Pub Date : 2023-08-01DOI: 10.3847/2041-8213/ace03c
Jonathan M. Miller, B. Mockler, E. Ramirez-Ruiz, P. Draghis, J. Drake, J. Raymond, M. Reynolds, Xin Xiang, Sol Bin Yun, A. Zoghbi
The proximity and duration of the tidal disruption event ASASSN-14li led to the discovery of narrow, blueshifted absorption lines in X-rays and UV. The gas seen in X-ray absorption is consistent with bound material close to the apocenter of elliptical orbital paths, or with a disk wind similar to those seen in Seyfert-1 active galactic nuclei. We present a new analysis of the deepest high-resolution XMM-Newton and Chandra spectra of ASASSN-14li. Driven by the relative strengths of He-like and H-like charge states, the data require [N/C] ≥ 2.4, in qualitative agreement with UV spectral results. Flows of the kind seen in the X-ray spectrum of ASASSN-14li were not clearly predicted in simulations of TDEs; this left open the possibility that the observed absorption might be tied to gas released in prior active galactic nucleus (AGN) activity. However, the abundance pattern revealed in this analysis points to a single star rather than a standard AGN accretion flow comprised of myriad gas contributions. The simplest explanation of the data is likely that a moderately massive star (M ≳ 3 M ⊙) with significant CNO processing was disrupted. An alternative explanation is that a lower mass star was disrupted that had previously been stripped of its envelope. We discuss the strengths and limitations of our analysis and these interpretations.
{"title":"Evidence of a Massive Stellar Disruption in the X-Ray Spectrum of ASASSN-14li","authors":"Jonathan M. Miller, B. Mockler, E. Ramirez-Ruiz, P. Draghis, J. Drake, J. Raymond, M. Reynolds, Xin Xiang, Sol Bin Yun, A. Zoghbi","doi":"10.3847/2041-8213/ace03c","DOIUrl":"https://doi.org/10.3847/2041-8213/ace03c","url":null,"abstract":"The proximity and duration of the tidal disruption event ASASSN-14li led to the discovery of narrow, blueshifted absorption lines in X-rays and UV. The gas seen in X-ray absorption is consistent with bound material close to the apocenter of elliptical orbital paths, or with a disk wind similar to those seen in Seyfert-1 active galactic nuclei. We present a new analysis of the deepest high-resolution XMM-Newton and Chandra spectra of ASASSN-14li. Driven by the relative strengths of He-like and H-like charge states, the data require [N/C] ≥ 2.4, in qualitative agreement with UV spectral results. Flows of the kind seen in the X-ray spectrum of ASASSN-14li were not clearly predicted in simulations of TDEs; this left open the possibility that the observed absorption might be tied to gas released in prior active galactic nucleus (AGN) activity. However, the abundance pattern revealed in this analysis points to a single star rather than a standard AGN accretion flow comprised of myriad gas contributions. The simplest explanation of the data is likely that a moderately massive star (M ≳ 3 M ⊙) with significant CNO processing was disrupted. An alternative explanation is that a lower mass star was disrupted that had previously been stripped of its envelope. We discuss the strengths and limitations of our analysis and these interpretations.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114840480","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}
Pub Date : 2023-07-31DOI: 10.3847/2041-8213/acebe3
N. Jiang, Ziying Zhou, Jiazheng Zhu, Yibo Wang, Ting-gui Wang
Recently, three optical tidal disruption event (TDE) candidates discovered by the Zwicky Transient Facility (ZTF) have been suggested to be coincident with high-energy neutrinos. They all exhibit unusually strong dust infrared echoes, with their peak times matching the neutrino arrival time even better than the optical peaks. We hereby report on two new TDE candidates that are spatially and temporally coincident with neutrinos by matching our sample of mid-infrared outbursts in nearby galaxies (MIRONG) with Gold alerts of IceCube high-energy neutrino events up to 2022 June. The two candidates show negligible optical variability according to their ZTF light curves and can therefore be classified as part of the growing population of obscured TDE candidates. The chance probability of finding two such candidates is about ∼3% by redistributing the MIRONG sources randomly in the Sloan Digital Sky Survey footprint, which will be as low as ∼0.1% (or ∼0.2%) if we limit to sources with increased fluxes (or variability amplitudes) comparable with the two matched sources. Our findings further support the potential connection between high-energy neutrinos and TDEs in dusty environments by increasing the total number of neutrino-associated TDE and TDE candidates to five, although the underlying physics remains poorly understood.
