Search Publications
Recovering Thermodynamics from Spectral Profiles observed by IRIS: A Machine and Deep Learning Approach
De Pontieu, Bart; Gošić, Milan; Sainz Dalda, Alberto +1 more
Inversion codes allow the reconstruction of a model atmosphere from observations. With the inclusion of optically thick lines that form in the solar chromosphere, such modeling is computationally very expensive because a non-LTE evaluation of the radiation field is required. In this study, we combine the results provided by these traditional metho…
New Constraints From Dust Lines on the Surface Densities of Protoplanetary Disks
Murray-Clay, Ruth; Pérez, Laura M.; Powell, Diana +2 more
We present new determinations of disk surface density, independent of an assumed dust opacity, for a sample of seven bright, diverse, protoplanetary disks using measurements of disk dust lines. We develop a robust method for determining the location of dust lines by modeling disk interferometric visibilities at multiple wavelengths. The disks in o…
Revealing the Stellar Mass and Dust Distributions of Submillimeter Galaxies at Redshift 2
Thomson, A. P.; Magnelli, B.; Ivison, R. J. +35 more
We combine high-resolution ALMA and HST/CANDELS observations of 20 submillimeter galaxies (SMGs), predominantly from the AS2UDS survey at z ≃ 2, with bright rest-frame optical counterparts ({K}{{s}}≲ 22.9) to investigate the resolved structural properties of their dust and stellar components. We derive two-dimensional stellar-mass distr…
High-resolution ALMA Observations of HD 100546: Asymmetric Circumstellar Ring and Circumplanetary Disk Upper Limits
Pineda, Jaime E.; Testi, Leonardo; Garufi, Antonio +7 more
We present long-baseline Atacama Large Millimeter/submillimeter Array observations of the 870 µm dust continuum emission and CO (3-2) from the protoplanetary disk around the Herbig Ae/Be star HD 100546, which is one of the few systems claimed to have two young embedded planets. These observations achieve a resolution of 4 au (3.8 mas), an rm…
The remarkable X-ray variability of IRAS 13224-3809 - I. The variability process
Young, A. J.; Fabian, A. C.; Reynolds, C. S. +17 more
We present a detailed X-ray timing analysis of the highly variable narrow-line Seyfert 1 (NLS1) galaxy IRAS 13224-3809. The source was recently monitored for 1.5 Ms with XMM-Newton, which, combined with 500 ks archival data, makes this the best-studied NLS1 galaxy in X-rays to date. We apply standard time- and Fourier-domain techniques in order to…
New evidence for the ubiquity of prominent polar dust emission in AGN on tens of parsec scales
Asmus, D.
The key ingredient of active galactic nuclei (AGN) unification, the dusty obscuring torus was so far held responsible for the observed mid-infrared (MIR) emission of AGN. However, the best studied objects with Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometric instrument (MIDI) show that instead a polar dusty wind is dominatin…
A Deep View into the Nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. I. Data and Stellar Population Characterization
Kacharov, N.; Böker, T.; Kamann, S. +9 more
The center of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) hosts a nuclear star cluster (NSC), M54, which is the only galaxy nucleus that can be resolved into individual stars at optical wavelengths. It is thus a key target for understanding the formation of NSCs and their relation to globular clusters (GCs). We present a large Multi-Unit Sp…
Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
Nakariakov, V. M.; Kolotkov, D. Y.; Zavershinskii, D. I.
Context. Rapidly decaying slow magnetoacoustic waves are regularly observed in the solar coronal structures, offering a promising tool for a seismological diagnostics of the coronal plasma, including its thermodynamical properties.
Aims: The effect of damping of standing slow magnetoacoustic oscillations in the solar coronal loops is investig…
The CIDA Variability Survey of Orion OB1. II. Demographics of the Young, Low-mass Stellar Populations
Berlind, Perry; Mateo, Mario; Bailey, John I., III +11 more
We present results of our large-scale, optical, multi-epoch photometric survey across ∼180 square degrees in the Orion OB1 association, complemented with extensive follow-up spectroscopy. Our focus is mapping and characterizing the off-cloud, low-mass, pre-main-sequence (PMS) populations. We report 2062 K- and M-type confirmed T Tauri members; 59%…
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2. I. Binarity from proper motion anomaly
Mérand, Antoine; Gieren, Wolfgang; Gallenne, Alexandre +8 more
Context. Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important classes of variable stars used as standard candles to estimate galactic and extragalactic distances. Their multiplicity is imperfectly known, particularly for RRLs. Astoundingly, to date only one RRL has convincingly been demonstrated to be a binary, TU UMa, out of tens of t…