Search Publications
A Binary Progenitor for the Type IIb Supernova 2011dh in M51
Nomoto, Ken'ichi; Bersten, Melina C.; Benvenuto, Omar G.
We perform binary stellar evolutionary calculations following the simultaneous evolution of both stars in the system to study a potential progenitor system for the Type IIb supernova 2011dh. Pre-explosion photometry as well as light-curve modeling has provided constraints on the physical properties of the progenitor system. Here, we present a clos…
Chandra X-Ray and Hubble Space Telescope Imaging of Optically Selected Kiloparsec-scale Binary Active Galactic Nuclei. I. Nature of the Nuclear Ionizing Sources
Shen, Yue; Strauss, Michael A.; Greene, Jenny E. +3 more
Kiloparsec-scale binary active galactic nuclei (AGNs) signal active supermassive black hole (SMBH) pairs in merging galaxies. Despite their significance, unambiguously confirmed cases remain scarce and most have been discovered serendipitously. In a previous systematic search, we optically identified four kpc-scale binary AGNs from candidates sele…
Shock-enhanced C+ Emission and the Detection of H2O from the Stephan's Quintet Group-wide Shock Using Herschel
Sturm, E.; Boulanger, F.; Falgarone, E. +20 more
We present the first Herschel spectroscopic detections of the [O I] 63 µm and [C II] 158 µm fine-structure transitions, and a single para-H2O line from the 35 × 15 kpc2 shocked intergalactic filament in Stephan's Quintet. The filament is believed to have been formed when a high-speed intruder to the group collided…
A Dynamical Signature of Multiple Stellar Populations in 47 Tucanae
Anderson, Jay; Dotter, Aaron; Rich, R. Michael +5 more
Based on the width of its main sequence, and an actual observed split when viewed through particular filters, it is widely accepted that 47 Tucanae contains multiple stellar populations. In this contribution, we divide the main sequence of 47 Tuc into four color groups, which presumably represent stars of various chemical compositions. The kinemat…
The Collisional Evolution of Debris Disks
Rieke, George H.; Gáspár, András; Balog, Zoltán
We explore the collisional decay of disk mass and infrared emission in debris disks. With models, we show that the rate of the decay varies throughout the evolution of the disks, increasing its rate up to a certain point, which is followed by a leveling off to a slower value. The total disk mass falls off vpropt -0.35 at its fastest poi…
Transit Observations of the Hot Jupiter HD 189733b at X-Ray Wavelengths
Schmitt, J. H. M. M.; Poppenhaeger, K.; Wolk, S. J.
We present new X-ray observations obtained with Chandra ACIS-S of the HD 189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter and an M-type stellar companion. We report a detection of the planetary transit in soft X-rays with a significantly deeper transit depth than observed in the optical. The X-ray data favor a transit…
Distance and Kinematics of the TW Hydrae Association from Parallaxes
Weinberger, Alycia J.; Anglada-Escudé, Guillem; Boss, Alan P.
From common proper motion and signatures of youth, researchers have identified about 30 members of a putative TW Hydrae Association. Only four of these had parallactic distances from Hipparcos. We have measured parallaxes and proper motions for 14 primary members. We combine these with literature values of radial velocities to show that the Galact…
The 0.5-2.22 µm Scattered Light Spectrum of the Disk around TW Hya: Detection of a Partially Filled Disk Gap at 80 AU
Weinberger, Alycia J.; Debes, John H.; Roberge, Aki +2 more
We present a 0.5-2.2 µm scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances >40 AU over this wide range of wavelengths, and identify the presence…
The Structure, Origin, and Evolution of Interstellar Hydrocarbon Grains
Tielens, A. G. G. M.; Chiar, J. E.; Ricca, A. +1 more
Many materials have been considered for the carrier of the hydrocarbon absorption bands observed in the diffuse interstellar medium (ISM). In order to refine the model for ISM hydrocarbon grains, we analyze the observed aromatic (3.28, 6.2 µm) and aliphatic (3.4 µm) hydrocarbon absorption features in the diffuse ISM along the line of s…
Mid-infrared Atomic Fine-structure Emission-line Spectra of Luminous Infrared Galaxies: Spitzer/IRS Spectra of the GOALS Sample
Veilleux, S.; Inami, H.; Armus, L. +18 more
We present the data and our analysis of mid-infrared atomic fine-structure emission lines detected in Spitzer/Infrared Spectrograph high-resolution spectra of 202 local Luminous Infrared Galaxies (LIRGs) observed as part of the Great Observatories All-sky LIRG Survey (GOALS). We readily detect emission lines of [S IV], [Ne II], [Ne V], [Ne III], […