Search Publications
The Kinematics of Massive Quiescent Galaxies at 1.4 < z < 2.1: Dark Matter Fractions, IMF Variation, and the Relation to Local Early-type Galaxies
Bender, Ralf; Mendel, J. Trevor; Nelson, Erica J. +10 more
We study the dynamical properties of massive quiescent galaxies at 1.4 < z < 2.1 using deep Hubble Space Telescope WFC3/F160W imaging and a combination of literature stellar velocity dispersion measurements and new near-infrared spectra obtained using the K-band Multi Object Spectrograph (KMOS) on the ESO Very Large Telescope. We use these d…
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of Single and Multiple Stellar Populations in Seven Bulge Globular Clusters
Anderson, J.; Milone, A. P.; Marino, A. F. +23 more
In the present work we analyzed seven globular clusters (GCs) selected from their location in the Galactic bulge and with metallicity values in the range -1.30 ≲ [Fe/H] ≲ -0.50. The aim of this work is first to derive cluster ages assuming single stellar populations and second to identify the stars from first (1G) and second generations (2G) from …
Observations of a GX 301-2 Apastron Flare with the X-Calibur Hard X-Ray Polarimeter Supported by NICER, the Swift XRT and BAT, and Fermi GBM
Lien, A.; Li, S.; Takahashi, H. +28 more
The accretion-powered X-ray pulsar GX 301-2 was observed with the balloon-borne X-Calibur hard X-ray polarimeter during late 2018 December, with contiguous observations by the Neutron star Interior Composition Explorer Mission (NICER) X-ray telescope, the Swift X-ray Telescope and Burst Alert Telescope, and the Fermi Gamma-ray Burst Monitor spanni…
The Nature of Ultra-diffuse Galaxies in Distant Massive Galaxy Clusters: A370 in the Hubble Frontier Fields
Lee, Myung Gyoon; Lee, Jeong Hwan; Kang, Jisu +1 more
We report the discovery of ultra-diffuse galaxies (UDGs) in Abell 370 (A370; z = 0.375). We find 46 UDGs in A370 from the images of the Hubble Frontier Fields. Most UDGs are low-luminosity red sequence galaxies, while a few of them are blue UDGs. We estimate the abundance of UDGs in A370, N(UDG) = 644 ± 104. Combining these results with those of A…
What is the Solar Wind Frame of Reference?
Wimmer-Schweingruber, Robert F.; Matteini, Lorenzo; Berger, Lars +6 more
Various solar wind ion species move with different speeds and theoretical considerations as well as limited observations in a region close to the Sun show that heavy solar wind ions tend to flow faster than protons, at least in less-aged fast solar wind streams. The solar wind flow carries the frozen-in interplanetary magnetic field (IMF) and this…
A 1201 s Orbital Period Detached Binary: The First Double Helium Core White Dwarf LISA Verification Binary
Bergeron, P.; Kilic, Mukremin; Bédard, A. +2 more
We report the discovery of a 1201 s orbital period binary, the third shortest-period detached binary known. Sloan Digital Sky Survey J232230.20 + 050942.06 contains two He-core white dwarfs orbiting with a 27° inclination. Located 0.76 kpc from the Sun, the binary has an estimated Laser Interferometer Space Antenna (LISA) 4 yr signal-to-noise rati…
The Structure of Tidal Disruption Event Host Galaxies on Scales of Tens to Thousands of Parsecs
Zabludoff, Ann I.; French, K. Decker; van Velzen, Sjoert +5 more
We explore the galaxy structure of four tidal disruption event (TDE) host galaxies on 30 pc to kiloparsec scales using Hubble Space Telescope WFC3 multiband imaging. The star formation histories of these hosts are diverse, including one post-starburst galaxy (ASASSN-14li), two hosts with recent weak starbursts (ASASSN-14ae and iPTF15af), and one e…
Strong Soft X-Ray Excess in 2015 XMM-Newton Observations of BL Lac OJ 287
Dewangan, G. C.; Pal, Main; Kushwaha, Pankaj +1 more
We report a strong soft X-ray excess in the BL Lacartae γ-ray blazar OJ 287 during long exposure in 2015 May, among two of the latest XMM-Newton observations performed in 2015 and 2018 May. In the case of the 2015 May observation, a log parabola model fits the EPIC-pn data well, while a log parabola plus a power law describes the overall simultane…
NuSTAR Perspective on High-redshift MeV Blazars
Ajello, M.; Gasparrini, D.; Marchesi, S. +7 more
With bolometric luminosities exceeding 1048 erg s-1, powerful jets, and supermassive black holes at their center, MeV blazars are some of the most extreme sources in the universe. Recently, the Fermi-Large Area Telescope detected five new γ-ray emitting MeV blazars beyond redshift z = 3.1. With the goal of precisely character…
Toward a Direct Measure of the Galactic Acceleration
De Rosa, Robert J.; Huber, Daniel; Rhode, Katherine L. +9 more
High-precision spectrographs can enable not only the discovery of exoplanets, but can also provide a fundamental measurement in Galactic dynamics. Over about 10 year baselines, the expected change in the line-of-sight velocity due to the Galaxy's gravitational field for stars at ∼kiloparsec scale distances above the Galactic midplane is ∼few tens …