SN 2009md: another faint supernova from a low-mass progenitor (original) (raw)
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SN 2008in—BRIDGING THE GAP BETWEEN NORMAL AND FAINT SUPERNOVAE OF TYPE IIP
The Astrophysical Journal, 2011
We present optical photometric and low-resolution spectroscopic observations of the Type II plateau supernova (SN) 2008in, which occurred in the outskirts of the nearly face-on spiral galaxy M 61. Photometric data in the X-rays, ultraviolet and near-infrared bands have been used to characterize this event. The SN field was imaged with the ROTSE-IIIb optical telescope about seven days before the explosion. This allowed us to constrain the epoch of the shock breakout to JD = 2454825.6. The duration of the plateau phase, as derived from the photometric monitoring, was ∼ 98 days. The spectra of SN 2008in show a striking resemblance to those of the archetypal low-luminosity IIP SNe 1997D and 1999br. A comparison of ejecta kinematics of SN 2008in with the hydrodynamical simulations of Type IIP SNe by indicates that it is a less energetic event (∼ 5 × 10 50 erg). However, the light curve indicates that the production of radioactive 56 Ni is significantly higher than that in the low-luminosity SNe. Adopting an interstellar absorption along the SN direction of A V ∼ 0.3 mag and a distance of 13.2 Mpc, we estimated a synthesized 56 Ni mass of ∼ 0.015M ⊙ . Employing semi-analytical formulae (Litvinova & Nadezhin 1985), we derived a pre-SN radius of ∼ 126R ⊙ , an explosion energy of ∼ 5.4 × 10 50 erg and a total ejected mass of ∼ 16.7M ⊙ . The latter indicates that the zero age main-sequence mass of the progenitor did not exceed 20M ⊙ . Considering the above properties of SN 2008in and its occurrence in a region of sub-solar metallicity ([O/H] ∼ 8.44 dex), it is unlikely that fall-back of the ejecta onto a newly formed black hole occurred in SN 2008in. We therefore favor a low-energy explosion scenario of a relatively compact, moderate-mass progenitor star that generates a neutron star.
Supernova 2012aw - a high-energy clone of archetypal Type IIP SN 1999em
Monthly Notices of the Royal Astronomical Society, 2013
We present densely-sampled U BV RI/griz photometric and low-resolution (6-10Å) optical spectroscopic observations from 4 to 270 days after explosion of a newly discovered type II SN 2012aw in a nearby (∼9.9 Mpc) galaxy M95. The light-curve characteristics of apparent magnitudes, colors, bolometric luminosity and the presence and evolution of prominent spectral features are found to have striking similarity with the archetypal IIP SNe 1999em, 1999gi and 2004et. The early time observations of SN 2012aw clearly detect minima in the light-curve of V , R and I bands near 37 days after explosion and this we suggest to be an observational evidence for emergence of recombination phase. The mid-plateau M V magnitude (−16.67 ± 0.04) lies in between the bright (∼ −18) and subluminous (∼ −15) IIP SNe. The mass of nickel is 0.06 ± 0.01 M ⊙. The SYNOW modelling of spectra indicate that the value and evolution of photospheric velocity is similar to SN 2004et, but about ∼600 km s −1 higher than that of SNe 1999em and 1999gi at comparable epochs. This trend is more apparent in the line velocities of Hα and Hβ. A comparison of ejecta velocity properties with that of existing radiation-hydrodynamical simulations indicate that the energy of explosion lies in the range 1-2×10 51 ergs; a further comparison of nebular phase [O i] doublet luminosity with SNe 2004et and 1987A indicate that the mass of progenitor star is about 14-15 M ⊙. The presence of high-velocity absorption features in the mid-to-late plateau and possibly in early phase spectra show signs of interaction between ejecta and the circumstellar matter; being consistent with its early-time detection at X-ray and radio wavebands.
