- ID:
- ivo://CDS.VizieR/J/MNRAS/377/1531
- Title:
- Optical & infrared photometry of SN 2004eo
- Short Name:
- J/MNRAS/377/1531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and infrared observations of the unusual Type Ia supernova (SN) 2004eo. The light curves and spectra closely resemble those of the prototypical SN 1992A, and the luminosity at maximum (M_B_=-19.08) is close to the average for a Type Ia supernova (SN Ia). However, the ejected ^56^Ni mass derived by modelling the bolometric light curve (about 0.45M_{sun}_) lies near the lower limit of the ^56^Ni mass distribution observed in normal SNe Ia. Accordingly, SN 2004eo shows a relatively rapid post-maximum decline in the light curve [{delta}m15(B)true=1.46], small expansion velocities in the ejecta and a depth ratio SiII{lambda}5972/SiII{lambda}6355 similar to that of SN 1992A. The physical properties of SN 2004eo cause it to fall very close to the boundary between the faint, low-velocity gradient and high-velocity gradient subgroups proposed by Benetti et al. Similar behaviour is seen in a few other SNe Ia. Thus, there may in fact exist a few SNe Ia with intermediate physical properties.
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- ID:
- ivo://CDS.VizieR/J/ApJ/896/165
- Title:
- Optical light curves of SN 2016hnk
- Short Name:
- J/ApJ/896/165
- Date:
- 03 Dec 2021 13:26:38
- Publisher:
- CDS
- Description:
- We present observations and modeling of SN 2016hnk, a Ca-rich supernova (SN) that is consistent with being the result of a He-shell double-detonation explosion of a C/O white dwarf. We find that SN2016hnk is intrinsically red relative to typical thermonuclear SNe and has a relatively low peak luminosity (M_B_=-15.4mag), setting it apart from low-luminosity SNe Ia. SN 2016hnk has a fast-rising light curve that is consistent with other Ca-rich transients (t_r_=15days). We determine that SN 2016hnk produced 0.03+/-0.01M_{sun}_ of ^56^Ni and 0.9+/-0.3M_{sun}_ of ejecta. The photospheric spectra show strong, high-velocity CaII absorption and significant line blanketing at {lambda}<5000{AA}, making it distinct from typical (SN 2005E-like) Ca-rich SNe. SN 2016hnk is remarkably similar to SN 2018byg, which was modeled as a He-shell double-detonation explosion. We demonstrate that the spectra and light curves of SN 2016hnk are well modeled by the detonation of a 0.02M_{sun}_ helium shell on the surface of a 0.85M_{sun}_ C/O white dwarf. This analysis highlights the second observed case of a He-shell double-detonation and suggests a specific thermonuclear explosion that is physically distinct from SNe that are defined simply by their low luminosities and strong [CaII] emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/3137
- Title:
- Optical/NIR light curves of SN 2009ib
- Short Name:
- J/MNRAS/450/3137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared photometry and spectroscopy of SN 2009ib, a Type II-P supernova in NGC 1559. This object has moderate brightness, similar to those of the intermediate-luminosity SNe 2008in and 2009N. Its plateau phase is unusually long, lasting for about 130d after explosion. The spectra are similar to those of the subluminous SN 2002gd, with moderate expansion velocities. We estimate the ^56^Ni mass produced as 0.046+/-0.015M_{sun}_. We determine the distance to SN 2009ib using both the expanding photosphere method (EPM) and the standard candle method. We also apply EPM to SN 1986L, a Type II-P SN that exploded in the same galaxy. Combining the results of different methods, we conclude the distance to NGC 1559 as D=19.8+/-3.0Mpc. We examine archival, pre-explosion images of the field taken with the Hubble Space Telescope, and find a faint source at the position of the SN, which has a yellow colour [(V-I)_0_=0.85mag]. Assuming it is a single star, we estimate its initial mass as M_ZAMS_=20M_{sun}_. We also examine the possibility, that instead of the yellow source the progenitor of SN 2009ib is a red supergiant star too faint to be detected. In this case, we estimate the upper limit for the initial zero-age main sequence (ZAMS) mass of the progenitor to be ~14-17M_{sun}_. In addition, we infer the physical properties of the progenitor at the explosion via hydrodynamical modelling of the observables, and estimate the total energy as ~0.55x10^51^erg, the pre-explosion radius as ~400R_{sun}_, and the ejected envelope mass as ~15M_{sun}_, which implies that the mass of the progenitor before explosion was ~16.5-17M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/1941
- Title:
- Optical/NIR photometry of OGLE-2012-SN-006
- Short Name:
- J/MNRAS/449/1941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical observations of the peculiar Type Ibn supernova (SN Ibn) OGLE-2012-SN-006, discovered and monitored by the Optical Gravitational Lensing Experiment-IV survey, and spectroscopically followed by Public ESO Spectroscopic Survey of Transient Objects (PESSTO) at late phases. Stringent pre-discovery limits constrain the explosion epoch with fair precision to JD=2456203.8+/-4.0. The rise time to the I-band light-curve maximum is about two weeks. The object reaches the peak absolute magnitude M_I_=-19.65+/-0.19 on JD=2456218.1+/-1.8. After maximum, the light curve declines for about 25 d with a rate of 4 mag (100 d)^-1^. The symmetric I-band peak resembles that of canonical Type Ib/c supernovae (SNe), whereas SNe Ibn usually exhibit asymmetric and narrower early-time light curves. Since 25 d past maximum, the light curve flattens