• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-04
Igor Andreoni, Wenbin Lu, Roger M. Smith, Frank J. Masci, Eric C. Bellm, Matthew J. Graham, David L. Kaplan, Mansi M. Kasliwal, Stephen Kaye, Thomas Kupfer, Russ R. Laher, Ashish A. Mahabal, Jakob Nordin, Michael Porter, Thomas A. Prince, Dan Reiley, Reed Riddle, Joannes Van Roestel, and Yuhan Yao

The discovery rate of fast radio bursts (FRBs) is increasing dramatically thanks to new radio facilities. Meanwhile, wide-field instruments such as the 47 deg 2 Zwicky Transient Facility (ZTF) survey the optical sky to study transient and variable sources. We present serendipitous ZTF observations of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) repeating source FRB 180916.J0158+65 that

更新日期：2020-06-04
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-04
K. Murawski, Z. E. Musielak, and D. Wójcik

Despite numerous observational and theoretical attempts, the heating problem of the solar chromosphere still remains unsolved. We develop a novel 3D two-fluid model that accounts for dynamics of charged species and neutrals, and use it to perform the numerical simulations of granulation driven jets and associated waves in a quiet region of the solar chromosphere. The energy carried by the waves is

更新日期：2020-06-04
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-03
Bin Chen, Sijie Yu, Katharine K. Reeves, and Dale E. Gary

We report microwave spectral imaging observations of an erupting magnetic flux rope during the early impulsive phase of the X8.2-class limb flare on 2017 September 10, obtained by the Expanded Owens Valley Solar Array. A few days prior to the eruption, when viewed against the disk, the flux rope appeared as a reverse S-shaped dark filament along the magnetic polarity inversion line. During the eruption

更新日期：2020-06-03
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-03
Deryl E. Long, Ke Zhang, Richard Teague, and Edwin A. Bergin

The recent Atacama Large Millimeter/submillimeter Array (ALMA) Disk Substructures at High Angular Resolution Project (DSHARP) survey provided illuminating results on the diversity of substructures in planet-forming disks. These substructures trace pebble-sized grains accumulated at local pressure maxima, possibly due to planet–disk interactions or other planet formation processes. DSHARP sources are

更新日期：2020-06-03
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-03
E. Platts, J. Xavier Prochaska, and Casey J. Law

We introduce a new technique to constrain the line-of-sight integrated electron density of our Galactic halo ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L49/apjlab930aieqn1.gif] {${\mathrm{DM}}_{\mathrm{MW},\mathrm{halo}}$} through analysis of the observed dispersion measure distributions of pulsars ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L49/apjlab930aieqn2.gif] {${\mathrm{DM}}_{\mathrm{pulsar}}$}

更新日期：2020-06-03
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-03
Kazumasa Ohno and Yui Kawashima

Spectral slopes in optical transmission spectra of exoplanetary atmospheres encapsulate information on the properties of exotic clouds. The slope is usually attributed to the Rayleigh scattering caused by tiny aerosol particles, whereas recent retrieval studies have suggested that the slopes are often steeper than the canonical Rayleigh slopes. Here, we propose that photochemical haze formed in vigorously

更新日期：2020-06-03
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-03
Á. Kóspál, P. Ábrahám, A. Carmona, L. Chen, J. D. Green, R. van Boekel, and J. A. White

FU Orionis–type stars are young stellar objects showing large outbursts due to highly enhanced accretion from the circumstellar disk onto the protostar. FU Orionis–type object (FUor) outbursts happen in a wide variety of sources from the very embedded ones to those with almost no sign of extended emission beyond the disk. The subsequent eruptions might gradually clear up the obscuring envelope material

更新日期：2020-06-03
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
Jared A. Goldberg and Lars Bildsten

Using Modules for Experiments in Stellar Astrophysics ( MESA )+ STELLA , we show that very different physical models can adequately reproduce a specific observed Type II-Plateau supernova (SN). We consider SN2004A, SN2004et, SN2009ib, SN2017eaw, and SN2017gmr, nickel-rich ( ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L45/apjlab9300ieqn1.gif] {${M}_{\mathrm{Ni}}\gt 0.03{M}_{\odot }$} ) events

