Pub Date : 2025-02-15DOI: 10.1016/j.newast.2025.102373
Mayukh R. Gangopadhyay , Nilanjana Kumar , Ankan Mukherjee , Mohit K. Sharma
A pseudo-Nambu Goldstone Boson (pNGB) arising from the breaking of a global symmetry () can be one of the most promising candidate for the quintessence model, to explain the late time acceleration of our universe. Motivated from the Composite Higgs scenario, we have investigated the case where the pNGB associated with develops a potential through its couplings with the particles that do not form the complete representations of . The Coleman Weinberg (CW) potential is generated via the external particles in the loop which are linked with the strongly interacting dynamics and can be computed predicatively.
The model of Dark Energy (DE) is tested against several latest cosmological observations such as supernovae data of Pantheon, Baryon Acoustic Oscillation (BAO), Redshift-space distortion (RSD) data etc. We have found that the fit prefers sub-Planckian value of the pNGB field decay constant. Moreover, we have found that the model predicts cosmological parameters well within the allowed range of the observation and thus gives a well motivated model of quintessence.
{"title":"Composite pseudo Nambu Goldstone quintessence","authors":"Mayukh R. Gangopadhyay , Nilanjana Kumar , Ankan Mukherjee , Mohit K. Sharma","doi":"10.1016/j.newast.2025.102373","DOIUrl":"10.1016/j.newast.2025.102373","url":null,"abstract":"<div><div>A pseudo-Nambu Goldstone Boson (pNGB) arising from the breaking of a global symmetry (<span><math><mrow><mi>G</mi><mo>→</mo><mi>H</mi></mrow></math></span>) can be one of the most promising candidate for the quintessence model, to explain the late time acceleration of our universe. Motivated from the Composite Higgs scenario, we have investigated the case where the pNGB associated with <span><math><mrow><mi>S</mi><mi>O</mi><mrow><mo>(</mo><mi>N</mi><mo>)</mo></mrow><mo>/</mo><mi>S</mi><mi>O</mi><mrow><mo>(</mo><mi>N</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow></mrow></math></span> develops a potential through its couplings with the particles that do not form the complete representations of <span><math><mi>G</mi></math></span>. The Coleman Weinberg (CW) potential is generated via the external particles in the loop which are linked with the strongly interacting dynamics and can be computed predicatively.</div><div>The model of Dark Energy (DE) is tested against several latest cosmological observations such as supernovae data of Pantheon, Baryon Acoustic Oscillation (BAO), Redshift-space distortion (RSD) data etc. We have found that the fit prefers sub-Planckian value of the pNGB field decay constant. Moreover, we have found that the model predicts cosmological parameters well within the allowed range of the observation and thus gives a well motivated model of quintessence.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102373"},"PeriodicalIF":1.9,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436863","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}
<div><div>This paper presents a multi epoch, detailed spectral and temporal analysis of the non-nuclear X-ray point sources of the massive elliptical galaxy NGC 1453, based on two XMM-Newton observational data. In the observation with Obs ID 0901620101, seven sources having net counts <span><math><mo>≥</mo></math></span> 100 were identified for PN data, which along with their corresponding MOS data were considered for the analysis. For the observation with Obs ID 0673770601, only three sources were found for PN and two sources for MOS-1 and MOS-2. The spectra of all the sources were simultaneously fitted using two empirical models: an absorbed power-law model and an absorbed disk blackbody model. Based on the estimated bolometric luminosities of the sources, six sources - X-1, X-2, X-3, X-4, X-6 and X-7 are categorized as HLXs with X-ray luminosity, <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>></mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>41</mn></mrow></msup><mi>e</mi><mi>r</mi><mi>g</mi><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> while one source, X-5, as an ELX with <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>></mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>40</mn></mrow></msup><mi>e</mi><mi>r</mi><mi>g</mi><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, within the error limit. Notably, for source X-1, the disk blackbody component is the dominant feature in both the observations. In the 2012 observation (Obs ID 0673770601), the source exhibits a soft, cool accretion disk with an inner disk temperature of <span><math><mrow><mi>k</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>∼</mo></mrow></math></span> 0.27 keV. By 2022 (Obs ID 0901620101), X-1 presents an even softer, supersoft spectrum, characterized by a significantly lower inner disk temperature of <span><math><mrow><mi>k</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>∼</mo></mrow></math></span> 0.17 keV and photon index <span><math><mrow><mi>Γ</mi><mo>></mo></mrow></math></span> 5. This shift over the span of a decade indicates a further softening of the source. In the present study, due to limited data availability, the Luminosity-Temperature (L-T) relation could not be strictly constrained. However, for the purpose of mass estimation, we have assumed that the L<span><math><mrow><mo>∼</mo><msup><mrow><mi>T</mi></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> relation holds. The observed further softening of the source (X-1), accompanied by a slight increase in luminosity in the later observation, suggests a potential inverse correlation between the inner disk temperature of the soft component and luminosity, which is consistent with the characteristics of beamed disk emission resulting from radiatively
