$. However, this is in tension with previous studies in which progenitor masses inferred by light curve modelling tend to favour high-mass solutions. Moreover, it has been argued that light curve modelling alone cannot provide a unique solution for the progenitor and explosion properties of SNe II. We develop a robust method which helps us to constrain the physical parameters of SNe II by fitting simultaneously their bolometric light curve and the evolution of the photospheric velocity to hydrodynamical models using statistical inference techniques. Pre-supernova red supergiant models were created using the stellar evolution code MESA, varying the initial progenitor mass. The explosion of these progenitors was then processed through hydrodynamical simulations, where the explosion energy, synthesised nickel mass, and the latter's spatial distribution within the ejecta were changed. We compare to observations via Markov chain Monte Carlo methods. We apply this method to a well-studied set of SNe with an observed progenitor in pre-explosion images and compare with results in the literature. Progenitor mass constraints are found to be consistent between our results and those derived by pre-SN imaging and the analysis of late-time spectral modelling. We have developed a robust method to infer progenitor and explosion properties of SN II progenitors which is consistent with other methods in the literature, which suggests that hydrodynamical modelling is able to accurately constrain physical properties of SNe II.

  • UBVRIz Light Curves of 51 Type II Supernovae
    The Astronomical Journal, 2016
    Co-Authors: Lluís Galbany, Mario Hamuy, Santiago González-gaitán, Mark M. Phillips, Nicholas B. Suntzeff, Jose Maza, Thomas De Jaeger, Tania Moraga, Kevin Krisciunas, Nidia Morrell
    Abstract:

    We present a compilation of UBV RIz light curves of 51 Type II Supernovae discovered during the course of four different surveys during 1986 to 2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being thus shorter (longer) for larger (smaller) s values.

  • A HUBBLE DIAGRAM from Type II Supernovae BASED SOLELY on PHOTOMETRY: The PHOTOMETRIC COLOR METHOD
    The Astrophysical Journal, 2015
    Co-Authors: T. De Jaeger, Claudia P. Gutiérrez, Joseph P. Anderson, Mario Hamuy, Santiago González-gaitán, Maximilian Stritzinger, Mark M. Phillips, Luis Bolt, Lluís Galbany, Christopher R. Burns
    Abstract:

    We present a Hubble diagram of Type II Supernovae using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I (CSP) for which optical and near-infrared light-curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a colour term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) colour and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric colour method (PCM) with the standardised candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag which compares with 0.43 mag from the PCM, for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of Supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow-up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data. Subject headings: cosmology: distance scale – galaxies: distances and redshifts – Stars: Supernovae: general

  • The rise-time of Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2015
    Co-Authors: Santiago González-gaitán, Claudia P. Gutiérrez, Joseph P. Anderson, Lluís Galbany, Nozomu Tominaga, Juan Molina, Filomena Bufano, Francisco Förster, G. Pignata, Melina C. Bersten
    Abstract:

    We investigate the early-time light-curves of a large sample of 223 Type II Supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g ′ -band (λeff = 4722u we find a distribution of fast rise-times with median of (7.5±0.3) days. Comparing these durations with analytical shock models of Rabinak & Waxman (2013); Nakar & Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radII. The inferred radII are on average much smaller than the radII obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.

  • The Rise-Time of Type II Supernovae
    arXiv: Solar and Stellar Astrophysics, 2015
    Co-Authors: Santiago González-gaitán, Claudia P. Gutiérrez, Joseph P. Anderson, Lluís Galbany, Nozomu Tominaga, Juan Molina, Filomena Bufano, Francisco Förster, G. Pignata, Melina C. Bersten
    Abstract:

    We investigate the early-time light-curves of a large sample of 223 Type II Supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g-band (4722A), we find a distribution of fast rise-times with median of (7.5+/-0.3) days. Comparing these durations with analytical shock models of Rabinak and Waxman (2013); Nakar and Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radII. The inferred radII are on average much smaller than the radII obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.

Joseph P. Anderson - One of the best experts on this subject based on the ideXlab platform.