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
Sarira Sahu and Carlos E. López Fortín

The detection of GRB 180722B and GRB 190114C in sub-TeV gamma-rays has opened up a new window to study gamma-ray bursts in high-energy gamma-rays. Recently it has been shown that the synchrotron and inverse Compton processes are responsible for the production of these high-energy gamma-rays during the afterglow. Here, for the first time we demonstrate that the photohadronic scenario that is successful

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
Wei-Jian Lu and Ying-Ru Lin

Evidence for quasar outflows can be detected via blueshifted broad absorption lines (BALs) in rest-frame ultraviolet spectra of quasars. We have identified 18 narrow absorption line (NAL) systems in the BAL system of SDSS J010612.22+001920.1, indicating that this BAL outflow has achieved a high degree of clumpiness. Moreover, these NAL systems are highly structured in velocity space and separated from

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
Luca Comisso, Emanuele Sobacchi, and Lorenzo Sironi

Synchrotron emission from astrophysical nonthermal sources usually assumes that the emitting particles are isotropic. By means of large-scale two- and three-dimensional particle-in-cell simulations, we demonstrate that the dissipation of magnetically dominated ( ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L40/apjlab93dcieqn1.gif] {${\sigma }_{0}\gg 1$} ) turbulence in pair plasmas leads to strongly

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
J. Cui, Ren Z.-P., Wu Z.-P., Wu X.-S., Hao Y.-Q., and Y. Wei

Normally, the Martian ionosphere displays a dusk enhancement due to continuous depletion of plasma via recombination during day-to-night transport. Using the extensive measurements made by the Neutral Gas and Ion Mass Spectrometer on board the Mars Atmosphere and Volatile Evolution spacecraft, we show that several species, including ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L43/apjlab930cieqn1

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-06-01
Amir Siraj and Abraham Loeb

There is evidence that ejecta from nearby supernovae have rained down on Earth in the past. Supernovae can accelerate preexisting dust grains in the interstellar medium to speeds of ∼0.01 c . We investigate the survival and impact of dust grains from supernovae on the Moon, finding that supernova dust grains can form detectable tracks with widths of ∼0.01–0.07 μ m and depths of ∼0.1–0.7 mm in lunar

更新日期：2020-06-01
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-31
Shivani Bhandari, Elaine M. Sadler, J. Xavier Prochaska, Sunil Simha, Stuart D. Ryder, Lachlan Marnoch, Keith W. Bannister, Jean-Pierre Macquart, Chris Flynn, Ryan M. Shannon, Nicolas Tejos, Felipe Corro-Guerra, Cherie K. Day, Adam T. Deller, Ron Ekers, Sebastian Lopez, Elizabeth K. Mahony, Consuelo Nuñez, and Chris Phillips

The Australian SKA Pathfinder (ASKAP) telescope has started to localize fast radio bursts (FRBs) to arcsecond accuracy from the detection of a single pulse, allowing their host galaxies to be reliably identified. We discuss the global properties of the host galaxies of the first four FRBs localized by ASKAP, which lie in the redshift range0.11 < z < 0.48. All four are massive galaxies (log( M * / M

更新日期：2020-05-31
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-31
Surajit Mondal, Divya Oberoi, and Atul Mohan

This Letter explores the relevance of nanoflare-based models for heating the quiet Sun corona. Using meterwave data from the Murchison Widefield Array, we present the first successful detection of impulsive emissions down to flux densities of ∼mSFU, about two orders of magnitude weaker than earlier attempts. These impulsive emissions have durations ≲1 s and are present throughout the quiet solar corona

更新日期：2020-05-31
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-31
Daniel Stern and Dominic J. Walton

MG 1131+0456 is a radio-selected gravitational lens, and is the first known Einstein ring. Discovered in 1988, the system consists of a bright ( S 74 MHz = 3.7 Jy) radio source imaged into a ring and two compact, flat-spectrum components separated by 2.″1. The ring is optically faint ( R = 23.3), rising steeply into the near- and mid-infrared ( K = 17.8; W2 = 13.4). The system has been intensively

更新日期：2020-05-31
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Kazimierz J. Borkowski, Stephen P. Reynolds, and William Miltich

