Monthly Notices of the Royal Astronomical Society: Letters最新文献_第5页

Mergers of black hole binaries driven by misaligned circumbinary discs 黑洞双星在错位环盘驱动下的合并

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-16 DOI: 10.1093/mnrasl/slad174

Rebecca G. Martin, Stephen Lepp, Bing Zhang, C. J. Nixon, Anna C. Childs

引用次数: 0

The Characteristic Shape of Damping Wings During Reionization 再电离过程中阻尼翼的特征形状

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-14 DOI: 10.1093/mnrasl/slad171

Huanqing Chen

{"title":"The Characteristic Shape of Damping Wings During Reionization","authors":"Huanqing Chen","doi":"10.1093/mnrasl/slad171","DOIUrl":"https://doi.org/10.1093/mnrasl/slad171","url":null,"abstract":"Abstract Spectroscopic analysis of Lyα damping wings of bright sources at z &gt; 6 is a promising way to measure the reionization history of the universe. However, the theoretical interpretation of the damping wings is challenging due to the inhomogeneous nature of the reionization process and the proximity effect of bright sources. In this Letter, we analyze the damping wings arising from the neutral patches in the radiative transfer cosmological simulation suite Cosmic Reionization on Computers (CROC). We find that the damping wing profile remains a tight function of volume-weighted neutral fraction &lt;xHI &gt; v, especially when &lt;xHI &gt; v &gt; 0.5, despite the patchy nature of reionization and the proximity effect. This small scatter indicates that with a well-measured damping wing profile, we could constrain the volume-weighted neutral fraction as precise as Δ &lt; xHI &gt; v ≲ 0.1 in the first half of reionization. Due to resonant Lyα absorption from the residual neutral hydrogen inside the ionized bubble, it may be challenging to find the starting point of the damping wing for faint sources like normal galaxies or gamma-ray bursts. However, for bright sources like quasars, it is hopeful to measure the entire damping wing and use them to measure the neutral fraction accurately.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134993284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Unipolar solar flares as a manifestation of ‘topological’ magnetic reconnection 单极太阳耀斑是 "拓扑 "磁重联的一种表现形式

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-13 DOI: 10.1093/mnrasl/slad162

Y. Dumin, B. Somov

引用次数: 0

Disc precession in Be/X-ray binaries drives superorbital variations of outbursts and colour B/X射线双星中的圆盘前冲驱动爆发和颜色的超轨道变化

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-11 DOI: 10.1093/mnrasl/slad170

R. Martin, P. Charles

{"title":"Disc precession in Be/X-ray binaries drives superorbital variations of outbursts and colour","authors":"R. Martin, P. Charles","doi":"10.1093/mnrasl/slad170","DOIUrl":"https://doi.org/10.1093/mnrasl/slad170","url":null,"abstract":"Superorbital periods that are observed in the brightness of Be/X-ray binaries may be driven by a misaligned and precessing Be star disc. We examine how the precessing disc model explains the superorbital variation of (i) the magnitude of the observed X-ray outbursts and (ii) the observed colour. With hydrodynamical simulations we show that the magnitude of the average accretion rate on to the neutron star, and therefore the X-ray outbursts, can vary by over an order of magnitude over the superorbital period for Be star spin-orbit misalignments ≳ 70○ as a result of weak tidal truncation. Most Be/X-ray binaries are redder at optical maximum when the disc is viewed closest to face-on since the disc adds a large red component to the emission. However, A0538-66 is redder at optical minimum. This opposite behaviour requires an edge-on disc at optical minimum and a radially narrow disc such that it does not add a large red signature when viewed face-on. For A0538-66, the misalignment of the disc to the binary orbit must be about 70 − 80○ and the inclination of the binary orbit to the line of sight must be similarly high, although restricted to <75○ by the absence of X-ray eclipses.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139279786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modelling the Light Curves of Transiting Exomoons: a Zero-order Photodynamic Agent Added to the Transit and Light Curve Modeller 凌日系外卫星的光曲线建模:添加到凌日和光曲线建模器中的零阶光动力学代理

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-09 DOI: 10.1093/mnrasl/slad169

Szilárd Kálmán, Szilárd Csizmadia, Attila Simon E, Kristine W F Lam, Adrien Deline, Jan-Vincent Harre, Gyula Szabó M

引用次数: 0

Prompt Gamma-Ray Burst Emission from Internal Shocks – New Insights 来自内部冲击的快速伽马射线爆发——新见解

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-08 DOI: 10.1093/mnrasl/slad168

