- ID:
- ivo://CDS.VizieR/J/ApJ/900/73
- Title:
- LRS2 spectra of SN 2019neq
- Short Name:
- J/ApJ/900/73
- Date:
- 13 Jan 2022 06:37:38
- Publisher:
- CDS
- Description:
- We present a spectroscopic analysis of the recently discovered fast-evolving Type I superluminous supernova (SLSN-I) SN 2019neq (at redshift z=0.1059). We compare it to the well-studied slowly evolving SLSN-I SN 2010kd (z=0.101). Our main goal is to search for spectroscopic differences between the two groups of SLSNe-I. Differences in the spectra may reveal different ejecta compositions and explosion mechanisms. Our investigation concentrates on optical spectra observed with the 10m Hobby-Eberly Telescope Low Resolution Spectrograph-2 at McDonald Observatory during the photospheric phase. We apply the SYN++ code to model the spectra of SN 2019neq taken at -4days, +5days, and +29days from maximum light. We examine the chemical evolution and ejecta composition of the SLSN by identifying the elements and ionization states in its spectra. We find that a spectral model consisting of OIII, CoIII, and SiIV gives a SYN++ fit that is comparable to the typical SLSN-I spectral model consisting of OII, and conclude that the true identification of those lines, at least in the case of SN 2019neq, is ambiguous. Based on modeling the entire optical spectrum, we classify SN 2019neq as a fast-evolving SLSN-I having a photospheric velocity gradient of dv/dt~375km/s/day, which is among the highest velocity gradients observed for an SLSN-I. Inferring the velocity gradient from the proposed FeII{lambda}5169 feature alone would result in dv/dt~100km/s/day, which is still within the observed range of fast-evolving SLSNe-I. In addition, we derive the number density of relevant ionization states for a variety of identified elements at the epoch of the three observations. Finally, we give constraints on the lower limit of the ejecta mass and find that both SLSNe have an ejecta mass at least one order of magnitude higher than normal SNe Ia, while the fast-evolving SN 2019neq has an ejecta mass a factor of two lower than the slowly evolving SN 2010kd. These mass estimates suggest the existence of a possible correlation between the evolution timescale and the ejected mass of SLSNe-I.
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Search Results
- ID:
- ivo://CDS.VizieR/II/189
- Title:
- Magnitude Observations of Type I Supernovae
- Short Name:
- II/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations (UBV or pg) of 81 supernovae of type I are presented. Only supernovae with multiple data are included. All SNe I for which observations in at least one of the four photometric filters, pg, B, V, and U could be found up to 1989 have been included. Most of the older SNe have been observed in the pg band whereas the B filter was used for more modern observations.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A66
- Title:
- Massive runaway and walkaway stars models
- Short Name:
- J/A+A/624/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform an extensive numerical study of the evolution of massive binary systems to predict the peculiar velocities that stars obtain when their companion collapses and disrupts the system. Our aim is to (i) identify which predictions are robust against model uncertainties and assess their implications, (ii) investigate which physical processes leave a clear imprint and may, therefore, be constrained observationally and (iii) provide a suite of publicly available model predictions, to allow for the use of kinematic constraints from the Gaia mission. We find that 22^+26^_-8_% of all massive binary systems merge prior to the first core-collapse in the system. Of the remainder, 86^+11^_-9_% become unbound because of the core-collapse. Remarkably, this rarely produce runaway stars (observationally defined as stars with velocities above 30km/s). These are outnumbered by more than an order of magnitude by slower unbound companions, or "walkaway stars". This is a robust outcome of our simulations and is due to the reversal of the mass ratio prior to the explosion and widening of the orbit, as we show analytically and numerically. For stars more massive than 15M_{sun}_, we estimate that 10^+5^_-8_% are walkaways and only 0.5^+1.0^_-0.4_% are runaways, nearly all of which have accreted mass from their companion. Our findings are consistent with earlier studies, however, the low runaway fraction we find is in tension with observed fractions of about 10%. Thus, astrometric data on presently single massive stars can potentially constrain the physics of massive binary evolution. Finally, we show that the high end of the mass distributions of runaway stars is very sensitive to the assumed black hole natal kicks and propose this as a potentially stringent test for the explosion mechanism. We also discuss companions remaining bound which can evolve into X-ray and gravitational wave sources.
