{"title":"Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations","authors":"Mohamad Shalaby","doi":"10.3847/2041-8213/ad99d8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad99d8","url":null,"abstract":"Energy dissipation in collisionless shocks is a key mechanism in various astrophysical environments. Its nonlinear nature complicates analytical understanding and necessitates particle-in-cell (PIC) simulations. This study examines the impact of reducing the ion-to-electron mass ratio (mr), to decrease computational cost, on energy partitioning in one spatial and three velocity-space dimension PIC simulations of strong, nonrelativistic, parallel electron–ion collisionless shocks using the SHARP code. We compare simulations with a reduced mass ratio (mr = 100) to those with a realistic mass ratio (mr = 1836) for shocks with high ( ) and low ( ) Alfvén Mach numbers. Our findings show that the mass ratio significantly affects particle acceleration and thermal energy dissipation. At high , a reduced mass ratio leads to more efficient electron acceleration and an unrealistically high ion flux at higher momentum. At low , it causes complete suppression of electron acceleration, whereas the realistic mass ratio enables efficient electron acceleration. The reduced mass ratio also results in excessive electron heating and lower heating in downstream ions at both Mach numbers, with slightly more magnetic field amplification at low . Consequently, the electron-to-ion temperature ratio is high at low due to reduced ion heating and remains high at high due to increased electron heating. In contrast, simulations with the realistic mr show that the ion-to-electron temperature ratio is independent of the upstream magnetic field, a result not observed in reduced mr simulations.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841445","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}
Kyle Kremer, Claire S. Ye, Craig O. Heinke, Anthony L. Piro, Scott M. Ransom and Frederic A. Rasio
{"title":"Can Slow Pulsars in Milky Way Globular Clusters Form via Partial Recycling?","authors":"Kyle Kremer, Claire S. Ye, Craig O. Heinke, Anthony L. Piro, Scott M. Ransom and Frederic A. Rasio","doi":"10.3847/2041-8213/ad9a4e","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9a4e","url":null,"abstract":"Alongside the population of several hundred radio millisecond pulsars currently known in Milky Way globular clusters, a subset of six slowly spinning pulsars (spin periods 0.3–4 s) are also observed. With inferred magnetic fields ≳1011 G and characteristic ages ≲108 yr, explaining the formation of these apparently young pulsars in old stellar populations poses a major challenge. One popular explanation is that these objects are not actually young but instead have been partially spun up via accretion from a binary companion. In this scenario, accretion in a typical low-mass X-ray binary (LMXB) is interrupted by a dynamical encounter with a neighboring object in the cluster. Instead of complete spin-up to millisecond spin periods, the accretion is halted prematurely, leaving behind a “partially recycled” neutron star. In this Letter, we use a combination of analytic arguments motivated by LMXB evolution and N-body simulations to show that this partial recycling mechanism is not viable. Realistic globular clusters are not sufficiently dense to interrupt mass transfer on the short timescales required to achieve such slow spin periods. We argue that collapse of massive white dwarfs and/or neutron star collisions are more promising ways to form slow pulsars in old globular clusters.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832199","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}
Michael Müller, Suvodip Mukherjee and Geoffrey Ryan
{"title":"Be Careful in Multimessenger Inference of the Hubble Constant: A Path Forward for Robust Inference","authors":"Michael Müller, Suvodip Mukherjee and Geoffrey Ryan","doi":"10.3847/2041-8213/ad8dd1","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8dd1","url":null,"abstract":"Multimessenger observations of coalescing binary neutron stars (BNSs) using gravitational-wave (GW) and electromagnetic- (EM) wave signals are a direct probe of the expansion history of the Universe and carry the potential to shed light on the disparity between low- and high-redshift measurements of the Hubble constant H0. To measure the value of H0 with such observations requires pristine inference of the luminosity distance and the true source redshift with minimal impact from systematics. In this analysis, we carry out joint inference on mock GW signals and their EM afterglows from BNS coalescences and find that the inclination angle inferred from the afterglow light curve and apparent superluminal motion can be precise but need not be accurate and is subject to a systematic uncertainty that could be as large as 1.5σ. This produces a disparity between the EM and GW inferred inclination angles, which if not carefully treated when combining observations can bias the inferred value of H0. We also find that already small misalignments of 3°–6° between the inherent system inclinations for the GW and EM emission can bias the inference by if not taken into account. As multimessenger BNS observations are rare, we must make the most out of a small number of events and harness the increased precision while avoiding a reduced accuracy. We demonstrate how to mitigate these potential sources of bias by jointly inferring the mismatch between the GW- and EM-based inclination angles and H0.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832198","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}