  • Progenitor properties of Type II Supernovae: fitting to hydrodynamical models using Markov chain Monte Carlo methods
    Astronomy & Astrophysics, 2020
    Co-Authors: Laureano Martinez, Joseph P. Anderson, Santiago González-gaitán, Francisco Förster, Melina C. Bersten, Gastón Folatelli
    Abstract:

    The progenitor and explosion properties of Type II Supernovae (SNe II) are fundamental to understand the evolution of massive stars. Special interest has been given to the range of initial masses of their progenitors, but despite the efforts made, it is still uncertain. Direct imaging of progenitors in pre-explosion images point out an upper initial mass cutoff of $\sim$18$M_{\odot}$. However, this is in tension with previous studies in which progenitor masses inferred by light curve modelling tend to favour high-mass solutions. Moreover, it has been argued that light curve modelling alone cannot provide a unique solution for the progenitor and explosion properties of SNe II. We develop a robust method which helps us to constrain the physical parameters of SNe II by fitting simultaneously their bolometric light curve and the evolution of the photospheric velocity to hydrodynamical models using statistical inference techniques. Pre-supernova red supergiant models were created using the stellar evolution code MESA, varying the initial progenitor mass. The explosion of these progenitors was then processed through hydrodynamical simulations, where the explosion energy, synthesised nickel mass, and the latter's spatial distribution within the ejecta were changed. We compare to observations via Markov chain Monte Carlo methods. We apply this method to a well-studied set of SNe with an observed progenitor in pre-explosion images and compare with results in the literature. Progenitor mass constraints are found to be consistent between our results and those derived by pre-SN imaging and the analysis of late-time spectral modelling. We have developed a robust method to infer progenitor and explosion properties of SN II progenitors which is consistent with other methods in the literature, which suggests that hydrodynamical modelling is able to accurately constrain physical properties of SNe II.

  • Luminous Type II Supernovae for their low expansion velocities
    arXiv: High Energy Astrophysical Phenomena, 2019
    Co-Authors: O. Rodriguez, Joseph P. Anderson, Takashi J. Moriya, Mark M. Phillips, Francisco Förster, G. Pignata, Alejandro Clocchiatti, J. L. Prieto, Christopher R. Burns, C. Contreras
    Abstract:

    We present optical and near-IR data of three Type II Supernovae (SNe II), SN 2008bm, SN 2009aj, and SN 2009au. These SNe display the following common characteristics: signs of early interaction of the ejecta with circumstellar material (CSM), blue $B\!-\!V$ colours, weakness of metal lines, low expansion velocities, and $V$-band absolute magnitudes 2-3 mag brighter than those expected for normal SNe II based on their expansion velocities. Two more SNe reported in the literature (SN 1983K and LSQ13fn) share properties similar to our sample. Analysing this set of five SNe II, which are luminous for their low expansion velocities (LLEV), we find that their properties can be reproduced assuming ejecta-CSM interaction that lasts between 4-11 weeks post explosion. The contribution of this interaction to the radiation field seems to be the dominant component determining the observed weakness of metal lines in the spectra rather than the progenitor metallicity. Based on hydrodynamic simulations, we find that the interaction of the ejecta with a CSM of ~3.6 M$_\odot$ can reproduce the light curves and expansion velocities of SN 2009aj. Using data collected by the Chilean Automatic Supernova Search, we estimate an upper limit for the LLEV SNe II fraction to be 2-4 per cent of all normal SNe II. With the current data-set, it is not clear whether the LLEV events are a separated class of SNe II with a different progenitor system, or whether they are the extreme of a continuum mediated by CSM interaction with the rest of the normal SN II population.

  • Comparison of the optical light curves of hydrogen-rich and hydrogen-poor Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: P. J. Pessi, Joseph P. Anderson, Mario Hamuy, Christopher R. Burns, C. Contreras, G. Folatelli, S. Davis, M. Bersten, B. Englert, Eric Hsiao
    Abstract:

    Type II Supernovae (SNe II) show strong hydrogen features in their spectra throughout their whole evolution while Type IIb Supernovae (SNe IIb) spectra evolve from dominant hydrogen lines at early times to increasingly strong helium features later on. However, it is currently unclear whether the progenitors of these supernova (SN) Types form a continuum in pre-SN hydrogen mass or whether they are physically distinct. SN light-curve morphology directly relates to progenitor and explosion properties such as the amount of hydrogen in the envelope, the pre-SN radius, the explosion energy and the synthesized mass of radioactive material. In this work we study the morphology of the optical-wavelength light curves of hydrogen-rich SNe II and hydrogen-poor SNe IIb to test whether an observational continuum exists between the two. Using a sample of 95 SNe (73 SNe II and 22 SNe IIb), we define a range of key observational parameters and present a comparative analysis between both Types. We find a lack of events that bridge the observed properties of SNe II and SNe IIb. Light curve parameters such as rise times and post-maximum decline rates and curvatures clearly separate both SN Types and we therefore conclude that there is no continuum, with the two SN Types forming two observationally distinct families. In the V-band a rise time of 17 days (SNe II lower, SNe IIb higher), and a magnitude difference between 30 and 40 days post explosion of 0.4 mag (SNe II lower, SNe IIb higher) serve as approximate thresholds to differentiate both Types.

