A A Chrimes, P G Jonker, A J Levan, D L Coppejans, N Gaspari, B P Gompertz, P J Groot, D B Malesani, A Mummery, E R Stanway, K Wiersema
ABSTRACT Luminous fast blue optical transients (LFBOTs) – the prototypical example being AT 2018cow – are a rare class of events whose origins are poorly understood. They are characterized by rapid evolution, featureless blue spectra at early times, and luminous X-ray and radio emission. LFBOTs thus far have been found exclusively at small projected offsets from star-forming host galaxies. We present Hubble Space Telescope, Gemini, Chandra, and Very Large Array observations of a new LFBOT, AT 2023fhn. The Hubble Space Telescope data reveal a large offset (>3.5 half-light radii) from the two closest galaxies, both at redshift z ∼ 0.24. The location of AT 2023fhn is in stark contrast with previous events, and demonstrates that LFBOTs can occur in a range of galactic environments.
发光快速蓝光瞬变(LFBOTs)——典型的例子是AT 2018cow——是一类罕见的事件，其起源尚不清楚。它们的特点是演化迅速，早期无特征的蓝色光谱，以及发光的x射线和射电发射。迄今为止，lfbot只在恒星形成宿主星系的小投影偏移处被发现。我们展示了哈勃太空望远镜、双子座、钱德拉和超大阵列对一个新的LFBOT, AT 2023fhn的观测。哈勃太空望远镜的数据显示，距离最近的两个星系有很大的偏移(>3.5半光半径)，两者的红移都在z ~ 0.24。AT 2023fhn的位置与之前的事件形成鲜明对比，并表明lfbot可以发生在一系列银河系环境中。
{"title":"AT2023fhn (the Finch): a luminous fast blue optical transient at a large offset from its host galaxy","authors":"A A Chrimes, P G Jonker, A J Levan, D L Coppejans, N Gaspari, B P Gompertz, P J Groot, D B Malesani, A Mummery, E R Stanway, K Wiersema","doi":"10.1093/mnrasl/slad145","DOIUrl":"https://doi.org/10.1093/mnrasl/slad145","url":null,"abstract":"ABSTRACT Luminous fast blue optical transients (LFBOTs) – the prototypical example being AT 2018cow – are a rare class of events whose origins are poorly understood. They are characterized by rapid evolution, featureless blue spectra at early times, and luminous X-ray and radio emission. LFBOTs thus far have been found exclusively at small projected offsets from star-forming host galaxies. We present Hubble Space Telescope, Gemini, Chandra, and Very Large Array observations of a new LFBOT, AT 2023fhn. The Hubble Space Telescope data reveal a large offset (>3.5 half-light radii) from the two closest galaxies, both at redshift z ∼ 0.24. The location of AT 2023fhn is in stark contrast with previous events, and demonstrates that LFBOTs can occur in a range of galactic environments.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646460","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}
M Gatti, N Jeffrey, L Whiteway, V Ajani, T Kacprzak, D Zürcher, C Chang, B Jain, J Blazek, E Krause, A Alarcon, A Amon, K Bechtol, M Becker, G Bernstein, A Campos, R Chen, A Choi, C Davis, J Derose, H T Diehl, S Dodelson, C Doux, K Eckert, J Elvin-Poole, S Everett, A Ferte, D Gruen, R Gruendl, I Harrison, W G Hartley, K Herner, E M Huff, M Jarvis, N Kuropatkin, P F Leget, N MacCrann, J McCullough, J Myles, A Navarro-Alsina, S Pandey, J Prat, M Raveri, R P Rollins, A Roodman, C Sanchez, L F Secco, I Sevilla-Noarbe, E Sheldon, T Shin, M Troxel, I Tutusaus, T N Varga, B Yanny, B Yin, Y Zhang, J Zuntz, S S Allam, O Alves, M Aguena, D Bacon, E Bertin, D