{"title":"Studying the nature of Ultraluminous X-ray sources in NGC 1453 with XMM-Newton","authors":"Praveen Kangjam , Dayananda Mayanglambam , A. Senorita Devi , Akram Chandrajit Singha","doi":"10.1016/j.newast.2025.102371","DOIUrl":"10.1016/j.newast.2025.102371","url":null,"abstract":"<div><div>This paper presents a multi epoch, detailed spectral and temporal analysis of the non-nuclear X-ray point sources of the massive elliptical galaxy NGC 1453, based on two XMM-Newton observational data. In the observation with Obs ID 0901620101, seven sources having net counts <span><math><mo>≥</mo></math></span> 100 were identified for PN data, which along with their corresponding MOS data were considered for the analysis. For the observation with Obs ID 0673770601, only three sources were found for PN and two sources for MOS-1 and MOS-2. The spectra of all the sources were simultaneously fitted using two empirical models: an absorbed power-law model and an absorbed disk blackbody model. Based on the estimated bolometric luminosities of the sources, six sources - X-1, X-2, X-3, X-4, X-6 and X-7 are categorized as HLXs with X-ray luminosity, <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>></mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>41</mn></mrow></msup><mi>e</mi><mi>r</mi><mi>g</mi><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> while one source, X-5, as an ELX with <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>></mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>40</mn></mrow></msup><mi>e</mi><mi>r</mi><mi>g</mi><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, within the error limit. Notably, for source X-1, the disk blackbody component is the dominant feature in both the observations. In the 2012 observation (Obs ID 0673770601), the source exhibits a soft, cool accretion disk with an inner disk temperature of <span><math><mrow><mi>k</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>∼</mo></mrow></math></span> 0.27 keV. By 2022 (Obs ID 0901620101), X-1 presents an even softer, supersoft spectrum, characterized by a significantly lower inner disk temperature of <span><math><mrow><mi>k</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>∼</mo></mrow></math></span> 0.17 keV and photon index <span><math><mrow><mi>Γ</mi><mo>></mo></mrow></math></span> 5. This shift over the span of a decade indicates a further softening of the source. In the present study, due to limited data availability, the Luminosity-Temperature (L-T) relation could not be strictly constrained. However, for the purpose of mass estimation, we have assumed that the L<span><math><mrow><mo>∼</mo><msup><mrow><mi>T</mi></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> relation holds. The observed further softening of the source (X-1), accompanied by a slight increase in luminosity in the later observation, suggests a potential inverse correlation between the inner disk temperature of the soft component and luminosity, which is consistent with the characteristics of beamed disk emission resulting from radiatively","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102371"},"PeriodicalIF":1.9,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422000","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}
Pub Date : 2025-02-08DOI: 10.1016/j.newast.2025.102370
Patrick N. Mwaniki , James O. Chibueze , Dismas S. Wamalwa
We investigated the structural characteristics of G7.7-3.7 at a higher resolution of 1284 MHz. MeerKAT observations revealed that G7.7-3.7 had an asymmetric spherical structure with filamentary features and various blowouts. The western boundary showed a strong bright blowout, while the southern perimeter showcased extended bright filaments with feather-like structures, which seemed disconnected from the western blowout. Moreover, the eastern region exhibited a blowout centered around a bright point source, with faint, elongated filaments extending north-west. These filaments connected the eastern point source to the western blowout, creating a uniform outward progression. Spectral index analysis indicated a steep spectrum ( ranged 0 to −3), suggesting a combination of synchrotron and a few traces of thermal emissions concentrated at the edges of bright blowouts. Analysis of MeerKAT and VLA data revealed that G7.7-3.7 had expanded by 9 ± 0.45 arcsec over a period of 31.907 years, corresponding to an expansion rate of 0.282 ± 0.014 arcsec yr−1. This expansion indicated a shock speed of 5883 ± 294 km s−1 and an age of 1636 ± 115 years. This age fits with the supernova explosion event of 386 CE and the MeerKAT observed data in 2023. The multi-wavelength investigation unveiled a distinctive structure within the southern radio blowout, encompassing a bright radio blowout, a prominent X-ray arc, and two faint optical filaments aligned with the X-ray bright arc. We attributed the bright radio blowouts to inhomogeneous mass outflow from shock-accelerated particles and the weakening of magnetic fields along its perimeter. Traces of thermal emissions, especially along the edges of blowouts, were likely due to shock-heated gas, which intensified in the southern region amid high-density Interstellar Medium (ISM). Therefore, these results supported a scenario in which the progenitor supernova of G7.7-3.7 exploded within ISM of varying density, generating the observed X-ray emissions and faint optical filaments. Our findings provided valuable insights into the dynamics and evolution of supernova remnants.
