Search Publications
HST spectrum and timing of the ultracompact X-ray binary candidate 47 Tuc X9
Maccarone, T. J.; Knigge, C.; van den Berg, M. +17 more
To confirm the nature of the donor star in the ultracompact X-ray binary candidate 47 Tuc X9, we obtained optical spectra (3000-10 000 Å) with the Hubble Space Telescope / Space Telescope Imaging Spectrograph. We find no strong emission or absorption features in the spectrum of X9. In particular, we place 3σ upper limits on the H α and He II λ4686…
A Synthetic Sample of Short-cadence Solar-like Oscillators for TESS
Chaplin, William J.; Davies, Guy R.; Girardi, Léo +4 more
NASA’s Transiting Exoplanet Survey Satellite (TESS) has begun a two-year survey of most of the sky, which will include light curves for thousands of solar-like oscillators sampled at a cadence of two minutes. To prepare for this steady stream of data, we present a mock catalog of light curves, designed to realistically mimic the properties of the …
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…
The straight and isolated G350.54+0.69 filament: density profile and star formation content
Liu, Hong-Li; Yuan, Jing-Hua; Stutz, Amelia
We investigate the global properties of the straight and isolated filamentary cloud G350.54+0.69 using the Herschelcontinuum and APEX molecular line data. The overall straight morphology is similar to that of two other well-studied nearby filaments (Musca and Taurus-B211/3), while the isolated nature of G350.54+0.69 appears similar to that of Musc…
Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9
Done, Chris; Safi-Harb, Samar; Hamaguchi, Kenji +194 more
We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5-0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8-80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant brea…
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…
Multi-spacecraft observations and transport simulations of solar energetic particles for the May 17th 2012 event
Dalla, S.; Guo, J.; Wimmer-Schweingruber, R. +3 more
Context. The injection, propagation and arrival of solar energetic particles (SEPs) during eruptive solar events is an important and current research topic of heliospheric physics. During the largest solar events, particles may have energies up to a few GeVs and sometimes even trigger ground-level enhancements (GLEs) at Earth. These large SEP even…
Molecular gas in AzTEC/C159: a star-forming disk galaxy 1.3 Gyr after the Big Bang
Magnelli, B.; Smolčić, V.; van Kampen, E. +23 more
We studied the molecular gas properties of AzTEC/C159, a star-forming disk galaxy at z = 4.567, in order to better constrain the nature of the high-redshift end of the submillimeter-selected galaxy (SMG) population. We secured 12CO molecular line detections for the J = 2 →1 and J = 5 →4 transitions using the Karl G. Jansky Very Large Ar…
Lurking systematics in predicting galaxy cold gas masses using dust luminosities and star formation rates
Janowiecki, Steven; Cortese, Luca; Goodwin, Adelle J. +1 more
We use galaxies from the Herschel Reference Survey to evaluate commonly used indirect predictors of cold gas masses. We calibrate predictions for cold neutral atomic and molecular gas using infrared dust emission and gas depletion time methods that are self-consistent and have ∼20 per cent accuracy (with the highest accuracy in the prediction of t…