Brooks, D L Burke, A Carnero Rosell, J Carretero, R Cawthon, L N da Costa, T M Davis, J De Vicente, S Desai, P Doel, J García-Bellido, G Giannini, G Gutierrez, I Ferrero, J Frieman, S R Hinton, D L Hollowood, K Honscheid, D J James, K Kuehn, O Lahav, J L Marshall, J Mena-Fernández, R Miquel, R L C Ogando, A Palmese, M E S Pereira, A A Plazas Malagón, M Rodriguez-Monroy, S Samuroff, E Sanchez, M Schubnell, M Smith, F Sobreira, E Suchyta, M E C Swanson, G Tarle, N Weaverdyck
ABSTRACT We measure the impact of source galaxy clustering on higher order summary statistics of weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not trace the underlying density field, we show that this effect can exceed measurement uncertainties for common higher order statistics for certain analysis choices. We evaluate the impact on different weak lensing observables, finding that third moments and wavelet phase harmonics are more affected than peak count statistics. Using Dark Energy Survey (DES) Year 3 (Y3) data, we construct null tests for the source-clustering-free case, finding a p-value of p = 4 × 10−3 (2.6σ) using third-order map moments and p = 3 × 10−11 (6.5σ) using wavelet phase harmonics. The impact of source clustering on cosmological inference can be either included in the model or minimized through ad hoc procedures (e.g. scale cuts). We verify that the procedures adopted in existing DES Y3 cosmological analyses were sufficient to render this effect negligible. Failing to account for source clustering can significantly impact cosmological inference from higher order gravitational lensing statistics, e.g. higher order N-point functions, wavelet-moment observables, and deep learning or field-level summary statistics of weak lensing maps.
{"title":"Detection of the significant impact of source clustering on higher-order statistics with DES Year 3 weak gravitational lensing data","authors":"M Gatti, N Jeffrey, L Whiteway, V Ajani, T Kacprzak, D Zürcher, C Chang, B Jain, J Blazek, E Krause, A Alarcon, A Amon, K Bechtol, M Becker, G Bernstein, A Campos, R Chen, A Choi, C Davis, J Derose, H T Diehl, S Dodelson, C Doux, K Eckert, J Elvin-Poole, S Everett, A Ferte, D Gruen, R Gruendl, I Harrison, W G Hartley, K Herner, E M Huff, M Jarvis, N Kuropatkin, P F Leget, N MacCrann, J McCullough, J Myles, A Navarro-Alsina, S Pandey, J Prat, M Raveri, R P Rollins, A Roodman, C Sanchez, L F Secco, I Sevilla-Noarbe, E Sheldon, T Shin, M Troxel, I Tutusaus, T N Varga, B Yanny, B Yin, Y Zhang, J Zuntz, S S Allam, O Alves, M Aguena, D Bacon, E Bertin, D Brooks, D L Burke, A Carnero Rosell, J Carretero, R Cawthon, L N da Costa, T M Davis, J De Vicente, S Desai, P Doel, J García-Bellido, G Giannini, G Gutierrez, I Ferrero, J Frieman, S R Hinton, D L Hollowood, K Honscheid, D J James, K Kuehn, O Lahav, J L Marshall, J Mena-Fernández, R Miquel, R L C Ogando, A Palmese, M E S Pereira, A A Plazas Malagón, M Rodriguez-Monroy, S Samuroff, E Sanchez, M Schubnell, M Smith, F Sobreira, E Suchyta, M E C Swanson, G Tarle, N Weaverdyck","doi":"10.1093/mnrasl/slad143","DOIUrl":"https://doi.org/10.1093/mnrasl/slad143","url":null,"abstract":"ABSTRACT