Dawei Li, Taotao Fang, Chong Ge, Teng Liu, Lin He, Zhiyuan Li, Fabrizio Nicastro, Xiaohu Yang, Xiaoxia Zhang and Yun-Liang Zheng
{"title":"Robust Detection of Hot Intragroup Medium in Optically Selected, Poor Galaxy Groups by eROSITA","authors":"Dawei Li, Taotao Fang, Chong Ge, Teng Liu, Lin He, Zhiyuan Li, Fabrizio Nicastro, Xiaohu Yang, Xiaoxia Zhang and Yun-Liang Zheng","doi":"10.3847/2041-8213/ad991c","DOIUrl":"https://doi.org/10.3847/2041-8213/ad991c","url":null,"abstract":"Over the last several decades, extensive research has been conducted on the baryon cycles within cosmic structures, encompassing a broad mass range from dwarf galaxies to galaxy clusters. However, a notable gap in understanding the cosmic baryon cycle is the poor galaxy groups with halo masses around 1013 M⊙. Poor galaxy groups, like our own Local Group, are prevalent throughout the Universe, yet robust detection of their hot, X-ray-emitting intragroup medium (IGrM) has remained elusive. The presence of this hot IGrM is crucial for addressing the long-standing “missing baryons” problem. Previous ROSAT-based studies were limited by a small number of X-ray bright samples, thus restricting the scope of their findings. Here, we show a robust detection of this hot IGrM in a large, optically selected poor groups sample, based on the stacked X-ray images from the eROSITA Final Equatorial Depth Survey. These groups are identified in DESI Legacy Survey with a mass range of log(Mhalo/h−1 M⊙) = 11.5–13.5 and a redshift range of z = 0.1–0.5. Additionally, our results indicate that despite its presence in virtually groups at all sizes, this gas component is still not sufficient to recover the universal baryon fraction, and hence the “missing baryons” problem still persists in poor galaxy groups.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142820621","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}
Shuai Zhang, Kaijun Liu, Quanqi Shi, Anmin Tian and Fei Yao
{"title":"The Shape of the Heliosphere Derived from the IBEX Ribbon","authors":"Shuai Zhang, Kaijun Liu, Quanqi Shi, Anmin Tian and Fei Yao","doi":"10.3847/2041-8213/ad992a","DOIUrl":"https://doi.org/10.3847/2041-8213/ad992a","url":null,"abstract":"The shape of the heliosphere remains largely uncertain due to the lack of in situ measurements. However, the energetic neutral atom (ENA) ribbon structure discovered by the Interstellar Boundary EXplorer (IBEX) satellite provides a new perspective. The present study reveals that the IBEX ribbon ENA flux, observed over a full solar cycle, correlates well with the solar wind ion flux measured at 1 au after a time delay of a few years. The time lag between the two can be used to estimate the heliopause distance and the heliosphere shape. The results show that the heliopause distance is shortest slightly south of the nose direction (∼100 au) and remains almost constant with the ecliptic longitude. However, the distance extends to ∼800 au toward the polar region, and it seems that there is no broadly symmetrical and elongated single heliospheric tail. While these features are consistent with the “croissant-like” model (no tail, but with two jet-like tail lobes) of the heliosphere, they cannot fully exclude the traditional “comet-like” model with a strong local interstellar medium magnetic field. Additional data and modeling are needed to ascertain the precise shape of the heliosphere.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142820798","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}
Anishya Harshan, Roberta Tripodi, Nicholas S. Martis, Gregor Rihtaršič, Maruša Bradač, Yoshihisa Asada, Gabe Brammer, Guillaume Desprez, Vince Estrada-Carpenter, Jasleen Matharu, Vladan Markov, Adam Muzzin, Lamiya Mowla, Gaël Noirot, Ghassan T. E. Sarrouh, Marcin Sawicki, Victoria Strait and Chris Willott
{"title":"Detailed Study of Stars and Gas in a z = 8.3 Massive Merger with Extreme Dust Conditions","authors":"Anishya Harshan, Roberta Tripodi, Nicholas S. Martis, Gregor Rihtaršič, Maruša Bradač, Yoshihisa Asada, Gabe Brammer, Guillaume Desprez, Vince Estrada-Carpenter, Jasleen Matharu, Vladan Markov, Adam Muzzin, Lamiya Mowla, Gaël Noirot, Ghassan T. E. Sarrouh, Marcin Sawicki, Victoria Strait and Chris Willott","doi":"10.3847/2041-8213/ad9741","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9741","url":null,"abstract":"We present galaxy MACS0416-Y1 at zspec = 8.312 as observed by the CAnadian NIRISS Unbiased Cluster Survey. MACS0416-Y1 has been shown to have extreme dust properties; thus, we study the physical properties and star formation histories of its resolved components. Overall, we find that MACS0416-Y1 is undergoing a star formation burst in three resolved clumps. The central clump is less massive compared to the other clumps and possibly formed in the merging process of the two larger clumps. Although the star formation history indicates an ongoing star formation burst, this gas-rich galaxy shows comparable star formation efficiency to cosmic noon galaxies. Using NIRSpec prism spectroscopy, we measure metallicity, , ionization parameter, , and electron temperature Te = 18000 ± 4000 K. The emission line ratios of the galaxy indicate an evolved interstellar medium similar to z ∼ 2 star-forming galaxies. Further, we find possible presence of ionization from an active galactic nucleus (AGN) using emission line diagnostics; however, we do not detect a broad-line component in the Hβ emission line. As this gas-rich galaxy is undergoing a major merger, we hypothesize that the high dust temperature in MACS0416-Y1 is caused by the star formation burst or a possible narrow-line AGN.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809644","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}