{"title":"Two Candidate Obscured Tidal Disruption Events Coincident with High-energy Neutrinos","authors":"N. Jiang, Ziying Zhou, Jiazheng Zhu, Yibo Wang, Ting-gui Wang","doi":"10.3847/2041-8213/acebe3","DOIUrl":"https://doi.org/10.3847/2041-8213/acebe3","url":null,"abstract":"Recently, three optical tidal disruption event (TDE) candidates discovered by the Zwicky Transient Facility (ZTF) have been suggested to be coincident with high-energy neutrinos. They all exhibit unusually strong dust infrared echoes, with their peak times matching the neutrino arrival time even better than the optical peaks. We hereby report on two new TDE candidates that are spatially and temporally coincident with neutrinos by matching our sample of mid-infrared outbursts in nearby galaxies (MIRONG) with Gold alerts of IceCube high-energy neutrino events up to 2022 June. The two candidates show negligible optical variability according to their ZTF light curves and can therefore be classified as part of the growing population of obscured TDE candidates. The chance probability of finding two such candidates is about ∼3% by redistributing the MIRONG sources randomly in the Sloan Digital Sky Survey footprint, which will be as low as ∼0.1% (or ∼0.2%) if we limit to sources with increased fluxes (or variability amplitudes) comparable with the two matched sources. Our findings further support the potential connection between high-energy neutrinos and TDEs in dusty environments by increasing the total number of neutrino-associated TDE and TDE candidates to five, although the underlying physics remains poorly understood.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129248784","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}
Pub Date : 2023-07-31DOI: 10.3847/2041-8213/acec3e
R. Middei, M. Perri, S. Puccetti, I. Liodakis, L. Di Gesu, A. Marscher, N. R. Cavero, F. Tavecchio, I. Donnarumma, Marco Laurenti, S. Jorstad, I. Agudo, H. Marshall, L. Pacciani, Dawoon E. Kim, Francisco José Aceituno, G. Bonnoli, V. Casanova, B. Agís-González, A. Sota, C. Casadio, J. Escudero, I. Myserlis, A. Sievers, P. M. Kouch, E. Lindfors, M. Gurwell, G. Keating, Ramprasad Rao, Sincheol Kang, Sang-Sung Lee, Sang-Hyun Kim, Wheeyeon Cheong, Hyeon-Woo Jeong, E. Angelakis, A. Kraus, L. Antonelli, M. Bachetti, L. Baldini, W. Baumgartner, R. Bellazzini, S. Bianchi, S. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, F. Capitanio, S. Castellano, E. Cavazzuti, Chien-Ting J. Chen, S. Ciprini, E. Costa, A. De Rosa, E. Del Monte, N. Di Lalla, A. Di Marco, V. Doroshenko, M. Dovc̆iak, S. Ehlert, T. Enoto, Y. Evangelista, S. Fabiani, R. Ferrazzoli, J. A. Garc'ia, S. Gunji, K. Hayashida, J. Heyl, W. Iwakiri, P. Kaaret, V. Karas, F. Kislat, T. Kitaguchi, J. Kolodziejczak, H. Krawczynski, F. La Monaca, L. Latronico, S.
The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ∼3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ∼17° day–1. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.