One of the youngest known remnants of a core-collapse supernova (SN) in our Galaxy is G320.4−1.2/MSH 15-5 2 , containing an energetic pulsar with a very short (1700 yr) spindown age and likely produced by a stripped-envelope SN Ibc. Bright X-ray and radio emission north of the pulsar overlaps with an H α nebula RCW 89. The bright X-rays there have a highly unusual and quite puzzling morphology, consisting

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Paz Beniamini, Rodolfo Barniol Duran, Maria Petropoulou, and Dimitrios Giannios

The joint detection of GW170817/GRB 170817 confirmed the long-standing theory that binary neutron star mergers produce short gamma-ray burst (sGRB) jets that can successfully break out of the surrounding ejecta. At the same time, the association with a kilonova provided unprecedented information regarding the physical properties (such as masses and velocities) of the different ejecta constituents.

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Yoonyoung Kim, David Jewitt, Max Mutchler, Jessica Agarwal, Man-To Hui, and Harold Weaver

Hubble Space Telescope observations of interstellar comet 2I/Borisov near perihelion show the ejection of large ( ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L34/apjlab9228ieqn1.gif] {$\gtrsim 100$} μ m) particles at ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L34/apjlab9228ieqn2.gif] {$\lesssim 9$} m s −1 speeds, with estimated mass-loss rates of ∼35 kg s −1 . The total mass loss from

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Thiem Hoang and Abraham Loeb

Planet Nine was proposed as an explanation for the clustering of orbits for some trans-Neptunian objects. Recently, the use of a subrelativistic spacecraft was proposed to indirectly probe Planet Nine's gravitational influence. Here we study the effects of the drag and electromagnetic forces exerted on a subrelativistic spacecraft by the interstellar medium (ISM) and compare these forces with the gravitational

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Mathilde Espinasse, Stéphane Corbel, Philip Kaaret, Evangelia Tremou, Giulia Migliori, Richard M. Plotkin, Joe Bright, John Tomsick, Anastasios Tzioumis, Rob Fender, Jerome A. Orosz, Elena Gallo, Jeroen Homan, Peter G. Jonker, James C. A. Miller-Jones, David M. Russell, and Sara Motta

The black hole MAXI J1820+070 was discovered during its 2018 outburst and was extensively monitored across the electromagnetic spectrum. Following the detection of relativistic radio jets, we obtained four Chandra X-ray observations taken between 2018 November and 2019 June, along with radio observations conducted with the Very Large Array and MeerKAT arrays. We report the discovery of X-ray sources

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-28
Partha Sarathi Pal, P. H. T. Tam, Weitang Liang, Chengye Cao, K. L. Li, C. Y. Hui, and A. K. H. Kong

Pulsar binaries, in particular redback systems, provide good sources to study the pulsar wind flow and its interaction with the companion stars. Fermi-LAT have proposed probable pulsar binary candidates in its catalogs. An orbital modulation search of binary candidates is an effective way to identify pulsar binary sources from the catalog. Transiting Exoplanet Survey Satellite (TESS) observes in survey

更新日期：2020-05-28
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-27
Yuri Levin, Andrei M. Beloborodov, and Ashley Bransgrove

Recently, the Canadian Hydrogen Intensity Mapping Experiment detected periodicity in the bursting rate of the repeating FRB 180916.J0158+65. In a popular class of models, the fast radio bursts (FRBs) are created by magnetic flares of a hyperactive magnetar driven by fast ambipolar diffusion in the core. We point out that in this scenario the magnetar is expected to precess freely with a period of weeks

更新日期：2020-05-27
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-26
Ilya Mandel and Tassos Fragos

The Laser Interferometer Gravitational-Wave Observatory (LIGO)-Virgo collaboration recently reported the properties of GW190412, a binary black hole merger with unequal component masses (mass ratio ##IMG## [http://ej.iop.org/images/2041-8205/895/2/L28/apjlab8e41ieqn1.gif] {${0.25}_{-0.04}^{+0.06}$} when using the EOBNR PHM approximant) and a non-vanishing effective spin aligned with the orbital angular

更新日期：2020-05-26
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-26
M. Kornbleuth, M. Opher, A. T. Michael, J. M. Sokół, G. Tóth, V. Tenishev, and J. F. Drake

