Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


1 - 2 / 2
Na začetekNa prejšnjo stran1Na naslednjo stranNa konec
1.
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, izvirni znanstveni članek

Opis: 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.
Najdeno v: ključnih besedah
Povzetek najdenega: ...supernovae:</font></</font></</font>font>font> general</font></</font></</font>font>font> – gravitational</</font>font></</font></</font>font></</font></</font>font>font>font> lensing:</</font>font></</font></</font>font></</font></</font>font>font>font> strong</</font>font></</font></</font>font></</font></</font>font>font>font></</font></</font>font></</font></</font>font>font>font> – galaxies:</</font>font> star formation – galaxies:</</font>font> clusters:</</font>font>... ...– galaxies:</</font>font> star formation – galaxies:</</font>font> clusters:</</font>font> individual:</</font>font></</font></</font>font></</font></</font>font>font>font> A</</font>font> 1689 – techniques: photometric...
Ključne besede: supernovae: general – gravitational lensing: strong – galaxies: star formation – galaxies: clusters: individual: A 1689 – techniques: photometric
Objavljeno: 23.01.2018; Ogledov: 2519; Prenosov: 0
.pdf Polno besedilo (2,64 MB)

2.
Searching for supernovae in the multiply-imaged galaxies behind the gravitational telescope A370
Tanja Petrushevska, Ariel Goobar, D. J. Lagattuta, R. Amanullah, Laura Hangard, S. Fabbro, C. Lindman, K. Paech, J. Richard, J.P. Kneib, 2017, izvirni znanstveni članek

Opis: Aims. Strong lensing by massive galaxy clusters can provide magnification of the flux and even multiple images of the galaxies that lie behind them. This phenomenon facilitates observations of high-redshift supernovae (SNe) that would otherwise remain undetected. Type Ia supernovae (SNe Ia) detections are of particular interest because of their standard brightness, since they can be used to improve either cluster lensing models or cosmological parameter measurements. Methods. We present a ground-based, near-infrared search for lensed SNe behind the galaxy cluster Abell 370. Our survey was based on 15 epochs of J-band observations with the HAWK-I instrument on the Very Large Telescope (VLT). We use Hubble Space Telescope (HST) photometry to infer the global properties of the multiply-imaged galaxies. Using a recently published lensing model of Abell 370, we also present the predicted magnifications and time delays between the images. Results. In our survey, we did not discover any live SNe from the 13 lensed galaxies with 47 multiple images behind Abell 370. This is consistent with the expectation of 0.09 ± 0.02 SNe calculated based on the measured star formation rate. We compare the expectations of discovering strongly lensed SNe in our survey and that performed with HST during the Hubble Frontier Fields (HFF) programme. We also show the expectations of search campaigns that can be conducted with future facilities, such as the James Webb Space Telescope (JWST) or the Wide-Field Infrared Survey Telescope (WFIRST). We show that the NIRCam instrument aboard the JWST will be sensitive to most SN multiple images in the strongly lensed galaxies and thus will be able to measure their time delays if observations are scheduled accordingly.
Najdeno v: ključnih besedah
Povzetek najdenega: ...A</</font>font>ims. Strong</</font></</font>font></</font></</font>font>font>font> lensing by massive galaxy clusters can provide... ...gravitational</</font>font></</font></</font>font></</font></</font>font>font>font> lensing:</</font>font></</font></</font>font></</font></</font>font>font>font> strong</</font>font></</font></</font>font></</font></</font>font>font>font> /</font></</font>font></</font></</font>font>font> supernovae:</font></</font></</font>font>font> general</font></</font></</font>font>font></</font></</font>font></</font></</font>font>font>font> /</font></</font>font></</font></</font>font>font> galaxies:</</font>font> clusters:</</font>font> individual:</</font>font> A</</font>font> 370</</font>font>...
Ključne besede: gravitational lensing: strong / supernovae: general / galaxies: clusters: individual: A 370
Objavljeno: 28.06.2018; Ogledov: 2394; Prenosov: 115
.pdf Polno besedilo (4,14 MB)

Iskanje izvedeno v 0 sek.
Na vrh