耀变体光谱能量分布的低能峰通常被归因于喷流中相对论性粒子的同步辐射。尽管关于喷射过程的共识，粒子加速机制仍然存在争议。在这里，我们提出了PG 1553+113的第一次x射线偏振观测，这是一个由成像x射线偏振探测器(IXPE)观测到的高同步峰耀变体。我们探测到沿电矢量位角ψ X = 86°±8°的X射线偏振度为(10±2)%。同时，射电和光偏振度降低了约3倍。在我们的IXPE指向期间，我们观察到IXPE时代的第一个孤儿光偏振摆动，因为PG 1553+113的光学角经历了大约125°的平滑单调旋转，速率为~ 17°day-1。我们没有在射电或x射线中发现类似旋转的证据，这表明x射线和光学发射区域是分开的，或者最多部分共空间。我们的光谱偏振结果提供了进一步的证据，证明耀变体中的稳态x射线发射起源于激波加速和能量分层的电子种群。
{"title":"IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing","authors":"R. Middei, M. Perri, S. Puccetti, I. Liodakis, L. Di Gesu, A. Marscher, N. R. Cavero, F. Tavecchio, I. Donnarumma, Marco Laurenti, S. Jorstad, I. Agudo, H. Marshall, L. Pacciani, Dawoon E. Kim, Francisco José Aceituno, G. Bonnoli, V. Casanova, B. Agís-González, A. Sota, C. Casadio, J. Escudero, I. Myserlis, A. Sievers, P. M. Kouch, E. Lindfors, M. Gurwell, G. Keating, Ramprasad Rao, Sincheol Kang, Sang-Sung Lee, Sang-Hyun Kim, Wheeyeon Cheong, Hyeon-Woo Jeong, E. Angelakis, A. Kraus, L. Antonelli, M. Bachetti, L. Baldini, W. Baumgartner, R. Bellazzini, S. Bianchi, S. Bongiorno, R. Bonino, A. Brez, N. Bucciantini, F. Capitanio, S. Castellano, E. Cavazzuti, Chien-Ting J. Chen, S. Ciprini, E. Costa, A. De Rosa, E. Del Monte, N. Di Lalla, A. Di Marco, V. Doroshenko, M. Dovc̆iak, S. Ehlert, T. Enoto, Y. Evangelista, S. Fabiani, R. Ferrazzoli, J. A. Garc'ia, S. Gunji, K. Hayashida, J. Heyl, W. Iwakiri, P. Kaaret, V. Karas, F. Kislat, T. Kitaguchi, J. Kolodziejczak, H. Krawczynski, F. La Monaca, L. Latronico, S.","doi":"10.3847/2041-8213/acec3e","DOIUrl":"https://doi.org/10.3847/2041-8213/acec3e","url":null,"abstract":"The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ∼3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ∼17° day–1. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114736438","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}
Pub Date : 2023-07-31DOI: 10.3847/2041-8213/ace42e
J. Connelly, J. Bollard, E. Amsellem, M. Schiller, K. Larsen, M. Bizzarro
We present a U-corrected Pb–Pb age of 4566.19 ± 0.20 Ma (1.11 ± 0.26 Myr after t 0) for the moderately volatile element rich, andesitic meteorite Erg Chech 002 (EC002). Our Al–Mg isochron defines a 26Al/27Al initial ratio of (8.65 ± 0.09) × 10−6 that corresponds to a 26Al/27Al ratio of 2.48−0.56+0.67 × 10−5 for the parent body precursor at the time of solar system formation. Whereas the published bulk chemistry and our high-precision Ca isotope measurement correspond to those for inner solar system materials, the 26Al/27Al ratio overlaps that for outer solar system CI chondrites. This indicates that the carriers and/or processes responsible for the nucleosynthetic isotope compositions for inner and outer disk materials are different than those controlling the heterogeneous distribution of 26Al. A low μ 26Mg* initial value of −6.1 ± 1.7 ppm infers a source region with a subchondritic Al/Mg ratio until 1.1 Myr after t 0 such that melt generation must have immediately preceded its crystallization. With 26Al as the main heating source, a modeled temperature–time path for a 100 km radius parent body with our inferred 26Al abundance suggests that accretion must have occurred before 0.5 Myr after t 0 to reach melting temperatures at appropriate depths within 1.1 Myr. This requires that the parent body formed very early within the protoplanetary disk, consistent with predictions of rapid formation of planetesimals by streaming instabilities within high-density dust filaments during the earliest phase of the protoplanetary disk. Finally, an absence of initial Pb in this otherwise moderately volatile-rich achondrite implies Pb was effectively sequestered to the Fe–Ni core.