Traditionally, the solar magnetic field has been considered to have a negligible effect in the outer regions of the heliosphere. Recent works have shown that the solar magnetic field may play a crucial role in collimating the plasma in the heliosheath. Interstellar Boundary Explorer (IBEX) observations of the heliotail indicated a latitudinal structure varying with energy in the energetic neutral atom

更新日期：2020-05-26
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-26
Kai Liao, Arman Shafieloo, Ryan E. Keeley, and Eric V. Linder

We determine the Hubble constant H 0 precisely (2.3% uncertainty) in a manner independent of the cosmological model through Gaussian process regression, using strong lensing and supernova data. Strong gravitational lensing of a variable source can provide a time-delay distance D Δ t and angular diameter distance to the lens D d . These absolute distances can anchor Type Ia supernovae, which give an

更新日期：2020-05-26
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-26
Alexander Zderic, Angela Collier, Maria Tiongco, and Ann-Marie Madigan

Disks of low-mass bodies on high-eccentricity orbits in near-Keplerian potentials can be dynamically unstable to buckling out of the plane. In this Letter, we present N -body simulations of the long-term behavior of such a system, finding apsidal clustering of the orbits in the disk plane. The timescale over which the clustering is maintained increases with number of particles, suggesting that lopsided

更新日期：2020-05-26
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-25
Diego Janches, Juan Sebastian Bruzzone, Robert J. Weryk, Jose Luis Hormaechea, Paul Wiegert, and Claudio Brunini

A strong and unexpected meteor shower outburst was observed by the Southern Argentina Agile MEteor Radar Orbital System (SAAMER-OS) at high southern ecliptic latitude within the South Toroidal region. The outburst, which was active throughout solar longitudes 351° and 352°, peaked at 09:30 UT on 2020 March 12, has a mean Sun-centered ecliptic radiant of λ − λ 0 ∼ 307.°5 and β ∼ −77.°2 and a geocentric

更新日期：2020-05-25
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-25
D. L. Coppejans, R. Margutti, G. Terreran, A. J. Nayana, E. R. Coughlin, T. Laskar, K. D. Alexander, M. Bietenholz, D. Caprioli, P. Chandra, M. R. Drout, D. Frederiks, C. Frohmaier, K. H Hurley, C. S. Kochanek, M. MacLeod, A. Meisner, P. E. Nugent, A. Ridnaia, D. J. Sand, D. Svinkin, C. Ward, S. Yang, A. Baldeschi, I. V. Chilingarian, Y. Dong, C. Esquivia, W. Fong, C. Guidorzi, P. Lundqvist, D. Milisavljevic

We present X-ray and radio observations of the Fast Blue Optical Transient CRTS-CSS161010 J045834−081803 (CSS161010 hereafter) at t = 69–531 days. CSS161010 shows luminous X-ray ( L x ∼ 5 × 10 39 erg s −1 ) and radio ( L ν ∼ 10 29 erg s −1 Hz −1 ) emission. The radio emission peaked at ∼100 days post-transient explosion and rapidly decayed. We interpret these observations in the context of synchrotron

更新日期：2020-05-25
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-25
Zhengyang Zou, Pingbing Zuo, Binbin Ni, Zhonglei Gao, Geng Wang, Zhengyu Zhao, Xueshang Feng, and Fengsi Wei

We report a two-step dropout event of radiation belt electron phase space density (PSD) induced by a typical magnetic cloud (MC) that drove an intense geomagnetic storm. The first and second steps of PSD dropout occurred, respectively, in the initial and main phases of the storm with a short-time partial recovery between the two dropouts. In this event, the initial phase after the sudden commencement

更新日期：2020-05-25
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-21
C. W. James, S. Osłowski, C. Flynn, P. Kumar, K. Bannister, S. Bhandari, W. Farah, M. Kerr, D. R. Lorimer, J.-P. Macquart, C. Ng, C. Phillips, D. C. Price, H. Qiu, R. M. Shannon, and R. Spiewak

The discovery of many repeating fast radio bursts (FRBs) by the Canadian Hydrogen Intensity Mapping Experiment, the high rate of individual bursts, and the observation of repeat bursts from a bright FRB initially detected by the Australian Square Kilometre Array Pathfinder (ASKAP) suggest a significant population of repeating FRBs. Here, we analyze the rate distribution of this population using results