We measure the impact of source galaxy clustering on higher order summary statistics of weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not trace the underlying density field, we show that this effect can exceed measurement uncertainties for common higher order statistics for certain analysis choices. We evaluate the impact on different weak lensing observables, finding that third moments and wavelet phase harmonics are more affected than peak count statistics. Using Dark Energy Survey (DES) Year 3 (Y3) data, we construct null tests for the source-clustering-free case, finding a p-value of p = 4 × 10−3 (2.6σ) using third-order map moments and p = 3 × 10−11 (6.5σ) using wavelet phase harmonics. The impact of source clustering on cosmological inference can be either included in the model or minimized through ad hoc procedures (e.g. scale cuts). We verify that the procedures adopted in existing DES Y3 cosmological analyses were sufficient to render this effect negligible. Failing to account for source clustering can significantly impact cosmological inference from higher order gravitational lensing statistics, e.g. higher order N-point functions, wavelet-moment observables, and deep learning or field-level summary statistics of weak lensing maps.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646748","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}
Carolina Andonie, David M Alexander, Claire Greenwell, Annagrazia Puglisi, Brivael Laloux, Alba V Alonso-Tetilla, Gabriela Calistro Rivera, Chris Harrison, Ryan C Hickox, Melanie Kaasinen, Andrea Lapi, Iván E López, Grayson Petter, Cristina Ramos Almeida, David J Rosario, Francesco Shankar, Carolin Villforth
ABSTRACT In the standard quasar model, the accretion disc obscuration is due to the canonical dusty torus. Here, we argue that a substantial part of the quasar obscuration can come from the interstellar medium (ISM) when the quasars are embedded in compact starbursts. We use an obscuration-unbiased sample of 578 infrared (IR) quasars at z ≈ 1–3 and archival Atacama Large Millimetre/submillimetre Array submillimetre host galaxy sizes to investigate the ISM contribution to the quasar obscuration. We calculate star formation rates (SFR) and ISM column densities for the IR quasars and a control sample of submillimetre galaxies (SMGs) not hosting quasar activity and show that: (1) the quasar obscured fraction is constant up to $rm SFRapprox 300 : {rm M}_{odot } : yr^{-1}$, and then increases towards higher SFR, suggesting that the ISM obscuration plays a significant role in starburst host galaxies, and (2) at $rm SFRgtrsim 300 : {rm M}_{odot } : yr^{-1}$, the SMGs and IR quasars have similarly compact submillimetre sizes ($R_{rm e}approx 0.5{!-!}3,mathrm{ kpc}$) and consequently, the ISM can heavily obscure the quasar, even reaching Compton-thick ($N_{rm H}gt 10^{24} rm : cm^{-2}$) levels in extreme cases. Based on our results, we infer that ${approx} 10{!-!}30~{{ rm per cent}}$ of the IR quasars with $rm SFRgtrsim 300 : {rm M}_{odot } : yr^{-1}$ are obscured solely by the ISM.