{"title":"Evidence for Very Early Planetesimal Formation and 26Al/27Al Heterogeneity in the Protoplanetary Disk","authors":"J. Connelly, J. Bollard, E. Amsellem, M. Schiller, K. Larsen, M. Bizzarro","doi":"10.3847/2041-8213/ace42e","DOIUrl":"https://doi.org/10.3847/2041-8213/ace42e","url":null,"abstract":"We present a U-corrected Pb–Pb age of 4566.19 ± 0.20 Ma (1.11 ± 0.26 Myr after t 0) for the moderately volatile element rich, andesitic meteorite Erg Chech 002 (EC002). Our Al–Mg isochron defines a 26Al/27Al initial ratio of (8.65 ± 0.09) × 10−6 that corresponds to a 26Al/27Al ratio of 2.48−0.56+0.67 × 10−5 for the parent body precursor at the time of solar system formation. Whereas the published bulk chemistry and our high-precision Ca isotope measurement correspond to those for inner solar system materials, the 26Al/27Al ratio overlaps that for outer solar system CI chondrites. This indicates that the carriers and/or processes responsible for the nucleosynthetic isotope compositions for inner and outer disk materials are different than those controlling the heterogeneous distribution of 26Al. A low μ 26Mg* initial value of −6.1 ± 1.7 ppm infers a source region with a subchondritic Al/Mg ratio until 1.1 Myr after t 0 such that melt generation must have immediately preceded its crystallization. With 26Al as the main heating source, a modeled temperature–time path for a 100 km radius parent body with our inferred 26Al abundance suggests that accretion must have occurred before 0.5 Myr after t 0 to reach melting temperatures at appropriate depths within 1.1 Myr. This requires that the parent body formed very early within the protoplanetary disk, consistent with predictions of rapid formation of planetesimals by streaming instabilities within high-density dust filaments during the earliest phase of the protoplanetary disk. Finally, an absence of initial Pb in this otherwise moderately volatile-rich achondrite implies Pb was effectively sequestered to the Fe–Ni core.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132342607","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}
Pub Date : 2023-07-27DOI: 10.3847/2041-8213/acea78
V. Liakh, R. Keppens
We present a 2.5D magnetohydrodynamic simulation of a systematically rotating prominence inside its coronal cavity using the open-source MPI-AMRVAC code. Our simulation starts from a nonadiabatic, gravitationally stratified corona, permeated with a sheared arcade magnetic structure. The flux rope (FR) is formed through converging and shearing footpoints driving, simultaneously applying randomized heating at the bottom. The latter induces a left–right asymmetry of temperature and density distributions with respect to the polarity inversion line. This asymmetry drives flows along the loops before the FR formation, which gets converted to net rotational motions upon reconnection of the field lines. As the thermal instability within the FR develops, angular momentum conservation about its axis leads to a systematic rotation of both hot coronal and cold condensed plasma. The initial rotational velocity exceeds 60 km s−1. The synthesized images confirm the simultaneous rotations of the coronal plasma seen in 211 and 193 Å and condensations seen in 304 Å. Furthermore, the formation of the dark cavity is evident in 211 and 193 Å images. Our numerical experiment is inspired by observations of so-called giant solar prominence tornadoes and reveals that asymmetric FR formation can be crucial in triggering rotational motions. We reproduce observed spinning motions inside the coronal cavity, augmenting our understanding of the complex dynamics of rotating prominences.
{"title":"Rotational Flows in Solar Coronal Flux Rope Cavities","authors":"V. Liakh, R. Keppens","doi":"10.3847/2041-8213/acea78","DOIUrl":"https://doi.org/10.3847/2041-8213/acea78","url":null,"abstract":"We present a 2.5D magnetohydrodynamic simulation of a systematically rotating prominence inside its coronal cavity using the open-source MPI-AMRVAC code. Our simulation starts from a nonadiabatic, gravitationally stratified corona, permeated with a sheared arcade magnetic structure. The flux rope (FR) is formed through converging and shearing footpoints driving, simultaneously applying randomized heating at the bottom. The latter induces a left–right asymmetry of temperature and density distributions with respect to the polarity inversion line. This asymmetry drives flows along the loops before the FR formation, which gets converted to net rotational motions upon reconnection of the field lines. As the thermal instability within the FR develops, angular momentum conservation about its axis leads to a systematic rotation of both hot coronal and cold condensed plasma. The initial rotational velocity exceeds 60 km s−1. The synthesized images confirm the simultaneous rotations of the coronal plasma seen in 211 and 193 Å and condensations seen in 304 Å. Furthermore, the formation of the dark cavity is evident in 211 and 193 Å images. Our numerical experiment is inspired by observations of so-called giant solar prominence tornadoes and reveals that asymmetric FR formation can be crucial in triggering rotational motions. We reproduce observed spinning motions inside the coronal cavity, augmenting our understanding of the complex dynamics of rotating prominences.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130648330","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}
Pub Date : 2023-07-27DOI: 10.3847/2041-8213/ace7ba
Sirina Prasad, Qizhou Zhang, J. Moran, Yue Cao, I. Jiménez-Serra, Jesús Martín-Pintado, Antonio Martínez-Henares, A. Baez--Rubio
MWC 349A is one of the rare stars known to have hydrogen radio recombination line (RRL) masers. The bright maser emission makes it possible to study the dynamics of the system at milliarcsecond (mas) precision. We present Atacama Large Millimeter/submillimeter Array observations of the 1.4 and 0.8 mm continuum emission of MWC 349A, as well as the H30α and H26α RRLs. Using the most extended array configuration of C43-10 with a maximum baseline of 16.2 km, we spatially resolved the H30α line and 1.4 mm continuum emission for the first time. In addition to the known H30α and H26α maser emission from a Keplerian disk at LSR velocities from −12 to 28 km s−1 and from an ionized wind for velocities between −12 to −40 km s−1 and 28 to 60 km s−1, we found evidence of a jet along the polar axis at V LSR from −85 to −40 km s−1 and +60 to +100 km s−1. These masers are found in a linear structure nearly aligned with the polar axis of the disk. If these masers lie close to the polar axis, their velocities could be as high as 575 km s−1, which cannot be explained solely by a single expanding wind as proposed in Báez-Rubio et al. We suggest that they originate from a high-velocity jet, likely launched by a magnetohydrodynamic wind. The jet appears to rotate in the same direction as the rotation of the disk. A detailed radiative transfer modeling of these emissions will further elucidate the origin of these masers in the wind.
