SN 2013dy is a Type Ia supernova (SN Ia) for which we have compiled an extraordinary data set spanning from 0.1 to ∼ 500 d after explosion. We present 10 epochs of ultraviolet (UV) through ...near-infrared (NIR) spectra with Hubble Space Telescope/Space Telescope Imaging Spectrograph, 47 epochs of optical spectra (15 of them having high resolution), and more than 500 photometric observations in the BVrRiIZYJH bands. SN 2013dy has a broad and slowly declining light curve (Δm
15(B) = 0.92 mag), shallow
$\mathrm{Si}\,\small {II}\,\lambda 6355$
absorption, and a low velocity gradient. We detect strong C ii in our earliest spectra, probing unburned progenitor material in the outermost layers of the SN ejecta, but this feature fades within a few days. The UV continuum of SN 2013dy, which is strongly affected by the metal abundance of the progenitor star, suggests that SN 2013dy had a relatively high-metallicity progenitor. Examining one of the largest single set of high-resolution spectra for an SN Ia, we find no evidence of variable absorption from circumstellar material. Combining our UV spectra, NIR photometry, and high-cadence optical photometry, we construct a bolometric light curve, showing that SN 2013dy had a maximum luminosity of
$10.0^{+4.8}_{-3.8} \times 10^{42}$
erg s−1. We compare the synthetic light curves and spectra of several models to SN 2013dy, finding that SN 2013dy is in good agreement with a solar-metallicity W7 model.
We describe the observing strategy, data reduction tools, and early results of a supernova (SN) search project, named SUDARE, conducted with the ESO VST telescope, which is aimed at measuring the ...rate of the different types of SNe in the redshift range 0.2 < z < 0.8. The search was performed in two of the best studied extragalactic fields, C DFS and C OSMOS, for which a wealth of ancillary data are available in the literature or in public archives. To accurately characterize the surveyed stellar population, we exploit public data and our own observations to measure the galaxy photometric redshifts and rest frame colours. The dispersion of the rate measurements for SNe-Ia is comparable to the scatter of the theoretical tracks for single degenerate (SD) and double degenerate (DD) binary systems models, therefore it is not possible to disentangle among the two different progenitor scenarios. Unlike recent claims, the core collapse SN rate is fully consistent with the prediction that is based on recent estimates of star formation history and standard progenitor mass range.
A comprehensive set of optical and near-infrared (NIR) photometry and spectroscopy is presented for the faint and fast 2008ha-like supernova (SN) 2010ae. Contingent on the adopted value of host ...extinction, SN 2010ae reached a peak brightness of −13.8 > MV > −15.3 mag, while modeling of the UVOIR light curve suggests it produced 0.003–0.007 M⊙ of 56Ni, ejected 0.30−0.60 M⊙ of material, and had an explosion energy of 0.04–0.30 × 1051 erg. The values of these explosion parameters are similar to the peculiar SN 2008ha –for which we also present previously unpublished early phase optical and NIR light curves – and places these two transients at the faint end of the 2002cx-like SN population. Detailed inspection of the post-maximum NIR spectroscopic sequence indicates the presence of a multitude of spectral features, which are identified through SYNAPPS modeling to be mainly attributed to Co ii. Comparison with a collection of published and unpublished NIR spectra of other 2002cx-like SNe, reveals that a Co ii footprint is ubiquitous to this subclass of transients, providing a link to Type Ia SNe. A visual-wavelength spectrum of SN 2010ae obtained at +252 days past maximum shows a striking resemblance to a similar epoch spectrum of SN 2002cx. However, subtle differences in the strength and ratio of calcium emission features, as well as diversity among similar epoch spectra of other 2002cx-like SNe indicates a range of physical conditions of the ejecta, highlighting the heterogeneous nature of thispeculiar class of transients.