{"title":"MeerKAT-based multi-wavelength study of supernova remnant G7.7-3.7 (SN386?)","authors":"Patrick N. Mwaniki , James O. Chibueze , Dismas S. Wamalwa","doi":"10.1016/j.newast.2025.102370","DOIUrl":"10.1016/j.newast.2025.102370","url":null,"abstract":"<div><div>We investigated the structural characteristics of G7.7-3.7 at a higher resolution of 1284 MHz. MeerKAT observations revealed that G7.7-3.7 had an asymmetric spherical structure with filamentary features and various blowouts. The western boundary showed a strong bright blowout, while the southern perimeter showcased extended bright filaments with feather-like structures, which seemed disconnected from the western blowout. Moreover, the eastern region exhibited a blowout centered around a bright point source, with faint, elongated filaments extending north-west. These filaments connected the eastern point source to the western blowout, creating a uniform outward progression. Spectral index analysis indicated a steep spectrum (<span><math><mi>α</mi></math></span> ranged <span><math><mo>∼</mo></math></span> 0 to <span><math><mo>∼</mo></math></span> −3), suggesting a combination of synchrotron and a few traces of thermal emissions concentrated at the edges of bright blowouts. Analysis of MeerKAT and VLA data revealed that G7.7-3.7 had expanded by 9 ± 0.45 arcsec over a period of 31.907 years, corresponding to an expansion rate of 0.282 ± 0.014 arcsec yr<sup>−1</sup>. This expansion indicated a shock speed of 5883 ± 294 km s<sup>−1</sup> and an age of 1636 ± 115 years. This age fits with the supernova explosion event of 386 CE and the MeerKAT observed data in 2023. The multi-wavelength investigation unveiled a distinctive structure within the southern radio blowout, encompassing a bright radio blowout, a prominent X-ray arc, and two faint optical filaments aligned with the X-ray bright arc. We attributed the bright radio blowouts to inhomogeneous mass outflow from shock-accelerated particles and the weakening of magnetic fields along its perimeter. Traces of thermal emissions, especially along the edges of blowouts, were likely due to shock-heated gas, which intensified in the southern region amid high-density Interstellar Medium (ISM). Therefore, these results supported a scenario in which the progenitor supernova of G7.7-3.7 exploded within ISM of varying density, generating the observed X-ray emissions and faint optical filaments. Our findings provided valuable insights into the dynamics and evolution of supernova remnants.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102370"},"PeriodicalIF":1.9,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387699","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}
Pub Date : 2025-01-31DOI: 10.1016/j.newast.2025.102360
Gyeong-Min Lee , Maurice H.P.M. van Putten
Large- galaxy surveys offer unprecedented opportunities to probe weak gravitation in galaxy dynamics that may contain correlations tracing background cosmology. Of particular interest is the potential of finite sensitivities to the background de Sitter scale of acceleration , where is the Hubble parameter and is the velocity of light. At sufficiently large , this is possibly probed by ensemble-averaged (“stacked”) rotation curves (RCs) at resolutions on par with present estimates of the Hubble parameter . Here, we consider the prospect for these studies using the large Mapping Nearby Galaxies at Apache Point Observatory MaNGA at APO survey. In a first and preliminary step, we consider unbiased control of sub-sample size by consistency in the three Position Angles, , from photometry and velocity fields of gas and stars by spectroscopy within 30°. In sub-samples of size , the scatter in-the-mean is found to reach one percent levels, differentiated over inclination angle and . In regular propagation of uncertainties, this scatter contributes to the standard error in-the-mean to the observable, where is determined by the choice of observables. As a lower bound to scatter in stacked RCs, MaNGA hereby appears promising for high-resolution analysis of sensitivity to RCs to background cosmology, notably across a sharp -transition (van Putten, 2018) of Newtonian to anomalous dynamics across and, further out, the baryonic Tully–Fisher relation. In turn, these markers provide a novel measurement of cosmological parameters including .
