Search Publications
Galaxy cluster mergers as triggers for the formation of jellyfish galaxies: case study of the A901/2 system
Chies-Santos, Ana L.; Lima Neto, Gastão B.; Roman-Oliveira, Fernanda V. +4 more
The A901/2 system is a rare case of galaxy cluster interaction, in which two galaxy clusters and two smaller groups are seen in route of collision with each other simultaneously. Within each of the four substructures, several galaxies with features indicative of jellyfish morphologies have been observed. In this paper, we propose a hydrodynamic mo…
Galactocentric acceleration in VLBI analysis. Findings of IVS WG8
Gipson, J. M.; Gordon, D.; MacMillan, D. S. +8 more
Aims: The IVS Working Group on Galactic Aberration (WG8) was established to investigate issues related to incorporating the effect of Galactic aberration in IVS analysis. The circular motion of the solar system barycenter around the Galactic center causes a change in aberration, which in the case of geodetic VLBI observing is over time scales…
Gaia 19ajj: A Young Star Brightening Due to Enhanced Accretion and Reduced Extinction
Hillenbrand, Lynne A.; Reipurth, Bo; Isaacson, Howard +2 more
We report on the source Gaia 19ajj, identifying it as a young star associated with a little-studied star-forming region seen along a complex line of sight through the Gum Nebula. The optical lightcurve recently recorded by Gaia exhibits a slow and unsteady 5.5 mag rise over about 3 yr, while the mid-infrared lightcurve from NEOWISE over the same t…
Transiting Planets Near the Snow Line from Kepler. I. Catalog
Kawahara, Hajime; Masuda, Kento
We present a comprehensive catalog of cool (period P ≳ 2 yr) transiting planet candidates in the 4 yr light curves from the prime Kepler mission. Most of the candidates show only one or two transits and have largely been missed in the original Kepler Object of Interest catalog. Our catalog is based on all known such candidates in the literature, a…
On the Orbital Decay of Globular Clusters in NGC 1052-DF2: Testing a Baryon-only Mass Model
van den Bosch, Frank C.; van Dokkum, Pieter; Dutta Chowdhury, Dhruba
The dark matter content of the ultra-diffuse galaxy NGC 1052-DF2, as inferred from globular cluster (GC) and stellar kinematics, carries a considerable amount of uncertainty, with current constraints also allowing for the complete absence of dark matter. We test the viability of such a scenario by examining whether in a “baryon-only” mass model th…
The brightening of the pulsar wind nebula of PSR B0540-69 after its spin-down-rate transition
Wang, Q. D.; Zhang, S. N.; Ge, M. Y. +6 more
It is believed that an isolated pulsar loses its rotational energy mainly through a relativistic wind consisting of electrons, positrons and possibly Poynting flux1-3. As it expands, this wind may eventually be terminated by a shock, where particles can be accelerated to energies of X-ray synchrotron emission, and a pulsar wind nebula (…
Estimating stellar ages and metallicities from parallaxes and broadband photometry: successes and shortcomings
Feltzing, Sofia; Howes, Louise M.; Lindegren, Lennart +2 more
A deep understanding of the Milky Way galaxy, its formation and evolution requires observations of huge numbers of stars. Stellar photometry, therefore, provides an economical method to obtain intrinsic stellar parameters. With the addition of distance information - a prospect made real for more than a billion stars with the second Gaia data relea…
The orbital anisotropy profiles of nearby globular clusters from Gaia Data Release 2
Bovy, Jo; Webb, Jeremy J.; Jindal, Abhinav
Gaia Data Release 2 provides a wealth of data to study the internal structure of nearby globular clusters (GCs). We use this data to investigate the internal kinematics of 10 nearby GCs, with a particular focus on their poorly studied outer regions. We apply a strict set of selection criteria to remove contaminating sources and create pure cluster…
Testing Shear Recovery with Field Distortion
Zhang, Jun; Li, Xiangchong; Luo, Wentao +7 more
The tilt, rotation, or offset of each CCD with respect to the focal plane, as well as the distortion of the focal plane itself, causes shape distortions in the observed objects, an effect typically known as field distortion (FD). We point out that FD provides a unique way of quantifying the accuracy of cosmic shear measurement. The idea is to stac…
The Effect of Binarity on Circumstellar Disk Evolution
Hinkley, Sasha; Rizzuto, Aaron C.; Kraus, Adam L. +6 more
We present new results on how the presence of stellar companions affects disk evolution based on a study of the 5-11 Myr old Upper Scorpius OB Association. Of the 50 G0-M3 Upper Sco members with disks in our sample, only seven host a stellar companion within 2″ and brighter than K = 15, compared to 35 of 75 members without disks. This matches a tr…