  • A HUBBLE DIAGRAM from Type II Supernovae BASED SOLELY on PHOTOMETRY: The PHOTOMETRIC COLOR METHOD
    The Astrophysical Journal, 2015
    Co-Authors: T. De Jaeger, Claudia P. Gutiérrez, Joseph P. Anderson, Mario Hamuy, Santiago González-gaitán, Maximilian Stritzinger, Mark M. Phillips, Luis Bolt, Lluís Galbany, Christopher R. Burns
    Abstract:

    We present a Hubble diagram of Type II Supernovae using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I (CSP) for which optical and near-infrared light-curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a colour term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) colour and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric colour method (PCM) with the standardised candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag which compares with 0.43 mag from the PCM, for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of Supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow-up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data. Subject headings: cosmology: distance scale – galaxies: distances and redshifts – Stars: Supernovae: general

  • The rise-time of Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2015
    Co-Authors: Santiago González-gaitán, Claudia P. Gutiérrez, Joseph P. Anderson, Lluís Galbany, Nozomu Tominaga, Juan Molina, Filomena Bufano, Francisco Förster, G. Pignata, Melina C. Bersten
    Abstract:

    We investigate the early-time light-curves of a large sample of 223 Type II Supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g ′ -band (λeff = 4722u we find a distribution of fast rise-times with median of (7.5±0.3) days. Comparing these durations with analytical shock models of Rabinak & Waxman (2013); Nakar & Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radII. The inferred radII are on average much smaller than the radII obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.

Claudia P. Gutiérrez - One of the best experts on this subject based on the ideXlab platform.

  • A HUBBLE DIAGRAM from Type II Supernovae BASED SOLELY on PHOTOMETRY: The PHOTOMETRIC COLOR METHOD
    The Astrophysical Journal, 2015
    Co-Authors: T. De Jaeger, Claudia P. Gutiérrez, Joseph P. Anderson, Mario Hamuy, Santiago González-gaitán, Maximilian Stritzinger, Mark M. Phillips, Luis Bolt, Lluís Galbany, Christopher R. Burns
    Abstract:

    We present a Hubble diagram of Type II Supernovae using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I (CSP) for which optical and near-infrared light-curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a colour term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) colour and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric colour method (PCM) with the standardised candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag which compares with 0.43 mag from the PCM, for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of Supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow-up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data. Subject headings: cosmology: distance scale – galaxies: distances and redshifts – Stars: Supernovae: general

  • The rise-time of Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2015
    Co-Authors: Santiago González-gaitán, Claudia P. Gutiérrez, Joseph P. Anderson, Lluís Galbany, Nozomu Tominaga, Juan Molina, Filomena Bufano, Francisco Förster, G. Pignata, Melina C. Bersten
    Abstract:

    We investigate the early-time light-curves of a large sample of 223 Type II Supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g ′ -band (λeff = 4722u we find a distribution of fast rise-times with median of (7.5±0.3) days. Comparing these durations with analytical shock models of Rabinak & Waxman (2013); Nakar & Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radII. The inferred radII are on average much smaller than the radII obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.

  • The Rise-Time of Type II Supernovae
    arXiv: Solar and Stellar Astrophysics, 2015
    Co-Authors: Santiago González-gaitán, Claudia P. Gutiérrez, Joseph P. Anderson, Lluís Galbany, Nozomu Tominaga, Juan Molina, Filomena Bufano, Francisco Förster, G. Pignata, Melina C. Bersten
    Abstract:

    We investigate the early-time light-curves of a large sample of 223 Type II Supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g-band (4722A), we find a distribution of fast rise-times with median of (7.5+/-0.3) days. Comparing these durations with analytical shock models of Rabinak and Waxman (2013); Nakar and Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radII. The inferred radII are on average much smaller than the radII obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.