{"title":"Obscuration beyond the nucleus: infrared quasars can be buried in extreme compact starbursts","authors":"Carolina Andonie, David M Alexander, Claire Greenwell, Annagrazia Puglisi, Brivael Laloux, Alba V Alonso-Tetilla, Gabriela Calistro Rivera, Chris Harrison, Ryan C Hickox, Melanie Kaasinen, Andrea Lapi, Iván E López, Grayson Petter, Cristina Ramos Almeida, David J Rosario, Francesco Shankar, Carolin Villforth","doi":"10.1093/mnrasl/slad144","DOIUrl":"https://doi.org/10.1093/mnrasl/slad144","url":null,"abstract":"ABSTRACT In the standard quasar model, the accretion disc obscuration is due to the canonical dusty torus. Here, we argue that a substantial part of the quasar obscuration can come from the interstellar medium (ISM) when the quasars are embedded in compact starbursts. We use an obscuration-unbiased sample of 578 infrared (IR) quasars at z ≈ 1–3 and archival Atacama Large Millimetre/submillimetre Array submillimetre host galaxy sizes to investigate the ISM contribution to the quasar obscuration. We calculate star formation rates (SFR) and ISM column densities for the IR quasars and a control sample of submillimetre galaxies (SMGs) not hosting quasar activity and show that: (1) the quasar obscured fraction is constant up to $rm SFRapprox 300 : {rm M}_{odot } : yr^{-1}$, and then increases towards higher SFR, suggesting that the ISM obscuration plays a significant role in starburst host galaxies, and (2) at $rm SFRgtrsim 300 : {rm M}_{odot } : yr^{-1}$, the SMGs and IR quasars have similarly compact submillimetre sizes ($R_{rm e}approx 0.5{!-!}3,mathrm{ kpc}$) and consequently, the ISM can heavily obscure the quasar, even reaching Compton-thick ($N_{rm H}gt 10^{24} rm : cm^{-2}$) levels in extreme cases. Based on our results, we infer that ${approx} 10{!-!}30~{{ rm per cent}}$ of the IR quasars with $rm SFRgtrsim 300 : {rm M}_{odot } : yr^{-1}$ are obscured solely by the ISM.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135647484","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}
ABSTRACT Two different temporal sections of a single gamma-ray burst (GRB) must be statistically similar to show an internal gravitational lensing signature. Here, two straightforward gravitational lensing tests are defined and applied: a light curve similarity test and a hardness similarity test. Gravitational millilensing has been claimed to be detected within several individual GRBs that contain two emission episodes separated by a time-delay. However, our analyses indicate that none of those claims satisfy both tests. The hardness similarity test performed on GRB 950830 and GRB 090717A found that the ratio between the second and the first emission episodes in each energy channel differed from the same ratio averaged over all detected energy channels at around 90 per cent confidence level. Also, a light curve similarity test performed on GRB 950830, GRB 090717A, and GRB 200716C separately found that it is unlikely that the two emission episodes in each GRB were drawn from a single parent emission episode for that GRB, with differences at the 3.0σ, 5.84σ, and 9.35σ confidence levels, respectively.
{"title":"Light Curve and Hardness Tests for Millilensing in GRB 950830, GRB 090717A, and GRB 200716C","authors":"Oindabi Mukherjee, Robert Nemiroff","doi":"10.1093/mnrasl/slad158","DOIUrl":"https://doi.org/10.1093/mnrasl/slad158","url":null,"abstract":"ABSTRACT Two different temporal sections of a single gamma-ray burst (GRB) must be statistically similar to show an internal gravitational lensing signature. Here, two straightforward gravitational lensing tests are defined and applied: a light curve similarity test and a hardness similarity test. Gravitational millilensing has been claimed to be detected within several individual GRBs that contain two emission episodes separated by a time-delay. However, our analyses indicate that none of those claims satisfy both tests. The hardness similarity test performed on GRB 950830 and GRB 090717A found that the ratio between the second and the first emission episodes in each energy channel differed from the same ratio averaged over all detected energy channels at around 90 per cent confidence level. Also, a light curve similarity test performed on GRB 950830, GRB 090717A, and GRB 200716C separately found that it is unlikely that the two emission episodes in each GRB were drawn from a single parent emission episode for that GRB, with differences at the 3.0σ, 5.84σ, and 9.35σ confidence levels, respectively.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135647596","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}
Philippe Brax, Carsten van de Bruck, Eleonora Di Valentino, William Giaré, Sebastian Trojanowski
ABSTRACT We revisit the possibility of using cosmological observations to constrain models that involve interactions between neutrinos and dark matter. We show that small-scale measurements of the cosmic microwave background (CMB) with a few per cent accuracy are critical to uncover unique signatures from models with tiny couplings that would require a much higher sensitivity at lower multipoles, such as those probed by the Planck satellite. We analyse the high-multipole data released by the Atacama Cosmology Telescope, both independently and in combination with Planck and baryon acoustic oscillation measurements, finding a compelling preference for a non-vanishing coupling, $log _{10}u_{nu textrm {DM}}=-5.20^{+1.2}_{-0.74}$ at 68 per cent confidence level. This aligns with other CMB-independent probes, such as Lyman-α. We illustrate how this coupling could be accounted for in the presence of dark matter interactions with a sterile neutrino.
