Search Publications
ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex
Kim, Kee-Tae; Li, Di; Liu, Tie +15 more
Stellar feedback from high-mass stars (e.g., H II regions) can strongly influence the surrounding interstellar medium and regulate star formation. Our new ALMA observations reveal sequential high-mass star formation taking place within one subvirial filamentary clump (the G9.62 clump) in the G9.62+0.19 complex. The 12 dense cores (MM1-MM12) detect…
An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS). IV. Discovery of High-redshift AGB Analogs
van Loon, J. Th.; Sonneborn, G.; Gehrz, R. D. +13 more
The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS) identified several candidate Asymptotic Giant Branch (AGB) stars in nearby dwarf galaxies and showed that dust can form even in very metal-poor systems ({\boldsymbol{Z}}∼ 0.008 {Z}⊙ ). Here, we present a follow-up survey with WFC3/IR on the Hubble Space Telescope (HST), usin…
A Comprehensive Library of X-Ray Pulsars in the Small Magellanic Cloud: Time Evolution of Their Luminosities and Spin Periods
Coe, M. J.; Drake, J. J.; Yang, J. +3 more
We have collected and analyzed the complete archive of XMM-Newton (116), Chandra (151), and RXTE (952) observations of the Small Magellanic Cloud (SMC), spanning 1997-2014. The resulting observational library provides a comprehensive view of the physical, temporal, and statistical properties of the SMC pulsar population across the luminosity range…
The NuSTAR Serendipitous Survey: Hunting for the Most Extreme Obscured AGN at >10 keV
Harrison, F. A.; Stern, D.; Alexander, D. M. +27 more
We identify sources with extremely hard X-ray spectra (I.e., with photon indices of {{Γ }}≲ 0.6) in the 13 deg2 NuSTAR serendipitous survey, to search for the most highly obscured active galactic nuclei (AGNs) detected at > 10 {keV}. Eight extreme NuSTAR sources are identified, and we use the NuSTAR data in combination with lower-ene…
Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates
Lee, Chien-Hsiu; Oguri, Masamune; Suyu, Sherry H. +2 more
We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well known, accurately measured time delays of the multiple images could pr…
Observations of the GRB Afterglow ATLAS17aeu and Its Possible Association with GW 170104
Inserra, C.; Rest, A.; Smartt, S. J. +26 more
We report the discovery and multiwavelength data analysis of the peculiar optical transient, ATLAS17aeu. This transient was identified in the sky map of the LIGO gravitational wave event GW 170104 by our ATLAS and Pan-STARRS coverage. ATLAS17aeu was discovered 23.1 hr after GW 170104 and rapidly faded over the next three nights, with a spectrum re…
The Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubble
Nikolov, Nikolay; Gibson, Neale P.; Sing, David K. +11 more
We present an optical eclipse observation of the hot Jupiter WASP-12b using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. These spectra allow us to place an upper limit of {A}g< 0.064 (97.5% confidence level) on the planet’s white light geometric albedo across 290-570 nm. Using six wavelength bins acro…
Detection of the Ultraviolet Spectrum of the Hot Subdwarf Companion of 60 Cygni (B1 Ve) from a Survey of IUE Spectra of Be Stars
Gies, Douglas R.; Wang, Luqian; Peters, Geraldine J.
We used archival International Ultraviolet Explorer (IUE) high-dispersion, short wavelength spectra data to search for evidence of the spectra of hot subdwarf companions of six rapidly rotating Be stars in binary systems. We searched for the signature of a hot companion through an analysis of the cross-correlation functions (CCFs) of observed and …
Fermi Non-detections of Four X-Ray Jet Sources and Implications for the IC/CMB Mechanism
Georganopoulos, Markos; Breiding, Peter; Meyer, Eileen T. +3 more
Since its launch in 1999, the Chandra X-ray observatory has discovered several dozen X-ray jets associated with powerful quasars. In many cases, the X-ray spectrum is hard and appears to come from a second spectral component. The most popular explanation for the kpc-scale X-ray emission in these cases has been inverse-Compton (IC) scattering of Co…
Properties of Turbulence in the Reconnection Exhaust: Numerical Simulations Compared with Observations
Sorriso-Valvo, L.; Goldman, M. V.; Newman, D. L. +6 more
The properties of the turbulence that develops in the outflows of magnetic reconnection have been investigated using self-consistent plasma simulations, in three dimensions. As commonly observed in space plasmas, magnetic reconnection is characterized by the presence of turbulence. Here we provide a direct comparison of our simulations with report…