Q2237+0305 source structure and dimensions from light curves simulation

Assuming a two-component quasar structure model consisting of a central compact source and an extended outer feature, we produce microlensing simulations for a population of star-like objects in the lens galaxy. Such a model is a simplified version of that adopted to explain the brightness variations observed in Q0957 (Schild & Vakulik 2003). The microlensing light curves generated for a range of source parameters were compared to the light curves obtained in the framework of the OGLE program. With a large number of trials we built, in the domain of the source structure parameters, probability distributions to find "good" realizations of light curves. The values of the source parameters which provide the maximum of the joint probability distribution calculated for all the image components, have been accepted as estimates for the source structure parameters. The results favour the two-component model of the quasar brightness structure over a single compact central source model, and in general the simulations confirm the Schild-Vakulik model that previously described successfully the microlensing and other properties of Q0957. Adopting 3300 km/s for the transverse velocity of the source, the effective size of the central source was determined to be about 2x10^15 cm, and Epsilon =2 was obtained for the ratio of the integral luminosity of the outer feature to that of the central source.Comment: 7 pages, 4 figures, LaTe

Color Effects Associated with the 1999 Microlensing Brightness Peaks in Gravitationally Lensed Quasar Q2237+0305

Photometry of the Q2237+0305gravitational lens in VRI spectral bands with the 1.5-m telescope of the high-altitude Maidanak observatory in 1995-2000 is presented. Monitoring of Q2237+0305 in July-October 2000, made at nearly daily basis, did not reveal rapid (night-to-night and intranight) variations of brightness of the components during this time period. Rather slow changes of magnitudes of the components were observed, such as 0.08 mag fading of B and C components and 0.05 mag brightening of D in R band during July 23 - October 7, 2000. By good luck three nights in 1999 were almost at the time of the strong brightness peak of image C, and approximately in the middle of the ascending slope of the image A brightness peak. The C component was the most blue one in the system in 1998 and 1999, having changed its (V-I) color from 0.56 mag to 0.12 mag since August 1997, while its brightness increased almost 1.2 mag during this time period. The A component behaved similarly between August 1998 and August 2000, having become 0.47 mag brighter in R, and at the same time, 0.15 mag bluer. A correlation between the color variations and variations of magnitudes of the components is demonstrated to be significant and reaches 0.75, with a regression line slope of 0.33. A color (V-I) vrs color (V-R) plot shows the components settled in a cluster, stretched along a line with a slope of 1.31. Both slopes are noticeably smaller than those expected if a standard galactic interstellar reddening law were responsible for the differences between the colors of images and their variations over time. We attribute the brightness and color changes to microlensing of the quasar's structure, which we conclude is more compact at shorter wavelengths, as predicted by most quasar models featuring an energizing central source.Comment: 14 pages, 7 figures, LaTeX, submitted to A&

Investigation of the properties of quantum-dimensional semiconductor particles A3B5 by scanning probe microscopy, obtained by liquid chemical etching

The study was carried out with the financial support of the Russian Foundation for Basic Research in the framework of scientific projects 17-07-00407-а and 17-07-00139

Библиотечно-информационная сфера и её отражение через призму научных журналов

The authors analyze scientific journals that are relevant for the publication of works by library and information researchers. The study methodology is based on the selection of peer-reviewed journals indexed in the Russian Science Citation Index (RSCI), embracing various thematic headings in the area of library and information studies. The list of journals comprises 38 titles within the following RSCI headings: Librarianship, Library Studies, Information Studies, Economics, Economic Studies, Sociology, and Science Studies. The presence/absence of the journal in the RSCI, RSCI, the White List and in the List of the Higher Attestation Commission with the indication of significance/importance category assigned to the journal (Q1, Q2, Q3) is shown. The findings of the study demonstrate that researchers in the library and information sphere have a relatively little choice for publishing their papers in scientific professional journals that meet all the requirements. The authors also examine thematic open access platforms (aggregators) and provide examples. They discuss the Portal for the Periodicals in Librarianship, Bibliography and Book Studies. The platform approach expands visibility of journals, especially of the regional ones, which contributes to the scientific research and science promotion.Рассмотрены научные журналы, актуальные для опубликования статей специалистов библиотечно-информационной сферы. Методика исследования ориентирована на отбор рецензируемых журналов, индексируемых в РИНЦ, имеющих разные тематические рубрики в зоне библиотечно-информационной тематики. Сформирован список журналов, представляющих интерес для специалистов библиотечно-информационной сферы, в который включены 38 журналов из следующих рубрик Государственного рубрикатора научной и технической информации (ГРНТИ): «Библиотечное дело. Библиотековедение», «Информатика», «Экономика. Экономические науки», «Социология», «Науковедение». Показано присутствие/отсутствие журнала в РИНЦ, RSCI, «Белом списке» и в Перечне ВАК с указанием присвоенной журналу категории значимости/важности (К1, К2, К3). Результаты исследования показали, что у специалистов библиотечно-информационной сферы выбор для опубликования статей в научных профессиональных журналах, соответствующих всем предъявляемым требованиям, невелик. В статье рассмотрены тематические платформы (агрегаторы) с открытым доступом, приведены примеры. Отмечено, что в России создана платформа по библиотечно-информационной деятельности – Портал научных периодических изданий по библиотековедению, библиографоведению и книговедению. Показано, что пока в России подобные платформы формируются не активно, хотя их создание важно как для авторов и читателей, так и для самих журналов. Платформенный подход расширяет видимость журналов, особенно региональных, в информационной среде, что помогает продвижению научных исследований и популяризации науки

Time delays in PG1115+080: new estimates

We report new estimates of the time delays in the quadruple gravitationally lensed quasar PG1115+080, obtained from the monitoring data in filter R with the 1.5-m telescope at the Maidanak Mountain (Uzbekistan, Central Asia) in 2004-2006. The time delays are 16.4 days between images C and B, and 12 days between C and A1+A2, with image C being leading for both pairs. The only known estimates of the time delays in PG1115 are those based on observations by Schechter et al. (1997) -- 23.7 and 9.4 days between images C and B, C and A1+A2, respectively, as calculated by Schechter et al., and 25 and 13.3 days as revised by Barkana (1997) for the same image components with the use of another method. The new values of time delays in PG 1115+080 may be expected to provide larger estimates of the Hubble constant thus decreasing a diversity between the H_0 estimates taken from gravitationally lensed quasars and with other methods.Comment: 5 pages, 2 figures, Accepted for publication in MNRAS Letter