{"title":"New Insights on ν-DM Interactions","authors":"Philippe Brax, Carsten van de Bruck, Eleonora Di Valentino, William Giaré, Sebastian Trojanowski","doi":"10.1093/mnrasl/slad157","DOIUrl":"https://doi.org/10.1093/mnrasl/slad157","url":null,"abstract":"ABSTRACT We revisit the possibility of using cosmological observations to constrain models that involve interactions between neutrinos and dark matter. We show that small-scale measurements of the cosmic microwave background (CMB) with a few per cent accuracy are critical to uncover unique signatures from models with tiny couplings that would require a much higher sensitivity at lower multipoles, such as those probed by the Planck satellite. We analyse the high-multipole data released by the Atacama Cosmology Telescope, both independently and in combination with Planck and baryon acoustic oscillation measurements, finding a compelling preference for a non-vanishing coupling, $log _{10}u_{nu textrm {DM}}=-5.20^{+1.2}_{-0.74}$ at 68 per cent confidence level. This aligns with other CMB-independent probes, such as Lyman-α. We illustrate how this coupling could be accounted for in the presence of dark matter interactions with a sterile neutrino.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646800","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}
ABSTRACT Stars in short-period binaries typically have spins that are aligned and synchronized with the orbit of their companion. In triple systems, however, the combination of spin and orbital precession can cause the star’s rotation to evolve to a highly misaligned and sub-synchronous equilibrium known as a Cassini state. We identify a population of recently discovered stars that exhibit these characteristics and which are already known to have tertiary companions. These third bodies have a suitable orbital period to allow the inner binary to evolve into the sub-synchronous Cassini state, which we confirm with orbital evolution models. We also compute the expected stellar obliquity and spin period, showing that the observed rotation rates are often slower than expected from equilibrium tidal models. However, we show that tidal dissipation via inertial waves can alter the expected spin–orbit misalignment angle and rotation rate, potentially creating the very slow rotation rates in some systems. Finally, we show how additional discoveries of such systems can be used to constrain the tidal physics and orbital evolution histories of stellar systems.
{"title":"Super Slowly Spinning Stars in Close Binaries","authors":"Jim Fuller, Catherine Felce","doi":"10.1093/mnrasl/slad150","DOIUrl":"https://doi.org/10.1093/mnrasl/slad150","url":null,"abstract":"ABSTRACT Stars in short-period binaries typically have spins that are aligned and synchronized with the orbit of their companion. In triple systems, however, the combination of spin and orbital precession can cause the star’s rotation to evolve to a highly misaligned and sub-synchronous equilibrium known as a Cassini state. We identify a population of recently discovered stars that exhibit these characteristics and which are already known to have tertiary companions. These third bodies have a suitable orbital period to allow the inner binary to evolve into the sub-synchronous Cassini state, which we confirm with orbital evolution models. We also compute the expected stellar obliquity and spin period, showing that the observed rotation rates are often slower than expected from equilibrium tidal models. However, we show that tidal dissipation via inertial waves can alter the expected spin–orbit misalignment angle and rotation rate, potentially creating the very slow rotation rates in some systems. Finally, we show how additional discoveries of such systems can be used to constrain the tidal physics and orbital evolution histories of stellar systems.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135647543","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}
ABSTRACT We report a comprehensive spectro-polarimetric study of the black hole binary LMC X-3 using simultaneous Imaging X-ray Polarimetry Explorer (IXPE), NICER, and NuSTAR observations in 0.5–20 keV energy band. The broad-band energy spectrum (0.5–20 keV) with NICER and NuSTAR is well described by the disc emission of temperature ∼1.1 keV and a weak Comptonizing tail beyond ∼10 keV. This evidently suggests a disc-dominated spectral state of the source with disc contribution of ∼96 per cent. The lack of variability (rms ∼ 0.5 per cent) in the power spectrum further corroborates the high/soft nature of the source. A significant polarization degree (PD) of 3.04 ± 0.40 per cent (>7σ) at a polarization angle of −44.24° ± 3.77° (>7σ) is found in 2–8 keV energy range of IXPE. In addition, PD is seen to increase with energy up to ∼4.35 ± 0.98 per cent (>3σ) in 4–8 keV band. Further, we attempt to constrain the source spin (a*) using broad-band spectral modelling that indicates a weakly rotating ‘hole’ in LMC X-3 with $a_{*}=0.273_{-0.012}^{+0.011},text{to},0.295_{-0.021}^{+0.008}$ (90 per cent confidence). Based on the spectro-polarimetric results, we infer that the polarization in LMC X-3 is resulted possibly due to the combined effects of the direct and/or reflected emissions from a partially ionized disc atmosphere. Finally, we discuss the relevance of our findings.