with a decline rate slower than that of the ^56^Co-^56^Fe decay, although at very late phases it steepens to approach that rate. However, other observables suggest that the match with the ^56^Co decay rate is a mere coincidence, and the radioactive decay is not the main mechanism powering the light curve of OGLE-2012-SN-006. An early-time spectrum is dominated by a blue continuum, with only a marginal evidence for the presence of HeI lines marking this SN type. This spectrum shows broad absorptions bluewards than 5000 {AA}, likely OII lines, which are similar to spectral features observed in superluminous SNe at early epochs. The object has been spectroscopically monitored by PESSTO from 90 to 180 d after peak, and these spectra show the typical features observed in a number of SN 2006jc-like events, including a blue spectral energy distribution and prominent and narrow ({nu}_FWHM_~1900 km/s) HeI emission lines. This suggests that the ejecta are interacting with He-rich circumstellar material. The detection of broad (10^4^ km/s) OI and CaII features likely produced in the SN ejecta (including the [OI] {lambda}{lambda}6300,6364 doublet in the latest spectra) lends support to the interpretation of OGLE-2012-SN-006 as a core-collapse event.
- ID:
- ivo://CDS.VizieR/J/ApJ/781/42
- Title:
- Optical photometry of SN 2010jl
- Short Name:
- J/ApJ/781/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive to uncertainties regarding the CSM density profile and the ejecta velocity. Here we outline a method to measure the mass of the optically thick CSM around such SNe. We present new visible-light and X-ray observations of SN 2010jl (PTF 10aaxf), including the first detection of an SN in the hard X-ray band using NuSTAR. The total radiated luminosity of SN 2010jl is extreme--at least 9x10^50^erg. By modeling the visible-light data, we robustly show that the mass of the circumstellar material within ~10^16^cm of the progenitor of SN 2010jl was in excess of 10M_{sun}_. This mass was likely ejected tens of years prior to the SN explosion. Our modeling suggests that the shock velocity during shock breakout was ~6000km/s, decelerating to ~2600km/s about 2yr after maximum light. Furthermore, our late-time NuSTAR and XMM spectra of the SN presumably provide the first direct measurement of SN shock velocity 2yr after the SN maximum light--measured to be in the range of 2000-4500km/s if the ions and electrons are in equilibrium, and >~2000km/s if they are not in equilibrium. This measurement is in agreement with the shock velocity predicted by our modeling of the visible-light data. Our observations also show that the average radial density distribution of the CSM roughly follows an r^-2^ law. A possible explanation for the >~10M_{sun}_ of CSM and the wind-like profile is that they are the result of multiple pulsational pair instability events prior to the SN explosion, separated from each other by years.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/30
- Title:
- Optical photometry of type Ia SN 2014J
- Short Name:
- J/ApJ/882/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive ground-based and Hubble Space Telescope (HST) photometry of the highly reddened, very nearby SN Ia 2014J in M82, covering the phases from 9 days before to about 900 days after the B-band maximum. SN 2014J is similar to other normal SNe Ia near the maximum light, but it shows flux excess in the B band in the early nebular phase. This excess flux emission can be due to light scattering by some structures of circumstellar materials located at a few 10^17^cm, consistent with a single-degenerate progenitor system or a double-degenerate progenitor system with mass outflows in the final evolution or magnetically driven winds around the binary system. At t~+300 to ~+500 days past the B-band maximum, the light curve of SN 2014J shows a faster decline relative to the 56Ni decay. That feature can be attributed to the significant weakening of the emission features around [FeIII]{lambda}4700 and [FeII]{lambda}5200 rather than the positron escape, as previously suggested. Analysis of the HST images taken at t>600 days confirms that the luminosity of SN 2014J maintains a flat evolution at the very late phase. Fitting the late-time pseudobolometric light curve with radioactive decay of ^56^Ni, ^57^Ni, and ^55^Fe isotopes, we obtain the mass ratio ^57^Ni/^56^Ni as 0.035+/-0.011, which is consistent with the corresponding value predicted from the 2D and 3D delayed-detonation models. Combined with early-time analysis, we propose that delayed-detonation through the single-degenerate scenario is most likely favored for SN 2014J.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1598
- Title:
- Optical spectroscopy of type Ia supernovae
- Short Name:
- J/AJ/135/1598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 432 low-dispersion optical spectra of 32 Type Ia supernovae (SNe Ia) that also have well-calibrated light curves. The coverage ranges from 6 epochs to 36 epochs of spectroscopy. Most of the data were obtained with the 1.5m Tillinghast telescope at the F.L. Whipple Observatory with typical wavelength coverage of 3700-7400{AA} and a resolution of ~7{AA}. B-band maximum; two-thirds of the SN B-band maximum; two-thirds of the SNe were observed before maximum brightness. Coverage for some SNe continues almost to the nebular phase. The consistency of the method of observation and the technique of reduction makes this an ideal data set for studying the spectroscopic diversity of SNe Ia.