- ID:
- ivo://CDS.VizieR/J/other/NewA/29.65
- Title:
- MASTER polarization observations
- Short Name:
- J/other/NewA/29.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of optical polarization observations performed with the MASTER robotic net (Lipunov et al., 2004AN....325..580L, 2010, Advances in Astronomy, article id. 349171, 1; Kornilov et al., 2012, Exp. Astron., 33, p. 173) for three types of objects: gamma-ray bursts, supernovae, and blazars. For the Swift gamma-ray bursts GRB100906A, GRB110422A, GRB121011A, polarization observations were obtained during very early stages of optical emission. For GRB100906A it was the first prompt optical polarization observation in the world. Photometry in polarizers is presented for Type Ia Supernova 2012bh during 20 days, starting on March 27, 2012. We find that the linear polarization of SN 2012bh at the early stage of the envelope expansion was less than 3%. Polarization measurements for the blazars OC 457, 3C 454.3, QSO B1215+303, 87GB 165943.2+395846 at single nights are presented. We infer the degree of the linear polarization and polarization angle. The blazars OC 457 and 3C 454.3 were observed during their periods of activity. The results show that MASTER is able to measure substantially polarized light; at the same time it is not suitable for determining weak polarization (less than 5%) of dim objects (fainter than 16m). Polarimetric observations of the optical emission from gamma-ray bursts and supernovae are necessary to investigate the nature of these transient objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/L21
- Title:
- Measured photometry of SN 2014J from HST
- Short Name:
- J/ApJ/788/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The wavelength dependence of the extinction of Type Ia SN 2014J in the nearby galaxy M82 has been measured using UV to near-IR photometry obtained with the Hubble Space Telescope, the Nordic Optical Telescope, and the Mount Abu Infrared Telescope. This is the first time that the reddening of an SN Ia is characterized over the full wavelength range of 0.2-2 {mu}m. A total-to-selective extinction, R_V_>= 3.1, is ruled out with high significance. The best fit at maximum using a Galactic type extinction law yields R_V_=1.4+/-0.1. The observed reddening of SN 2014J is also compatible with a power-law extinction, A_{lambda}_/A_V_=({lambda}/{lambda}_V_)^p^ as expected from multiple scattering of light, with p=-2.1+/-0.1. After correcting for differences in reddening, SN 2014J appears to be very similar to SN 2011fe over the 14 broadband filter light curves used in our study.
- ID:
- ivo://CDS.VizieR/J/ApJ/857/51
- Title:
- Measuring dark energy properties with PS1 SNe. II.
- Short Name:
- J/ApJ/857/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 1169 Pan-STARRS supernovae (SNe) and 195 low-z (z<0.1) SNe Ia to measure cosmological parameters. Though most Pan-STARRS SNe lack spectroscopic classifications, in a previous paper we demonstrated that photometrically classified SNe can be used to infer unbiased cosmological parameters by using a Bayesian methodology that marginalizes over core-collapse (CC) SN contamination. Our sample contains nearly twice as many SNe as the largest previous SN Ia compilation. Combining SNe with cosmic microwave background (CMB) constraints from Planck, we measure the dark energy equation-of-state parameter w to be -0.989+/-0.057 (stat+sys). If w evolves with redshift as w(a)=w0+wa(1-a), we find w0=-0.912+/-0.149 and wa=-0.513+/-0.826. These results are consistent with cosmological parameters from the Joint Light-curve Analysis and the Pantheon sample. We try four different photometric classification priors for Pan-STARRS SNe and two alternate ways of modeling CC SN contamination, finding that no variant gives a w differing by more than 2% from the baseline measurement. The systematic uncertainty on w due to marginalizing over CC SN contamination, {sigma}_w_^CC^=0.012, is the third-smallest source of systematic uncertainty in this work. We find limited (1.6{sigma}) evidence for evolution of the SN color-luminosity relation with redshift, a possible systematic that could constitute a significant uncertainty in future high-z analyses. Our data provide one of the best current constraints on w, demonstrating that samples with ~5% CC SN contamination can give competitive cosmological constraints when the contaminating distribution is marginalized over in a Bayesian framework.