{"title":"First detection of X-ray polarization in thermal state of LMC X-3: Spectro-polarimetric study with <i>IXPE</i>","authors":"Seshadri Majumder, Ankur Kushwaha, Santabrata Das, Anuj Nandi","doi":"10.1093/mnrasl/slad148","DOIUrl":"https://doi.org/10.1093/mnrasl/slad148","url":null,"abstract":"ABSTRACT We report a comprehensive spectro-polarimetric study of the black hole binary LMC X-3 using simultaneous Imaging X-ray Polarimetry Explorer (IXPE), NICER, and NuSTAR observations in 0.5–20 keV energy band. The broad-band energy spectrum (0.5–20 keV) with NICER and NuSTAR is well described by the disc emission of temperature ∼1.1 keV and a weak Comptonizing tail beyond ∼10 keV. This evidently suggests a disc-dominated spectral state of the source with disc contribution of ∼96 per cent. The lack of variability (rms ∼ 0.5 per cent) in the power spectrum further corroborates the high/soft nature of the source. A significant polarization degree (PD) of 3.04 ± 0.40 per cent (&gt;7σ) at a polarization angle of −44.24° ± 3.77° (&gt;7σ) is found in 2–8 keV energy range of IXPE. In addition, PD is seen to increase with energy up to ∼4.35 ± 0.98 per cent (&gt;3σ) in 4–8 keV band. Further, we attempt to constrain the source spin (a*) using broad-band spectral modelling that indicates a weakly rotating ‘hole’ in LMC X-3 with $a_{*}=0.273_{-0.012}^{+0.011},text{to},0.295_{-0.021}^{+0.008}$ (90 per cent confidence). Based on the spectro-polarimetric results, we infer that the polarization in LMC X-3 is resulted possibly due to the combined effects of the direct and/or reflected emissions from a partially ionized disc atmosphere. Finally, we discuss the relevance of our findings.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646526","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}
ABSTRACT When a compact object is formed, an impulse (kick) will be imparted to the system by the mass lost during the core-collapse supernova (SN). A number of other mechanisms may impart an additional kick on the system, although evidence for these natal kicks in black hole systems remains limited. Updated Gaia astrometry has recently identified a number of high peculiar velocity (in excess of Galactic motion) compact objects. Here, we focus on the black hole low-mass X-ray binary H 1705−250, which has a peculiar velocity $upsilon _{mathrm{pec}}, =, 221^{+101}_{-108}, ,mathrm{km}, mathrm{s}^{-1}$. Using population synthesis to reconstruct its evolutionary history (assuming formation via isolated binary evolution within the Galactic plane), we constrain the properties of the progenitor and pre-SN orbit. The magnitude of a kick solely due to mass-loss is found to be ∼30 km s−1, which cannot account for the high present-day peculiar motion. We therefore deduce that the black hole received an additional natal kick at formation, and place limits on its magnitude, finding it to be ∼295 km s−1 (minimum 90 km s−1). This furthers the argument that these kicks are not limited to neutron stars.