We present an extensive optical and near-infrared photometric and spectroscopic campaign of the Type IIP supernova SN 2012aw. The data set densely covers the evolution of SN 2012aw shortly after the ...explosion through the end of the photospheric phase, with two additional photometric observations collected during the nebular phase, to fit the radioactive tail and estimate the super(56)Ni mass. Also included in our analysis is the previously published Swift UV data, therefore providing a complete view of the ultraviolet-optical-infrared evolution of the photospheric phase. On the basis of our data set, we estimate all the relevant physical parameters of SN 2012aw with our radiation-hydrodynamics code: envelope mass M sub(env) ~ 20 M sub(middot in circle), progenitor radius R ~ 3 x 10 super(13) cm (~430 R sub(middot in circle)), explosion energy E ~ 1.5 foe, and initial super(56)Ni mass ~0.06M sub(middot in circle). These mass and radius values are reasonably well supported by independent evolutionary models of the progenitor, and may suggest a progenitor mass higher than the observational limit of 16.5 + or - 1.5M sub(middot in circle) of the Type IIP events.
Abstract
We present our analysis of the Type II supernova DLT16am (SN 2016ija). The object was discovered during the ongoing
(DLT40) one-day cadence supernova search at
in the “edge-on” nearby (
) ...galaxy NGC 1532. The subsequent prompt and high-cadenced spectroscopic and photometric follow-up revealed a highly extinguished transient, with
, consistent with a standard extinction law with
R
V
= 3.1 and a bright (
) absolute peak magnitude. A comparison of the photometric features with those of large samples of SNe II reveals a fast rise for the derived luminosity and a relatively short plateau phase, with a slope of
, consistent with the photometric properties typical of those of fast-declining SNe II. Despite the large uncertainties on the distance and the extinction in the direction of DLT16am, the measured photospheric expansion velocity and the derived absolute
V
-band magnitude at
after the explosion match the existing luminosity–velocity relation for SNe II.
We conducted a search for luminous outbursts prior to the explosion of Type IIn supernovae (SNe IIn). We built a sample of 27 objects spectroscopically classified as SNe IIn and all located at ...$z<0.015$. Using deep archival SN fields images ---taken up to nearly 20 years prior to the SN explosions themselves--- from transient surveys (PTF, ZTF, DES and CHASE) and major astronomical observatories (European Southern Observatory, ESO and National Optical Astronomy Observatory, NOAO), we found at least one outburst years to months before the explosion of seven SNe IIn, with the earliest precursor being 10 years prior to the explosion of SN 2019bxq.
The maximum absolute magnitudes of the outbursts range between $-$11.5 mag and $-$15 mag, and the eruptive phases last for a few weeks to a few years.
The $g-r$ colour measured for three objects during their outburst is relatively red, with $g-r$ ranging between 0.5 and 1.0 mag. This is similar to the colour expected during the eruptions of luminous blue variables.
We note that the light curves of SNe with pre-SN outbursts have faster decline rates than those of the SNe that do not show pre-SN outbursts.
SN 2011fh is remarkable, as it is still visible 12 years after the luminous SN-like event, indicating that the progenitor possibly survived, or that the interaction is still ongoing.
We detect precursor activity in 29<!PCT!> of bona fide SNe IIn in our sample.
However, a quantitative assessment of the observational biases affecting the sample suggests that this fraction is an underestimation of the intrinsic precursor occurrence rate.
Purpose
Inguinal hernia repair is one of the most performed procedure all over the world with more than 20 million procedures performed each year. Due to the lack of data in literature about the ...learning curve of the Lichtenstein procedure, we decided to reproduce a research on learning curves with the same methodology proposed in our previous study about laparoscopic hernia repair. The aim of this multicentre study was to analyse how many cases are required to achieve the learning curve for a Lichtenstein procedure.
Methods
We performed a retrospective analysis of the first 100 Lichtenstein procedures performed by 4 trainees from three different institutions and compared them with the same number of procedures performed by 3 senior surgeons from the same institutions. The data about the achieving of learning curve were evaluated with CUSUM and KPSS test.
Results
No differences about biometrical features were found between the seven groups of patients. CUSUM analysis showed that the trainees achieve the learning curve after 37–42 procedures, reaching an operative time similar to that one of the senior surgeons.