A low-luminosity core-collapse supernova very similar to SN 2005cs
Monthly Notices of the Royal Astronomical Society, 2020
We present observations and analysis of PSN J17292918+7542390, a low-luminosity Type II-P supernova (LL SN IIP). The observed sample of such events is still low, and their nature is still under debate. Such SNe are similar to SN 2005cs, a well-observed LL Type II-P event, having low expansion velocities, and small ejected 56Ni mass. We have developed a robust and relatively fast Monte Carlo code that fits semi-analytic models to light curves of core-collapse SNe. This allows the estimation of the most important physical parameters, like the radius of the progenitor star, the mass of the ejected envelope, the mass of the radioactive nickel synthesized during the explosion, among others. PSN J17292918+7542390 has R0=91−70+119times1011,textcmR_0 = 91_{-70}^{+119} \times 10^{11} \, \text{cm}R0=91−70+119times1011,textcm, Mtextej=9.89−1.00+2.10,mathrmModotM_\text{ej} = 9.89_{-1.00}^{+2.10} \, \mathrm{ M}_{\odot }Mtextej=9.89_−1.00+2.10,mathrmModot, Emboxkin=0.65−0.18+0.19,textfoeE_{\mbox{kin}} = 0.65_{-0.18}^{+0.19} \, \text{foe}Emboxkin=0.65_−0.18+0.19,textfoe, and vmboxexp=3332−347+216v_{\mbox{exp}} = 3332_{-347}^{+216}vmboxexp=3332−347+216 km s−1, for its progenitor radius, ejecta mass, kinetic energy, ...
The Astrophysical Journal, 2008
SN 2006tf is the third most luminous supernova (SN) discovered so far, after SN 2005ap and SN 2006gy. SN 2006tf is valuable because it provides a link between two regimes: (1) luminous type IIn supernovae powered by emission directly from interaction with circumstellar material (CSM), and (2) the most extremely luminous SNe where the CSM interaction is so optically thick that energy must diffuse out from an opaque shocked shell. As SN 2006tf evolves, it slowly transitions from the second to the first regime as the clumpy shell becomes more porous. This link suggests that the range in properties of the most luminous SNe is largely determined by the density and speed of hydrogen-rich material ejected shortly before they explode. The total energy radiated by SN 2006tf was at least 7 × 10 50 ergs. If the bulk of this luminosity came from the thermalization of shock kinetic energy, then the star needs to have ejected ∼18 M ⊙ in the 4-8 yr before core collapse, and another 2-6 M ⊙ in the decades before that. A Type Ia explosion is therefore excluded. From the Hα emission-line profile, we derive a blast-wave speed of 2,000 km s −1 that does not decelerate, and from the narrow P Cygni absorption from pre-shock gas we deduce that the progenitor's wind speed was ∼190 km s −1. This is reminiscent of the wind speeds of luminous blue variables (LBVs), but not of red supergiants or Wolf-Rayet stars. We propose that like SN 2006gy, SN 2006tf marked the death of a very massive star that retained a hydrogen envelope until the end of its life, and suffered extreme LBV-like mass loss in the decades before it exploded.
Low luminosity Type II supernovae - II. Pointing towards moderate mass precursors
Monthly Notices of the Royal Astronomical Society, 2014
We present new data for five under-luminous type II-plateau supernovae (SNe IIP), namely SN 1999gn, SN 2002gd, SN 2003Z, SN 2004eg and SN 2006ov. This new sample of low-luminosity SNe IIP (LL SNe IIP) is analyzed together with similar objects studied in the past. All of them show a flat light curve plateau lasting about 100 days, an under luminous late-time exponential tail, intrinsic colours that are unusually red, and spectra showing prominent and narrow P-Cygni lines. A velocity of the ejected material below 10 3 km s −1 is inferred from measurements at the end of the plateau. The 56 Ni masses ejected in the explosion are very small ( 10 −2 M ⊙ ). We investigate the correlations among 56 Ni mass, expansion velocity of the ejecta and absolute magnitude in the middle of the plateau, confirming the main findings of Hamuy , according to which events showing brighter plateau and larger expansion velocities are expected to produce more 56 Ni. We propose that these faint objects represent the low luminosity tail of a continuous distribution in parameters space of SNe IIP. The physical properties of the progenitors at the explosion are estimated through the hydrodynamical modeling of the observables for two representative events of this class, namely SN 2005cs and SN 2008in. We find that the majority of LL SNe IIP, and quite possibly all, originate in the core-collapse of intermediate mass stars, in the mass range 10-15 M ⊙ .
