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81.
Ја измеривме стапката на супернова експлозиите во раниот Универзум преку гравитациски телескоп
Tanja Petrushevska, 2016, popular article

Abstract: Еднаш во околу сто години, супернова ќе експлодира во некоја галаксија и по неколку недели нејзиниот сјај ќе замре. Суперновите се многу ретки феномени во вселената и поради нивната минлива природа, астрономите тешко ги наоѓале во минатото. Пред 30 години, биле откривани околу две супернови месечно. Денес, ние наоѓаме супернови секојдневно. Но, овие супернови се наоѓаат типично на околу милијарда светлосни години, а тие уште подалечните, сè уште се во ограничен број. Суперновите се една од најсветлите експлозии што постојат, па затоа и можеме да ги видиме со нашите телескопи на тие неверојатни растојанија. Како споредба, доволно е да помислиме дека нашата соседна галаксија Андромеда се наоѓа на “само” 2,5 милиони светлосни години. Сепак, ако имаме за задача да измериме колкава е стапката на супернови што експлодираат во далечната вселена, тоа нема да биде лесно. На растојанија поголеми од четири милијарди светлосни години, суперновите тешко се наоѓаат, едноставно затоа што нивната светлина станува премногу слаба кога стигнува до нас. Ова е особено проблематично за проучување на стапката експлозиите на супернова кои што се последица од смртта на масивните ѕвезди. Овој тип на супернови во просек се побледи и често се наоѓаат во средини каде што светлината е апсорбирана од прашина. Исто така, поради ширењето на вселената, светлината од оддалечените објекти се поместува на подолги бранови должини. Од Земјата, телескопските набљудувања во делот што е блиску до инфрацрвениот дел од спектарот претставуваат предизвик, бидејќи атмосферата е многу светла и променлива во овој дел од спектарот.
Found in: osebi
Keywords: супернова, универзум, биг бенг, астрономија
Published: 29.01.2018; Views: 1876; Downloads: 0
.pdf Fulltext (1,05 MB)

82.
Почетен курс по астрономија (3): Астрономски мерки и објекти
Tanja Petrushevska, 2009, popular article

Abstract: Оваа година е Меѓународна година на астрономијата прогласена од УНЕСКО. По тој повод ЕМИТЕР ќе се обиде да ја приближи астрономијата до читателите со повеќе пригодни статии, како и со овој курс за астрономи - почетници. Модерната астрономија го истражува целиот универзум и неговите различни форми на материја и енергија. Масите и димензиите на астрономските објекти обично се огромни, но за да ги разбереме нивните карактеристики, се проучуваат и најмалите делови од материјата, молекулите, атомите и елементарните честички. Густините, температурите и магнетните полиња во универзумот можат да бидат многу пати поголеми од граничните вредности што можат да се достигнат на Земјата. Унивезумот е огромно поле за проучување, не само поради својата големина, но и поради вариететот на објектите и феномените кој што се дел од него.
Found in: osebi
Keywords: introductory course in astronomy
Published: 29.01.2018; Views: 1745; Downloads: 0
.pdf Fulltext (1,98 MB)

83.
Извештај од симпозиумот "Улогата на астрономијата во општеството и културата"
Tanja Petrushevska, 2009, popular article

Abstract: По завршувањето на церемонијата на отворањето на Меѓународната година на астрономијата (МГА), за која читавте во претходниот број на ЕМИТЕР, во просториите на УНЕСКО во Париз од 19 до 23 јануари беше одржан Симпозиум за улогата на астрономијата во општеството и културата. Симпозиумот беше организиран од страна на Меѓународната астрономска унија (International Astronomy Union, IAU) во рамките на настани за одбележување на МГА. На овој симпозиум учествуваше и македонска делегација.
Found in: osebi
Keywords: report from the international symposium "The role of astronomy in society and culture! organized by the International Astronomy Union
Published: 29.01.2018; Views: 2278; Downloads: 0
.pdf Fulltext (1,14 MB)

84.
Истражување на Вселената со супернови
Tanja Petrushevska, invited lecture at foreign university

Abstract: Lecture at the Physics department in Skopje, Macedonia.
Found in: osebi
Keywords: public lecture, supernovae, cosmology
Published: 02.02.2018; Views: 2219; Downloads: 0
.pdf Fulltext (96,89 KB)

85.
PM SPECIAL – ALLDELES NY UPPTÄCKT INOM SUPERNOVOR OCH GRAVITATIONSLINSNING
Katarina Bendtz, Tanja Petrushevska, other performed works

Abstract: I dagarna offentliggjordes att astrofysikerna på (iPTF) Intermediate Palomar Transient Factory detekterat en supernova typ 1a som vars ljus just nu böjs av en galax. Fenomenet kallas ”gravitational lensing” och är en effekt av att rumtiden kröks av massiva objekt, som vi diskuterade i Professor Magenta avsnitt om maskhål. Tanja Petrushevska är doktorand på Stockholms universitet och medlem av iPTF. Hon och de andra i iPTF skriver just nu på artikeln om upptäckten som hon berättar mer om i detta PM special!
Found in: osebi
Summary of found: ...i Professor Magenta avsnitt om maskhål. Tanja Petrushevska är doktorand på Stockholms universitet och medlem...
Keywords: interview, astrophysics outreach
Published: 06.02.2018; Views: 2053; Downloads: 0
.pdf Fulltext (1,99 MB)

