Search Publications
The Pisces Plume and the Magellanic wake
Carballo-Bello, Julio A.; Erkal, Denis; Belokurov, Vasily +5 more
Using RR Lyrae stars in the Gaia Data Release 2 and Pan-STARRS1 we study the properties of the Pisces overdensity, a diffuse substructure in the outer halo of the Milky Way. We show that along the line of sight, Pisces appears as a broad and long plume of stars stretching from 40 to 110 kpc with a steep distance gradient. On the sky Pisces's elong…
Millimeter Mapping at z ∼ 1: Dust-obscured Bulge Building and Disk Growth
Übler, Hannah; Price, Sedona H.; Belli, Sirio +16 more
A randomly chosen star in today’s universe is most likely to live in a galaxy with stellar mass between the Milky Way and Andromeda. It remains uncertain, however, how the structural evolution of these bulge-disk systems proceeded. Most of the unobscured star formation we observe by building Andromeda progenitor s at 0.7 < z < 1.5 occurs in …
Testing Systematics of Gaia DR2 Parallaxes with Empirical Surface Brightness: Color Relations Applied to Eclipsing Binaries
Breuval, Louise; Gieren, Wolfgang; Pietrzyński, Grzegorz +18 more
Using a sample of 81 galactic, detached eclipsing binary stars we investigated the global zero-point shift of their parallaxes with the Gaia Data Release 2 (DR2) parallaxes. The stars in the sample lay in a distance range of 0.04-2 kpc from the Sun. The photometric parallaxes ϖ Phot of the eclipsing binaries were determined by applying …
Anatomy of a Cooling Flow: The Feedback Response to Pure Cooling in the Core of the Phoenix Cluster
Sharon, K.; Gladders, M. D.; Gaspari, M. +17 more
We present new, deep observations of the Phoenix cluster from Chandra, the Hubble Space Telescope, and the Karl Jansky Very Large Array. These data provide an order-of-magnitude improvement in depth and/or angular resolution over previous observations at X-ray, optical, and radio wavelengths. We find that the one-dimensional temperature and entrop…
Lessons from the curious case of the `fastest' star in Gaia DR2
Evans, N. W.; Koposov, S. E.; Seabroke, G. +6 more
Gaia DR2 5932173855446728064 was recently proposed to be unbound from the Milky Way based on the -614.3± 2.5 km s^{-1} median radial velocity given in Gaia DR2. We obtained eight epochs of spectroscopic follow-up and find a very different median radial velocity of -56.5 ± 5.3 km s^{-1}. If this difference were to be explained by binarity, then the…
The Ultracool SpeXtroscopic Survey. I. Volume-limited Spectroscopic Sample and Luminosity Function of M7-L5 Ultracool Dwarfs
Burgasser, Adam J.; Faherty, Jacqueline K.; Gagné, Jonathan +9 more
We present a volume-limited, spectroscopically verified sample of M7-L5 ultracool dwarfs (UCDs) within 25 pc. The sample contains 410 sources, of which 93% have trigonometric distance measurements (80% from Gaia DR2) and 81% have low-resolution (R ∼ 120), near-infrared (NIR) spectroscopy. We also present an additional list of 60 sources that may b…
The Gaia ultracool dwarf sample - II. Structure at the end of the main sequence
Caballero, J. A.; Sarro, L. M.; Marocco, F. +4 more
We identify and investigate known late M, L, and T dwarfs in the Gaia second data release. This sample is being used as a training set in the Gaia data processing chain of the ultracool dwarfs work package. We find 695 objects in the optical spectral range M8-T6 with accurate Gaia coordinates, proper motions, and parallaxes which we combine with p…
Testing asteroseismology with Gaia DR2: hierarchical models of the Red Clump
Chaplin, William J.; Davies, Guy R.; García, Rafael A. +8 more
Asteroseismology provides fundamental stellar parameters independent of distance, but subject to systematics under calibration. Gaia DR2 has provided parallaxes for a billion stars, which are offset by a parallax zero-point (ϖzp). Red Clump (RC) stars have a narrow spread in luminosity, thus functioning as standard candles to calibrate …
On the dynamics of the Small Magellanic Cloud through high-resolution ASKAP H I observations
McClure-Griffiths, N. M.; Dickey, John M.; Staveley-Smith, L. +10 more
We use new high-resolution H I data from the Australian Square Kilometre Array Pathfinder to investigate the dynamics of the Small Magellanic Cloud (SMC). We model the H I gas component as a rotating disc of non-negligible angular size, moving into the plane of the sky, and undergoing nutation/precession motions. We derive a high-resolution (∼10 p…
Radial Variations in Grain Sizes and Dust Scale Heights in the Protoplanetary Disk around HD 163296 Revealed by ALMA Polarization Observations
Kataoka, Akimasa; Ohashi, Satoshi
The disk of HD 163296 shows ring and gap substructures in observations with the Atacama Large Millimeter/submillimeter Array. In addition, this is the only disk where the rings and gaps are spatially resolved in millimeter-wave polarization measurements. In this paper, we conduct radiative transfer modeling that includes self-scattering polarizati…