更新日期：2020-05-21
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-21
Victor Réville, Marco Velli, Alexis P. Rouillard, Benoit Lavraud, Anna Tenerani, Chen Shi, and Antoine Strugarek

In contrast with the fast solar wind, which originates in coronal holes, the source of the slow solar wind is still debated. Often intermittent and enriched with low first ionization potential elements—akin to what is observed in closed coronal loops—the slow wind could form in bursty events nearby helmet streamers. Slow winds also exhibit density perturbations that have been shown to be periodic and

更新日期：2020-05-21
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-21
Angel D. Martínez, Valeria Quintero Ortega, J. C. Buitrago-Casas, Juan Carlos Martínez Oliveros, Benjamín Calvo-Mozo, and Charles Lindsey

We examine a strong, coherent, highly impulsive acoustic transient radiated into the solar interior by the flare SOL20110730T02:04-M9.3. The acoustic spectrum of this transient extends out to 10 mHz. The fine diffraction limit of this high-frequency component of the flare acoustic transient allows us to discriminate different source components in operation during the flare. Acoustic-source power density

更新日期：2020-05-21
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-21
Masashi Nashimoto, Makoto Hattori, and Yuji Chinone

We evaluate the degradation of the accuracy of the component separation between the cosmic microwave background (CMB) and foreground components caused by neglect of absorption of the CMB’s monopole component by the galactic interstellar matter. The amplitude of the temperature anisotropy caused by the CMB shadow, due to dust components, is about 1 μ K. This value is comparable to the required noise

更新日期：2020-05-21
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-20
Giacomo Fragione, Abraham Loeb, and Frederic A. Rasio