Caldon T. Whyte, L. H. Quiroga-Nuñez, Manasvi Lingam and Paola Pinilla
{"title":"Potential for Life to Exist and be Detected on Earth-like Planets Orbiting White Dwarfs","authors":"Caldon T. Whyte, L. H. Quiroga-Nuñez, Manasvi Lingam and Paola Pinilla","doi":"10.3847/2041-8213/ad9821","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9821","url":null,"abstract":"With recent observations confirming exoplanets orbiting white dwarfs, there is growing interest in exploring and quantifying the habitability of temperate rocky planets around white dwarfs. In this work, the limits of the habitable zone of an Earth-like planet around a white dwarf are computed based on the incident stellar flux, and these limits are utilized to assess the duration of habitability at a given orbital distance. For a typical 0.6M⊙ white dwarf an Earth-like planet at ∼0.012 au could remain in the temporally evolving habitable zone, maintaining conditions to support life, for nearly 7 Gyr. Also, additional constraints on habitability are studied for the first time by imposing the requirement of receiving sufficient photon fluxes for UV-mediated prebiotic chemistry and photosynthesis. We demonstrate that these thresholds are comfortably exceeded by planets in the habitable zone. The prospects for detecting atmospheric biosignatures are also evaluated and shown to require integration times on the order of 1 hr or less for ongoing space observations with JWST.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809645","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}
Przemek Mróz, Krzysztof Król, Hélène Szegedi, Philip Charles, Kim L. Page, Andrzej Udalski, David A. H. Buckley, Gulab Dewangan, Pieter Meintjes, Michał K. Szymański, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Radosław Poleski, Jan Skowron, Krzysztof Ulaczyk, Mariusz Gromadzki, Krzysztof Rybicki, Patryk Iwanek, Marcin Wrona and Mateusz J. Mróz
{"title":"Millinovae: A New Class of Transient Supersoft X-Ray Sources without a Classical Nova Eruption","authors":"Przemek Mróz, Krzysztof Król, Hélène Szegedi, Philip Charles, Kim L. Page, Andrzej Udalski, David A. H. Buckley, Gulab Dewangan, Pieter Meintjes, Michał K. Szymański, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Radosław Poleski, Jan Skowron, Krzysztof Ulaczyk, Mariusz Gromadzki, Krzysztof Rybicki, Patryk Iwanek, Marcin Wrona and Mateusz J. Mróz","doi":"10.3847/2041-8213/ad969b","DOIUrl":"https://doi.org/10.3847/2041-8213/ad969b","url":null,"abstract":"Some accreting binary systems containing a white dwarf (such as classical novae or persistent supersoft sources) are seen to emit low-energy X-rays with temperatures of ∼ 106 K and luminosities exceeding 1035 erg s−1. These X-rays are thought to originate from nuclear burning on the white dwarf surface, either caused by a thermonuclear runaway (classical novae) or a high mass-accretion rate that sustains steady nuclear burning (persistent sources). The discovery of transient supersoft X-rays from ASASSN-16oh challenged these ideas, as no clear signatures of mass ejection indicative of a classical nova eruption were detected, and the origin of these X-rays remains controversial. It was unclear whether this star was one of a kind or representative of a larger, as yet undiscovered, group. Here, we present the discovery of 29 stars located in the direction of the Magellanic Clouds exhibiting long-duration, symmetrical optical outbursts similar to that seen in ASASSN-16oh. We observed one of these objects during an optical outburst and found it to be emitting transient supersoft X-rays, while no signatures of mass ejection (indicative of a classical nova eruption) were detected. We therefore propose that these objects form a homogeneous group of transient supersoft X-ray sources, which we dub “millinovae” because their optical luminosities are approximately a 1000 times fainter than those of ordinary classical novae.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815735","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}
XRISM Collaboration, Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, María Díaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Satoshi Eguchi, Teruaki Enoto, Yuichiro Ezoe, Adam Foster, Ryuichi Fujimoto, Yutaka Fujita, Yasushi Fukazawa, Kotaro Fukushima, Akihiro Furuzawa, Luigi Gallo, Javier A. García, Liyi Gu, Matteo Guainazzi, Kouichi Hagino, Kenji Hamaguchi, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Natalie Hell, Edmund Hodges-Kluck, Ann Hornschemeier, Yuto Ichinohe, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Timothy Kallman, Erin Kara, Satoru Katsuda, Yoshiaki Kanemaru, Richard Kelley, Caroline Kilbourne, Shunji Kitamoto, Shogo Kobayashi, Takayoshi Kohmura, Aya Kubota, Maurice Leutenegger, Michael Loewenstein, Yoshitomo Maeda, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsu..