- ID:
- ivo://CDS.VizieR/J/A+A/587/L7
- Title:
- Metallicity from Type II SN from (i)PTF
- Short Name:
- J/A+A/587/L7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Type IIP supernovae (SNe IIP) have recently been proposed as metallicity (Z) probes. The spectral models of Dessart et al. (2014MNRAS.440.1856D) showed that the pseudo-equivalent width of FeII {lambda}5018 (pEW_5018_) during the plateau phase depends on the primordial Z, but there was a paucity of SNe IIP exhibiting pEW_5018_ that were compatible with Z<0.4Z_{sun}_. This lack might be due to some physical property of the SN II population or to the fact that those SNe have been discovered in luminous, metal-rich targeted galaxies. Here we use SN II observations from the untargeted (intermediate) Palomar Transient Factory [(i)PTF] survey, aiming to investigate the pEW_5018_ distribution of this SN population and, in particular, to look for the presence of SNe II at lower Z. We perform pEW_5018_ measurements on the spectra of a sample of 39 (i)PTF SNe II, selected to have well-constrained explosion epochs and light-curve properties. Based on the comparison with the pEW_5018_ spectral models, we subgrouped our SNe into four Z bins from Z=~0.1 Z_{sun}_ up to Z=~2 Z_{sun}_. We also independently investigated the Z of the hosts by using their absolute magnitudes and colors and, in a few cases, using strong-line diagnostics from spectra. We searched for possible correlations between SN observables, such as their peak magnitudes and the Z inferred from pEW_5018_. We found 11 events with pEW_5018_ that were small enough to indicate Z=~0.1 Z_{sun}_. The trend of pEW_5018_ with Z matches the Z estimates obtained from the host-galaxy photometry, although the significance of the correlation is weak. We also found that SNe with brighter peak magnitudes have smaller pEW_5018_ and occur at lower Z.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/1367
- Title:
- 12mm line survey towards W28 SNR
- Short Name:
- J/MNRAS/411/1367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 12mm Mopra observations of dense molecular gas towards the W28 supernova remnant (SNR) field. The focus is on the dense molecular gas towards the TeV gamma-ray sources detected by the HESS telescopes, which likely trace the cosmic rays from W28 and possibly other sources in the region. Using the NH_3_ inversion transitions we reveal several dense cores inside the molecular clouds,
- ID:
- ivo://CDS.VizieR/J/ApJ/732/65
- Title:
- Modeling the local velocity field with SNIa
- Short Name:
- J/ApJ/732/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We apply statistically rigorous methods of nonparametric risk estimation to the problem of inferring the local peculiar velocity field from nearby Type Ia supernovae (SNIa). We use two nonparametric methods -weighted least squares (WLS) and coefficient unbiased (CU)- both of which employ spherical harmonics to model the field and use the estimated risk to determine at which multipole to truncate the series. We show that if the data are not drawn from a uniform distribution or if there is power beyond the maximum multipole in the regression, a bias is introduced on the coefficients using WLS. CU estimates the coefficients without this bias by including the sampling density making the coefficients more accurate but not necessarily modeling the velocity field more accurately. After applying nonparametric risk estimation to SNIa data, we find that there are not enough data at this time to measure power beyond the dipole. The WLS Local Group bulk flow is moving at 538+/-86km/s toward (l,b)=(258+/-10{deg},36+/-11{deg}) and the CU bulk flow is moving at 446+/-101km/s toward (l,b)=(273+/-11{deg},46+/-8{deg}). We find that the magnitude and direction of these measurements are in agreement with each other and previous results in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/13
- Title:
- Models and yields of 13-120M_{sun}_ massive stars
- Short Name:
- J/ApJS/237/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new grid of presupernova models of massive stars extending in mass between 13 and 120M_{sun}_, covering four metallicities (i.e., [Fe/H]=0, -1, -2, and -3) and three initial rotation velocities (i.e., 0, 150, and 300km/s). The explosion has been simulated following three different assumptions in order to show how the yields depend on the remnant mass-initial mass relation. An extended network from H to Bi is fully coupled to the physical evolution of the models. The main results can be summarized as follows. (a) At solar metallicity, the maximum mass exploding as a red supergiant (RSG) is of the order of 17M_{sun}_ in the nonrotating case, with the more massive stars exploding as Wolf-Rayet (WR) stars. All rotating models, conversely, explode as WR stars. (b) The interplay between the core He-burning and the H-burning shell, triggered by the rotation-induced instabilities, drives the synthesis of a large primary amount of all the products of CNO, not just ^14^N. A fraction of them greatly enriches the radiative part of the He core (and is responsible for the large production of F), and a fraction enters the convective core, leading therefore to an important primary neutron flux able to synthesize heavy nuclei up to Pb. (c) In our scenario, remnant masses of the order of those inferred from the first detections of gravitational waves (GW 150914, GW 151226, GW 170104, GW 170814) are predicted at all metallicities for none or moderate initial rotation velocities.