- ID:
- ivo://CDS.VizieR/J/other/ApSS/347.365
- Title:
- Paired galaxies and their supernovae
- Short Name:
- J/other/ApSS/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The statistical study of SN hosts shows that there is no significant difference between morphologies of hosts in our sample and the larger general sample of SN hosts in the Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8). The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. The distributions and mean distances of SNe are consistent with previous results compiled with the larger sample. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies. SN types are not correlated with the luminosity ratio of host and neighbor galaxies in pairs. The orientation of SNe with respect to the preferred direction toward neighbor galaxy is found to be isotropic and independent of kinematical properties of the galaxy pair.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A146
- Title:
- Pair-instability supernovae models
- Short Name:
- J/A+A/566/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Both recent observations and stellar evolution models suggest that pair-instability supernovae (PISNe) could occur in the local Universe, at metallicities below Z_{sun}_/3. Previous PISN models were mostly produced at very low metallicities in the context of the early Universe. We present new PISNe models at a metallicity of Z=0.001, which are relevant for the local Universe. We take the self-consistent stellar evolutionary models of pair-instability progenitors with initial masses of 150 and 250 solar masses at metallicity of Z=0.001 by Langer et al. (2007A&A...475L..19L) and follow the evolution of these models through the supernova explosions, using a hydrodynamics stellar evolution code with an extensive nuclear network including 200 isotopes. Both models explode as PISNe without leaving a compact stellar remnant. Our models produce a nucleosynthetic pattern that is generally similar to that of Population III PISN models, which is mainly characterized by the production of large amounts of elements and a strong deficiency of the odd-charged elements. However, the odd-even effect in our models is significantly weaker than that found in Population III models. The comparison with the nucleosynthetic yields from core-collapse supernovae at a similar metallicity (Z=0.002) indicates that PISNe could have strongly influenced the chemical evolution below Z=0.002, assuming a standard initial mass function. The odd-even effect is predicted to be most prominent for the intermediate mass elements between silicon and calcium. With future observations of chemical abundances in Population II stars, our result can be used to constrain the number of PISNe that occurred during the past evolution of our Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/38
- Title:
- Palomar Transient Factory photometric observations
- Short Name:
- J/ApJ/793/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a Palomar Transient Factory (PTF) archival search for blue transients that lie in the magnitude range between "normal" core-collapse and superluminous supernovae (i.e., with -21<=M_R(peak)_<=-19). Of the six events found after excluding all interacting Type IIn and Ia-CSM supernovae, three (PTF09ge, 09axc, and 09djl) are coincident with the centers of their hosts, one (10iam) is offset from the center, and a precise offset cannot be determined for two (10nuj and 11glr). All the central events have similar rise times to the He-rich tidal disruption candidate PS1-10jh, and the event with the best-sampled light curve also has similar colors and power-law decay. Spectroscopically, PTF09ge is He-rich, while PTF09axc and 09djl display broad hydrogen features around peak magnitude. All three central events are in low star formation hosts, two of which are E+A galaxies. Our spectrum of the host of PS1-10jh displays similar properties. PTF10iam, the one offset event, is different photometrically and spectroscopically from the central events, and its host displays a higher star formation rate. Finding no obvious evidence for ongoing galactic nuclei activity or recent star formation, we conclude that the three central transients likely arise from the tidal disruption of a star by a supermassive black hole. We compare the spectra of these events to tidal disruption candidates from the literature and find that all of these objects can be unified on a continuous scale of spectral properties. The accumulated evidence of this expanded sample strongly supports a tidal disruption origin for this class of nuclear transients.