{"title":"The XRISM/Resolve View of the Fe K Region of Cyg X-3","authors":"XRISM Collaboration, Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, María Díaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Satoshi Eguchi, Teruaki Enoto, Yuichiro Ezoe, Adam Foster, Ryuichi Fujimoto, Yutaka Fujita, Yasushi Fukazawa, Kotaro Fukushima, Akihiro Furuzawa, Luigi Gallo, Javier A. García, Liyi Gu, Matteo Guainazzi, Kouichi Hagino, Kenji Hamaguchi, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Natalie Hell, Edmund Hodges-Kluck, Ann Hornschemeier, Yuto Ichinohe, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Timothy Kallman, Erin Kara, Satoru Katsuda, Yoshiaki Kanemaru, Richard Kelley, Caroline Kilbourne, Shunji Kitamoto, Shogo Kobayashi, Takayoshi Kohmura, Aya Kubota, Maurice Leutenegger, Michael Loewenstein, Yoshitomo Maeda, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsu..","doi":"10.3847/2041-8213/ad8ed0","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8ed0","url":null,"abstract":"The X-ray binary system Cygnus X-3 (4U 2030+40, V1521 Cyg) is luminous but enigmatic owing to the high intervening absorption. High-resolution X-ray spectroscopy uniquely probes the dynamics of the photoionized gas in the system. In this Letter, we report on an observation of Cyg X-3 with the XRISM/Resolve spectrometer, which provides unprecedented spectral resolution and sensitivity in the 2–10 keV band. We detect multiple kinematic and ionization components in absorption and emission whose superposition leads to complex line profiles, including strong P Cygni profiles on resonance lines. The prominent Fe xxv Heα and Fe xxvi Lyα emission complexes are clearly resolved into their characteristic fine-structure transitions. Self-consistent photoionization modeling allows us to disentangle the absorption and emission components and measure the Doppler velocity of these components as a function of binary orbital phase. We find a significantly higher velocity amplitude for the emission lines than for the absorption lines. The absorption lines generally appear blueshifted by ∼−500–600 km s−1. We show that the wind decomposes naturally into a relatively smooth and large-scale component, perhaps associated with the background wind itself, plus a turbulent, denser structure located close to the compact object in its orbit.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809647","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}
Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang and Min Wang
{"title":"A New View of the Spiral Structure of the Northern Outer Milky Way in Carbon Monoxide","authors":"Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang and Min Wang","doi":"10.3847/2041-8213/ad9605","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9605","url":null,"abstract":"Based on 32,162 molecular clouds from the Milky Way Imaging Scroll Painting project, we obtain new face-on molecular gas maps of the northern outer Galaxy. The total molecular gas surface density map reveals three segments of spirals, extending 16–43 kpc in length. The Perseus and Outer arms stand out prominently, appearing as quasi-continuous structures along most of their length. At the Galactic outskirts, about 1306 clouds connect the two segments of the new spiral arm discovered by T. M. Dame & P. Thaddeus (2011) in the first quadrant and Y. Sun et al. in the second quadrant, possibly extending the arm into the outer third quadrant. Logarithmic spirals can be fitted to the CO arm segments with pitch angles ranging from 4∘ to 12∘. These CO arms extend beyond previous CO studies and the optical radius, reaching a Galactic radius of about 22 kpc, comparable to the H i radial range.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809681","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}