Engineering topics

Moriya, T. J.

Publications and source records attributed to Moriya, T. J..

6 records

DOE OSTI2022

The Quest for New Correlations in the Realm of the Gamma-Ray Burst—Supernova Connection

Gamma-ray bursts (GRBs) are very energetic cosmological transients. Long GRBs are usually associated with Type Ib/c supernovae (SNe), and we refer to them as GRB-SNe. Since the associated SN for a given GRB is observed only at low redshift, a possible selection effect exists when we consider intrinsically faint sources that cannot be observed at high redshift. Thus, it is important to explore the possible relationships between GRB and SN parameters after these have been corrected for astrophysical biases due to the instrumental selection effects and redshift evolution of the variables involved. So far, only GRB prompt emission properties have been checked against the SN Ib/c properties without considering the afterglow (AG). This work investigates the existence of relationships among GRBs’ prompt and AG and associated SN properties. We investigate 91 bidimensional correlations among the SN and GRB observables before and after their correction for selection biases and evolutionary effects. As a result of this investigation, we find hints of a new correlation with a Pearson correlation coefficient >0.50 and a probability of being drawn by chance <0.05. This correlation is between the luminosity at the end of the GRB optical plateau emission and the rest-frame peak time of the SN. According to this relation, the brightest optical plateaus are accompanied by the largest peak times. This correlation is corrected for selection biases and redshift evolution and may provide new constraints for the astrophysical models associated with the GRB-SN connection.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2020

Carnegie Supernova Project II: The Slowest Rising Type Ia Supernova LSQ14fmg and Clues to the Origin of Super-Chandrasekhar/03fg-like Events

The Type Ia supernova (SN Ia) LSQ14fmg exhibits exaggerated properties that may help to reveal the origin of the "super-Chandrasekhar"(or 03fg-like) group. The optical spectrum is typical of a 03fg-like SN Ia, but the light curves are unlike those of any SNe Ia observed. The light curves of LSQ14fmg rise extremely slowly. At -23 rest-frame days relative to B-band maximum, LSQ14fmg is already brighter than M V = -19 mag before host extinction correction. Here, the observed color curves show a flat evolution from the earliest observation to approximately 1 week after maximum. The near-infrared light curves peak brighter than -20.5 mag in the J and H bands, far more luminous than any 03fg-like SNe Ia with near-infrared observations. At 1 month past maximum, the optical light curves decline rapidly. The early, slow rise and flat color evolution are interpreted to result from an additional excess flux from a power source other than the radioactive decay of the synthesized 56 Ni. The excess flux matches the interaction with a typical superwind of an asymptotic giant branch (AGB) star in density structure, mass-loss rate, and duration. The rapid decline starting at around 1 month past B-band maximum may be an indication of rapid cooling by active carbon monoxide (CO) formation, which requires a low-temperature and high-density environment. These peculiarities point to an AGB progenitor near the end of its evolution and the core degenerate scenario as the likely explosion mechanism for LSQ14fmg.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. Here, we report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 10 50 ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