{"title":"Prospects for high-resolution probes of galaxy dynamics tracing background cosmology in MaNGA","authors":"Gyeong-Min Lee , Maurice H.P.M. van Putten","doi":"10.1016/j.newast.2025.102360","DOIUrl":"10.1016/j.newast.2025.102360","url":null,"abstract":"<div><div>Large-<span><math><mi>N</mi></math></span> galaxy surveys offer unprecedented opportunities to probe weak gravitation in galaxy dynamics that may contain correlations tracing background cosmology. Of particular interest is the potential of finite sensitivities to the background de Sitter scale of acceleration <span><math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>d</mi><mi>S</mi></mrow></msub><mo>=</mo><mi>c</mi><mi>H</mi></mrow></math></span>, where <span><math><mi>H</mi></math></span> is the Hubble parameter and <span><math><mi>c</mi></math></span> is the velocity of light. At sufficiently large <span><math><mi>N</mi></math></span>, this is possibly probed by ensemble-averaged (“stacked”) rotation curves (RCs) at resolutions on par with present estimates of the Hubble parameter <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>. Here, we consider the prospect for these studies using the large <span><math><mi>N</mi></math></span> <em>Mapping Nearby Galaxies at Apache Point Observatory</em> MaNGA at APO survey. In a first and preliminary step, we consider unbiased control of sub-sample size by consistency in the three Position Angles, <span><math><mi>θ</mi></math></span> , from photometry and velocity fields of gas and stars by spectroscopy within 30°. In sub-samples of size <span><math><mrow><mi>N</mi><mo>=</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>i</mi></mrow></msub><mrow><mo>(</mo><mi>θ</mi><mo>)</mo></mrow></mrow></math></span>, the scatter in-the-mean <span><math><mrow><mi>σ</mi><mo>/</mo><msqrt><mrow><mi>N</mi></mrow></msqrt></mrow></math></span> is found to reach one percent levels, differentiated over inclination angle <span><math><mi>i</mi></math></span> and <span><math><mi>θ</mi></math></span>. In regular propagation of uncertainties, this scatter contributes <span><math><mrow><mi>κ</mi><mi>σ</mi><mo>/</mo><msqrt><mrow><mi>N</mi></mrow></msqrt></mrow></math></span> to the standard error in-the-mean to the observable, where <span><math><mi>κ</mi></math></span> is determined by the choice of observables. As a lower bound to scatter in stacked RCs, MaNGA hereby appears promising for high-resolution analysis of sensitivity to RCs to background cosmology, notably across a sharp <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span>-transition (van Putten, 2018) of Newtonian to anomalous dynamics across <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>d</mi><mi>S</mi></mrow></msub></math></span> and, further out, the baryonic Tully–Fisher relation. In turn, these markers provide a novel measurement of cosmological parameters including <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102360"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accretion disks is crucial in studying black holes, serving as the singular source of electromagnetic radiation. The existence of singularity inherent in black holes necessitates an examination of regular cores. In this work, we study standard thin accretion disks around regular black holes (RBHs) with a nonlinear electrodynamics source. By comparing the radiant energy, luminosity derivative, and temperature of six types of RBHs with a nonlinear electrodynamics source, both among themselves and with Schwarzschild black holes, we aim to identify observable features. Our results show that the non-zero charge parameter of RBHs with a nonlinear electrodynamics source causes the radius of the innermost stable circular orbit of the accretion disk to be displaced inwards towards smaller values of . We also obtain that the mass-to-radiant conversion efficiency for RBHs with a nonlinear electrodynamics source is higher than that of Schwarzschild black holes. Finally, we compare the free parameter of RBHs with a nonlinear electrodynamics source to the spin parameter of the Kerr black hole to extract potential observables. Our results indicate that the maximum spin that RBHs with a nonlinear electrodynamics source can mimic is approximately 0.9.
