ABSTRACT
The division between stripped-envelope supernovae (SE-SNe) and superluminous supernovae (SLSNe) is not well-defined in either photometric or spectroscopic space. While a sharp luminosity ...threshold has been suggested, there remains an increasing number of transitional objects that reach this threshold without the spectroscopic signatures common to SLSNe. In this work, we present data and analysis on four SNe transitional between SE-SNe and SLSNe; the He-poor SNe 2019dwa and 2019cri, and the He-rich SNe 2019hge and 2019unb. Each object displays long-lived and variable photometric evolution with luminosities around the SLSN threshold of Mr < −19.8 mag. Spectroscopically however, these objects are similar to SE-SNe, with line velocities lower than either SE-SNe and SLSNe, and thus represent an interesting case of rare transitional events.
Abstract
We present optical and near-infrared photometric and spectroscopic observations of the fast-declining Type Ia supernova (SN) 2015bo. SN 2015bo is underluminous (
M
B
= −17.50 ± 0.15 mag) and ...has a fast-evolving light curve (Δm15(
B
) = 1.91 ± 0.01 mag and
s
BV
= 0.48 ± 0.01). It has a unique morphology in the observed
V
−
r
color curve, where it is bluer than all other supernovae (SNe) in the comparison sample. A
56
Ni mass of 0.17 ± 0.03
M
⊙
was derived from the peak bolometric luminosity, which is consistent with its location on the luminosity–width relation. Spectroscopically, SN 2015bo is a cool SN in the Branch classification scheme. The velocity evolution measured from spectral features is consistent with 1991bg-like SNe. SN 2015bo has a SN twin (similar spectra)
and
sibling (same host galaxy), SN 1997cn. Distance moduli of
μ
= 34.33 ± 0.01 (stat) ±0.11 (sys) mag and
μ
= 34.34 ± 0.04 (stat) ± 0.12 (sys) mag are derived for SN 2015bo and SN 1997cn, respectively. These distances are consistent at the 0.06
σ
level with each other, and they are also consistent with distances derived using surface-brightness fluctuations and redshift-corrected cosmology. This suggests that fast-declining SNe could be accurate distance indicators, which should not be excluded from future cosmological analyses.
Amphiphilic and lipophilic donor-acceptor naphthalimide-oligothiophene assemblies exhibiting almost identical intramolecular properties, but differing in their intermolecular interactions, have been ...synthesized. Here we analyze the effect of replacing the normally used lipophilic alkyl chains with hydrophilic ones in directing molecular aggregation from an antiparallel to a parallel stacking. This different molecular packing of the amphiphilic, NIP-3TAmphi, and lipophilic, NIP-3TLipo, systems is assessed by electronic spectroscopies, scanning electronic microscopy and DFT quantum-chemical calculations. Theoretical calculations indicate that the presence of amphiphilic interactions promotes a face-to-face parallel arrangement of neighbor molecules, which induces improved electronic coupling and therefore enhances the charge transport ability and photoconducting properties of this type of materials. Time of flight and photoconducting measurements are used to determine the impact of the amphiphilic and lipophilic interactions on their possible performance in optoelectronic devices.
We present a spectroscopic analysis of the most nearby Type I superluminous supernova (SLSN-I), SN 2018bsz. The photometric evolution of SN 2018bsz has several surprising features, including an ...unusual pre-peak plateau and evidence for rapid formation of dust ≳200 d post-peak. We show here that the spectroscopic and polarimetric properties of SN 2018bsz are also unique. While its spectroscopic evolution closely resembles SLSNe-I, with early O
II
absorption and C
II
P Cygni profiles followed by Ca, Mg, Fe, and other O features, a multi-component H
α
profile appearing at ∼30 d post-maximum is the most atypical. The H
α
is at first characterised by two emission components, one at ∼+3000 km s
−1
and a second at ∼ − 7500 km s
−1
, with a third, near-zero-velocity component appearing after a delay. The blue and central components can be described by Gaussian profiles of intermediate width (
FWHM
∼ 2000–6000 km s
−1
), but the red component is significantly broader (
FWHM
≳ 10 000 km s
−1
) and Lorentzian. The blue H
α
component evolves towards a lower-velocity offset before abruptly fading at ∼ + 100 d post-maximum brightness, concurrently with a light curve break. Multi-component profiles are observed in other hydrogen lines, including Pa
β
, and in lines of Ca
II
and He
I
. Spectropolarimetry obtained before (10.2 d) and after (38.4 d) the appearance of the H lines shows a large shift on the Stokes
Q
–
U
plane consistent with SN 2018bsz undergoing radical changes in its projected geometry. Assuming the supernova is almost unpolarised at 10.2 d, the continuum polarisation at 38.4 d reaches
P
∼ 1.8%, implying an aspherical configuration. We propose that the observed evolution of SN 2018bsz can be explained by highly aspherical, possibly disk-like, circumstellar material (CSM) with several emitting regions. After the supernova explosion, the CSM is quickly overtaken by the ejecta, but as the photosphere starts to recede, the different CSM regions re-emerge, producing the peculiar line profiles. Based on the first appearance of H
α
, we can constrain the distance of the CSM to be less than ∼6.5 × 10
15
cm (430 AU), or even lower (≲87 AU) if the pre-peak plateau is related to an eruption that created the CSM. The presence of CSM has been inferred previously for other SLSNe-I, both directly and indirectly. However, it is not clear whether the rare properties of SN 2018bsz can be generalised for SLSNe-I, for example in the context of pulsational pair instability, or whether they are the result of an uncommon evolutionary path, possibly involving a binary companion.
