Search Publications
NuSTAR Unveils a Compton-thick Type 2 Quasar in Mrk 34
Harrison, F. A.; Stern, D.; Zhang, W. W. +27 more
We present Nuclear Spectroscopic Telescope Array (NuSTAR) 3-40 keV observations of the optically selected Type 2 quasar (QSO2) SDSS J1034+6001 or Mrk 34. The high-quality hard X-ray spectrum and archival XMM-Newton data can be fitted self-consistently with a reflection-dominated continuum and a strong Fe Kα fluorescence line with equivalent width …
The Angular Clustering of WISE-selected Active Galactic Nuclei: Different Halos for Obscured and Unobscured Active Galactic Nuclei
Stern, D.; Assef, R. J.; Yan, Lin +1 more
We calculate the angular correlation function for a sample of ~170,000 active galactic nuclei (AGNs) extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 - W2 > 0.8) and 4.6 µm flux densities brighter than 0.14 mJy). The sample is expected to be >90% reliable at identifying AGNs …
A Survey for Hα Pulsar Bow Shocks
Romani, Roger W.; