Serbian Astronomical Journal最新文献

Modeling quasar variability through self-organizing map-based neural process 通过基于自组织图谱的神经过程建模类星体的可变性

IF 0.8 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2024-07-03 DOI: 10.2298/SAJ2408017C

Iva Čvorović‐Hajdinjak

引用次数: 0

Proper motion of Cygnus Loop shock filaments 天鹅座环形冲击丝的适当运动

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2024-03-08 DOI: 10.2298/SAJ2307009V

M. Vucetic, N. Milanovic, D. Urosevic, J. Raymond, D. Onic, S. Milosevic, N. Petrov

{"title":"Proper motion of Cygnus Loop shock filaments","authors":"M. Vucetic, N. Milanovic, D. Urosevic, J. Raymond, D. Onic, S. Milosevic, N. Petrov","doi":"10.2298/SAJ2307009V","DOIUrl":"https://doi.org/10.2298/SAJ2307009V","url":null,"abstract":"We determined the shock speed in the Galactic supernova remnant Cygnus Loop,\u0000 using the proper motion of its optical filaments and the latest estimate of\u0000 its distance. The proper motion was measured by comparing H? images of the\u0000 remnant observed in two epochs: 1993 (Kitt Peak National Observatory) and\u0000 2018/2019 (National Astronomical Observatory Rozhen and Astronomical Station\u0000 Vidojevica). We derived shock speed for 35 locations along different\u0000 filaments, which is twice as much as in earlier studies of the north-eastern\u0000 part of the Cygnus Loop. For the first time, we have measured the shock\u0000 speed of the radiative filaments in this region. Three of the analyzed\u0000 locations where we measured the proper motion of filaments are radiative,\u0000 based on their presence in [SII] images from the second epoch. The other\u0000 filaments are non-radiative. The speed we obtained for the non-radiative\u0000 filaments is in the range of 240{650 km s-1, with an estimate for the\u0000 uncertainty of 70 km s-1. These values are mostly in agreement with previous\u0000 studies. The radiative filaments have lower speeds of 100-160 ?70 km s-1,\u0000 which is in agreement with the assumption that they are older in\u0000 evolutionary terms. This clear distinction between the speed of the two\u0000 types of filaments proves that [SII] emission can be used for identifying\u0000 radiative filaments in supernova remnants.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140257186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Newly found Mayan records of astronomical phenomena in Dresden Codex 德累斯顿手抄本中新发现的玛雅天文现象记录

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2023-01-01 DOI: 10.2298/saj2306029v

J. Vondrák, V. Böhm, B. Böhm

{"title":"Newly found Mayan records of astronomical phenomena in Dresden Codex","authors":"J. Vondrák, V. Böhm, B. Böhm","doi":"10.2298/saj2306029v","DOIUrl":"https://doi.org/10.2298/saj2306029v","url":null,"abstract":"The rich culture of old Maya gave birth to a very complicated and complex calendar; they also recorded important historical events and many significant astronomical phenomena. The main source of information is represented by Dresden Codex (DC), one of the four preserved Mayan hieroglyphic literal legacies. DC roughly covers the interval between 280 and 1325 AD. The old problem of precise Mayan dating with respect to our calendar is traditionally called correlation; it expresses the difference in days between the Long Count of the Mayan calendar and the Julian Date, used in presentday astronomy. There exist more than fifty published correlations that differ one from the other by as much as several centuries. Historians mostly accept the so called Goodman-Mart?nez-Thompson (GMT) value of 584 283 days, which is based mostly on historical events extracted from the sources of a postclassical period of Mayan history. On the contrary, brothers B?hm used precisely dated astronomical data from classical period to derive the B?hm correlation (BB) of 622 261 days. Unlike the GMT correlation it is in excellent agreement with the astronomical phenomena recorded in DC. Since then we published several papers supporting the validity of BB correlation and its advantage over GMT in the classical period of Mayan history. To this end, we used more records of astronomical phenomena discovered in DC. This study describes six records of planetary conjunctions that we found recently on p. 37 of DC that concern planets Mercury, Venus, Mars, Jupiter, and Saturn. All of these records coincide with the real occurrences of these phenomena within several days, if BB correlation is applied.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68675248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A search for fast radio bursts associated with gamma-ray bursts using the YNAO 40-m radio telescope 使用YNAO 40米射电望远镜搜索与伽马射线暴相关的快速射电暴

