Search Publications
Long-lived Protoplanetary Disks in Multiple Systems: The VLA View of HD 98800
Duchêne, Gaspard; Ribas, Álvaro; Espaillat, Catherine C. +1 more
The conditions and evolution of protoplanetary disks in multiple systems can be considerably different from those around single stars, which may have important consequences for planet formation. We present Very Large Array (VLA) 8.8 mm (34 GHz) and 5 cm (6 GHz) observations of the quadruple system HD 98800, which consists of two spectroscopic bina…
Detection of an Optical/UV Jet/Counterjet and Multiple Spectral Components in M84
Sparks, William B.; Georganopoulos, Markos; Chiaberge, Marco +3 more
We report an optical/UV jet and counterjet in M84, previously unreported in archival Hubble Space Telescope imaging. With archival VLA, ALMA, and Chandra imaging, we examine the first well-sampled spectral energy distribution of the inner jet of M84, where we find that multiple co-spatial spectral components are required. In particular, the ALMA d…
X-Ray Properties of AGN in Brightest Cluster Galaxies. I. A Systematic Study of the Chandra Archive in the 0.2 < z < 0.3 and 0.55 < z < 0.75 Redshift Range
Risaliti, Guido; Lusso, Elisabeta; Nardini, Emanuele +5 more
We present a search for nuclear X-ray emission in the brightest cluster galaxies (BCGs) of a sample of groups and clusters of galaxies extracted from the Chandra archive. The exquisite angular resolution of Chandra allows us to obtain robust photometry at the position of the BCG, and to firmly identify unresolved X-ray emission when present, thank…
Broadband X-Ray Spectral Analysis of the Double-nucleus Luminous Infrared Galaxy Mrk 463
Imanishi, Masatoshi; Tanimoto, Atsushi; Ueda, Yoshihiro +4 more
We present a broadband (0.4-70 keV) X-ray spectral analysis of the luminous infrared galaxy (LIRG) system Mrk 463 observed with Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton, which contains double active galactic nuclei (AGNs; Mrk 463E and Mrk 463W) with a separation of ∼3.8 kpc. Detecting their transmitted hard X-ray >…
Can a Bright and Energetic X-Ray Pulsar Be Hiding Amid the Debris of SN 1987A?
Esposito, Paolo; Rea, Nanda; Matsuura, Mikako +3 more
The mass of the stellar precursor of supernova (SN) 1987A and the burst of neutrinos observed at the moment of the explosion are consistent with the core-collapse formation of a neutron star. However, no compelling evidence for the presence of a compact object of any kind in SN 1987A has been found yet in any band of the electromagnetic spectrum, …
Constraints on Cosmic-ray Acceleration Efficiency in Balmer Shocks of Two Young Type Ia Supernova Remnants in the Large Magellanic Cloud
Hughes, John P.; Pandya, Viraj; McCully, Curtis +2 more
We present results from an optical study of two young Balmer-dominated remnants of SNIa in the Large Magellanic Cloud, 0509-67.5 and 0519-69.0, in an attempt to search for signatures of efficient cosmic-ray (CR) acceleration. We combine proper motion measurements with corresponding optical spectroscopic measurements of the Hα line at multiple rim …
On the Apparent Absence of Wolf-Rayet+Neutron Star Systems: The Curious Case of WR124
Hamann, W. -R.; Chu, Y. -H.; Guerrero, M. A. +8 more
Among the different types of massive stars in advanced evolutionary stages is the enigmatic WN8h type. There are only a few Wolf-Rayet (WR) stars with this spectral type in our Galaxy. It has long been suggested that WN8h-type stars are the products of binary evolution that may harbor neutron stars (NS). One of the most intriguing WN8h stars is th…
Star Cluster Ages in the Gaia Era
Choi, Jieun; Conroy, Charlie; Ting, Yuan-Sen +3 more
We use the framework developed as part of the MESA Isochrones and Stellar Tracks (MIST) project to assess the utility of several types of observables in jointly measuring the age and 1D stellar model parameters in star clusters. We begin with a pedagogical overview summarizing the effects of stellar model parameters, such as the helium abundance, …
The Triggering of the 2014 March 29 Filament Eruption
Harra, Louise K.; Matthews, Sarah A.; Kusano, Kanya +3 more
The X1 flare and associated filament eruption occurring in NOAA Active Region 12017 on SOL2014-03-29 has been a source of intense study. In this work, we analyze the results of a series of nonlinear force-free field extrapolations of the flare’s pre- and post-flare periods. In combination with observational data provided by the IRIS, Hinode, and S…
Stellar Populations in the Outer Disk and Halo of the Spiral Galaxy M101
Mihos, J. Christopher; Harding, Paul; Durrell, Patrick R. +2 more
We use deep Hubble Space Telescope imaging in the outskirts of the nearby spiral M101 to study stellar populations in the galaxy’s outer disk and halo. Our Advanced Camera for Surveys (ACS) field lies 17.‧6 (36 kpc) from the center of M101 and targets the blue “NE Plume” of M101's outer disk, while the parallel Wide Field Camera 3 (WFC3) field lie…