Conclusions
In conclusion, we have shown that the number of procedures required to reach the learning curve from the beginning of surgical residency is around 40 hernia repairs. This number, produced in a controlled environment under strict supervision, could be the minimum requirement to start the procedure of accreditation and specialization in hernia surgery and is higher and steeper than previously reported.
The rise-time of Type II supernovae González-Gaitán, S.; Tominaga, N.; Molina, J. ...
Monthly Notices of the Royal Astronomical Society,
08/2015, Letnik:
451, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We investigate the early-time light curves of a large sample of 223 Type II supernovae (SNe II) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and ...sufficient non-detections prior to explosion, we constrain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At rest-frame g
′ band (λeff = 4722 Å), we find a distribution of fast rise-times with median of (7.5 ± 0.3) d. Comparing these durations with analytical shock models of Rabinak & Waxman and Nakar & Sari, and hydrodynamical models of Tominaga et al., which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radii. The inferred radii are on average much smaller than the radii obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either (a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or (b) the delayed and prolonged shock breakout of the collapse of an RSG with an extended atmosphere or embedded within pre-SN circumstellar material.
We present the one-year long observing campaign of SN 2012A which exploded in the nearby (9.8 Mpc) irregular galaxy NGC 3239. The photometric evolution is that of a normal Type IIP supernova, but the ...plateau is shorter and the luminosity not as constant as in other supernovae of this type. The absolute maximum magnitude, with M
B
= −16.23 ± 0.16 mag, is close to the average for SN IIP. Thanks also to the strong UV flux in the early phase, SN 2012A reached a peak luminosity of about 2 × 1042 erg s−1, which is brighter than those of other SNe with a similar 56Ni mass. The latter was estimated from the luminosity in the exponential tail of the light curve and found to be M(56Ni) = 0.011 ± 0.004 M, which is intermediate between standard and faint SN IIP. The spectral evolution of SN 2012A is also typical of SN IIP, from the early spectra dominated by a blue continuum and very broad (∼104 km s−1) Balmer lines, to the late-photospheric spectra characterized by prominent P-Cygni features of metal lines (Fe ii, Sc ii, Ba ii, Ti ii, Ca ii, Na i D). The photospheric velocity is moderately low, ∼3 × 103 km s−1 at 50 d, for the low optical depth metal lines. The nebular spectrum obtained 394 d after the shock breakout shows the typical features of SNe IIP and the strength of the O i doublet suggests a progenitor of intermediate mass, similar to SN 2004et (∼15 M). A candidate progenitor for SN 2012A has been identified in deep, pre-explosion K
′-band Gemini North Near-InfraRed Imager and Spectrometer images, and found to be consistent with a star with a bolometric magnitude −7.08 ± 0.36 (log L/L = 4.73 ± 0.14 dex). The magnitude of the recovered progenitor in archival images points towards a moderate-mass
star as the precursor of SN 2012A. The explosion parameters and progenitor mass were also estimated by means of a hydrodynamical model, fitting the bolometric light curve, the velocity and the temperature evolution. We found a best fit for a kinetic energy of 0.48 foe, an initial radius of 1.8 × 1013 cm and ejecta mass of 12.5 M. Even including the mass for the compact remnant, this appears fully consistent with the direct measurements given above.
We report the results of a three-year-long dedicated monitoring campaign of a restless luminous blue variable (LBV) in NGC 7259. The object, named SN 2009ip, was observed photometrically and ...spectroscopically in the optical and near-infrared domains. In this paper, we present the full historical data set from 2009 to 2012 with multi-wavelength dense coverage of the two high-luminosity events between 2012 August and September. We construct bolometric light curves and measure the total luminosities of these eruptive or explosive events. We propose that the high intrinsic luminosity of the latest peak, the variability history of SN 2009ip, and the detection of broad spectral lines indicative of high-velocity ejecta are consistent with a pulsational pair-instability event, and that the star may have survived the last outburst. The question of the survival of the LBV progenitor star and its future fate remain open issues, only to be answered with future monitoring of this historically unique explosion.
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