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2023-01-01 DOI: 10.2298/saj2306039z

Y.F. Zhang, Z. Wen, N. Wang, L. Hao, J. Yuan, R. Yuen, X. Duan, Z. Wang

引用次数: 0

The influence of metallicity on helium and CO core masses in massive stars 金属丰度对大质量恒星中氦和CO核心质量的影响

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2023-01-01 DOI: 10.2298/saj2306001p

Jelena Petrović

{"title":"The influence of metallicity on helium and CO core masses in massive stars","authors":"Jelena Petrović","doi":"10.2298/saj2306001p","DOIUrl":"https://doi.org/10.2298/saj2306001p","url":null,"abstract":"We present the results of 58 detailed evolutionary models of massive single stars and close binary systems with the Solar and Small Magellanic Cloud (SMC) metallicity computed with the MESA (Modules for Experiments in Stellar Astrophysics) numerical code. Helium core masses of single stars (30 M? - 75 M?) with metallicities of 0.02 and 0.0021 are in the range of 9.26 M? - 29.56 M? and 11.62 M? - 33.96 M?, respectively. Their carbon-oxygen (CO) core masses are between 5.44 M? and 25.04 M? vs. 8.23 M? and 28.38 M? for the Solar vs. SMC metallicity, accounting for an average difference of 25%. To investigate the influence of metallicity on helium and carbon-oxygen core masses in massive close Case A binary systems, detailed evolutionary models of binary systems in the mass range of 30 M? to 40 M? are calculated. The initial orbital period is set to 3 days and the accretion efficiency to 10%. The helium core mass range for primary stars with lower metallicity is 10.61 - 16.21 M? vs. 7.94 - 11.69 M? for z = 0.02. The resulting CO core masses of primary stars for the SMC metallicity are on average about 50% larger than for the Solar metallicity, so the effect is more prominent than in the case of single stars. The black hole formation limit for primary stars with the SMC metallicity is under 30 M?. While the least massive primary stars with Solar metallicity end up as neutron stars, all primary stars with the SMC metallicity and all secondary stars complete their evolution as black holes. The double compact objects resulting from the presented models are of two types: mixed neutron star-black hole systems (4 models) and double black holes (18 models). We also derive the relation between the final helium core mass and the carbon-oxygen core mass and show that it does not depend on metallicity. We confirm the CO/helium core mass ratio to be larger in binary systems than for single stars.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68675648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A potential survival strategy during the late heavy bombardment 在猛烈轰炸后期可能的生存策略

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2023-01-01 DOI: 10.2298/saj2306009h

Hegner von

{"title":"A potential survival strategy during the late heavy bombardment","authors":"Hegner von","doi":"10.2298/saj2306009h","DOIUrl":"https://doi.org/10.2298/saj2306009h","url":null,"abstract":"The Late Heavy Bombardment (LHB) represents a period of time in which an increased number of impactors collided with the Earth. While there were continuous collisions of impactors globally, these would be perceived by populations of life as locally infrequent, as they occurred at different times and locations across the planet. These impactions presented a severe and unpredictable environmental pressure on life, as they could at any moment destroy organisms and their local habitats. However, such an environment could potentially lead to the selection of a particular evolutionary strategy, bet hedging, which is an adaptation to unpredictability itself. Thus, a model for analysing this has been put forward in the form of a system of rings arising from an impact-consisting of the inner primary and outer secondary rings, which demonstrates the dynamic interplay between the external pressure from impact dynamics and life's evolutionary response towards it. The model demonstrates that there is a longer relaxed period where organisms thrive and a short violent period where they must survive three violent events and respond to a potentially different environment. This evolutionary strategy consistently results in a higher number of surviving organisms compared to other evolutionary strategies; thus, it may have played a crucial role in life's endurance through the LHB-an insight relevant to astrobiology.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68675218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Astronomical observatory site selection using fuzzy AHP and BWM methods 基于模糊层次分析法和BWM方法的天文台选址

