Search Publications
Are Models for Core-collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?
Badenes, Carles; Lee, Shiu-Hang; Ellison, Donald C. +4 more
The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby supernova remnants are a strong discriminant of both progenitor type and circumstellar environment has implications for our understanding of supernova progenitor evolution. Using models for the chemical composition of core-collapse supernova (CCSN) ejecta,…
Quiescent Compact Galaxies at Intermediate Redshift in the COSMOS Field. The Number Density
Hwang, Ho Seong; Geller, Margaret J.; Damjanov, Ivana +1 more
We investigate the evolution of compact galaxy number density over the redshift range 0.2\lt z\lt 0.8. Our sample consists of galaxies with secure spectroscopic redshifts observed in the COSMOS field. With the large uncertainties, the compact galaxy number density trend with redshift is consistent with a constant value over the interval 0.2\lt z\l…
Saturn's G and D Rings Provide Nearly Complete Measured Scattering Phase Functions of Nearby Debris Disks
Hedman, Matthew M.; Stark, Christopher C.
The appearance of debris disks around distant stars depends upon the scattering/phase function (SPF) of the material in the disk. However, characterizing the SPFs of these extrasolar debris disks is challenging because only a limited range of scattering angles are visible to Earth-based observers. By contrast, Saturn’s tenuous rings can be observe…
Interstellar Dust Properties from a Survey of X-Ray Halos
Smith, Randall K.; Valencic, Lynne A.
Interstellar dust grains produce X-ray halos around bright sources due to small-angle X-ray scattering. Numerous studies have examined these halos, but no systematic study has yet tested the available halo data against the large number of well-defined dust models in circulation. We have therefore obtained the largest sample to date of X-ray dust h…
Jet-ISM Interaction in the Radio Galaxy 3C 293: Jet-driven Shocks Heat ISM to Power X-Ray and Molecular H2 Emission
Appleton, P. N.; Guillard, P.; Emonts, B. +3 more
We present a 70 ks Chandra observation of the radio galaxy 3C 293. This galaxy belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have very luminous emission from warm molecular hydrogen. In radio galaxies, the molecular gas appears to be heated by jet-driven shocks, but exactly how this mechanism works is still poorly unde…
Light Echoes from Supernova 2014J in M82
Crotts, Arlin P. S.
Type Ia SN 2014J exploded in the nearby starburst galaxy M82 = NGC 3032 and was discovered at Earth about seven days later on 2014 January 21, reaching maximum light in V around 2014 February 5. SN 2014J is the closest SN Ia in at least four decades and probably many more. Recent Hubble Space Telescope/WFC3 imaging (2014 September 5 and 2015 Febru…
Radial Evolution of a Magnetic Cloud: MESSENGER, STEREO, and Venus Express Observations
Forsyth, R. J.; Zurbuchen, T. H.; Raines, J. M. +3 more
The Solar Orbiter and Solar Probe Plus missions will provide observations of magnetic clouds closer to the Sun than ever before, and it will be good preparation for these missions to make full use of the most recent in situ data sets from the inner heliosphere—namely, those provided by MErcury Surface, Space ENvironment, GEochemistry, and Ranging …
An Optically Obscured AGN in a Low Mass, Irregular Dwarf Galaxy: A Multi-Wavelength Analysis of J1329+3234
Secrest, N. J.; Fischer, J.; Satyapal, S. +6 more
Supermassive black holes (SMBHs) are found ubiquitously in large, bulge-dominated galaxies throughout the local universe, yet little is known about their presence and properties in bulgeless and low-mass galaxies. This is a significant deficiency, since the mass distribution and occupation fraction of nonstellar black holes provide important obser…
Cloud Structure of the Nearest Brown Dwarfs. II. High-amplitude Variability for Luhman 16 A and B in and out of the 0.99 µm FeH feature
Apai, Dániel; Crossfield, Ian J. M.; Radigan, Jacqueline +4 more
The re-emergence of the 0.99 µm FeH feature in brown dwarfs of early- to mid-T spectral type has been suggested as evidence for cloud disruption where flux from deep, hot regions below the Fe cloud deck can emerge. The same mechanism could account for color changes at the L/T transition and photometric variability. We present the first obser…
Overturning the Case for Gravitational Powering in the Prototypical Cooling Lyα Nebula
Momcheva, Ivelina; Brammer, Gabriel B.; Fynbo, Johan P. U. +2 more
The Nilsson et al. Lyα nebula has often been cited as the most plausible example of an Lyα nebula powered by gravitational cooling. In this paper, we bring together new data from the Hubble Space Telescope and the Herschel Space Observatory as well as comparisons to recent theoretical simulations in order to revisit the questions of the local envi…