MWC 349A是已知具有氢射电重组线(RRL)脉泽的罕见恒星之一。明亮的脉泽发射使得以毫角秒(mas)精度研究系统动力学成为可能。利用阿塔卡马大型毫米/亚毫米阵列对MWC 349A的1.4和0.8 mm连续发射以及H30α和H26α RRLs进行了观测。利用C43-10最大基线为16.2 km的最大扩展阵列配置，首次对H30α线和1.4 mm连续辐射进行了空间分辨。除了已知的H30α和H26α脉泽辐射，来自开普勒盘的LSR速度为- 12至28 km s−1，以及电离风的速度为- 12至- 40 km s−1和28至60 km s−1，我们还发现了沿极轴在V LSR从- 85至- 40 km s−1和+60至+100 km s−1的射流的证据。这些脉泽是在一个线性结构中发现的，几乎与圆盘的极轴对齐。如果这些脉泽靠近极轴，它们的速度可能高达575 km s - 1，这不能像Báez-Rubio等人提出的那样仅仅用单一的膨胀风来解释。我们认为它们起源于高速射流，可能是由磁流体动力风发射的。射流似乎与圆盘的旋转方向相同。这些辐射的详细辐射传输模型将进一步阐明这些微波激射器在风中的起源。
{"title":"Detection of a High-velocity Jet from MWC 349A Traced by Hydrogen Recombination Line Maser Emission","authors":"Sirina Prasad, Qizhou Zhang, J. Moran, Yue Cao, I. Jiménez-Serra, Jesús Martín-Pintado, Antonio Martínez-Henares, A. Baez--Rubio","doi":"10.3847/2041-8213/ace7ba","DOIUrl":"https://doi.org/10.3847/2041-8213/ace7ba","url":null,"abstract":"MWC 349A is one of the rare stars known to have hydrogen radio recombination line (RRL) masers. The bright maser emission makes it possible to study the dynamics of the system at milliarcsecond (mas) precision. We present Atacama Large Millimeter/submillimeter Array observations of the 1.4 and 0.8 mm continuum emission of MWC 349A, as well as the H30α and H26α RRLs. Using the most extended array configuration of C43-10 with a maximum baseline of 16.2 km, we spatially resolved the H30α line and 1.4 mm continuum emission for the first time. In addition to the known H30α and H26α maser emission from a Keplerian disk at LSR velocities from −12 to 28 km s−1 and from an ionized wind for velocities between −12 to −40 km s−1 and 28 to 60 km s−1, we found evidence of a jet along the polar axis at V LSR from −85 to −40 km s−1 and +60 to +100 km s−1. These masers are found in a linear structure nearly aligned with the polar axis of the disk. If these masers lie close to the polar axis, their velocities could be as high as 575 km s−1, which cannot be explained solely by a single expanding wind as proposed in Báez-Rubio et al. We suggest that they originate from a high-velocity jet, likely launched by a magnetohydrodynamic wind. The jet appears to rotate in the same direction as the rotation of the disk. A detailed radiative transfer modeling of these emissions will further elucidate the origin of these masers in the wind.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121393152","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}
Pub Date : 2023-07-25DOI: 10.3847/2041-8213/ace9dc
K. Iłkiewicz, J. Mikołajewska, K. Stoyanov
T CrB is a symbiotic recurrent nova that exhibits quiescent and active phases between its classical nova eruptions. The statistical properties of these active phases have been poorly studied thus far. Because of that their nature remained unknown. Here we study statistical properties of the active phases and show that they are consistent with outburst and superoutbursts observed in SU UMa–type dwarf novae. The recurrence time of these outbursts is consistent with theoretical predictions for similar systems. Moreover, the visual and X-ray evolution of the last active phase is consistent with a superoutburst. This suggests that T CrB is a dwarf nova with an extremely long orbital period, closely related to SU UMa dwarf novae. The similarities between the last superoutburst and the reported activity preceding the 1946 nova eruption may suggest that the next classical nova eruption in T CrB could be indeed soon expected.