86.
Supernovae seen through gravitational telescopes
Tanja Petrushevska, 2018, published scientific conference contribution abstract (invited lecture)

Abstract: Galaxies, and clusters of galaxies, can act as gravitational lenses and magnify the light of objects behind them. The effect enables observations of very distant supernovae, that otherwise would be too faint to be detected by existing telescopes, and allows studies of the frequency and properties of these rare phenomena when the universe was young. Under the right circumstances, multiple images of the lensed supernovae can be observed, and due to the variable nature of the objects, the difference between the arrival times of the images can be measured. Since the images have taken different paths through space before reaching us, the time-differences are sensitive to the expansion rate of the universe. One class of supernovae, Type Ia, are of particular interest to detect. Their well known brightness can be used to determine the magnification, which can be used to understand the lensing systems. I will also report our discovery of the first resolved multiply-imaged gravitationally lensed supernova Type Ia.
Found in: osebi
Keywords: lensed supernovae, strong lensing
Published: 03.05.2018; Views: 2300; Downloads: 0
.pdf Fulltext (541,15 KB)
This document has many files! More...

87.
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, original scientific article

Abstract: 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.
Found in: osebi
Keywords: gravitational lensing: strong / supernovae: general / galaxies: clusters: individual: A 370
Published: 28.06.2018; Views: 2401; Downloads: 115
.pdf Fulltext (4,14 MB)

88.
Prospects for lensed supernovae behind galaxy clusters with the James Webb Space Telescope
Tanja Petrushevska, 2018, published scientific conference contribution abstract

Abstract: Galaxies, and clusters of galaxies, can act as gravitational lenses and magnify the light of objects behind them. The effect enables observations of very distant supernovae, that otherwise would be too faint to be detected by existing telescopes, and allows studies of the frequency and properties of these rare phenomena when the universe was young. Under the right circumstances, multiple images of the lensed supernovae can be observed, and due to the variable nature of the objects, the difference between the arrival times of the images can be measured. Since the images have taken different paths through space before reaching us, the time-differences are sensitive to the expansion rate of the universe. One class of supernovae, Type Ia, are of particular interest to detect. Their well known brightness can be used to determine the magnification, which can be used to understand the lensing systems. I will also report our discovery of the first resolved multiply-imaged gravitationally lensed supernova Type Ia. I will 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).
Found in: osebi
Keywords: Strong lensing, Hubble constant, measuring expansion history with time delays, lensed supernovae
Published: 09.07.2018; Views: 2405; Downloads: 115
.pdf Fulltext (4,14 MB)

89.
Prospects for observing lensed supernovae behind galaxy clusters with JWST
Tanja Petrushevska, 2018, unpublished conference contribution

Abstract: Contributed talk at the international conference "The Universe as a telescope: probing the cosmos at all scales with strong lensing" in Milan 3-7 September 2018
Found in: osebi
Keywords: strong lensing, supernovae, JWST, LSST
Published: 12.09.2018; Views: 1747; Downloads: 0
.pdf Fulltext (48,18 KB)
This document has many files! More...

90.
FIRST EFFORT TO FIGHT LIGHT POLLUTION IN MACEDONIA
Tanja Petrushevska, 2018, professional article

Abstract: Light pollution is a serious problem in majority of European countries, with negative effects on the environment, animal life and human health. Not only light pollution is causing unnecessary electricity consumption, it also prevents the citizens to enjoy the dark night sky. Following the experience in Slovenia and Friuli Venezia Giulia, Italy with approaching this problem, we proposed a joined effort to perform field measurements of the light pollution, increase the awareness of this issue to the public and the policy makers in Macedonia. Light pollution is a very interdisciplinary field that necessitates the collaboration of policy makers, environmentalist, amateur and professional astronomers. The proposal was submitted to proESOF initiative in Trieste, Italy. This initiative consists of the organisation of collaborative events in North East Italy and the Balkan countries where the objective is to spread science for the benefit to the citizens. ProESOF events will happen before 2020, after which the main event “Trieste – European City of Science” will follow. Our proposal has been positively judged by the proESOF evaluators, and currently we are waiting for their decision regarding the financial support they will provide. The first step will to train a group of people to perform field measurements of light pollution. The second step is to share these results, so the target is the general public in Macedonia. To successfully fight light pollution, anti-light pollution laws have to be made and enforced, so relevant politicians and law makers in Macedonia will be included. We will use the local team who has experience and contacts with the media, so that this event gets covered well. This will be a first meeting of this kind in Skopje, Macedonia which will join experts of the region and offer new ideas to fight light pollution in Macedonia and the Balkans. Macedonia is one of the few countries that is lacking any initiative when it comes to light pollution. It is very important to act timely, also because in Macedonia there are still some regions with dark sky that can be saved. Italy and Slovenia have collaborated previously on several occasion regarding light pollution: the purpose of the project Public Lighting of the Future that was running from 2011 to 2014 was to create a common methodology and database. After our proposed workshop and measurement, the aim will be to include Macedonia in this common effort to fight light light pollution.
Found in: osebi
Keywords: light pollution
Published: 11.09.2018; Views: 1993; Downloads: 0
.pdf Fulltext (3,08 MB)

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