{"title":"Accretion disk around the regular black holes with a nonlinear electrodynamics source","authors":"Minou Khoshrangbaf , Amin Rezaei Akbarieh , K. Atazadeh , Hossein Motavalli","doi":"10.1016/j.newast.2025.102354","DOIUrl":"10.1016/j.newast.2025.102354","url":null,"abstract":"<div><div>Accretion disks is crucial in studying black holes, serving as the singular source of electromagnetic radiation. The existence of singularity inherent in black holes necessitates an examination of regular cores. In this work, we study standard thin accretion disks around regular black holes (RBHs) with a nonlinear electrodynamics source. By comparing the radiant energy, luminosity derivative, and temperature of six types of RBHs with a nonlinear electrodynamics source, both among themselves and with Schwarzschild black holes, we aim to identify observable features. Our results show that the non-zero charge parameter of RBHs with a nonlinear electrodynamics source causes the radius of the innermost stable circular orbit of the accretion disk to be displaced inwards towards smaller values of <span><math><mi>r</mi></math></span>. We also obtain that the mass-to-radiant conversion efficiency for RBHs with a nonlinear electrodynamics source is higher than that of Schwarzschild black holes. Finally, we compare the free parameter of RBHs with a nonlinear electrodynamics source to the spin parameter of the Kerr black hole to extract potential observables. Our results indicate that the maximum spin that RBHs with a nonlinear electrodynamics source can mimic is approximately 0.9.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102354"},"PeriodicalIF":1.9,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153392","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}
Pub Date : 2025-01-27DOI: 10.1016/j.newast.2025.102357
Xuan-Qi Tang , Chao-Yue Li , Lin-Qiao Jiang , Jie Wei , Jie Zheng , Kai Huang , Jia-Xing Wang , Hao-Yi Yang , Jing-Zhou Li , Xiao-Man Tian , Jian-Hui Yang
<div><div>V551 Dra and CN Hyi are both W UMa-type contact binaries. Basing on TESS data, we conduct analyses of their orbital period variations. The results indicate that the O - C curve of V551 Dra shows a long-term upward trend, with <span><math><mrow><mi>d</mi><mi>P</mi><mo>/</mo><mi>d</mi><mi>t</mi><mo>=</mo><mn>2</mn><mo>.</mo><mn>80</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup><mi>d</mi><mi>a</mi><mi>y</mi><mi>⋅</mi><mi>y</mi><mi>e</mi><mi>a</mi><msup><mrow><mi>r</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, which could be attributed to mass transfer from the less massive component to the more massive one. Additionally, a periodic variation with an amplitude of <span><math><mrow><mi>A</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>000954</mn><mi>d</mi><mi>a</mi><mi>y</mi><mi>s</mi></mrow></math></span> and a period of <span><math><mrow><mi>P</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>31</mn><mi>y</mi><mi>e</mi><mi>a</mi><mi>r</mi><mi>s</mi></mrow></math></span> was superimposed. The periodic variation in the orbital period may be due to the light-travel time effect caused by a third body. We estimate the minimum mass of the third body to be <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>48</mn><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></mrow></math></span>. The primary of V551 Dra, although less massive, is oversized and overluminous compared to standard mainsequence stars, suggesting it has evolved through substantial mass loss, while the more massive secondary remains on the main sequence, indicating a stable mass transfer phase. In contrast, The O - C curve of CN Hyi exhibits a long-term decreasing trend, with <span><math><mrow><mi>d</mi><mi>P</mi><mo>/</mo><mi>d</mi><mi>t</mi><mo>=</mo><mo>−</mo><mn>1</mn><mo>.</mo><mn>09</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup><mi>d</mi><mi>a</mi><mi>y</mi><mi>⋅</mi><mi>y</mi><mi>e</mi><mi>a</mi><msup><mrow><mi>r</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. Due to the intermediate contact nature of the binary system, this long-term period decrease is likely to be caused by mass transfer from the more massive primary star to the less massive secondary star. The primary of CN Hyi resides on the main sequence, while the oversized and overluminous secondary suggests significant material accretion. These findings suggest differing evolutionary pathways for W-subtype and A-subtype contact binaries. V551 Dra appears to exhibit stable mass transfer dynamics, whereas CN Hyi may potentially experience more dynamic structural changes as it evolves. In addition to these evolutionary considerations, we hypothesize that the period variation of CN Hyi may also be attributed by the light-travel time effect of a third body, given the common occurrence of third bodies in contact systems. Considering
