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451. Velocities and EW of PTF SNe Ia
ID:
ivo://CDS.VizieR/J/MNRAS/444/3258
Title:
Velocities and EW of PTF SNe Ia
Short Name:
J/MNRAS/444/3258
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an investigation of the optical spectra of 264 low-redshift (z<0.2) Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory, an untargeted transient survey. We focus on velocity and pseudo-equivalent width measurements of the SiII 4130, 5972, and 6355{AA} lines, as well those of the CaII near-infrared (NIR) triplet, up to +5days relative to the SN B-band maximum light. We find that a high-velocity component of the CaII NIR triplet is needed to explain the spectrum in ~95% of SNe Ia observed before -5days, decreasing to ~80% at maximum. The average velocity of the CaII high-velocity component is ~8500km/s higher than the photospheric component. We confirm previous results that SNe Ia around maximum light with a larger contribution from the high-velocity component relative to the photospheric component in their CaII NIR feature have, on average, broader light curves and lower CaII NIR photospheric velocities. We find that these relations are driven by both a stronger high-velocity component and a weaker contribution from the photospheric CaII NIR component in broader light curve SNe Ia. We identify the presence of CII in very-early-time SN Ia spectra (before -10days), finding that >40% of SNe Ia observed at these phases show signs of unburnt material in their spectra, and that CII features are more likely to be found in SNe Ia having narrower light curves.
452. VRIJHK photometry of SN 2002cv
ID:
ivo://CDS.VizieR/J/MNRAS/384/107
Title:
VRIJHK photometry of SN 2002cv
Short Name:
J/MNRAS/384/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present VRIJHK photometry, and optical and near-infrared spectroscopy, of the heavily extinguished Type Ia supernova (SN Ia) 2002cv, located in NGC 3190, which is also the parent galaxy of the SN Ia 2002bo. SN 2002cv, not visible in the blue, has a total visual extinction of 8.74+/-0.21mag. In spite of this, we were able to obtain the light curves between 10 and +207d from the maximum in the I band, and also to follow the spectral evolution, deriving its key parameters. We found the peak I-band brightness to be I_max_=16.57+/-0.10mag, the maximum absolute I magnitude to be M_max_I=18.79+/-0.20, and the parameter {delta}m15(B) specifying the width of the B-band light curve to be 1.46+/-0.17mag. The latter was derived using the relations between this parameter and {delta}m40(I) and the time-interval {delta}t_max_(I) between the two maxima in the I-band light curve. As has been found for previously observed, highly extinguished SNe Ia, a small value of 1.59+/-0.07 was obtained here for the ratio RV of the total-to-selective extinction ratio for SN 2002cv, which implies a small mean size for the grains along the line of sight towards us. Since it was found for SN 2002bo a canonical value of 3.1, here we present a clear evidence of different dust properties inside NGC 3190.
453. X-ray emission from 28 SNe (IIn, Ibn or SLSN-I)
ID:
ivo://CDS.VizieR/J/ApJ/763/42
Title:
X-ray emission from 28 SNe (IIn, Ibn or SLSN-I)
Short Name:
J/ApJ/763/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
Here we report on a search, using Swift/XRT and Chandra, for X-ray emission from 28 SNe that belong to classes whose progenitors are suspected to be embedded in dense circumstellar matter (CSM). Our sample includes 19 Type IIn SNe, one Type Ibn SN, and eight hydrogen-poor superluminous SNe (SLSN-I such as SN 2005ap). Two SNe (SN 2006jc and SN 2010jl) have X-ray properties that are roughly consistent with the expectation for X-rays from a collisionless shock in optically thick CSM. However, the X-ray emission from SN 2006jc can also be explained as originating in an optically thin region. Thus, we propose that the optical light curve of SN 2010jl is powered by shock breakout in CSM. We suggest that two other events (SN 2010al and SN 2011ht) were too X-ray bright during the SN maximum optical light to be explained by the shock-breakout model. We conclude that the light curves of some, but not all, SNe IIn/Ibn are powered by shock breakout in CSM. For the rest of the SNe in our sample, including all of the SLSN-I events, our X-ray limits are not deep enough and were typically obtained too early (i.e., near the SN maximum light) for definitive conclusions about their nature. Late-time X-ray observations are required in order to further test whether these SNe are indeed embedded in dense CSM.