  • Analysis of blueshifted emission peaks in Type II Supernovae
    Monthly Notices of the Royal Astronomical Society, 2014
    Co-Authors: Joseph P. Anderson, Claudia P. Gutiérrez, Mario Hamuy, Gastón Folatelli, Nidia Morrell, Maximilian Stritzinger, Mark M. Phillips, Luc Dessart, Wendy L. Freedman, Santiago González-gaitán
    Abstract:

    In classical P-Cygni profiles, theory predicts emission to p eak at zero rest velocity. However, supernova spectra exhibit emission that is generally blue shifted. While this characteristic has been reported in many Supernovae, it is rarely discussed in any detail. Here we present an analysis of Hα emission-peaks using a dataset of 95 Type II Supernovae, quantifying their strength and time evolution. Using a post-explosion time of 30 d, we observe a systematic blueshift of Hα emission, with a mean value of ‐2000 km s 1 . This offset is greatest at early times but vanishes as Supernovae become nebular. Simulations of Dessart et al. (2013) match the observed behaviour, reproducing both its strength and evolution in time. Such blueshifts are a fundamental feature of supernova spectra as they are intimately tied to the density distribution of ejecta, which falls more rapidly than in stellar wi nds. This steeper density structure causes line emission/absorption to be much more confined; it also exacerbates the occultation of the receding part of the ejecta, biasing line emission to t he blue for a distant observer. We conclude that blue-shifted emission-peak offsets of sever al thousand km s 1 are a generic property of observations, confirmed by models, of photosphe ric-phase Type II Supernovae.

  • Hα Spectral Diversity of Type II Supernovae: Correlations with Photometric Properties
    The Astrophysical Journal, 2014
    Co-Authors: Claudia P. Gutiérrez, Joseph P. Anderson, Mario Hamuy, Gastón Folatelli, Santiago González-gaitán, Nidia Morrell, Maximilian Stritzinger, Mark M. Phillips, Patrick J. Mccarthy, Nicholas B. Suntzeff
    Abstract:

    We present a spectroscopic analysis of the H{sub α} profiles of hydrogen-rich Type II Supernovae. A total of 52 Type II Supernovae having well-sampled optical light curves and spectral sequences were analyzed. Concentrating on the H{sub α} P-Cygni profile we measure its velocity from the FWHM of the emission and the ratio of absorption to emission (a/e) at a common epoch at the start of the recombination phase, and search for correlations between these spectral parameters and photometric properties of the V-band light curves. Testing the strength of various correlations we find that a/e appears to be the dominant spectral parameter in terms of describing the diversity in our measured supernova properties. It is found that Supernovae with smaller a/e have higher H{sub α} velocities, more rapidly declining light curves from maximum during the plateau and radioactive tail phase, are brighter at maximum light, and have shorter optically thick phase durations. We discuss possible explanations of these results in terms of physical properties of Type II Supernovae, speculating that the most likely parameters that influence the morphologies of H{sub α} profiles are the mass and density profile of the hydrogen envelope, together with additional emission components due to circumstellar interaction.

Samantha K. Cargill - One of the best experts on this subject based on the ideXlab platform.

  • the berkeley sample of Type II Supernovae bvri light curves and spectroscopy of 55 sne II
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: T. De Jaeger, Weikang Zheng, Benjamin E. Stahl, A. V. Filippenko, Thomas G. Brink, A. Bigley, Kyle Blanchard, P. K. Blanchard, J. Bradley, Samantha K. Cargill
    Abstract:

    In this work, BVRI light curves of 55 Type II Supernovae (SNe II) from the Lick Observatory Supernova Search programme obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 d for a total of 5093 photometric points. In average, V-band plateau declines with a rate of 1.29 mag (100 d)^−1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudo-equivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 d post-explosion and has a median ejecta expansion velocity at 50 d post-explosion of 6500 km s^−1 (H α line) and a standard dispersion of 2000 km s^−1. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16M_⊙. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators.

  • The Berkeley sample of Type II Supernovae: BVRI light curves and spectroscopy of 55 SNe II
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: T. De Jaeger, Weikang Zheng, Benjamin E. Stahl, A. V. Filippenko, Thomas G. Brink, A. Bigley, Kyle Blanchard, P. K. Blanchard, J. Bradley, Samantha K. Cargill
    Abstract:

    In this work, BVRI light curves of 55 Type II Supernovae (SNe II) from the Lick Observatory Supernova Search programme obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 d for a total of 5093 photometric points. In average, V-band plateau declines with a rate of 1.29 mag (100 d)^−1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudo-equivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 d post-explosion and has a median ejecta expansion velocity at 50 d post-explosion of 6500 km s^−1 (H α line) and a standard dispersion of 2000 km s^−1. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass

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