{"title":"Orbital period study of two contact W UMa-type contact binaries: V551 Dra and CN Hyi","authors":"Xuan-Qi Tang , Chao-Yue Li , Lin-Qiao Jiang , Jie Wei , Jie Zheng , Kai Huang , Jia-Xing Wang , Hao-Yi Yang , Jing-Zhou Li , Xiao-Man Tian , Jian-Hui Yang","doi":"10.1016/j.newast.2025.102357","DOIUrl":"10.1016/j.newast.2025.102357","url":null,"abstract":"<div><div>V551 Dra and CN Hyi are both W UMa-type contact binaries. Basing on TESS data, we conduct analyses of their orbital period variations. The results indicate that the O - C curve of V551 Dra shows a long-term upward trend, with <span><math><mrow><mi>d</mi><mi>P</mi><mo>/</mo><mi>d</mi><mi>t</mi><mo>=</mo><mn>2</mn><mo>.</mo><mn>80</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>7</mn></mrow></msup><mi>d</mi><mi>a</mi><mi>y</mi><mi>⋅</mi><mi>y</mi><mi>e</mi><mi>a</mi><msup><mrow><mi>r</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, which could be attributed to mass transfer from the less massive component to the more massive one. Additionally, a periodic variation with an amplitude of <span><math><mrow><mi>A</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>000954</mn><mi>d</mi><mi>a</mi><mi>y</mi><mi>s</mi></mrow></math></span> and a period of <span><math><mrow><mi>P</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>31</mn><mi>y</mi><mi>e</mi><mi>a</mi><mi>r</mi><mi>s</mi></mrow></math></span> was superimposed. The periodic variation in the orbital period may be due to the light-travel time effect caused by a third body. We estimate the minimum mass of the third body to be <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>48</mn><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></mrow></math></span>. The primary of V551 Dra, although less massive, is oversized and overluminous compared to standard mainsequence stars, suggesting it has evolved through substantial mass loss, while the more massive secondary remains on the main sequence, indicating a stable mass transfer phase. In contrast, The O - C curve of CN Hyi exhibits a long-term decreasing trend, with <span><math><mrow><mi>d</mi><mi>P</mi><mo>/</mo><mi>d</mi><mi>t</mi><mo>=</mo><mo>−</mo><mn>1</mn><mo>.</mo><mn>09</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup><mi>d</mi><mi>a</mi><mi>y</mi><mi>⋅</mi><mi>y</mi><mi>e</mi><mi>a</mi><msup><mrow><mi>r</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. Due to the intermediate contact nature of the binary system, this long-term period decrease is likely to be caused by mass transfer from the more massive primary star to the less massive secondary star. The primary of CN Hyi resides on the main sequence, while the oversized and overluminous secondary suggests significant material accretion. These findings suggest differing evolutionary pathways for W-subtype and A-subtype contact binaries. V551 Dra appears to exhibit stable mass transfer dynamics, whereas CN Hyi may potentially experience more dynamic structural changes as it evolves. In addition to these evolutionary considerations, we hypothesize that the period variation of CN Hyi may also be attributed by the light-travel time effect of a third body, given the common occurrence of third bodies in contact systems. Considering","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102357"},"PeriodicalIF":1.9,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153394","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}
The hydrodynamical cosmological simulation EAGLE is used to model the Halo Occupation Distribution (HOD) of moderate X-ray luminosity active galactic nuclei (mXAGN), extending previous work using only dark matter simulations and empirical relations. By examining mergers as a triggering mechanism, we focus on halos typical of galaxy groups and cluster-like systems with masses . We analyze simulation data to create catalogs of central and satellite galaxies. We study their merger history we quantify the percentage of minor and major mergers in the mXAGN sample. We obtain the HOD for central and satellite mXAGN across a redshift interval from to the present epoch. Our results indicate that, across most redshifts, minor mergers slightly predominate as the primary mechanism for triggering mXAGN.
