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Insight-HXMT, NuSTAR, and INTEGRAL Data Show Disk Truncation in the Hard State of the Black Hole X-Ray Binary MAXI J1820+070
Zdziarski, Andrzej A.; You, Bei; Szanecki, Michał +2 more
We study X-ray and soft gamma-ray spectra from the hard state of the accreting black hole binary MAXI J1820+070. We perform an analysis of joint spectra from HXMT, NuSTAR, and INTEGRAL. We find an overall agreement between the spectra from all three satellites. Satisfactory fits to the data require substantial spectral complexity, with our models …
VLT/MUSE Observations of SDSS J1029+2623: Toward a High-precision Strong Lensing Model
Brammer, Gabriel B.; Acebron, Ana; Nonino, Mario +9 more
We present a strong lensing analysis of the galaxy cluster SDSS J1029+2623 at z = 0.588, one of the few currently known lens clusters with multiple images of a background (z = 2.1992) quasar with a measured time delay. We use archival Hubble Space Telescope multiband imaging and new Multi Unit Spectroscopic Explorer follow-up spectroscopy to build…
Turbulence in Milky Way Star-forming Regions Traced by Young Stars and Gas
Kounkel, Marina; Li, Hui; Zheng, Yong +3 more
The interstellar medium (ISM) is turbulent over vast scales and in various phases. In this paper, we study turbulence with different tracers in four nearby star-forming regions: Orion, Ophiuchus, Perseus, and Taurus. We combine the APOGEE-2 and Gaia surveys to obtain the full six-dimensional measurements of positions and velocities of young stars …
Residual Abundances in GALAH DR3: Implications for Nucleosynthesis and Identification of Unique Stellar Populations
Buder, Sven; Weinberg, David H.; Johnson, Jennifer A. +3 more
We investigate the [X/Mg] abundances of 16 elements for 82,910 Galactic disk stars from GALAH+ DR3. We fit the median trends of low-Ia and high-Ia populations with a two-process model, which describes stellar abundances in terms of a prompt core-collapse and delayed Type-Ia supernova component. For each sample star, we fit the amplitudes of these …
Causes and Consequences of Magnetic Complexity Changes within Interplanetary Coronal Mass Ejections: A Statistical Study
Lugaz, Noé; Scolini, Camilla; Winslow, Réka M. +3 more
We present the first statistical analysis of complexity changes affecting the magnetic structure of interplanetary coronal mass ejections (ICMEs), with the aim of answering the questions: How frequently do ICMEs undergo magnetic complexity changes during propagation? What are the causes of such changes? Do the in situ properties of ICMEs differ de…
Current Challenges in Cepheid Distance Calibrations Using Gaia Early Data Release 3
Madore, Barry F.; Freedman, Wendy L.; Lee, Abigail J. +1 more
Using parallaxes from Gaia Early Data Release 3 (EDR3), we determine multi-wavelength BVI c , JHK s , and [3.6] and [4.5] micron absolute magnitudes for 37 nearby Milky Way Cepheids, covering the period range between 5 and 60 days. We apply these period-luminosity relations to Cepheids in the Large and Small Magellanic Clou…
Wide Twin Binaries are Extremely Eccentric: Evidence of Twin Binary Formation in Circumbinary Disks
Ting, Yuan-Sen; Rix, Hans-Walter; Zakamska, Nadia L. +3 more
The Gaia mission recently revealed an excess population of equal-mass "twin" wide binaries, with mass ratio q ≳ 0.95, extending to separations of at least 1000 au. The origin of this population is an enigma: Twin binaries are thought to form via correlated accretion in circumbinary disks, but the typical observed protostellar disks have radii of ~…
Contribution of Gaia Sausage to the Galactic Stellar Halo Revealed by K Giants and Blue Horizontal Branch Stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan Digital Sky Survey, and Gaia
Bird, Sarah A.; Zhao, Gang; Yang, Chengqun +2 more
We explore the contribution of the Gaia Sausage to the stellar halo of the Milky Way by making use of a Gaussian mixture model (GMM) and applying it to halo star samples of Large Sky Area Multi-Object Fiber Spectroscopic Telescope K giants, Sloan Extension for Galactic Understanding and Exploration K giants, and Sloan Digital Sky Survey blue horiz…
Dissecting the Different Components of the Modest Accretion Bursts of the Very Young Protostar HOPS 373
Herczeg, Gregory J.; Manoj, P.; Johnstone, Doug +11 more
Observed changes in protostellar brightness can be complicated to interpret. In our James Clerk Maxwell Telescope (JCMT) Transient Monitoring Survey, we discovered that a young binary protostar, HOPS 373, is undergoing a modest 30% brightness increase at 850 µm, caused by a factor of 1.8-3.3 enhancement in the accretion rate. The initial bur…
Searching Far and Long. I. Pilot ALMA 2 mm Follow-up of Bright Dusty Galaxies as a Redshift Filter
Casey, Caitlin M.; Long, Arianna S.; Zavala, Jorge A. +5 more
A complete census of dusty star-forming galaxies (DSFGs) at early epochs is necessary to constrain the obscured contribution to the cosmic star formation rate density (CSFRD); however, DSFGs beyond z ~ 4 are both rare and hard to identify from photometric data alone due to degeneracies in submillimeter photometry with redshift. Here, we present a …