Search Publications
NuSTAR Discovery of an Unusually Steady Long-term Spin-up of the Be Binary 2RXP J130159.6-635806
Hailey, Charles J.; Chakrabarty, Deepto; Fürst, Felix +14 more
We present spectral and timing analyses of Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the accreting X-ray pulsar 2RXP J130159.6-635806. The source was serendipitously observed during a campaign focused on the gamma-ray binary PSR B1259-63 and was later targeted for a dedicated observation. The spectrum has a typical shape for a…
Carbon, Helium, and Proton Kinetic Temperatures in a Cygnus Loop Shock Wave
Blair, William P.; Raymond, John C.; Ghavamian, Parviz +1 more
Observations of SN 1006 have shown that ions and electrons in the plasma behind fast supernova remnant shock waves are far from equilibrium, with the electron temperature much lower than the proton temperature and ion temperatures approximately proportional to ion mass. In the ∼360 km s-1shock waves of the Cygnus Loop, on the other hand…
Signatures of Kinematic Substructure in the Galactic Stellar Halo
Spergel, David N.; Lisanti, Mariangela; Madau, Piero
Tidal debris from infalling satellites can leave observable structure in the phase-space distribution of the Galactic halo. Such substructure can be manifest in the spatial and/or velocity distributions of the stars in the halo. This paper focuses on a class of substructure that is purely kinematic in nature, with no accompanying spatial features.…
The North Galactic Pole Rift and the Local Hot Bubble
Kuntz, K. D.; Snowden, S. L.; Lallement, R. +2 more
The North Galactic Pole Rift (NGPR) is one of the few distinct neutral hydrogen clouds at high Galactic latitudes that have well-defined distances. It is located at the edge of the Local Cavity (LC) and provides an important test case for understanding the Local Hot Bubble (LHB), the presumed location for the hot diffuse plasma responsible for muc…
Gone in a Blaze of Glory: The Demise of Comet C/2015 D1 (SOHO)
Battams, Karl; Clark, David; Ye, Quan-Zhi +2 more
We present studies of C/2015 D1 (SOHO), the first sunskirting comet ever seen from ground stations over the past half century. The Solar and Heliospheric Observatory (SOHO) witnessed its peculiar light curve with a huge dip followed by a flare-up around perihelion: the dip was likely caused by sublimation of olivines, directly evidenced by a coinc…
Investigating the Consistency of Stellar Evolution Models with Globular Cluster Observations via the Red Giant Branch Bump
Chaboyer, B.; Joyce, M.
Synthetic Red Giant Branch Bump (RGBB) magnitudes are generated with the most recent theoretical stellar evolution models computed with the Dartmouth Stellar Evolution Program (DSEP) code. They are compared to the observational work of Nataf et al., who present RGBB magnitudes for 72 globular clusters. A DSEP model using a chemical composition wit…
Spatial Structures in the Globular Cluster Distribution of the 10 Brightest Virgo Galaxies
Zezas, A.; Fabbiano, G.; D'Abrusco, R.
We report the discovery of significant localized structures in the projected two-dimensional spatial distributions of the Globular Cluster (GC) systems of the 10 brightest galaxies in the Virgo Cluster. We use catalogs of GCs extracted from the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Virgo Cluster Survey (ACSVCS) imaging dat…
Computational Modeling of the Class I Low-Mass Protostar Elias 29 Applying Optical Constants of Ices Processed By High Energy Cosmic Ray Analogs
Rocha, W. R. M.; Pilling, S.
We present a study of the effects of high energy cosmic rays (CRs) over the astrophysical ices, observed toward the embedded class I protostar Elias 29, by using computational modeling and laboratory data. Its spectrum was observed with the Infrared Space Observatory (ISO) covering 2.3-190 µm. The modeling employed the three-dimensional Mont…
On the Black Hole Mass---X-Ray Excess Variance Scaling Relation for Active Galactic Nuclei in the Low-mass Regime
Yuan, Weimin; Pan, Hai-Wu; Liu, Bifang +2 more
Recent studies of active galactic nuclei (AGNs) found a statistically inverse linear scaling between the X-ray normalized excess variance {σ }{rms}2 (variability amplitude) and the black hole (BH) mass spanning over {M}{BH}={10}6-{10}9 {M}⊙ . Suggested as having a small scatter, thi…
A ∼32-70 K Formation Temperature Range for the Ice Grains Agglomerated by Comet 67 P/Churyumov-Gerasimenko
Altwegg, K.; Rubin, M.; Mousis, O. +4 more
Grand Canonical Monte Carlo simulations are used to reproduce the N2/CO ratio ranging between 1.7 × 10-3 and 1.6 × 10-2 observed in situ in the Jupiter-family comet 67 P/Churyumov-Gerasimenko (67 P) by the ROSINA mass spectrometer on board the Rosetta spacecraft. By assuming that this body has been agglomerated fro…