{"title":"Exploring the halo occupation distribution for moderate X-ray luminosity active galactic nuclei in the EAGLE cosmological simulation","authors":"Liliana Altamirano-Dévora , Héctor Aceves , Angel Castro , Takamitsu Miyaji","doi":"10.1016/j.newast.2025.102361","DOIUrl":"10.1016/j.newast.2025.102361","url":null,"abstract":"<div><div>The hydrodynamical cosmological simulation <em>EAGLE</em> is used to model the Halo Occupation Distribution (HOD) of moderate X-ray luminosity active galactic nuclei (mXAGN), extending previous work using only dark matter simulations and empirical relations. By examining mergers as a triggering mechanism, we focus on halos typical of galaxy groups and cluster-like systems with masses <span><math><mrow><mo>≥</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>12</mn><mo>.</mo><mn>75</mn></mrow></msup><mspace></mspace><mi>M</mi><mo>⊙</mo><mspace></mspace><msup><mrow><mi>h</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. We analyze simulation data to create catalogs of central and satellite galaxies. We study their merger history we quantify the percentage of minor and major mergers in the mXAGN sample. We obtain the HOD for central and satellite mXAGN across a redshift interval from <span><math><mrow><mi>z</mi><mo>=</mo><mn>2</mn></mrow></math></span> to the present epoch. Our results indicate that, across most redshifts, minor mergers slightly predominate as the primary mechanism for triggering mXAGN.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102361"},"PeriodicalIF":1.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153395","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}
Pub Date : 2025-01-21DOI: 10.1016/j.newast.2025.102358
Bin Zhang , Yidan Gao
In this paper, we present the first investigation of the short period eclipsing binary GY Psc. We find that GY Psc is a shallow W-subtype binary with a mass ratio of = 2.522. We also find that its light curves show different O’Connell effect, which can be explained by the evolution of the cool star-spots. At the same time, the diagram reveals a cyclic oscillation with a period of years and an amplitude of 0.033883 days. The cyclic oscillation is interpreted as the light travel-time effect via the presence of a stellar black hole candidate. The minimum mass of the tertiary companion is estimated to be = 12.99 . All the results reveal that GY Psc may be a triple system with active star-spot activity.
{"title":"The first study of the short period contact binary GY Psc","authors":"Bin Zhang , Yidan Gao","doi":"10.1016/j.newast.2025.102358","DOIUrl":"10.1016/j.newast.2025.102358","url":null,"abstract":"<div><div>In this paper, we present the first investigation of the short period eclipsing binary GY Psc. We find that GY Psc is a shallow W-subtype binary with a mass ratio of <span><math><mi>q</mi></math></span> = 2.522. We also find that its light curves show different O’Connell effect, which can be explained by the evolution of the cool star-spots. At the same time, the <span><math><mrow><mi>O</mi><mo>−</mo><mi>C</mi></mrow></math></span> diagram reveals a cyclic oscillation with a period of <span><math><mrow><mi>P</mi><mo>=</mo><mn>3</mn><mo>.</mo><mn>85</mn></mrow></math></span> years and an amplitude of 0.033883 days. The cyclic oscillation is interpreted as the light travel-time effect via the presence of a stellar black hole candidate. The minimum mass of the tertiary companion is estimated to be <span><math><msub><mrow><mi>M</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> = 12.99 <span><math><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>. All the results reveal that GY Psc may be a triple system with active star-spot activity.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102358"},"PeriodicalIF":1.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153390","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}
Pub Date : 2025-01-20DOI: 10.1016/j.newast.2025.102356
Meenu Prajapati, Mamta Gulati
Interaction between the intracluster medium (ICM) and the interstellar medium (ISM) plays a crucial role in galaxy evolution. Surveys of galaxy clusters have shown that ram pressure stripping (RPS) is a dominant mechanism that removes the cold gas reservoir from cluster galaxies. We extend the analytical model for ram pressure stripping by Singh et al. (2019) to include asymmetries in the disc, such as spiral arms and regular magnetic fields along the spiral arms. Non-thermal pressure from magnetic fields acts against the ram pressure and leads to greater gas retention in galaxies. Our analytical modelling of spiral galaxies with magnetic fields shows that a strong magnetic field, with a strength of G, significantly enhances gas retention at the centre of a galaxy as it approaches the core of a cluster, thereby suppressing the stripping rates. We find that magnetic fields stronger than G are critical for retaining gas all the way to the cluster centre. While both magnetic fields and galaxy mass contribute to the retention of gas, the influence of magnetic fields is particularly significant, especially in typical spiral galaxies where unusually high masses are not present. Our results may help in explaining why gas-rich galaxies can still be observed in dense cluster environments despite the strong stripping forces.