The bumpy light curve of Type IIn supernova iPTF13z over 3 years

A core-collapse (CC) supernova (SN) of Type IIn is dominated by the interaction of SN ejecta with the circumstellar medium (CSM). Some SNe IIn (e.g. SN 2006jd) have episodes of re-brightening ("bumps") in their light curves. We present iPTF13z, a Type IIn SN discovered on 2013 February 1 by the intermediate Palomar Transient Factory (iPTF). This SN showed at least five bumps in its declining light curve between 130 and 750 days after discovery. We analyse this peculiar behaviour and try to infer the properties of the CSM, of the SN explosion, and the nature of the progenitor star. We obtained multi-band optical photometry for over 1000 days after discovery with the P48 and P60 telescopes at Palomar Observatory. We obtained low-resolution optical spectra during the same period. We did an archival search for progenitor outbursts. We analyse the photometry and the spectra, and compare iPTF13z to other SNe IIn. In particular we derive absolute magnitudes, colours, a pseudo-bolometric light curve, and the velocities of the different components of the spectral lines. A simple analytical model is used to estimate the properties of the CSM. iPTF13z had a light curve peaking at M r ≤ 18.3 mag. The five bumps during its decline phase had amplitudes ranging from 0.4 to 0.9 mag and durations between 20 and 120 days. The most prominent bumps appeared in all the different optical bands, when covered. The spectra of this SN showed typical SN IIn characteristics, with emission lines of Hα (with broad component FWHM ~ 10 3 - 10 4 km s -1 and narrow component FWHM ~ 10 2 km s -1 ) and He i, but also with Fe ii, Ca ii, Na i D and Hβ P Cygni profiles (with velocities of ~ 10 3 km s -1 ). A pre-explosion outburst was identified lasting ≳ 50 days, with M r ≤ 15 mag around 210 days before discovery. Large, variable progenitor mass-loss rates (≳ 0.01M ⊙ yr -1 ) and CSM densities (10 -16 g cm -3) are derived. The SN was hosted by a metal-poor dwarf galaxy at redshift z = 0.0328. We suggest that the light curve bumps of iPTF13z arose from SN ejecta interacting with denser regions in the CSM, possibly produced by the eruptions of a luminous blue variable progenitor star.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2013

ULTRA-STRIPPED TYPE Ic SUPERNOVAE FROM CLOSE BINARY EVOLUTION

Recent discoveries of weak and fast optical transients raise the question of their origin. We investigate the minimum ejecta mass associated with core-collapse supernovae (SNe) of Type Ic. We show that mass transfer from a helium star to a compact companion can produce an ultra-stripped core which undergoes iron core collapse and leads to an extremely fast and faint SN Ic. In this Letter, a detailed example is presented in which the pre-SN stellar mass is barely above the Chandrasekhar limit, resulting in the ejection of only ∼0.05-0.20 M {sub ☉} of material and the formation of a low-mass neutron star (NS). We compute synthetic light curves of this case and demonstrate that SN 2005ek could be explained by our model. We estimate that the fraction of such ultra-stripped to all SNe could be as high as 10{sup –3}-10{sup –2}. Finally, we argue that the second explosion in some double NS systems (for example, the double pulsar PSR J0737–3039B) was likely associated with an ultra-stripped SN Ic.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2013

PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010jl

Supernovae (SNe) have been proposed to be the main production sites of dust grains in the universe. However, our knowledge of their importance to dust production is limited by observationally poor constraints on the nature and amount of dust particles produced by individual SNe. In this paper, we present a spectrum covering optical through near-Infrared (NIR) light of the luminous Type IIn supernova 2010jl around one and a half years after the explosion. This unique data set reveals multiple signatures of newly formed dust particles. The NIR portion of the spectrum provides a rare example where thermal emission from newly formed hot dust grains is clearly detected. We determine the main population of the dust species to be carbon grains at a temperature of ∼1350-1450 K at this epoch. The mass of the dust grains is derived to be ∼(7.5-8.5) × 10{sup –4} M{sub ☉}. Hydrogen emission lines show wavelength-dependent absorption, which provides a good estimate of the typical size of the newly formed dust grains (∼< 0.1 μm, and most likely ∼< 0.01 μm). We believe the dust grains were formed in a dense cooling shell as a result of a strong SN-circumstellar media (CSM) interaction. The dust grains occupy ∼10% of the emitting volume, suggesting an inhomogeneous, clumpy structure. The average CSM density must be ∼> 3 × 10{sup 7} cm{sup –3}, corresponding to a mass loss rate of ∼> 0.02 M{sub ☉} yr{sup –1} (for a mass loss wind velocity of ∼100 km s{sup –1}). This strongly supports a scenario in which SN 2010jl and probably other luminous SNe IIn are powered by strong interactions within very dense CSM, perhaps created by Luminous-Blue-Variable-like eruptions within the last century before the explosion.

79 ASTRONOMY AND ASTROPHYSICS↗