T - CrB是一颗共生的复发新星，在其经典新星爆发之间表现出静止和活跃的阶段。迄今为止，对这些活性相的统计性质研究甚少。因此，它们的性质仍然不为人知。本文研究了活动阶段的统计性质，并表明它们与SU uma型矮新星中观测到的爆发和超爆发相一致。这些爆发的重现时间与类似系统的理论预测一致。此外，最后一个活跃期的视觉和x射线演化与一次超爆发相一致。这表明T CrB是一颗轨道周期极长的矮新星，与SU UMa矮新星关系密切。上次超级爆发与1946年新星爆发之前报道的活动之间的相似之处可能表明，T CrB的下一次经典新星爆发确实很快就会发生。
{"title":"Symbiotic Star T CrB as an Extreme SU UMa–type Dwarf Nova","authors":"K. Iłkiewicz, J. Mikołajewska, K. Stoyanov","doi":"10.3847/2041-8213/ace9dc","DOIUrl":"https://doi.org/10.3847/2041-8213/ace9dc","url":null,"abstract":"T CrB is a symbiotic recurrent nova that exhibits quiescent and active phases between its classical nova eruptions. The statistical properties of these active phases have been poorly studied thus far. Because of that their nature remained unknown. Here we study statistical properties of the active phases and show that they are consistent with outburst and superoutbursts observed in SU UMa–type dwarf novae. The recurrence time of these outbursts is consistent with theoretical predictions for similar systems. Moreover, the visual and X-ray evolution of the last active phase is consistent with a superoutburst. This suggests that T CrB is a dwarf nova with an extremely long orbital period, closely related to SU UMa dwarf novae. The similarities between the last superoutburst and the reported activity preceding the 1946 nova eruption may suggest that the next classical nova eruption in T CrB could be indeed soon expected.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115123338","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}
Pub Date : 2023-07-24DOI: 10.3847/2041-8213/ace9da
A. Cikota, Ivonne Toro Bertolla, Xiaosheng Huang, Saul Baltasar, Nicolas Ratier-Werbin, W. Sheu, C. Storfer, N. Suzuki, D. Schlegel, R. Cartier, S. Torres, S. Cikota, E. Jullo
Gravitational lensing provides unique insights into astrophysics and cosmology, including the determination of galaxy mass profiles and constraining cosmological parameters. We present spectroscopic confirmation and lens modeling of the strong lensing system DESI-253.2534+26.8843, discovered in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys data. This system consists of a massive elliptical galaxy surrounded by four blue images forming an Einstein Cross pattern. We obtained spectroscopic observations of this system using the Multi Unit Spectroscopic Explorer on ESO’s Very Large Telescope and confirmed its lensing nature. The main lens, which is the elliptical galaxy, has a redshift of z L1 = 0.636 ± 0.001, while the spectra of the background source images are typical of a starburst galaxy and have a redshift of z s = 2.597 ± 0.001. Additionally, we identified a faint galaxy foreground of one of the lensed images, with a redshift of z L2 = 0.386. We employed the GIGA-Lens modeling code to characterize this system and determined the Einstein radius of the main lens to be θE=2.″520−0.031+0.032 , which corresponds to a velocity dispersion of σ = 379 ± 2 km s−1. Our study contributes to a growing catalog of this rare kind of strong lensing system and demonstrates the effectiveness of spectroscopic integral field unit observations and advanced modeling techniques in understanding the properties of these systems.