当一个致密的天体形成时，在核心坍缩超新星(SN)过程中损失的质量会给系统传递一个脉冲(踢)。许多其他机制可能会给系统带来额外的冲击，尽管黑洞系统中这些先天冲击的证据仍然有限。最新的盖亚天体测量最近发现了一些高特殊速度(超过银河系运动)的致密天体。在这里，我们关注黑洞低质量x射线双星h1705 - 250，它有一个特殊的速度$upsilon _{ mathm {pec}}， =， 221^{+101}_{-108}， ， mathm {km}， mathm {s}^{-1}$。利用种群综合重建其演化历史(假设在银道平面内通过孤立的双星演化形成)，我们约束了其祖先和前sn轨道的性质。仅由质量损失引起的踢的量级被发现为~ 30 km s−1，这不能解释当今的高特殊运动。因此，我们推断黑洞在形成时受到了额外的出生冲击，并对其大小进行了限制，发现它的大小为~ 295 km s - 1(最小90 km s - 1)。这进一步证明了这些踢动并不局限于中子星。
{"title":"On the natal kick of the black hole X-ray binary H 1705–250","authors":"Cordelia Dashwood Brown, Poshak Gandhi, Yue Zhao","doi":"10.1093/mnrasl/slad151","DOIUrl":"https://doi.org/10.1093/mnrasl/slad151","url":null,"abstract":"ABSTRACT When a compact object is formed, an impulse (kick) will be imparted to the system by the mass lost during the core-collapse supernova (SN). A number of other mechanisms may impart an additional kick on the system, although evidence for these natal kicks in black hole systems remains limited. Updated Gaia astrometry has recently identified a number of high peculiar velocity (in excess of Galactic motion) compact objects. Here, we focus on the black hole low-mass X-ray binary H 1705−250, which has a peculiar velocity $upsilon _{mathrm{pec}}, =, 221^{+101}_{-108}, ,mathrm{km}, mathrm{s}^{-1}$. Using population synthesis to reconstruct its evolutionary history (assuming formation via isolated binary evolution within the Galactic plane), we constrain the properties of the progenitor and pre-SN orbit. The magnitude of a kick solely due to mass-loss is found to be ∼30 km s−1, which cannot account for the high present-day peculiar motion. We therefore deduce that the black hole received an additional natal kick at formation, and place limits on its magnitude, finding it to be ∼295 km s−1 (minimum 90 km s−1). This furthers the argument that these kicks are not limited to neutron stars.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646575","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}
ABSTRACT The pulsar magnetosphere is divided into a corotating region of closed field lines surrounded by open field lines that emanate from the two poles of the star, extend to infinity, and are separated by an equatorial current sheet. The three regions meet at a magnetospheric Y-point. In steady-state solutions of the ideal force-free magnetosphere, the Y-point may lie at any distance inside the light cylinder. Time-dependent force-free simulations, however, develop closed-line regions that extend all the way to the light cylinder. On the other hand, Particle-in-Cell (PIC) solutions consistently develop smaller closed-line regions. In order to understand this effect, we solve the pulsar equation with an improved numerical method. We show that the total electromagnetic energy stored in the ideal force-free magnetosphere manifests a subtle minimum when the closed-line region extends to only 90 per cent of the light cylinder, and thus argue that the system will spontaneously choose this particular configuration. Furthermore, we argue that the intersection of the corotating region with the equatorial current sheet is at right angles, literally leading to a T-point.