Moderately luminous Type II supernovae
Astronomy & Astrophysics, 2013
Context. Core-collapse Supernovae (CC-SNe) descend from progenitors more massive than about 8 M. Because of the young age of the progenitors, the ejecta may eventually interact with the circumstellar medium (CSM) via highly energetic processes detectable in the radio, X-ray, ultraviolet (UV) and, sometimes, in the optical domains. Aims. In this paper we present ultraviolet, optical and near infrared observations of five Type II SNe, namely SNe 2009dd, 2007pk, 2010aj, 1995ad, and 1996W. Together with few other SNe they form a group of moderately luminous Type II events. We investigate the photometric similarities and differences among these bright objects. We also attempt to characterise them by analysing the spectral evolutions, in order to find some traces of CSM-ejecta interaction. Methods. We collected photometry and spectroscopy with several telescopes in order to construct well-sampled light curves and spectral evolutions from the photospheric to the nebular phases. Both photometry and spectroscopy indicate a degree of heterogeneity in this sample. Modelling the data of SNe 2009dd, 2010aj and 1995ad allows us to constrain the explosion parameters and the properties of the progenitor stars. Results. The light curves have luminous peak magnitudes (−16.95 < M B < −18.70). The ejected masses of 56 Ni for three SNe span a wide range of values (2.8 × 10 −2 M < M(56 Ni) < 1.4 × 10 −1 M), while for a fourth (SN 2010aj) we could determine a stringent upper limit (7 × 10 −3 M). Clues of interaction, such as the presence of high velocity (HV) features of the Balmer lines, are visible in the photospheric spectra of SNe 2009dd and 1996W. For SN 2007pk we observe a spectral transition from a Type IIn to a standard Type II SN. Modelling the observations of SNe 2009dd, 2010aj and 1995ad with radiation hydrodynamics codes, we infer kinetic plus thermal energies of about 0.2-0.5 foe, initial radii of 2-5 × 10 13 cm and ejected masses of ∼5.0-9.5 M. Conclusions. These values suggest moderate-mass, super-asymptotic giant branch (SAGB) or red super-giants (RSG) stars as SN precursors, in analogy with other luminous Type IIP SNe 2007od and 2009bw.
Observational properties of SNe Ia progenitors close to the explosion
Monthly Notices of the Royal Astronomical Society, 2018
We determine the expected signal in various observational bands of Supernovae Ia progenitors just before the explosion by assuming the rotating Double Degenerate scenario. Our results are valid also for all the evolutionary scenarios invoking rotation as the driving mechanism of the accretion process as well as the evolution up to the explosion. We find that the observational properties depend mainly on the mass of the exploding object, even if the angular momentum evolution after the end of the mass accretion phase and before the onset of C-burning plays a non-negligible role. Just before the explosion the magnitude M_V ranges between 9 and 11 mag, while the colour (F225W-F555W) is about -1.64 mag. The photometric properties remain constant for a few decades before the explosion. During the last few months the luminosity decreases very rapidly. The corresponding decline in the optical bands varies from few hundredths up to one magnitude, the exact value depending on both the WD tot...
The Type II supernovae 2006V and 2006au: two SN 1987A-like events
Astronomy & Astrophysics, 2012
Context. Supernova 1987A revealed that a blue supergiant (BSG) star can end its life as a core-collapse supernova (SN). SN 1987A and other similar objects exhibit properties that distinguish them from ordinary Type II Plateau (IIP) SNe, whose progenitors are believed to be red supergiants (RSGs). Similarities among 1987A-like events include a long rise to maximum, early luminosity fainter than that of normal Type IIP SNe, and radioactivity acting as the primary source powering the light curves. Aims. We present and analyze two SNe monitored by the Carnegie Supernova Project that are reminiscent of SN 1987A. Methods. Optical and near-infrared (NIR) light curves, and optical spectroscopy of SNe 2006V and 2006au are presented. These observations are compared to those of SN 1987A, and are used to estimate properties of their progenitors. Results. Both objects exhibit a slow rise to maximum and light curve evolution similar to that of SN 1987A. At the earliest epochs, SN 2006au also displays an initial dip which we interpret as the signature of the adiabatic cooling phase that ensues shock breakout. SNe 2006V and 2006au are both found to be bluer, hotter and brighter than SN 1987A. Spectra of SNe 2006V and 2006au are similar to those of SN 1987A and other normal Type II objects, although both consistently exhibit expansion velocities higher than SN 1987A. Semi-analytic models are fit to the UVOIR light curve of each object from which physical properties of the progenitors are estimated. This yields ejecta mass estimates of Mej ≈ 20 M⊙, explosion energies of E ≈ 2 − 3 × 10 51 erg, and progenitor radii of R ≈ 75 − 100 R⊙ for both SNe. Conclusions. The progenitors of SNe 2006V and 2006au were most likely BSGs with a larger explosion energy as compared to that of SN 1987A.