4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2023-01-01 DOI: 10.2298/saj230530001y

A. Yılmaz

{"title":"Astronomical observatory site selection using fuzzy AHP and BWM methods","authors":"A. Yılmaz","doi":"10.2298/saj230530001y","DOIUrl":"https://doi.org/10.2298/saj230530001y","url":null,"abstract":"Establishing an observatory often involves complex decisions, such as choosing a site based on multiple conicting criteria. In this study, we develop a multi-criteria decision analysis process by combining Geographic Information System (GIS) analysis with the (MCDA) Multi-Criteria Decision Analysis and use this process to determine the most suitable sites for the construction of an observatory in the Malatya urban area. GIS was used to calculate, classify, and analyze criteria, while FAHP (Fuzzy Analytic Hierarchy Processes, Buckley's method) and BWM(MCDA type Best-Worst Method) methods were used to weight the decision criteria and determine their effects on alternative sites. While the Cloud Cover criterion in the BWM method was the most important criterion with 28%, the most important criterion for the FAHP method had a comparable value of 27.8%. Meteorological criteria were the most important criteria group with values of 50.4% according to the FAHP method and 44.6% according to the BWM method. The study is based on meteorological, geographic, and anthropogenic datasets, suggesting the most appropriate sites for the astronomical observatory within the boundaries of the study area. The proposed sites are the result of site selection, which is the first phase of site selection for astronomical observatories. This site selection is important to limit the number of field alternatives. It is necessary to conduct field tests among the proposed areas and select the final site according to the results. The successful use of GIS and more than one MCDA method will pave the way for the development of various methods for astronomical observatory site determination.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135319830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stellar coronal mass ejections 恒星日冕物质抛射

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2022-12-18 DOI: 10.2298/SAJ2205001L

M. Leitzinger, P. Odert

引用次数: 0

Dark matter mass loss in galaxy flybys: dependence on impact parameter 星系飞掠中的暗物质质量损失:对撞击参数的依赖

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2022-03-16 DOI: 10.2298/SAJ210915001M

A. Mitravsinovi'c

{"title":"Dark matter mass loss in galaxy flybys: dependence on impact parameter","authors":"A. Mitravsinovi'c","doi":"10.2298/SAJ210915001M","DOIUrl":"https://doi.org/10.2298/SAJ210915001M","url":null,"abstract":"Galaxy flybys, interactions where two independent halos inter-penetrate but detach at a later time and do not merge, occur frequently at lower redshifts. These interactions can significantly impact the evolution of individual galaxies from mass loss and shape transformation to the emergence of tidal features and the formation of morphological disc structures. The main focus of this paper is on the dark matter mass loss of the secondary, intruder galaxy, with the goal of determining a functional relationship between impact parameter and dark matter mass loss. Series of N-body simulations of typical galaxy flybys (10:1 mass ratio) with differing impact parameters show that dark matter halo leftover mass of intruder galaxy follows logarithmic growth law with impact parameter, regardless of the way total halo mass is estimated. Lost mass then, clearly, follows exponential decay law. Stellar component stretches faster as impact parameter decreases, following exponential decay law with impact parameter. Functional dependence on impact parameter in all cases seems universal, but fitting parameters are likely sensitive to interaction parameters and initial conditions (e.g. mass ratio of interacting galaxies, the initial relative velocity of intruder galaxy, interaction duration). While typical flybys, investigated here, could not be the sole culprit behind the formation of ultra-diffuse or dark matter deficient galaxies, their effects should not be disregarded as they can at least contribute substantially. Rare, atypical and stronger flybys are worth exploring further.","PeriodicalId":48878,"journal":{"name":"Serbian Astronomical Journal","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68675184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mercury and orbfit packages for numerical integration of planetary systems: implementation of the yarkovsky and yorp effects 行星系统数值集成的水星和轨道包:亚尔科夫斯基和约普效应的实现

IF 0.5 4区物理与天体物理

Serbian Astronomical Journal Pub Date : 2022-02-28 DOI: 10.2298/SAJ2204051F

M. Fenucci, B. Novakovi'c

引用次数: 1