{"title":"On the pulsar Y-point","authors":"I Contopoulos, D Ntotsikas, K N Gourgouliatos","doi":"10.1093/mnrasl/slad153","DOIUrl":"https://doi.org/10.1093/mnrasl/slad153","url":null,"abstract":"ABSTRACT The pulsar magnetosphere is divided into a corotating region of closed field lines surrounded by open field lines that emanate from the two poles of the star, extend to infinity, and are separated by an equatorial current sheet. The three regions meet at a magnetospheric Y-point. In steady-state solutions of the ideal force-free magnetosphere, the Y-point may lie at any distance inside the light cylinder. Time-dependent force-free simulations, however, develop closed-line regions that extend all the way to the light cylinder. On the other hand, Particle-in-Cell (PIC) solutions consistently develop smaller closed-line regions. In order to understand this effect, we solve the pulsar equation with an improved numerical method. We show that the total electromagnetic energy stored in the ideal force-free magnetosphere manifests a subtle minimum when the closed-line region extends to only 90 per cent of the light cylinder, and thus argue that the system will spontaneously choose this particular configuration. Furthermore, we argue that the intersection of the corotating region with the equatorial current sheet is at right angles, literally leading to a T-point.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135647390","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}
Jiayin Li, Lisa Kaltenegger, Dang Pham, David Ruppert
ABSTRACT More than 5000 extrasolar planets have already been detected. JWST and near-term ground-based telescopes like the Extremely Large Telescope (ELT), Giant Magellan Telescope (GMT), Thirty Meter Telescope (TMT), and upcoming telescopes such as the Nancy Grace Roman Space Telescope, Xuntian, and Ariel are designed to characterize the atmosphere of directly imaged Jovian planets. Here, we used five diverse machine learning algorithms to investigate how well broad-band filter photometric fluxes could initially characterize giant exoplanets. We use an established grid of 8813 reflected light model spectra of different metallicities, planet–star distances, and cloud properties to assess the performance of several machine learning algorithms on both noiseless and noisy data to provide classification and regression results as a function of signal to noise of the data. In all cases, the algorithms were tested on noisy validation data. The results show that the use of machine learning to characterize giant planets from reflected broad-band filter photometry provides a promising tool for initial characterization, with over 65 per cent accuracy in characterizing metallicity for signal-to-noise ratios (S/N) ≳ 30, over 80 per cent for cloud coverage for S/N ≳ 30. This approach will allow initial characterization for large surveys of giant exoplanets and prioritization for spectroscopy observations of a subset of these worlds.
{"title":"Characterization of Extrasolar Giant Planets with Machine Learning","authors":"Jiayin Li, Lisa Kaltenegger, Dang Pham, David Ruppert","doi":"10.1093/mnrasl/slad155","DOIUrl":"https://doi.org/10.1093/mnrasl/slad155","url":null,"abstract":"ABSTRACT More than 5000 extrasolar planets have already been detected. JWST and near-term ground-based telescopes like the Extremely Large Telescope (ELT), Giant Magellan Telescope (GMT), Thirty Meter Telescope (TMT), and upcoming telescopes such as the Nancy Grace Roman Space Telescope, Xuntian, and Ariel are designed to characterize the atmosphere of directly imaged Jovian planets. Here, we used five diverse machine learning algorithms to investigate how well broad-band filter photometric fluxes could initially characterize giant exoplanets. We use an established grid of 8813 reflected light model spectra of different metallicities, planet–star distances, and cloud properties to assess the performance of several machine learning algorithms on both noiseless and noisy data to provide classification and regression results as a function of signal to noise of the data. In all cases, the algorithms were tested on noisy validation data. The results show that the use of machine learning to characterize giant planets from reflected broad-band filter photometry provides a promising tool for initial characterization, with over 65 per cent accuracy in characterizing metallicity for signal-to-noise ratios (S/N) ≳ 30, over 80 per cent for cloud coverage for S/N ≳ 30. This approach will allow initial characterization for large surveys of giant exoplanets and prioritization for spectroscopy observations of a subset of these worlds.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135646806","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：