SN 1999ga: a low-luminosity linear type II supernova?
Astronomy and Astrophysics, 2009
Context. Type II-linear supernovae are thought to arise from progenitors that have lost most of their H envelope by the time of the explosion, and they are poorly understood because they are only occasionally discovered. It is possible that they are intrinsically rare, but selection effects due to their rapid luminosity evolution may also play an important role in limiting the number of detections. In this context, the discovery of a subluminous type II-linear event is even more interesting. Aims. We investigate the physical properties and characterise the explosion site of the type II SN 1999ga, which exploded in the nearby spiral galaxy NGC 2442. Methods. Spectroscopic and photometric observations of SN 1999ga allow us to constrain the energetics of the explosion and to estimate the mass of the ejected material, shedding light on the nature of the progenitor star in the final stages of its life. The study of the environment in the vicinity of the explosion site provides information on a possible relation between these unusual supernovae and the properties of the galaxies hosting them. Results. Despite the lack of early-time observations, we provide reasonable evidence that SN 1999ga was probably a type II-linear supernova that ejected a few solar masses of material, with a very small amount of radioactive elements of the order of 0.01M ⊙ .
A deeper search for the progenitor of the Type Ic supernova 2002ap
Monthly Notices of the Royal Astronomical Society, 2007
Images of the site of the Type Ic Supernova 2002ap taken before explosion were analysed previously by Smartt et al. (2002). We have uncovered new unpublished, archival pre-explosion images from the Canada-France-Hawaii Telescope (CFHT) that are vastly superior in depth and image quality. In this paper we present a further search for the progenitor star of this unusual Type Ic supernova. Aligning high-resolution Hubble Space Telescope (HST) observations of the supernova itself with the archival CFHT images allowed us to pinpoint the location of the progenitor site on the ground based observations. We find that a source visible in the B and R band pre-explosion images close to the position of the SN is (1) not coincident with the SN position within the uncertainties of our relative astrometry, and (2) is still visible ∼4.7 yrs post explosion in late-time observations taken with the William Herschel Telescope. We therefore conclude that it is not the progenitor of SN 2002ap. We derived absolute limiting magnitudes for the progenitor of M B-4.2 ± 0.5 and M R-5.1 ± 0.5. These are the deepest limits yet placed on a Type Ic supernova progenitor. We rule out all massive stars with initial masses greater than 7-8M ⊙ (the lower mass limit for stars to undergo core collapse) that have not evolved to become Wolf-Rayet stars. This is consistent with the prediction that Type Ic supernovae should result from the explosions of Wolf-Rayet stars. Comparing our luminosity limits with stellar models of single stars at appropriate metallicity (Z=0.008) and with standard mass loss rates, we find no model that produces a Wolf-Rayet star of low enough mass and luminosity to be classed as a viable progenitor. Models with twice the standard mass loss rates provide possible single star progenitors but all are initially more massive than 30-40M ⊙. We conclude that any single star progenitor must have experienced at least twice the standard mass loss rates, been initially more massive than 30 − 40M ⊙ and exploded as a W-R star of final mass 10-12M ⊙. Alternatively a progenitor star of lower initial mass may have evolved in an interacting binary system. Mazzali et al. (2002) propose such a binary scenario for the progenitor of SN 2002ap in which a star of initial mass 15-20M ⊙ is stripped by its binary companion, becoming a 5M ⊙ Wolf-Rayet star prior to explosion. We constrain any possible binary companion to a main sequence star of 20M ⊙ , a neutron star or a black hole. By combining the pre-explosion limits with the ejecta mass estimates and constraints from X-ray and radio observations we conclude that any binary interaction most likely occurred as Case B mass transfer, either with or without a subsequent common envelope evolution phase.