454. Yields of Fe and Zn for different types of SNe
ID:
ivo://CDS.VizieR/J/ApJ/855/63
Title:
Yields of Fe and Zn for different types of SNe
Short Name:
J/ApJ/855/63
Date:
21 Oct 2021
Publisher:
CDS
Description:
The heaviest iron-peak element Zinc (Zn) has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show an increasing trend of [Zn/Fe] ratios toward lower metallicity. However, the enrichment of Zn in galaxies is not well understood due to poor knowledge of astrophysical sites of Zn, as well as metal mixing in galaxies. Here we show possible explanations for the observed trend by taking into account electron-capture supernovae (ECSNe) as one of the sources of Zn in our chemodynamical simulations of dwarf galaxies. We find that the ejecta from ECSNe contribute to stars with [Zn/Fe]>~0.5. We also find that scatters of [Zn/Fe] in higher metallicities originate from the ejecta of type Ia supernovae. On the other hand, it appears difficult to explain the observed trends if we do not consider ECSNe as a source of Zn. These results come from an inhomogeneous spatial metallicity distribution due to the inefficiency of the metal mixing. We find that the optimal value of the scaling factor for the metal diffusion coefficient is ~0.01 in the shear- based metal mixing model in smoothed particle hydrodynamics simulations. These results suggest that ECSNe could be one of the contributors of the enrichment of Zn in galaxies.
455. YJK for Type Ia supernovae
ID:
ivo://CDS.VizieR/J/MNRAS/448/1345
Title:
YJK for Type Ia supernovae
Short Name:
J/MNRAS/448/1345
Date:
21 Oct 2021
Publisher:
CDS
Description:
Type Ia supernovae (SNe Ia) have been proposed to be much better distance indicators at near-infrared (NIR) compared to optical wavelengths - the effect of dust extinction is expected to be lower and it has been shown that SNe Ia behave more like `standard candles' at NIR wavelengths. To better understand the physical processes behind this increased uniformity, we have studied the Y, J and H-filter light curves of 91 SNe Ia from the literature. We show that the phases and luminosities of the first maximum in the NIR light curves are extremely uniform for our sample. The phase of the second maximum, the late-phase NIR luminosity and the optical light-curve shape are found to be strongly correlated, in particular more luminous SNe Ia reach the second maximum in the NIR filters at a later phase compared to fainter objects. We also find a strong correlation between the phase of the second maximum and the epoch at which the SN enters the Lira law phase in its optical colour curve (epochs ~15 to 30d after B-band maximum). The decline rate after the second maximum is very uniform in all NIR filters. We suggest that these observational parameters are linked to the nickel and iron mass in the explosion, providing evidence that the amount of nickel synthesized in the explosion is the dominating factor shaping the optical and NIR appearance of SNe Ia.
456. Z-dependent yields of double detonations
ID:
ivo://CDS.VizieR/J/A+A/656/A94
Title:
Z-dependent yields of double detonations
Short Name:
J/A+A/656/A94
Date:
22 Feb 2022
Publisher:
CDS
Description:
Double detonations in sub-Chandrasekhar mass carbon-oxygen white dwarfs with helium shell are a potential explosion mechanism for a Type Ia supernova. It comprises a shell detonation and subsequent core detonation. The focus of our study is on the effect of the progenitor metallicity on the nucleosynthetic yields. For this, we compute and analyse a set of eleven different models with varying core and shell masses at four different metallicities each. This results in a total of 44 models at metallicities between 0.01Z_{sun}_ and 3Z_{sun}_. Our models show a strong impact of the metallicity in the high density regime. The presence of ^22^$Ne causes a neutron-excess which shifts the production from ^56^Ni to stable isotopes such as ^54^Fe and ^58^Ni in the {alpha}-rich freeze-out regime. The isotopes of the metallicity implementation further serve as seed nuclei for additional reactions in the shell detonation. Most significantly, the production of ^55^Mn increases with metallicity confirming the results of previous work. A comparison of elemental ratios relative to iron shows a relatively good match to solar values for some models. Super-solar values are reached for Mn at 3Z_{sun}_ and solar values in some models at Z_{sun}_. This indicates that the required contribution of Type Ia supernovae originating from Chandrasekhar mass WDs can be lower than estimated in previous work to reach solar values of [Mn/Fe] at [Fe/H]=0. Our galactic chemical evolution models suggest that Type Ia supernovae from sub-Chandrasekhar mass white dwarfs, along with core-collapse supernovae, could account for more than 80% of the solar Mn abundance. Using metallicity-dependent Type Ia supernova yields helps to reproduce the upward trend of [Mn/Fe] as a function of metallicity for the solar neighborhood. These chemical evolution predictions, however, depend on the massive star yields adopted in the calculations.