Sk Minhajur Rahaman, Jonathan Granot, Paz Beniamini

{"title":"Prompt Gamma-Ray Burst Emission from Internal Shocks – New Insights","authors":"Sk Minhajur Rahaman, Jonathan Granot, Paz Beniamini","doi":"10.1093/mnrasl/slad168","DOIUrl":"https://doi.org/10.1093/mnrasl/slad168","url":null,"abstract":"Abstract Internal shocks are a leading candidate for the dissipation mechanism that powers the prompt γ-ray emission in gamma-ray bursts (GRBs). In this scenario a compact central source produces an ultra-relativistic outflow with varying speeds, causing faster parts or shells to collide with slower ones. Each collision produces a pair of shocks – a forward shock (FS) propagating into the slower leading shell and a reverse shock (RS) propagating into the faster trailing shell. The RS’s lab-frame speed is always smaller, while the RS is typically stronger than the FS, leading to different conditions in the two shocked regions that both contribute to the observed emission. We show that optically-thin synchrotron emission from both (weaker FS + stronger RS) can naturally explain key features of prompt GRB emission such as the pulse shapes, time-evolution of the νFν peak flux and photon-energy, and the spectrum. Particularly, it can account for two features commonly observed in GRB spectra: (i) a sub-dominant low-energy spectral component (often interpreted as “photospheric”-like), or (ii) a doubly-broken power-law spectrum with the low-energy spectral slope approaching the slow cooling limit. Both features can be obtained while maintaining high overall radiative efficiency without any fine-tuning of the physical conditions.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"30 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135430040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Extremely strong C iv λ1550 nebular emission in the extremely low-metallicity star-forming galaxy J2229+2725 极低金属丰度恒星形成星系J2229+2725中极强的C iv λ1550星云发射

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-07 DOI: 10.1093/mnrasl/slad166

Izotov, Y. I., Schaerer, D., Guseva, N. G., Thuan, T. X., Worseck, G.

{"title":"Extremely strong C <scp>iv</scp> λ1550 nebular emission in the extremely low-metallicity star-forming galaxy J2229+2725","authors":"Izotov, Y. I., Schaerer, D., Guseva, N. G., Thuan, T. X., Worseck, G.","doi":"10.1093/mnrasl/slad166","DOIUrl":"https://doi.org/10.1093/mnrasl/slad166","url":null,"abstract":"Using Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of one of the most metal-poor dwarf star-forming galaxies (SFG) in the local Universe, J2229+2725, we have discovered an extremely strong nebular CIV 1549, 1551 emission-line doublet, with an equivalent width of 43A, several times higher than the value observed so far in low-redshift SFGs. Together with other extreme characteristics obtained from optical spectroscopy (oxygen abundance 12+log(O/H)=7.085+/-0.031, ratio O32 = I([OIII]5007)/I([OII]3727) ~ 53, and equivalent width of the Hbeta emission line EW(Hbeta) = 577A), this galaxy greatly increases the range of physical properties for dwarf SFGs at low redshift and is a likely analogue of the high-redshift dwarf SFGs responsible for the reionization of the Universe. We find the ionizing radiation in J2229+2725 to be stellar in origin and the high EW(CIV 1549,1551) to be due to both extreme ionization conditions and a high carbon abundance, with a corresponding log C/O = -0.38, that is ~ 0.4 dex higher than the average value for nearby low-metallicity SFGs.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"8 29","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135540472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Infrared spectroscopy of SWIFT J0850.8-4219: Identification of the second red supergiant X-ray binary in the Milky Way SWIFT J0850.8-4219的红外光谱:银河系中第二个红超巨星x射线双星的识别

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-06 DOI: 10.1093/mnrasl/slad164

