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1.
iPTF Discoveries of SNe Ia
Raphael Ferretti, Tanja Petrushevska, 2014, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel#4807) reports the following SNe Ia:
Keywords: supernovae, transients
Published in RUNG: 26.01.2018; Views: 3103; Downloads: 0
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2.
iPTF Discoveries of Recent Type Ia Supernovae
Raphael Ferretti, Tanja Petrushevska, 2015, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel#4807) reports the following SNe Ia:
Keywords: supernovae, transients
Published in RUNG: 25.01.2018; Views: 2965; Downloads: 0
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3.
iPTF Discoveries of Recent Type Ia Supernovae
Raphael Ferretti, Tanja Petrushevska, 2015, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W). See ATel #7112 for additional details. The approved classification (and/or subsequent) spectra are made publicly available through WISeREP (Yaron & Gal-Yam 2012).
Keywords: supernovae, transients
Published in RUNG: 25.01.2018; Views: 2789; Downloads: 0
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4.
iPTF Discoveries of Recent Type Ia Supernovae
Raphael Ferretti, Tanja Petrushevska, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W). See ATel #7112 for additional details. The approved classification (and/or subsequent) spectra are made publicly available through WISeREP (Yaron & Gal-Yam 2012).
Keywords: Supernova, Transient
Published in RUNG: 24.01.2018; Views: 2758; Downloads: 0
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5.
iPTF Discoveries of Recent Core-Collapse Supernovae
F. Taddia, Raphael Ferretti, C. Fremling, Anders Nyholm, S. Papadogiannakis, Tanja Petrushevska, L. Hangard, 2015, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Core-Collapse SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).
Keywords: Supernovae, Transients
Published in RUNG: 24.01.2018; Views: 3369; Downloads: 0
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6.
iPTF Discoveries of Recent Type Ia Supernovae
Raphael Ferretti, Tanja Petrushevska, 2016, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).
Keywords: Supernovae, Transients
Published in RUNG: 23.01.2018; Views: 3240; Downloads: 0
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7.
iPTF Discoveries of Recent Type Ia Supernovae
Raphael Ferretti, Tanja Petrushevska, 2016, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following Type Ia SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artefacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).
Keywords: Supernovae, Transient
Published in RUNG: 23.01.2018; Views: 3112; Downloads: 0
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8.
Probing gas and dust in the tidal tail of NGC 5221 with the type Ia supernova iPTF16abc
Raphael Ferretti, Rahman Amanullah, Ariel Goobar, Tanja Petrushevska, 2017, original scientific article

Abstract: Context. Type Ia supernovae (SNe Ia) can be used to address numerous questions in astrophysics and cosmology. Due to their well known spectral and photometric properties, SNe Ia are well suited to study gas and dust along the lines-of-sight to the explosions. For example, narrow Na I D and Ca II H&K absorption lines can be studied easily, because of the well-defined spectral continuum of SNe Ia around these features. Aims. We aim to study the gas and dust along the line-of-sight to iPTF16abc, which occurred in an unusual location, in a tidal arm, 80 kpc from centre of the galaxy NGC 5221. Methods. Using a time-series of high-resolution spectra, we have examined narrow Na I D and Ca II H&K absorption features for variations in time, which would be indicative for circumstellar (CS) matter. Furthermore, we have taken advantage of the well known photometric properties of SNe Ia to determine reddening due to dust along the line-of-sight. Results. From the lack of variations in Na I D and Ca II H&K, we determine that none of the detected absorption features originate from the CS medium of iPTF16abc. While the Na I D and Ca II H&K absorption is found to be optically thick, a negligible amount of reddening points to a small column of interstellar dust. Conclusions. We find that the gas along the line-of-sight to iPTF16abc is typical of what might be found in the interstellar medium (ISM) within a galaxy. It suggests that we are observing gas that has been tidally stripped during an interaction of NGC 5221 with one of its neighbouring galaxies in the past ∼109 yr. In the future, the gas clouds could become the locations of star formation. On a longer time scale, the clouds might diffuse, enriching the circum-galactic medium (CGM) with metals. The gas profile along the line-of-sight should be useful for future studies of the dynamics of the galaxy group containing NGC 5221.
Keywords: supernovae: individual: iPTF16abc – galaxies: individual: NGC 5221 – galaxies: ISM – galaxies
Published in RUNG: 23.01.2018; Views: 3222; Downloads: 0
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9.
Testing for redshift evolution of Type Ia supernovae using the strongly lensed PS1-10afx at z = 1.4
Tanja Petrushevska, Rahman Amanullah, Mattia Bulla, Markus Kromer, Raphael Ferretti, Ariel Goobar, Semeli Papadogiannakis, 2017, original scientific article

