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61.
iPTF discovery and classification of bright transients
Nadejda Blagorodnova, Tanja Petrushevska, 2017, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery of the following bright transients. We report as ATel alerts all objects brighter than 19 mag. Our discoveries are reported in three filters: sdss-r, Mould-R and Mould-I, denoted as g, r and i. All three are in the AB magnitude system.
Keywords: Supernovae, Transients
Published in RUNG: 23.01.2018; Views: 3360; Downloads: 0
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62.
iPTF discovery and identification of bright transients
Thomas Kupfer, Tanja Petrushevska, 2017, other component parts

Abstract: The intermediate Palomar Transient Factory (ATel #4807) reports the discovery of the following bright transients. We report as ATel alerts all objects brighter than 19 mag. Our discoveries are reported in two filters: sdss-g and Mould-I, denoted as g, and I. Both are in the AB magnitude system.
Keywords: Supernovae, Transient
Published in RUNG: 23.01.2018; Views: 3009; Downloads: 0
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63.
VizieR Online Data Catalog: Measured photometry of SN 2014J from HST (Amanullah+, 2014)
R. Amanullah, Tanja Petrushevska, complete scientific database of research data

Abstract: We obtained observations (Program DD-13621; PI: Goobar) of SN 2014J with HST in the four UV broadband filters F218W, F225W, F275W, and F336W for seven epochs using a total of seven HST orbits during Cycle 21. In addition to this we also obtained optical broad-, medium-, and narrowband photometry in filters F467M, F631N, and F845M for visits (1, 3) and optical broadband photometry using F438W, F555W, and F814W for the remaining five visits. All observations were obtained with the Wide-Field Camera-3 (WFC3) using the UVIS aperture UVIS2-C512C-SUB.
Keywords: Supernovae, Photometry: HST, Photometry: UBVRI, Photometry: infrared, Extinction
Published in RUNG: 23.01.2018; Views: 3386; Downloads: 0
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64.
Color Me Intrigued: The Discovery of iPTF 16fnm, an SN 2002cx-like Object
A. A. Miller, Tanja Petrushevska, 2017, original scientific article

Abstract: Modern wide-field, optical time-domain surveys must solve a basic optimization problem: maximize the number of transient discoveries or minimize the follow-up needed for the new discoveries. Here, we describe the Color Me Intrigued experiment, the first from the intermediate Palomar Transient Factory (iPTF) to search for transients simultaneously in the gPTF and RPTF bands. During the course of this experiment, we discovered iPTF 16fnm, a new member of the 02cx-like subclass of Type Ia supernovae (SNe). iPTF 16fnm peaked at Mg 15.09 0.17 mag PTF =-  , making it the second-least-luminous known SN Ia. iPTF 16fnm exhibits all the hallmarks of the 02cx-like class: (i) low luminosity at peak, (ii) low ejecta velocities, and (iii) a non-nebular spectrum several months after peak. Spectroscopically, iPTF 16fnm exhibits a striking resemblance to two other low-luminosity 02cx-like SNe: SN 2007qd and SN 2010ae. iPTF 16fnm and SN 2005hk decline at nearly the same rate, despite a 3 mag difference in brightness at peak. When considering the full subclass of 02cx-like SNe, we do not find evidence for a tight correlation between peak luminosity and decline rate in either the g′ or r′ band. We measure the relative rate of 02cx-like SNe to normal SNe Ia and find rN N 02 Ia cx = 33- + 25 158%. We further examine the g′ − r′ evolution of 02cx-like SNe and find that their unique color evolution can be used to separate them from 91bg-like and normal SNe Ia. This selection function will be especially important in the spectroscopically incomplete Zwicky Transient Facility/Large Synoptic Survey Telescope (LSST) era. Finally, we close by recommending that LSST periodically evaluate, and possibly update, its observing cadence to maximize transient science.
Keywords: methods: observational – surveys – supernovae: general – supernovae: individual (SN 2002cx, SN 2005hk, iPTF 16fnm)
Published in RUNG: 23.01.2018; Views: 3234; Downloads: 0
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65.
Supernovae seen through gravitational telescopes
Tanja Petrushevska, 2017, doctoral dissertation