The origin of the black hole (BH) binary mergers observed by LIGO-Virgo is still uncertain, as are the boundaries of the stellar BH mass function. Stellar evolution models predict a dearth of BHs both at masses ≳50 ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L15/apjlab9093ieqn1.gif] {${M}_{\odot }$} and ≲5 ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L15/apjlab9093ieqn2.gif] {${M}_{\odot 更新日期：2020-05-20 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-20 Jiaqing Bi, Nienke van der Marel, Ruobing Dong (董若冰), Takayuki Muto, Rebecca G. Martin, Jeremy L. Smallwood, Jun Hashimoto, Hauyu Baobab Liu, Hideko Nomura, Yasuhiro Hasegawa, Michihiro Takami, Mihoko Konishi, Munetake Momose, Kazuhiro D. Kanagawa, Akimasa Kataoka, Tomohiro Ono, Michael L. Sitko, Sanemichi Z. Takahashi, Kengo Tomida, and Takashi Tsukagoshi GW Ori is a hierarchical triple system with a rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12 CO J = 2 − 1 molecular gas emission of the disk. For the first time, we identify three dust rings in the GW Ori disk at ∼46, 188, and 338 au, with estimated dust mass of 74, 168, and 245 Earth masses, respectively. To our knowledge 更新日期：2020-05-20 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-20 Mark H. Jones, Carole A. Haswell, John R. Barnes, Daniel Staab, and René Heller We analyze TESS photometry of DMPP-1 (HD 38677; TIC 66560666), a nearby F8V star hosting hot super-Earth planets and a warm Neptune. Using the Transit Least Squares algorithm and other methods we find a transit signal at ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L17/apjlab8f2bieqn1.gif] {$P={3.2854}_{-0.0025}^{+0.0032}} days with depth ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L17/apjlab8f2bieqn2 更新日期：2020-05-20 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-20 Gyungin Shin, Yong-Jae Moon, Eunsu Park, Hyunjin Jeong, Harim Lee, and Sung-Ho Bae In this Letter, we generate realistic high-resolution (1024 × 1024 pixels) pseudo-magnetograms from Ca ii K images using a deep learning model based on conditional generative adversarial networks. For this, we consider a model “pix2pixHD” that is specifically devised for high-resolution image translation tasks. We use Ca ii K 393.3 nm images from the Precision Solar Photometric Telescope at the Rome 更新日期：2020-05-20 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-19 Pengfei Qin, Yasong Ge, Aimin Du, Can Huang, Ying Zhang, Hao Luo, Jiaming Ou, Tielong Zhang, and Lican shan Magnetosphere–ionosphere coupling is representative of a class of astrophysical problems involving the interaction between very different plasma regimes that are connected by magnetic fields. It is a major issue of the planet’s (e.g., Earth, Jupiter, Saturn) system how the magnetospheric plasma is coupled to the planet’s ionosphere/atmosphere. Due to their roles on energy transport and conversion in 更新日期：2020-05-19 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-19 Noemie Globus and Roger D. Blandford Biological molecules chose one of two structurally chiral systems which are related by reflection in a mirror. It is proposed that this choice was made, causally, by cosmic rays, which are known to play a major role in mutagenesis. It is shown that magnetically polarized cosmic rays that dominate at ground level today can impose a small, but persistent, chiral bias in the rate at which they induce 更新日期：2020-05-19 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-19 Nikos Sioulas, Heinz Isliker, and Loukas Vlahos We analyze the stochastic acceleration of particles inside a fully developed turbulent plasma. It is well known that large-amplitude magnetic fluctuations and coherent structures in such an environment obey a fractal scaling, and our specific aim is to study for the first time the effects of the fractality of these environments on stochastic acceleration. We have shown that an injected Maxwellian energy 更新日期：2020-05-19 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-19 Iminhaji Ablimit, Gang Zhao, Chris Flynn, and Sarah A. Bird With the increasing number of large stellar survey projects, the quality and quantity of excellent tracers for studying the Milky Way are rapidly growing, one of which is the classical Cepheids. Classical Cepheids are high-precision standard candles with very low typical uncertainties (<3%) available via the mid-infrared period–luminosity relation. About 3500 classical Cepheids identified from the 更新日期：2020-05-19 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-18 Angelo Ricarte, Michael Tremmel, Priyamvada Natarajan, and Thomas Quinn The dense environment of a galaxy cluster can radically transform the content of in-falling galaxies. Recent observations have found a significant population of active galactic nuclei (AGN) within “jellyfish galaxies,” galaxies with trailing tails of gas and stars that indicate significant ram pressure stripping. The relationship between AGN and ram pressure stripping is not well understood. In this 更新日期：2020-05-18 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-18 J. Xu, F. Z. Peng, C. T. Russell, B. Giles, P.