引力透镜为天体物理学和宇宙学提供了独特的见解，包括确定星系质量剖面和约束宇宙学参数。我们提出了在暗能量光谱仪器(DESI)遗留成像调查数据中发现的强透镜系统DESI-253.2534+26.8843的光谱确认和透镜模型。这个系统由一个巨大的椭圆星系组成，周围环绕着四个蓝色图像，形成爱因斯坦十字图案。我们使用ESO甚大望远镜上的多单元光谱探测器获得了该系统的光谱观测结果，并证实了它的透镜性质。主透镜为椭圆星系，红移z L1 = 0.636±0.001，而背景源图像为典型的星暴星系，红移z s = 2.597±0.001。此外，我们在其中一张透镜图像中发现了一个暗淡的星系前景，其红移为z L2 = 0.386。我们使用GIGA-Lens建模代码对该系统进行了表征，并确定了主透镜的爱因斯坦半径为θE=2.″520−0.031+0.032，对应的速度色散为σ = 379±2 km s−1。我们的研究有助于增加这种罕见的强透镜系统的目录，并证明了光谱积分场单位观测和先进的建模技术在理解这些系统特性方面的有效性。
{"title":"DESI-253.2534+26.8843: A New Einstein Cross Spectroscopically Confirmed with Very Large Telescope/MUSE and Modeled with GIGA-Lens","authors":"A. Cikota, Ivonne Toro Bertolla, Xiaosheng Huang, Saul Baltasar, Nicolas Ratier-Werbin, W. Sheu, C. Storfer, N. Suzuki, D. Schlegel, R. Cartier, S. Torres, S. Cikota, E. Jullo","doi":"10.3847/2041-8213/ace9da","DOIUrl":"https://doi.org/10.3847/2041-8213/ace9da","url":null,"abstract":"Gravitational lensing provides unique insights into astrophysics and cosmology, including the determination of galaxy mass profiles and constraining cosmological parameters. We present spectroscopic confirmation and lens modeling of the strong lensing system DESI-253.2534+26.8843, discovered in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys data. This system consists of a massive elliptical galaxy surrounded by four blue images forming an Einstein Cross pattern. We obtained spectroscopic observations of this system using the Multi Unit Spectroscopic Explorer on ESO’s Very Large Telescope and confirmed its lensing nature. The main lens, which is the elliptical galaxy, has a redshift of z L1 = 0.636 ± 0.001, while the spectra of the background source images are typical of a starburst galaxy and have a redshift of z s = 2.597 ± 0.001. Additionally, we identified a faint galaxy foreground of one of the lensed images, with a redshift of z L2 = 0.386. We employed the GIGA-Lens modeling code to characterize this system and determined the Einstein radius of the main lens to be θE=2.″520−0.031+0.032 , which corresponds to a velocity dispersion of σ = 379 ± 2 km s−1. Our study contributes to a growing catalog of this rare kind of strong lensing system and demonstrates the effectiveness of spectroscopic integral field unit observations and advanced modeling techniques in understanding the properties of these systems.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121692103","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}
Pub Date : 2023-07-23DOI: 10.3847/2041-8213/acea73
Lulu Zhang, Luis C. Ho Kavli Institute for Astronomy, Astrophysics, P. University, D. Astronomy, S. O. Physics
We combine mid-infrared diagnostics obtained from integral-field-unit observations taken with Mid-Infrared Instrument/Medium Resolution Spectrograph on the James Webb Space Telescope with cold molecular gas information derived from Atacama Large Millimeter/submillimeter Array observations of CO(1–0) emission to investigate the star formation rate and efficiency within the central ∼1.5 kpc × 1.3 kpc region of the Seyfert 1 galaxy NGC 7469 on ∼100 pc scales. The active nucleus leaves a notable imprint on its immediate surroundings by elevating the temperature of the warm molecular gas, driving an ionized gas outflow on subkiloparsec scales, and selectively destroying small dust grains. These effects, nevertheless, have relatively little impact on the cold circumnuclear medium or its ability to form stars. Most of the star formation in NGC 7469 is confined to a clumpy starburst ring, but the star formation efficiency remains quite elevated even for the nuclear region that is most affected by the active nucleus.