Abstract: Context. The light from distant supernovae (SNe ) can be magnified through gravitational lensing when a foreground galaxy is located along the line of sight. This line-up allows for detailed studies of SNe at high redshift that otherwise would not be possible. Spectroscopic observations of lensed high-redshift Type Ia supernovae (SNe Ia) are of particular interest since they can be used to test for evolution of their intrinsic properties. The use of SNe Ia for probing the cosmic expansion history has proven to be an extremely powerful method for measuring cosmological parameters. However, if systematic redshift-dependent properties are found, their usefulness for future surveys could be challenged. Aims. We investigate whether the spectroscopic properties of the strongly lensed and very distant SN Ia PS1-10afx at z = 1.4, deviates from the well-studied populations of normal SNe Ia at nearby or intermediate distance. Methods. We created median spectra from nearby and intermediate-redshift spectroscopically normal SNe Ia from the literature at −5 and +1 days from light-curve maximum. We then compared these median spectra to those of PS1-10afx. Results. We do not find signs of spectral evolution in PS1-10afx. The observed deviation between PS1-10afx and the median templates are within what is found for SNe at low and intermediate redshift. There is a noticeable broad feature centred at λ ∼ 3500 Å, which is present only to a lesser extent in individual low- and intermediate-redshift SN Ia spectra. From a comparison with a recently developed explosion model, we find this feature to be dominated by iron peak elements, in particular, singly ionized cobalt and chromium.
Keywords: supernovae: individual: PS1-10afx – gravitational lensing: strong – supernovae: general
Published in RUNG: 23.01.2018; Views: 3837; Downloads: 0
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10.
High-redshift supernova rates measured with the gravitational telescope A 1689
Tanja Petrushevska, R. Amanullah, Ariel Goobar, S. Fabbro, Joel Johansson, Tor Kjellsson, Chris Lidman, K. Paech, Johan Richard, H. Dahle, Raphael Ferretti, J.P. Kneib, M. Limousin, Jakob Nordin, V. Stanishev, 2016, original scientific article

Abstract: Aims. We present a ground-based, near-infrared search for lensed supernovae behind the massive cluster Abell 1689 at z = 0.18, which is one of the most powerful gravitational telescopes that nature provides. Methods. Our survey was based on multi-epoch J-band observations with the HAWK-I instrument on VLT, with supporting optical data from the Nordic Optical Telescope. Results. Our search resulted in the discovery of five photometrically classified, core-collapse supernovae with high redshifts of 0.671 < z < 1.703 and magnifications in the range ∆m = −0.31 to −1.58 mag, as calculated from lensing models in the literature. Owing to the power of the lensing cluster, the survey had the sensitivity to detect supernovae up to very high redshifts, z ∼ 3, albeit for a limited region of space. We present a study of the core-collapse supernova rates for 0.4 ≤ z < 2.9, and find good agreement with previous estimates and predictions from star formation history. During our survey, we also discovered two Type Ia supernovae in A 1689 cluster members, which allowed us to determine the cluster Ia rate to be 0.14+0.19 −0.09 ± 0.01 SNuB h 2 (SNuB ≡ 10−12 SNe L −1 ,B yr−1), where the error bars indicate 1σ confidence intervals, statistical and systematic, respectively. The cluster rate normalized by the stellar mass is 0.10+0.13 −0.06 ± 0.02 in SNuM h 2 (SNuM ≡ 10−12 SNe M−1 yr−1). Furthermore, we explore the optimal future survey for improving the core-collapse supernova rate measurements at z & 2 using gravitational telescopes, and for detections with multiply lensed images, and we find that the planned WFIRST space mission has excellent prospects. Conclusions. Massive clusters can be used as gravitational telescopes to significantly expand the survey range of supernova searches, with important implications for the study of the high-z transient Universe.
Keywords: supernovae: general – gravitational lensing: strong – galaxies: star formation – galaxies: clusters: individual: A 1689 – techniques: photometric
Published in RUNG: 23.01.2018; Views: 3850; Downloads: 0
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