457. ZTF early observations of Type Ia SNe. I. LCs
ID:
ivo://CDS.VizieR/J/ApJ/886/152
Title:
ZTF early observations of Type Ia SNe. I. LCs
Short Name:
J/ApJ/886/152
Date:
21 Oct 2021
Publisher:
CDS
Description:
Early-time observations of Type Ia supernovae (SNe Ia) are essential to constrain the properties of their progenitors. In this paper, we present high-quality light curves of 127 SNe Ia discovered by the Zwicky Transient Facility (ZTF) in 2018. We describe our method to perform forced point-spread function photometry, which can be applied to other types of extragalactic transients. With a planned cadence of six observations per night (three g + three r), all of the 127 SNe Ia are detected in both g and r bands more than 10 days (in the rest frame) prior to the epoch of g-band maximum light. The redshifts of these objects range from z=0.0181 to 0.165; the median redshift is 0.074. Among the 127 SNe, 50 are detected at least 14 days prior to maximum light (in the rest frame), with a subset of nine objects being detected more than 17 days before g-band peak. This is the largest sample of young SNe Ia collected to date; it can be used to study the shape and color evolution of the rising light curves in unprecedented detail. We discuss six peculiar events in this sample: one 02cx-like event ZTF18abclfee (SN2018crl), one Ia-CSM SN ZTF18aaykjei (SN2018cxk), and four objects with possible super-Chandrasekhar mass progenitors: ZTF18abhpgje (SN2018eul), ZTF18abdpvnd (SN2018dvf), ZTF18aawpcel (SN2018cir), and ZTF18abddmrf (SN2018dsx).
458. Zwicky Transient Facility BTS. I.
ID:
ivo://CDS.VizieR/J/ApJ/895/32
Title:
Zwicky Transient Facility BTS. I.
Short Name:
J/ApJ/895/32
Date:
16 Mar 2022 00:25:08
Publisher:
CDS
Description:
The Zwicky Transient Facility (ZTF) is performing a three-day cadence survey of the visible northern sky (~3{pi}) with newly found transient candidates announced via public alerts. The ZTF Bright Transient Survey (BTS) is a large spectroscopic campaign to complement the photometric survey. BTS endeavors to spectroscopically classify all extragalactic transients with m_peak_<~18.5mag in either the g_ZTF_ or r_ZTF_ filters, and publicly announce said classifications. BTS discoveries are predominantly supernovae (SNe), making this the largest flux-limited SN survey to date. Here we present a catalog of 761 SNe, classified during the first nine months of ZTF (2018 April 1-2018 December 31). We report BTS SN redshifts from SN template matching and spectroscopic host-galaxy redshifts when available. We analyze the redshift completeness of local galaxy catalogs, the redshift completeness fraction (RCF; the ratio of SN host galaxies with known spectroscopic redshift prior to SN discovery to the total number of SN hosts). Of the 512 host galaxies with SNe Ia, 227 had previously known spectroscopic redshifts, yielding an RCF estimate of 44%{+/-}4%. The RCF decreases with increasing distance and decreasing galaxy luminosity (for z<0.05, or ~200Mpc, RCF~0.6). Prospects for dramatically increasing the RCF are limited to new multifiber spectroscopic instruments or wide-field narrowband surveys. Existing galaxy redshift catalogs are only ~50% complete at r~16.9mag. Pushing this limit several magnitudes deeper will pay huge dividends when searching for electromagnetic counterparts to gravitational wave events or sources of ultra-high-energy cosmic rays or neutrinos.