Kishalay De, Fiona A Daly, Roberto Soria

{"title":"Infrared spectroscopy of SWIFT J0850.8-4219: Identification of the second red supergiant X-ray binary in the Milky Way","authors":"Kishalay De, Fiona A Daly, Roberto Soria","doi":"10.1093/mnrasl/slad164","DOIUrl":"https://doi.org/10.1093/mnrasl/slad164","url":null,"abstract":"Abstract High mass X-ray binaries hosting red supergiant (RSG) donors are a rare but crucial phase in massive stellar evolution, with only one source previously known in the Milky Way. In this letter, we present the identification of the second Galactic RSG X-ray binary SWIFT J0850.8-4219. We identify the source 2MASS 08504008-4211514 as the likely infrared counterpart with a chance coincidence probability ≈5 × 10−6. We present a 1.0 − 2.5 μm spectrum of the counterpart, exhibiting features characteristic of late-type stars and an exceptionally strong He I emission line, corroborating the identification. Based on i) the strength of the 12CO(2,0) band, ii) strong CN bandheads and absent TiO bandheads at ≈1.1 μm and iii) equivalent width of the Mg I 1.71 μm line, we classify the counterpart to be a K3−K5 type RSG with an effective temperature of 3820 ± 100 K, located at a distance of ≈12 kpc. We estimate the source X-ray luminosity to be (4 ± 1) × 1035 erg s−1, with a hard photon index (Γ &lt; 1), arguing against a white dwarf accretor but consistent with a magnetized neutron star in the propeller phase. Our results highlight the potential of systematic NIR spectroscopy of Galactic hard X-ray sources in completing our census of the local X-ray binary population.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"66 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135685125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

S 8 increases with effective redshift in ΛCDM cosmology 在ΛCDM宇宙学中，s8随有效红移而增加

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-03 DOI: 10.1093/mnrasl/slad165

S A Adil, Ö Akarsu, M Malekjani, E Ó Colgáin, S Pourojaghi, A A Sen, M M Sheikh-Jabbari

{"title":"<i>S</i> 8 increases with effective redshift in ΛCDM cosmology","authors":"S A Adil, Ö Akarsu, M Malekjani, E Ó Colgáin, S Pourojaghi, A A Sen, M M Sheikh-Jabbari","doi":"10.1093/mnrasl/slad165","DOIUrl":"https://doi.org/10.1093/mnrasl/slad165","url":null,"abstract":"Abstract Hubble constant H0 and weighted amplitude of matter fluctuations S8 determinations are biased to higher and lower values, respectively, in the late Universe with respect to early Universe values inferred by the Planck collaboration within flat ΛCDM cosmology. If these anomalies are physical, i.e. not due to systematics, they naively suggest that H0 decreases and S8 increases with effective redshift. Here, subjecting matter density today Ωm to a prior, corresponding to a combination of Planck CMB and BAO data, we perform a consistency test of the Planck-ΛCDM cosmology and show that S8 determinations from fσ8(z) constraints increase with effective redshift. Due to the redshift evolution, a ∼3σ tension in the S8 parameter with Planck at lower redshifts remarkably becomes consistent with Planck within 1σ at high redshifts. This provides corroborating support for an S8 discrepancy that is physical in origin. We further confirm that the flat ΛCDM model is preferred over a theoretically ad hoc model with a jump in S8 at a given redshift. In the absence of the CMB+BAO Ωm prior, we find that &gt;3σ tensions with Planck in low redshift data are ameliorated by shifts in the parameters in high redshift data. Results here and elsewhere suggest that the ΛCDM cosmological parameters are redshift dependent. Fitting parameters that evolve with redshift is a recognisable hallmark of model breakdown.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"7 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Unique spectral manifestations around the D3 line observed in the region close to the seismic source of a large solar flare 在靠近大型太阳耀斑震源的区域观测到的D3线周围独特的光谱表现

Monthly Notices of the Royal Astronomical Society: Letters Pub Date : 2023-11-03 DOI: 10.1093/mnrasl/slad163

N I Lozitska, I I Yakovkin, V G Lozitsky

{"title":"Unique spectral manifestations around the D3 line observed in the region close to the seismic source of a large solar flare","authors":"N I Lozitska, I I Yakovkin, V G Lozitsky","doi":"10.1093/mnrasl/slad163","DOIUrl":"https://doi.org/10.1093/mnrasl/slad163","url":null,"abstract":"ABSTRACT The main goal of our research is to search for super-strong magnetic fields in active processes on the Sun. Our method is based on Stokes V spectro-polarimetry in a wide spectral range from −14 Å to +29 Å relative to the D3 He i line. The object of the study is the area of a seismic source in the large solar flare on 2003 October 28 of the X17.2/4B class. The novelty of our study: we found characteristic spectral manifestations – secondary Stokes V peaks – far from D3 line, at distances of several angstroms. These secondary peaks have the following features: (a) their amplitudes reach 4 per cent – almost an order of magnitude more than previously detected in other flares, (b) in the general picture, the sign of the circular polarization changes when passing through the D3 centre, and (c) narrower spectral peculiarities were found at distances of +4.0, +6.3, and +8.5 Å, where the polarization sign also changes sharply. This unusual feature likely results from significant factors in the area of the seismic source, including substantial descending plasma velocities which exceed 400 km s−1 and, perhaps, super-strong magnetic fields.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0