Abstract: Gravitational lenses such as galaxies and galaxy clusters, can magnify the flux of background galaxies. These galaxies at high redshift can host supernovae (SNe) which, thanks to the magnification boost due to lensing, can be observed, otherwise too faint to be detected by current telescopes. Under the right circumstances, the background galaxies may also have multiple images due to the strong lensing. Of particular interest is to detect lensed supernovae of type Ia (SNe Ia), because of their standard brightness. They could help improve lensing models and, if multiple images are observed, the Hubble constant can be measured independently. In this thesis, we use galaxy clusters as gravitational telescopes to search for lensed SNe at high redshift. We performed ground-based, near-infrared and optical search campaigns towards the massive clusters Abell 1689 and 370, which are among the most powerful gravitational telescopes known. Our search resulted in the discovery of five photometrically classified, core- collapse SNe at redshifts of 0.671 < z < 1.703 with significant magnification from the cluster. Owing to the power of the lensing cluster, we calculated the volumetric core-collapse SN rates for 0.4  z < 2.9, and find good agreement with previous estimates and predictions from cosmic star formation history. During our survey, we also discovered two SNe Ia in A1689 cluster members, which allowed us to determine the cluster Ia rate. Furthermore, we discuss the expectations of finding lensed SNe at high redshift in simulated search campaigns that can be conducted with upcoming ground- and space-based telescopes. Magnification from a galaxy lens also allows for detailed studies of the SN properties at high redshift that otherwise would not be possible. Spec- troscopic observations of lensed high-redshift SNe Ia are of particular interest since they can be used to test for evolution of the standard candle nature of these objects. However, if systematic redshift-dependent properties are found, their utility for future surveys could be challenged. We investigate whether the properties of the strongly lensed and very distant SN Ia PS1- 10afx at z = 1.4, deviates from the well-studied nearby and intermediate populations of normal SNe Ia. In other study, we report the discovery of the first resolved multiply-imaged gravitationally lensed SN Ia.
Keywords: supernovae, gravitational telescopes, galaxy clusters, lensed supernovae, strong lensing, astronomical surveys and telescopes
Published in RUNG: 23.01.2018; Views: 3957; Downloads: 0
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66.
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: 3111; Downloads: 0
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67.
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: 3711; Downloads: 0
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68.
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: 3726; Downloads: 0
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69.
VizieR Online Data Catalog: Photometry of SN 2013gh and iPTF13dge (Ferretti+, 2016)
Raphael Ferretti, Tanja Petrushevska, complete scientific database of research data

Abstract: Measured photometry of type Ia supernovae 2013gh and iPTF13dge are presented. Furthermore, the effective light-curve-width-corrected phase and the natural magnitude in specified filters have been computed. Thereby, the corresponding Galactic absorption (Ax_MW) and the filter corrections (Kx) to the corresponding rest-frame filter for SN 2011fe as described by Amanullah et al. (2015MNRAS.453.3300A) are presented. The corrected magnitude can be obtained as X-AXMW-KX. All corrections have been calculated after the SN 2011fe template has been reddened with the best-fit Fitzpatrick (1999PASP..111...63F) law, for each SN. Furthermore, the V magnitude and corrections for each phase phase are included. The V magnitude was either measured (M) or calculated (D) using the SNooPy model. The V magnitude is only shown for data points used in the colour analysis, with phases between -10 and +35-days. The corrected colour can be obtained as (X-AXMW-KX)-(V-AVMW-KV) and can be compared with the corresponding colour of SN 2011fe in order to study the reddening laws of the SNe.
Keywords: Supernovae, Photometry: UBV, Photometry: ugriz, Photometry: ultraviolet
Published in RUNG: 23.01.2018; Views: 3736; Downloads: 0
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70.
SEARCH FOR LENSED SUPERNOVAE BY MASSIVE GALAXY CLUSTERS WITH THE 2.5m NORDIC OPTICAL TELESCOPE
Tanja Petrushevska, 2013, published scientific conference contribution

Abstract: We shortly present here the ongoing project by the Stockholm supernova group about the search of high-z supernovae with the ALFOSC camera at the Nordic Optical Telescope by using galaxy clusters as gravitational telescope.
Keywords: gravitational telescopes, Abell 1689, galaxy clusters, telescopes, lensed supernovae, strong lensing
Published in RUNG: 23.01.2018; Views: 3788; Downloads: 0
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