{"title":"Galactic magnetic field and spiral arms against gas quenching due to Ram pressure","authors":"Meenu Prajapati, Mamta Gulati","doi":"10.1016/j.newast.2025.102356","DOIUrl":"10.1016/j.newast.2025.102356","url":null,"abstract":"<div><div>Interaction between the intracluster medium (ICM) and the interstellar medium (ISM) plays a crucial role in galaxy evolution. Surveys of galaxy clusters have shown that ram pressure stripping (RPS) is a dominant mechanism that removes the cold gas reservoir from cluster galaxies. We extend the analytical model for ram pressure stripping by Singh et al. (2019) to include asymmetries in the disc, such as spiral arms and regular magnetic fields along the spiral arms. Non-thermal pressure from magnetic fields acts against the ram pressure and leads to greater gas retention in galaxies. Our analytical modelling of spiral galaxies with magnetic fields shows that a strong magnetic field, with a strength of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> G, significantly enhances gas retention at the centre of a galaxy as it approaches the core of a cluster, thereby suppressing the stripping rates. We find that magnetic fields stronger than <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></math></span> G are critical for retaining gas all the way to the cluster centre. While both magnetic fields and galaxy mass contribute to the retention of gas, the influence of magnetic fields is particularly significant, especially in typical spiral galaxies where unusually high masses are not present. Our results may help in explaining why gas-rich galaxies can still be observed in dense cluster environments despite the strong stripping forces.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102356"},"PeriodicalIF":1.9,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152959","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}
Pub Date : 2025-01-18DOI: 10.1016/j.newast.2025.102355
Bhupendra Kumar Shukla , R.K. Tiwari , A. Beesham , Değer Sofuoğlu
In this study, we investigate Modified Chaplygin gas solutions within the framework of theory of gravity, a modified gravitational theory that seeks to address the limitations of the conventional Lambda cold dark matter model. gravity offers a novel perspective on cosmic dynamics by incorporating a non-minimal coupling between the geometry and the matter, allowing for a richer understanding of the expansion of the universe. We explore the implications of modified Chaplygin gas, characterized by its unique equation of state (eos), which transitions from a matter-dominated phase to a dark energy-dominated phase, thereby influencing the evolution of the energy density and pressure across cosmic redshifts. Our findings reveal significant insights into the interplay between different energy components, highlighting the transition from positive to negative pressure as a hallmark of the role of dark energy in driving the accelerated expansion of the universe. This research not only enhances our comprehension of cosmic evolution, but also provides a compelling framework for future investigations into the nature of dark energy and its impact on the ultimate fate of the universe.
{"title":"Modified Chaplygin gas solutions of f(Q) theory of gravity","authors":"Bhupendra Kumar Shukla , R.K. Tiwari , A. Beesham , Değer Sofuoğlu","doi":"10.1016/j.newast.2025.102355","DOIUrl":"10.1016/j.newast.2025.102355","url":null,"abstract":"<div><div>In this study, we investigate Modified Chaplygin gas solutions within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> theory of gravity, a modified gravitational theory that seeks to address the limitations of the conventional Lambda cold dark matter model. <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity offers a novel perspective on cosmic dynamics by incorporating a non-minimal coupling between the geometry and the matter, allowing for a richer understanding of the expansion of the universe. We explore the implications of modified Chaplygin gas, characterized by its unique equation of state (eos), which transitions from a matter-dominated phase to a dark energy-dominated phase, thereby influencing the evolution of the energy density and pressure across cosmic redshifts. Our findings reveal significant insights into the interplay between different energy components, highlighting the transition from positive to negative pressure as a hallmark of the role of dark energy in driving the accelerated expansion of the universe. This research not only enhances our comprehension of cosmic evolution, but also provides a compelling framework for future investigations into the nature of dark energy and its impact on the ultimate fate of the universe.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"117 ","pages":"Article 102355"},"PeriodicalIF":1.9,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153389","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}
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