-A. Lindqvist, R. B. Torbert, R. E. Ergun, and J. L. Burch With high-resolution data of the recently launched Magnetospheric Multiscale mission, the present study reports an asymmetric guide-field reconnection at the dayside magnetopause, which has a density asymmetry N MSP / N MSH ∼ 15 on the two sides of the current sheet and a guide field B g ∼ 1.4 B L , MSH in the out-of-plane direction, exhibiting all the two-fluid features including Alfvénic plasma jets 更新日期：2020-05-18 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-18 Alberto Rodríguez-Ardila and Marcos A. Fonseca-Faria We report the first characterization of an extended outflow of high ionized gas in the Circinus Galaxy by means of the coronal line (CL) [Fe vii] λ 6087. This emission is located within the ionization cone already detected in the [O iii] λ 5007 line and is found to extend up to a distance of ∼700 pc from the active galactic nucleus. The gas distribution appears clumpy, with several knots of emission 更新日期：2020-05-18 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-17 Weiwei Zhu, Di Li, Rui Luo, Chenchen Miao, Bing Zhang, Laura Spitler, Duncan Lorimer, Michael Kramer, David Champion, Youling Yue, Andrew Cameron, Marilyn Cruces, Ran Duan, Yi Feng, Jun Han, George Hobbs, Chenhui Niu, Jiarui Niu, Zhichen Pan, Lei Qian, Dai Shi, Ningyu Tang, Pei Wang, Hongfeng Wang, Mao Yuan, Lei Zhang, Xinxin Zhang, Shuyun Cao, Li Feng, Hengqian Gan, Long Gao, Xuedong Gu, Minglei Guo We report the discovery of a highly dispersed fast radio burst (FRB), FRB 181123, from an analysis of ∼1500 hr of drift scan survey data taken using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The pulse has three distinct emission components, which vary with frequency across our 1.0–1.5 GHz observing band. We measure the peak flux density to be >0.065 Jy and the corresponding 更新日期：2020-05-17 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-17 Pakorn Wongwaitayakornkul, Hui Li, and Paul M. Bellan Fast magnetic reconnection involving non-MHD microscale physics is believed to underlie both solar eruptions and laboratory plasma current disruptions. While there is extensive research on both the MHD macroscale physics and the non-MHD microscale physics, the process by which large-scale MHD couples to the microscale physics is not well understood. An MHD instability cascade from a kink to a secondary 更新日期：2020-05-17 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-14 Yen-Chen Pan Ejecta velocity of Type Ia supernovae (SNe Ia) is one powerful tool to differentiate between progenitor scenarios and explosion mechanisms. Here we revisit the relation between photospheric Si ii λ 6355 velocities ( v Si ii ) and host-galaxy properties with ∼280 SNe Ia. A more stringent criterion on the phase of SN spectra is adopted to classify SNe Ia in terms of their photospheric velocities. We 更新日期：2020-05-14 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-14 Z. G. Dai and S. Q. Zhong The periodic activity of the repeating fast radio burst (FRB) 180916.J0158+65 was recently reported by the CHIME/FRB Collaboration team. From this source 28 bursts not only show a ∼16 day period with an active phase of ∼4.0 days, but they also exhibit a broken power law in differential energy distribution. In this Letter, we suggest that FRB 180916.J0158+65-like periodic FRBs could provide a unique 更新日期：2020-05-14 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-14 Riouhei Nakatani, Hauyu Baobab Liu, Satoshi Ohashi, Yichen Zhang, Tomoyuki Hanawa, Claire Chandler, Yoko Oya, and Nami Sakai We analyze multifrequency, high-resolution continuum data obtained by the Atacama Large Millimeter/submillimeter Array and the Jansky Very Lary Array to study the detailed structure of the dust distribution in the infant disk of a Class 0/I source, L1527 IRS. We find three clumps aligning in the north–south direction in the 7 mm radio continuum image. The three clumps remain even after subtracting 更新日期：2020-05-14 • Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-14 C. Ashall, J. Lu, C. Burns, E. Y. Hsiao, M. Stritzinger, N. B. Suntzeff, M. Phillips, E. Baron, C. Contreras, S. Davis, L. Galbany, P. Hoeflich, S. Holmbo, N. Morrell, E. Karamehmetoglu, K. Krisciunas, S. Kumar, M. Shahbandeh, and S. Uddin We present a new method to photometrically delineate between various sub-types of Type Ia supernovae (SNe Ia). Using the color-stretch parameters, s BV or s gr , and the time of i -band primary maximum relative to the B -band ( ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L3/apjlab8e37ieqn1.gif] {{t}_{\max }^{i-B}\$} ) or g -band ( ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L3/apjlab8e37ieqn2