{"title":"The Interaction between AGN and Starburst Activity in the Circumnuclear Region of NGC 7469 as Viewed with JWST","authors":"Lulu Zhang, Luis C. Ho Kavli Institute for Astronomy, Astrophysics, P. University, D. Astronomy, S. O. Physics","doi":"10.3847/2041-8213/acea73","DOIUrl":"https://doi.org/10.3847/2041-8213/acea73","url":null,"abstract":"We combine mid-infrared diagnostics obtained from integral-field-unit observations taken with Mid-Infrared Instrument/Medium Resolution Spectrograph on the James Webb Space Telescope with cold molecular gas information derived from Atacama Large Millimeter/submillimeter Array observations of CO(1–0) emission to investigate the star formation rate and efficiency within the central ∼1.5 kpc × 1.3 kpc region of the Seyfert 1 galaxy NGC 7469 on ∼100 pc scales. The active nucleus leaves a notable imprint on its immediate surroundings by elevating the temperature of the warm molecular gas, driving an ionized gas outflow on subkiloparsec scales, and selectively destroying small dust grains. These effects, nevertheless, have relatively little impact on the cold circumnuclear medium or its ability to form stars. Most of the star formation in NGC 7469 is confined to a clumpy starburst ring, but the star formation efficiency remains quite elevated even for the nuclear region that is most affected by the active nucleus.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133017727","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}
Pub Date : 2023-07-21DOI: 10.3847/2041-8213/ace977
V. Rivilla, M. Sanz-Novo, Izaskun Jim'enez-Serra, Jesús Martín-Pintado, L. Colzi, S. Zeng, Andr'es Meg'ias, Á. López-Gallifa, Antonio Mart'inez-Henares, S. Massalkhi, B. Tercero, P. de Vicente, S. Mart'in, David San Andr'es, M. Requena-Torres, J. Alonso
We report the first detection in the interstellar medium (ISM) of a C2H5O2N isomer: syn-glycolamide (NH2C(O)CH2OH). The exquisite sensitivity at sub-mK levels of an ultradeep spectral survey carried out with the Yebes 40 m and IRAM 30 m telescopes toward the G+0.693–0.027 molecular cloud has allowed us to unambiguously identify multiple transitions of this species. We derived a column density of (7.4 ± 0.7) × 1012 cm−2, which implies a molecular abundance with respect to H2 of 5.5 × 10−11. The other C2H5O2N isomers, including the higher-energy anti conformer of glycolamide and two conformers of glycine, were not detected. The upper limit derived for the abundance of glycine indicates that this amino acid is surely less abundant than its isomer glycolamide in the ISM. The abundances of the C2H5O2N isomers cannot be explained in terms of thermodynamic equilibrium; thus, chemical kinetics need to be invoked. While the low abundance of glycine might not be surprising, based on the relative low abundances of acids in the ISM compared to other compounds (e.g., alcohols, aldehydes, or amines), several chemical pathways can favor the formation of its isomer glycolamide. It can be formed through radical–radical reactions on the surface of dust grains. The abundances of these radicals can be significantly boosted in an environment affected by a strong ultraviolet field induced by cosmic rays, such as that expected in G+0.693–0.027. Therefore, as shown by several recent molecular detections toward this molecular cloud, it stands out as the best target to discover new species with carbon, oxygen, and nitrogen with increasing chemical complexity.
{"title":"First Glycine Isomer Detected in the Interstellar Medium: Glycolamide (NH2C(O)CH2OH)","authors":"V. Rivilla, M. Sanz-Novo, Izaskun Jim'enez-Serra, Jesús Martín-Pintado, L. Colzi, S. Zeng, Andr'es Meg'ias, Á. López-Gallifa, Antonio Mart'inez-Henares, S. Massalkhi, B. Tercero, P. de Vicente, S. Mart'in, David San Andr'es, M. Requena-Torres, J. Alonso","doi":"10.3847/2041-8213/ace977","DOIUrl":"https://doi.org/10.3847/2041-8213/ace977","url":null,"abstract":"We report the first detection in the interstellar medium (ISM) of a C2H5O2N isomer: syn-glycolamide (NH2C(O)CH2OH). The exquisite sensitivity at sub-mK levels of an ultradeep spectral survey carried out with the Yebes 40 m and IRAM 30 m telescopes toward the G+0.693–0.027 molecular cloud has allowed us to unambiguously identify multiple transitions of this species. We derived a column density of (7.4 ± 0.7) × 1012 cm−2, which implies a molecular abundance with respect to H2 of 5.5 × 10−11. The other C2H5O2N isomers, including the higher-energy anti conformer of glycolamide and two conformers of glycine, were not detected. The upper limit derived for the abundance of glycine indicates that this amino acid is surely less abundant than its isomer glycolamide in the ISM. The abundances of the C2H5O2N isomers cannot be explained in terms of thermodynamic equilibrium; thus, chemical kinetics need to be invoked. While the low abundance of glycine might not be surprising, based on the relative low abundances of acids in the ISM compared to other compounds (e.g., alcohols, aldehydes, or amines), several chemical pathways can favor the formation of its isomer glycolamide. It can be formed through radical–radical reactions on the surface of dust grains. The abundances of these radicals can be significantly boosted in an environment affected by a strong ultraviolet field induced by cosmic rays, such as that expected in G+0.693–0.027. Therefore, as shown by several recent molecular detections toward this molecular cloud, it stands out as the best target to discover new species with carbon, oxygen, and nitrogen with increasing chemical complexity.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124931878","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}
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