Search Publications
Abundance Analysis of Stars at Large Radius in the Sextans Dwarf Spheroidal Galaxy
Caldwell, Nelson; Placco, Vinicius M.; Mateo, Mario +5 more
We present the stellar parameters and chemical abundances of 30 elements for five stars located at large radii (3.5-10.7 times the half-light radius) in the Sextans dwarf spheroidal galaxy. We selected these stars using proper motions, radial velocities, and metallicities, and we confirm them as metal-poor members of Sextans with -3.34 ≤ [Fe/H] ≤ …
Reanalysis of the X-Ray-burst-associated FRB 200428 with Insight-HXMT Observations
Zhang, S.; Zhang, S. N.; Dai, Z. G. +15 more
A double-peak X-ray burst from the Galactic magnetar SGR J1935+2154 was discovered to be associated with the two radio pulses of FRB 200428 separated by 28.97 ± 0.02 ms. Precise measurements of the timing and spectral properties of the X-ray bursts are helpful for understanding the physical origin of fast radio bursts. In this paper, we have recon…
Giant Impacts and Debris Disk Morphology
Duchêne, Gaspard; Esposito, Thomas M.; Kalas, Paul +2 more
Certain debris disks have nonaxisymmetric shapes in scattered light which are unexplained. The appearance of a disk depends on how its constituent Keplerian ellipses are arranged. The more the ellipses align apsidally, the more nonaxisymmetric the disk. Apsidal alignment is automatic for fragments released from a catastrophic collision between sol…
Multipoint study of the energy release and transport in the 28 March 2022, M4 flare using STIX, EUI, and AIA during the first Solar Orbiter nominal mission perihelion
Krucker, Säm; Veronig, Astrid M.; Dissauer, Karin +8 more
Context. The Spectrometer Telescope for Imaging X-rays (STIX) on board Solar Orbiter enables exciting multipoint studies of energy release and transport in solar flares by observing the Sun from many different distances and vantage points out of the Sun-Earth line.
Aims: We present a case study of an M4-class flare that occurred on 28 March 2…
A Catalog of Distance Determinations for the LAMOST DR8 K Giants in the Galactic Halo
Zhao, Gang; Rix, Hans-Walter; Yang, Chengqun +4 more
We present a catalog of distances for 19,544 K giants drawn from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR8. Most of them are located in the halo of the Milky Way up to ~120 kpc. There are 15% K giants without Sloan Digital Sky Survey (SDSS) photometry, for which we supplements with Pan-STARRS1 (PS1) photometry calibrat…
The VISCACHA survey. VIII. Chemical evolution history of the Small Magellanic Cloud west halo clusters
Minniti, D.; Bica, E.; Maia, F. +12 more
The chemical evolution history of the Small Magellanic Cloud (SMC) has been a matter of debate for decades. The challenges in understanding the SMC chemical evolution are related to a very slow star formation rate (SFR) combined with bursts triggered by the multiple interactions between the SMC and the Large Magellanic Cloud, a significant (∼0.5 d…
Disintegration of Long-period Comet C/2021 A1 (Leonard)
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
We present imaging observations of the disintegrating long-period comet C/2021 A1 (Leonard). High-resolution observations with the Hubble Space Telescope show no evidence for surviving fragments, and place a 3σ upper limit on their possible radius of ~60 m (albedo 0.1 assumed). In contrast, wide-field observations from the Swan Hill Observatory, A…
The structural properties of multiple populations in the dynamically young globular cluster NGC 2419
Vesperini, Enrico; Cadelano, Mario; Dalessandro, Emanuele +3 more
NGC 2419 is likely the globular cluster (GC) with the lowest dynamical age in the Galaxy. This makes it an extremely interesting target for studying the properties of its multiple populations (MPs), as they are likely to have been affected only modestly by long-term dynamical evolution effects. Here we present for the first time a detailed analysi…
Searching for the warm-hot intergalactic medium using XMM-Newton high-resolution X-ray spectra
Churazov, E.; Kallman, T. R.; García, Javier A. +1 more
The problem of missing baryons in the local universe remains an open question. One proposed alternative is that at low redshifts missing baryons are in the form of the warm-hot intergalactic medium (WHIM). In order to test this idea, we present a detailed analysis of X-ray high-resolution spectra of six extragalactic sources, Mrk 421, 1ES 1028+511…
In-flight validation of the Metis visible-light polarimeter coronagraph on board Solar Orbiter
Sasso, C.; Romoli, M.; Andretta, V. +21 more
Context. The Metis coronagraph is one of the remote sensing instruments of the ESA-NASA Solar Orbiter mission. The goal for the instrument is to enable the study of the solar atmosphere and solar wind by simultaneously acquiring images of the solar corona at two different wavelengths: visible light (VL), within a band ranging from 580 nm to 640 nm…