Astronomy Letters-A Journal of Astronomy and Space Astrophysics最新文献_第5页

Microlensing by a Cluster of Primordial Black Holes 原始黑洞群的微透镜效应

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-04-01 DOI: 10.1134/S1063773725700562

K. A. Toshchenko, P. V. Baklanov, K. M. Belotsky, S. I. Blinnikov

{"title":"Microlensing by a Cluster of Primordial Black Holes","authors":"K. A. Toshchenko, P. V. Baklanov, K. M. Belotsky, S. I. Blinnikov","doi":"10.1134/S1063773725700562","DOIUrl":"10.1134/S1063773725700562","url":null,"abstract":"Numerous programs to search for microlensing events have constrained the possibility of the existence of dark matter (DM) in the form of compact objects in the halo of our Galaxy. These constraints on the DM fraction have been obtained under the assumption of single, widely spaced objects. We investigate the microlensing by primordial black holes (PBHs) gathered into clusters. In this case, during the microlensing by PBHs the influence of both neighboring PBHs and the combined gravitational potential from the entire cluster should be taken into account, making the shape of the light curve for a microlensing event much more complicated. Events with such complex light curves are not detected in the observational MACHO, EROS, OGLE, POINT-AGAPE, and HSC experiments. It has been shown that the fraction of DM in the form of PBHs (up to (93%) for the models under study) is not recorded in these observational experiments. However, a significant fraction of PBHs that may be considered as single lenses remains for all models; therefore, PBH clustering does not allow the constraint from microlensing on the fraction of PBHs in DM to be completely lifted.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 8","pages":"461 - 469"},"PeriodicalIF":0.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606472","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

Constraints on Features in the Cosmological Power Spectrum from Observations of the Epoch of Reionization 再电离时代观测对宇宙功率谱特征的限制

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-04-01 DOI: 10.1134/S1063773725080018

O. R. Skorikov, S. V. Pilipenko, M. V. Tkachev

引用次数: 0

A New Estimate of the Zero-Point Shift of the Gaia DR3 Parallaxes Obtained from a Comparison with VLBI Measurements of Masers and Radio Stars 从脉泽和射电星的VLBI测量比较中获得的盖亚DR3视差零点位移的新估计

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-04-01 DOI: 10.1134/S1063773725700616

V. V. Bobylev

引用次数: 0

Observations of the Hyades Open Cluster during the SRG/eROSITA All-Sky Survey 在SRG/eROSITA全天巡天期间对毕宿星团的观测

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-13 DOI: 10.1134/S1063773725700549

I. M. Khamitov, I. F. Bikmaev, M. R. Gilfanov, R. A. Sunyaev, P. S. Medvedev, M. A. Gorbachev, A. S. Sklyanov, P. D. Efremova, S. S. Panarin

{"title":"Observations of the Hyades Open Cluster during the SRG/eROSITA All-Sky Survey","authors":"I. M. Khamitov, I. F. Bikmaev, M. R. Gilfanov, R. A. Sunyaev, P. S. Medvedev, M. A. Gorbachev, A. S. Sklyanov, P. D. Efremova, S. S. Panarin","doi":"10.1134/S1063773725700549","DOIUrl":"10.1134/S1063773725700549","url":null,"abstract":"Using data from the all-sky X-ray survey with the eROSITA telescope onboard the SRG orbital observatory and the optical catalog of Hyades cluster members constructed from Gaia data, we have investigated the X-ray emission from cluster stars. Of the 395 cluster members located in the eastern Galactic part of the sky, eROSITA detects X-ray emission from 290 stars, 171 of which have been found for the first time in X-rays. At the Hyades distance (({sim}47) pc) the median eROSITA sensitivity in this sky region corresponds to a 0.3–2.3 keV luminosity (L_{X}sim 2.6times 10^{27}) erg s({}^{-1}), allowing 100(%) of the stars with spectral types from F0 to K5 to be detected within the Hyades tidal radius. We have also investigated objects in the Hyades tidal tail, where X-ray emission was recorded from 114 of the 281 known tidal tail members, 59 of which have been found in X-rays for the first time. For six sources a strong (more than a factor of 10) X-ray variability on a time scale of six months has been recorded. All of them are late-M stars with binarity. The (R_{X}=log(L_{X}/L_{textrm{bol}})) distribution of Hyades stars is distinctly bimodal. The left peak at (R_{X}sim{-}4.7) is formed predominantly by FGK stars, while the right peak at (R_{X}sim{-}3.2) consists mostly of M stars. The dependence of (R_{X}) on the Rossby number (Ro) is different for M and FGK stars. For M stars at small Rossby numbers (R_{X}sim{-}3) and depends weakly on (Ro), while at (Rogtrsim 0.2) a rapid decrease in (R_{X}) is observed. At the same time, most of the F, G, and K stars lie in a fairly compact region with (Rosim 0.3{-}0.8) and (R_{X}sim{-}4.7).","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 7","pages":"412 - 435"},"PeriodicalIF":0.8,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338997","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

