Search Publications
Disintegrating Asteroid P/2013 R3
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
Splitting of the nuclei of comets into multiple components has been frequently observed but, to date, no main-belt asteroid has been observed to break up. Using the Hubble Space Telescope, we find that main-belt asteroid P/2013 R3 consists of 10 or more distinct components, the largest up to 200 m in radius (assumed geometric albedo of 0.05) each …
The Light Curve of SN 1987A Revisited: Constraining Production Masses of Radioactive Nuclides
Seitenzahl, Ivo R.; Timmes, F. X.; Magkotsios, Georgios
We revisit the evidence for the contribution of the long-lived radioactive nuclides 44Ti, 55Fe, 56Co, 57Co, and 60Co to the UVOIR light curve of SN 1987A. We show that the V-band luminosity constitutes a roughly constant fraction of the bolometric luminosity between 900 and 1900 days, and we o…
NuSTAR and XMM-NEWTON Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk
Harrison, F. A.; Stern, D.; Zhang, W. W. +24 more
We present a spectral analysis of four coordinated NuSTAR+XMM-Newton observations of the Seyfert galaxy NGC 1365. These exhibit an extreme level of spectral variability, which is primarily due to variable line-of-sight absorption, revealing relatively unobscured states in this source for the first time. Despite the diverse range of absorption stat…
Weak Hard X-Ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-Ray Weakness
Harrison, F. A.; Stern, D.; Zhang, W. W. +19 more
We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a p…
The Dynamical Fingerprint of Core Scouring in Massive Elliptical Galaxies
Saglia, R. P.; Thomas, J.; Bender, R. +2 more
The most massive elliptical galaxies have low-density centers or cores that differ dramatically from the high-density centers of less massive ellipticals and bulges of disk galaxies. These cores have been interpreted as the result of mergers of supermassive black hole binaries, which depopulate galaxy centers by gravitationally slingshotting centr…
Fingerprints of Galactic Loop I on the Cosmic Microwave Background
Liu, Hao; Mertsch, Philipp; Sarkar, Subir
We investigate possible imprints of galactic foreground structures such as the "radio loops" in the derived maps of the cosmic microwave background. Surprisingly, there is evidence for these not only at radio frequencies through their synchrotron radiation, but also at microwave frequencies where emission by dust dominates. This suggests the mecha…
Constraints on the Progenitor System of the Type Ia Supernova 2014J from Pre-explosion Hubble Space Telescope Imaging
Filippenko, Alexei V.; Cenko, S. Bradley; Kelly, Patrick L. +7 more
We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ≈ 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble …
Wide Cool and Ultracool Companions to Nearby Stars from Pan-STARRS 1
Chambers, Kenneth C.; Magnier, Eugene A.; Wainscoat, Richard J. +18 more
We present the discovery of 57 wide (>5'') separation, low-mass (stellar and substellar) companions to stars in the solar neighborhood identified from Pan-STARRS 1 (PS1) data and the spectral classification of 31 previously known companions. Our companions represent a selective subsample of promising candidates and span a range in spectral type…
Infall of Nearby Galaxies into the Virgo Cluster as Traced with Hubble Space Telescope
Dolphin, Andrew E.; Wu, Po-Feng; Shaya, Edward J. +2 more
We measured the tip of the red giant branch distances to nine galaxies in the direction to the Virgo cluster using the Advanced Camera for Surveys on the Hubble Space Telescope. These distances put seven galaxies (GR 34, UGC 7512, NGC 4517, IC 3583, NGC 4600, VCC 2037, and KDG 215) in front of Virgo and two galaxies (IC 3023 and KDG 177) likely in…
Molecular Gas in the X-Ray Bright Group NGC 5044 as Revealed by ALMA
Ohyama, Youichi; Brighenti, Fabrizio; Jones, Christine +17 more
An ALMA observation of the early-type galaxy NGC 5044, which resides at the center of an X-ray bright group with a moderate cooling flow, detected 24 molecular structures within the central 2.5 kpc. The masses of the molecular structures vary from 3 × 105 M ⊙ to 107 M ⊙ and the CO(2-1) linewidths vary fr…