Amphiphilic and lipophilic donor-acceptor naphthalimide-oligothiophene assemblies exhibiting almost identical intramolecular properties, but differing in their intermolecular interactions, have been ...synthesized. Here we analyze the effect of replacing the normally used lipophilic alkyl chains with hydrophilic ones in directing molecular aggregation from an antiparallel to a parallel stacking. This different molecular packing of the amphiphilic,
NIP-3T
Amphi
, and lipophilic,
NIP-3T
Lipo
, systems is assessed by electronic spectroscopies, scanning electronic microscopy and DFT quantum-chemical calculations. Theoretical calculations indicate that the presence of amphiphilic interactions promotes a face-to-face parallel arrangement of neighbor molecules, which induces improved electronic coupling and therefore enhances the charge transport ability and photoconducting properties of this type of materials. Time of flight and photoconducting measurements are used to determine the impact of the amphiphilic and lipophilic interactions on their possible performance in optoelectronic devices.
Analysis of molecular aggregation directed by amphiphilic and lipophilic interactions.
We present a spectroscopic analysis of Type I superluminous supernova (SLSN-I), SN 2018bsz. While it closely resembles SLSNe-I, the multi-component H\(\alpha\) line appearing at \(\sim30\) d ...post-maximum is the most atypical. The H\(\alpha\) is characterised by two emission components, one at \(+3000\) km/s and a second at \(-7500\) km/s, with a third, near-zero velocity component appearing after a delay. The blue and central components can be described by Gaussian profiles of intermediate width, but the red component is significantly broader and Lorentzian. The blue component evolves towards lower velocity before fading at \(100\) d post-peak, concurrently with a light curve break. Multi-component profiles are observed in other hydrogen lines including Pa\(\beta\), and in lines of Ca II and He I. Spectropolarimetry obtained before (10.2 d) and after (38.4 d) the appearance of the H lines show a large shift on the Stokes \(Q\) -- \(U\) plane consistent with SN 2018bsz undergoing radical changes in its geometry. Assuming the SN is almost unpolarised at 10.2 d, the continuum polarisation at 38.4 d reaches \(P \sim1.8\%\) implying a highly asymmetric configuration. We propose that the observed evolution of SN 2018bsz can be explained by highly aspherical CSM. After the SN explosion, the CSM is quickly overtaken by the ejecta, but as the photosphere starts to recede, the different CSM regions re-emerge producing the peculiar line profiles. Based on the first appearance of H\(\alpha\), we can constrain the distance of the CSM to be less than \(430\) AU, or even lower (\(<87\) AU) if the pre-peak plateau is related to an eruption that created the CSM. The presence of CSM has been inferred for other SLSNe-I. However, it is not clear whether the rare properties of SN 2018bsz can be generalised for SLSNe-I or whether they are the result of an uncommon evolutionary path, possibly involving a binary companion.
The division between stripped-envelope supernovae (SE-SNe) and superluminous supernovae (SLSNe) is not well defined in either photometric or spectroscopic space. While a sharp luminosity threshold ...has been suggested, there remains an increasing number of transitional objects that reach this threshold without the spectroscopic signatures common to SLSNe. In this work we present data and analysis on four SNe transitional between SE-SNe and SLSNe; the He-poor SNe 2019dwa and 2019cri, and the He-rich SNe 2019hge and 2019unb. Each object displays long-lived and variable photometric evolution with luminosities around the SLSN threshold of \(M_r < -19.8\) mag. Spectroscopically however, these objects are similar to SE-SNe, with line velocities lower than either SE-SNe and SLSNe, and thus represent an interesting case of rare transitional events.