Characteristics of the X-ray Spectra for Active Galactic Nuclei from the SRG/ART-XC All-Sky Survey Based on Swift/XRT Archival Data 基于Swift/XRT档案数据的SRG/ART-XC全天巡天活动星系核x射线光谱特征

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-13 DOI: 10.1134/S1063773725700550

A. D. Sokolov, S. Yu. Sazonov, G. S. Uskov

引用次数: 0

Double White Dwarf ZTF J0538(boldsymbol{+})1953 As the Brightest Verification Binary for Space Laser Interferometers 双白矮星ZTF J0538 (boldsymbol{+}) 1953作为空间激光干涉仪最亮的验证双星

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-13 DOI: 10.1134/S1063773725700525

S. V. Antipin, A. A. Belinski, L. N. Berdinkov, A. M. Zubareva, N. A. Maslennikova, K. A. Postnov, I. A. Strakhov

{"title":"Double White Dwarf ZTF J0538(boldsymbol{+})1953 As the Brightest Verification Binary for Space Laser Interferometers","authors":"S. V. Antipin, A. A. Belinski, L. N. Berdinkov, A. M. Zubareva, N. A. Maslennikova, K. A. Postnov, I. A. Strakhov","doi":"10.1134/S1063773725700525","DOIUrl":"10.1134/S1063773725700525","url":null,"abstract":"A decrease in the orbital period of the ultracompact binary white dwarf ZTF J0538(+)1953, which is one of the Galactic verification binaries in the millihertz frequency range for planned space laser interferometers, has been measured. Based on photometric observations carried out at the 2.5-m telescope of the Caucasian Mountain Observatory of Sternberg Astronomical Institute of Moscow State University (CMO SAI MSU), an O-C diagram is constructed. It can be described by quadratic elements of the brightness variations, which is in agreement to a decrease rate of the orbital period of the system of (dP/dt={-}(1.16pm 0.22)times 10^{-11}) s/s. The decrease rate of the orbital period in the quadrupole approximation for the emission of gravitational waves by a binary system corresponds to its chirp mass (mathcal{M}=0.434pm 0.05;M_{odot}), which turned out to be ({sim}30%) higher than the value obtained earlier from spectroscopic mass determination. The chirp mass of ZTF J0538(+)1953 inferred from the measured orbital decay rate makes this system the brightest Galactic verification binary for LISA and TianQin space interferometers with a signal-to-noise ratio of ({approx}119) and ({approx}30) over 5 and 2.5 years of observations, respectively.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 7","pages":"436 - 442"},"PeriodicalIF":0.8,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338995","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

HD 188101: A Spotted B Star with Abundance Anomalies HD 188101：一颗有丰富异常的斑点B星

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-13 DOI: 10.1134/S1063773725700537

R. M. Bayazitov, L. I. Mashonkina, Yu. V. Pakhomov, I. A. Yakunin

引用次数: 0

Analytical Approaches for a Rapid Prediction of the Gravitational Waveforms from Relativistic Binary Systems 相对论双星引力波快速预测的解析方法

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S1063773725700495

A. V. Mishakina, S. I. Blinnikov

引用次数: 0

Shells and Bubbles around Compact Clusters of Massive Stars: 3D MHD Simulations 大质量星团周围的壳和气泡：3D MHD模拟