更新日期：2020-05-14
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-14
Shany Danieli, Pieter van Dokkum, Roberto Abraham, Charlie Conroy, Andrew E. Dolphin, and Aaron J. Romanowsky

Previous studies have shown that the large, diffuse galaxies NGC 1052-DF2 and NGC 1052-DF4 both have populations of unusually luminous globular clusters as well as a very low dark matter content. Here we present newly obtained deep Hubble Space Telescope Advanced Camera for Surveys imaging of one of these galaxies, NGC 1052-DF4. We use these data to measure the distance of the galaxy from the location

更新日期：2020-05-14
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-13
Lorenzo Pino, Jean-Michel Désert, Matteo Brogi, Luca Malavolta, Aurélien Wyttenbach, Michael Line, Jens Hoeijmakers, Luca Fossati, Aldo Stefano Bonomo, Valerio Nascimbeni, Vatsal Panwar, Laura Affer, Serena Benatti, Katia Biazzo, Andrea Bignamini, Franscesco Borsa, Ilaria Carleo, Riccardo Claudi, Rosario Cosentino, Elvira Covino, Mario Damasso, Silvano Desidera, Paolo Giacobbe, Avet Harutyunyan, Antonino

We present the first detection of atomic emission lines from the atmosphere of an exoplanet. We detect neutral iron lines from the dayside of KELT-9b ( T eq ∼ 4000 K). We combined thousands of spectrally resolved lines observed during one night with the HARPS-N spectrograph ( R ∼ 115,000), mounted at the Telescopio Nazionale Galileo. We introduce a novel statistical approach to extract the planetary

更新日期：2020-05-13
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-13
Ke Zhu, Frédéric Moynier, Martin Schiller, and Martin Bizzarro

Chondrules are major components of chondrites and are believed to drive the accretion of planetary embryos. As such, constraining the timing and origin of chondrules is central for understanding the early evolution of the solar system and the formation of planets. Enstatite chondrites (ECs) have isotope compositions for multiple elements that match that of the Earth and, thus, are considered to be

更新日期：2020-05-13
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-12
Drummond B. Fielding, Eve C. Ostriker, Greg L. Bryan, and Adam S. Jermyn

A common situation in galactic and intergalactic gas involves cold dense gas in motion relative to hot diffuse gas. Kelvin–Helmholtz instability creates a turbulent mixing layer and populates the intermediate-temperature phase, which often cools rapidly. The energy lost to cooling is balanced by the advection of hot high enthalpy gas into the mixing layer, resulting in growth and acceleration of the

更新日期：2020-05-12
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-12
N. Magyar and V. M. Nakariakov

Using full three-dimensional magnetohydrodynamic numerical simulations, we study the effects of magnetic field sigmoidity or helicity on the properties of the fundamental kink oscillation of solar coronal loops. Our model consists of a single denser coronal loop, embedded in a plasma with dipolar force-free magnetic field with a constant α -parameter. For the loop with no sigmoidity, we find that the

更新日期：2020-05-12
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-12

The primary challenge in the study of explosive astrophysical transients is their detection and characterization using multiple messengers. For this purpose, we have developed a new data-driven discovery framework, based on deep learning. We demonstrate its use for searches involving neutrinos, optical supernovae, and gamma-rays. We show that we can match or substantially improve upon the performance

更新日期：2020-05-12
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-11
A. Reid, B. Zhigulin, M. Carlsson, and M. Mathioudakis

We analyze a grid of radiative hydrodynamic simulations of solar flares to study the energy balance and response of the atmosphere to nonthermal electron beam heating. The appearance of chromospheric bubbles is one of the most notable features that we find in the simulations. These pockets of chromospheric plasma get trapped between the transition region and the lower atmosphere as it is superheated

更新日期：2020-05-11
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-11
Xiang-Gao Wang, Long Li, Yuan-Pei Yang, Jia-Wei Luo, Bing Zhang, Da-Bin Lin, En-Wei Liang, and Song-Mei Qin

The physical origin of fast radio bursts (FRBs) is unknown. Young magnetars born from gamma-ray bursts (GRBs) have been suggested as a possible central engine of FRBs. We test such a hypothesis by systematically searching for GRB–FRB spatial associations from 110 FRBs and 1440 GRBs. We find that one FRB event discovered by the Parkes telescope, FRB 171209, is spatially coincident with a historical

更新日期：2020-05-11
• Astrophys. J. Lett. (IF 8.374) Pub Date : 2020-05-07
B. Lavraud, N. Fargette, V. Réville, A. Szabo, J. Huang, A. P. Rouillard, N. Viall, T. D. Phan, J. C. Kasper, S. D. Bale, M. Berthomier, J. W. Bonnell, A. W. Case, T. Dudok de Wit, J. P. Eastwood, V. Génot, K. Goetz, L. S. Griton, J. S Halekas, P. Harvey, R. Kieokaew, K. G. Klein, K. E. Korreck, A. Kouloumvakos, D. E. Larson, M. Lavarra, R. Livi, P. Louarn, R. J. MacDowall, M. Maksimovic, D. Malaspina

We present heliospheric current sheet (HCS) and plasma sheet (HPS) observations during Parker Solar Probe’s (PSP) first orbit around the Sun. We focus on the eight intervals that display a true sector boundary (TSB; based on suprathermal electron pitch angle distributions) with one or several associated current sheets. The analysis shows that (1) the main density enhancements in the vicinity of the

更新日期：2020-05-07
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