We present optical and near-infrared photometric and spectroscopic observations of the fast-declining Type Ia Supernova (SN) 2015bo. SN 2015bo is under-luminous (M\(_B\) = -17.67 \(\pm\) 0.15 mag) ...and has a fast-evolving light curve (\(\Delta \mathrm{m}_{15}\mathrm{(B)}\) = 1.91 \(\pm\) 0.01 mag and \(s_{BV}\) = 0.48 \(\pm\) 0.01). It has a unique morphology in the \(V-r\) color curve, where it is bluer than all other SNe in the comparison sample. A \(^{56}\)Ni mass of 0.17 \(\pm\) 0.03 \(M_{\odot}\) was derived from the peak bolometric luminosity, which is consistent with its location on the luminosity-width relation. Spectroscopically, SN 2015bo is a Cool SN in the Branch classification scheme. The velocity evolution measured from spectral features is consistent with 1991bg-like SNe. SN 2015bo has a SN twin (similar spectra) and sibling (same host galaxy), SN 1997cn. Distance moduli of \(\mu\) = 34.33 \(\pm\) 0.01 (stat) \(\pm\)0.11 (sys) mag and \(\mu\) = 34.34 \(\pm\) 0.04 (stat) \(\pm\) 0.12 (sys) mag were derived for SN 2015bo and SN 1997cn, respectively. These distances are consistent at the 0.06-\(\sigma\) level with each other, and are also consistent with distances derived using surface-brightness fluctuations and redshift-corrected cosmology. This suggests that fast-declining SNe could be accurate distance indicators which should not be excluded from future cosmological analyses.
Inversion of the connections of amidine linkers combined with controlled oligothiophene chain catenation in oligothiophene–naphthalimide assemblies provides an efficient method to tune the HOMO and ...LUMO values in this type of assemblies. This modification also suppresses the intramolecular charge transfer (ICT) band normally found in this type of derivatives, also delocalizing the frontier molecular orbitals over the whole conjugated skeleton. The resultant assemblies were used in the fabrication of field‐effect transistors, which showed well‐balanced ambipolar transport.
Link's awakening: Inversion of the connections of the amidine linkers combined with controlled oligothiophene chain catenation in oligothiophene–naphthalimide assemblies provide an efficient method to tune the HOMO and LUMO energy levels, thus promoting ambipolarity in field‐effect transistors.
World Health Organization Disability Assessment Schedule (WHODAS) 2.0 is currently one of the most used instruments in disability assessment. The objective of this study was to analyze the clinically ...reliable change of WHODAS 2.0 by applying both Classical Test Theory (CTT) and the Item Response Theory (IRT).
The sample consisted of 179 patients with dual pathology. The standard error of measurement (SEM) was estimated using the CTT and the rating testlet model.
Reliability estimated by Cronbach's alpha provided acceptable values for all domains. The Rasch analysis revealed an adequate capacity to discriminate between people with high and low disability in terms of total scores but not in terms of domains. The SEM varies according to the baseline scores, failing to detect clinically reliable change in patients with lower scores. Kappa coefficients are low for the most of dimensions (except participation) and adequate for total scores.
The use of total WHODAS 2.0 scores may be useful from a clinical perspective; however, more evidence is required for domain scores to support its usefulness. The decision to use the CTT or the IRT impacts in terms of calculating clinically reliable change.
•The present study is one of the first to analyze the clinically reliable change of World Health Organization Disability Assessment Schedule (WHODAS) scores. In addition, it compares the results applying both the Classical Test Theory and a Rasch testlet model. In this sense, results contribute to improve clinical decisions when applying this scale.•In general, WHODAS 2.0 show difficulties in detecting clinically reliable improvements in patients with mental disorders with medium levels of disfunctioning.•There were no statistically significant changes between baseline and follow-up. In contrast, there is a high percentage of patients presenting clinically significant change.•The use of CTT or Rasch Testlet has a strong practical impact on the RCI.•Total scores for WHODAS 2.0 might be a useful instrument to assess intervention change in mental health disorders patients with high levels of disability.
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