Search Publications
The Optical-Mid-infrared Extinction Law of the l = 165° Sightline in the Galactic Plane: Diversity of the Extinction Law in the Diffuse Interstellar Medium
Wang, Shu; de Grijs, Richard; Zhao, He +2 more
Understanding the effects of dust extinction is important to properly interpret observations. The optical total-to-selective extinction ratio, {R}V={A}V/E(B-V), is widely used to describe extinction variations in ultraviolet and optical bands. Since the {R}V=3.1 extinction curve adequately represents the average ex…
The Hard X-Ray Emission of the Blazar PKS 2155-304
Misra, R.; Dewangan, G. C.; Gaur, Haritma +4 more
The synchrotron peak of the X-ray bright High Energy Peaked Blazar PKS 2155-304 occurs in the UV-EUV region and hence its X-ray emission (0.6-10 keV) lies mostly in the falling part of the synchrotron hump. We aim to study the X-ray emission of PKS 2155-304 during different intensity states in 2009-2014 using the XMM-Newton satellite. We studied t…
Deep HST Imaging in 47 Tucanae: A Global Dynamical Model
Anderson, J.; Heyl, J.; Kalirai, J. +3 more
Multi-epoch observations with the Advanced Camera Survey and WFC3 on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within 47 Tucanae. We confront analytic models of the globular cluster with the observed stellar proper motions that probe along the main sequence from just above 0.8-0.1M ⊙ as well…
The Class 0 Protostar BHR71: Herschel Observations and Dust Continuum Models
Dunham, Michael M.; Green, Joel D.; Yang, Yao-Lun +2 more
We use Herschel spectrophotometry of BHR71, an embedded Class 0 protostar, to provide new constraints on its physical properties. We detect 645 (non-unique) spectral lines among all spatial pixels. At least 61 different spectral lines originate from the central region. A CO rotational diagram analysis shows four excitation temperature components, …
Proper Motions and Structural Parameters of the Galactic Globular Cluster M71
Dalessandro, E.; Massari, D.; Ferraro, F. R. +4 more
By exploiting two ACS/HST data sets separated by a temporal baseline of ∼7 years, we have determined the relative stellar proper motions (PMs; providing membership) and the absolute PM of the Galactic globular cluster M71. The absolute PM has been used to reconstruct the cluster orbit within a Galactic, three-component, axisymmetric potential. M71…
Lyα Absorbers and the Coma Cluster
Yoon, Joo Heon; Putman, M. E.
The spatial and kinematic distribution of warm gas in and around the Coma Cluster is presented through observations of Lyα absorbers using background QSOs. Updates to the Lyα absorber distribution found in Yoon et al. for the Virgo Cluster are also presented. At 0.2-2.0R vir of Coma we identify 14 Lyα absorbers ({N}{{H}{{I}}}…
Individual, Model-independent Masses of the Closest Known Brown Dwarf Binary to the Sun
Lu, Jessica R.; Kalas, Paul; De Rosa, Robert J. +18 more
At a distance of ∼2 pc, our nearest brown dwarf neighbor, Luhman 16 AB, has been extensively studied since its discovery 3 years ago, yet its most fundamental parameter—the masses of the individual dwarfs—has not been constrained with precision. In this work, we present the full astrometric orbit and barycentric motion of Luhman 16 AB and the firs…
Discovery of a Satellite of the Large Trans-Neptunian Object (225088) 2007 OR10
Pál, András; Vinkó, József; Marton, Gábor +6 more
2007 OR10 is currently the third largest known dwarf planet in the trans-Neptunian region, with an effective radiometric diameter of ∼1535 km. It has a slow rotation period of ∼45 hr that was suspected to be caused by tidal interactions with a satellite undetected at that time. Here, we report on the discovery of a likely moon of 2007 O…
Tycho-Gaia Astrometric Solution Parallaxes and Proper Motions for Five Galactic Globular Clusters
van der Marel, Roeland P.; Watkins, Laura L.
We present a pilot study of Galactic globular cluster (GC) proper motion (PM) determinations using Gaia data. We search for GC stars in the Tycho-Gaia Astrometric Solution (TGAS) catalog from Gaia Data Release 1 (DR1), and identify five members of NGC 104 (47 Tucanae), one member of NGC 5272 (M3), five members of NGC 6121 (M4), seven members of NG…
Toward the Understanding of the Physical Origin of Recombining Plasma in the Supernova Remnant IC 443
Uchida, Hiroyuki; Tsuru, Takeshi Go; Tanaka, Takaaki +2 more
We perform a spatially resolved spectroscopic analysis of X-ray emission from the supernova remnant (SNR) IC 443 with Suzaku. All of the spectra are well reproduced by a model consisting of a collisional ionization equilibrium (CIE) and two recombining plasma (RP) components. Although previous X-ray studies found an RP in the northeastern region, …