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S106377372570046X

D. V. Badmaev, A. M. Bykov, M. E. Kalyashova

{"title":"Shells and Bubbles around Compact Clusters of Massive Stars: 3D MHD Simulations","authors":"D. V. Badmaev, A. M. Bykov, M. E. Kalyashova","doi":"10.1134/S106377372570046X","DOIUrl":"10.1134/S106377372570046X","url":null,"abstract":"We present the results of our three-dimensional magnetohydrodynamic (3D MHD) simulations of the plasma flow structure in the vicinity of a compact young massive star cluster at the cluster evolution phase governed by Wolf–Rayet stars. This phase takes place for a cluster with an age of a few million years close to the onset of supernova explosions; the well-known objects Westerlund 1 and 2 are the prototype. The collisions of powerful winds from massive stars in the cluster core calculated as the interactions of individual outflows from stars are accompanied by their partial thermalization and produce a collective cluster wind. We consider the MHD expansion dynamics of the bubble blown by the cluster wind as a function of the density of the surrounding interstellar medium with a uniform magnetic field. We show that when expanding in a cold neutral medium, the collective wind of the cluster is able to change the topology of its parent cloud in the time of the Wolf–Rayet phase, sweeping up more than (10^{4};M_{odot}) of gas in ({sim}2times 10^{5}) yr and producing thin dense extended shells with amplified magnetic fields. In a cold neutral medium with a density ({sim}20) cm({}^{-3}) and a magnetic field ({sim}3.5)\u0000 (mu)G a thin shell with a characteristic cellular structure of the density and magnetic field distributions is formed around the cluster wind bubble. The cellular magnetic field structure manifests itself in the parts of the shell that expand in a direction transverse to the orientation of the external magnetic field. The magnetic fields in the shell are amplified to strengths ({gtrsim}50)\u0000 (mu)G. The cellular structure formation is associated with the development of instabilities. The bubble expansion in a warm neutral interstellar medium is also accompanied by the formation of a shell with an amplified magnetic field.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 6","pages":"361 - 374"},"PeriodicalIF":0.8,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338398","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

GRB 241105A—The Most Distant Short Gamma-Ray Burst? GRB 241105a -最遥远的短伽马射线暴？

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S1063773725700483

P. Yu. Minaev, D. S. Svinkin, A. S. Pozanenko, D. D. Frederiks

{"title":"GRB 241105A—The Most Distant Short Gamma-Ray Burst?","authors":"P. Yu. Minaev, D. S. Svinkin, A. S. Pozanenko, D. D. Frederiks","doi":"10.1134/S1063773725700483","DOIUrl":"10.1134/S1063773725700483","url":null,"abstract":"This paper is devoted to a detailed study of the prompt gamma-ray emission from GRB 241105A based on data from the GBM/Fermi, SPI-ACS/INTEGRAL, Konus–Wind, and BAT/Swift instruments and its X-ray and optical afterglow light curves obtained by various observatories. A bright short main episode followed by a longer and less intense emission can be distinguished in the prompt emission light curve, which is a characteristic feature of short (Type I) bursts with extended emission. A spectral analysis has shown that the main burst episode has a hard energy spectrum typical for short bursts. The extended emission spectrum can be described by a power law with a photon index (gamma={-}1.6pm 0.2) in the energy range up to a few MeV, making it the hardest extended emission among the observed short bursts. In addition, on the (E_{p,i}{-}E_{textrm{iso}}) and (T_{90,i}{-}EH) planes the main episode of GRB 241105A occupies a position typical for short GRBs. At the same time, the X-ray and optical afterglow light curves of GRB 241105A are brightest among the short GRBs (with measured redshifts), which may suggest that the burst belongs to the events connected with the core collapse of massive stars (Type II GRBs). If, however, the hypothesis about the connection of GRB 241105A with the class of short GRBs caused by the mergers of compact objects is valid, then it will be the most distant of the short bursts (the redshift of GRB 241105A is (z=2.681)).","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 6","pages":"327 - 348"},"PeriodicalIF":0.8,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338397","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