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A New Look at an Old Cluster: The Membership, Rotation, and Magnetic Activity of Low-mass Stars in the 1.3 Gyr Old Open Cluster NGC 752
Kraus, A.; Bochanski, J. J.; Covey, K. R. +8 more
The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1 Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf members earlier than mid-K. We supplement past membership catalogs with candidates selected with updated phot…
Hidden in Plain Sight: A Massive, Dusty Starburst in a Galaxy Protocluster at z = 5.7 in the COSMOS Field
Schinnerer, Eva; Scoville, Nick; Carilli, Christopher L. +7 more
We report the serendipitous discovery of a dusty, starbursting galaxy at z = 5.667 (hereafter called CRLE) in close physical association with the “normal” main-sequence galaxy HZ10 at z = 5.654. CRLE was identified by detection of [C II], [N II], and CO(2-1) line emission, making it the highest-redshift, most luminous starburst in the COSMOS field…
Absolute Hubble Space Telescope Proper Motion (HSTPROMO) of Distant Milky Way Globular Clusters: Galactocentric Space Velocities and the Milky Way Mass
van der Marel, Roeland P.; Watkins, Laura L.; Bellini, Andrea +4 more
We present Hubble Space Telescope (HST) absolute proper motion (PM) measurements for 20 globular clusters (GCs) in the Milky Way (MW) halo at Galactocentric distances {R}GC}≈ 10{--}100 kpc, with a median per-coordinate PM uncertainty of 0.06 {mas} {yr}}-1. Young and old halo GCs do not show systematic differences in their 3D …
The First Tidally Disrupted Ultra-faint Dwarf Galaxy?: A Spectroscopic Analysis of the Tucana III Stream
Bechtol, K.; Smith, M.; D'Andrea, C. B. +69 more
We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucana III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member …
Spiral Arms in Disks: Planets or Gravitational Instability?
Dong, Ruobing; Najita, Joan R.; Brittain, Sean
Spiral arm structures seen in scattered-light observations of protoplanetary disks can potentially serve as signposts of planetary companions. They can also lend unique insights into disk masses, which are critical in setting the mass budget for planet formation but are difficult to determine directly. A surprisingly high fraction of disks that ha…
Frequently Occurring Reconnection Jets from Sunspot Light Bridges
Solanki, Sami K.; Ni, Lei; Chen, Yajie +12 more
Solid evidence of magnetic reconnection is rarely reported within sunspots, the darkest regions with the strongest magnetic fields and lowest temperatures in the solar atmosphere. Using the world’s largest solar telescope, the 1.6 m Goode Solar Telescope, we detect prevalent reconnection through frequently occurring fine-scale jets in the Hα line …
A Close Relationship between Lyα and Mg II in Green Pea Galaxies
Verhamme, Anne; Scarlata, Claudia; Henry, Alaina +2 more
The Mg II λλ2796, 2803 doublet is often used to measure interstellar medium absorption in galaxies, thereby serving as a diagnostic for feedback and outflows. However, the interpretation of Mg II remains confusing, due to resonant trapping and re-emission of the photons, analogous to Lyα. Therefore, in this paper, we present new MMT Blue Channel S…
Kronos and Krios: Evidence for Accretion of a Massive, Rocky Planetary System in a Comoving Pair of Solar-type Stars
Hogg, David W.; Price-Whelan, Adrian M.; Spergel, David N. +3 more
We report and discuss the discovery of a significant difference in the chemical abundances of a comoving pair of bright solar-type stars, HD 240430 and HD 240429. The two stars have an estimated 3D separation of ≈0.6 pc (≈0.01 pc projected) at a distance of r ≈ 100 pc with nearly identical 3D velocities, as inferred from Gaia TGAS parallaxes and p…
Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Cluster. VI. Improved Data Reduction and Internal-kinematic Analysis of NGC 362
Vesperini, Enrico; Anderson, Jay; Ferraro, Francesco R. +6 more
We present an improved data-reduction technique to obtain high-precision proper motions (PMs) of globular clusters (GCs) using Hubble Space Telescope data. The new reduction is superior to the one presented in the first paper of this series for the faintest sources in very crowded fields. We choose the GC NGC 362 as a benchmark to test our new pro…
Black Hole-Galaxy Scaling Relationships for Active Galactic Nuclei with Reverberation Masses
Bentz, Misty C.; Manne-Nicholas, Emily
We have utilized high-resolution optical Hubble Space Telescope images and deep, ground-based near-infrared images to examine the host galaxies of 37 active galactic nuclei (AGNs) with reverberation-based black hole masses. Using two-dimensional image decompositions, we have separated the host galaxy from the bright central AGN, allowing a re-exam…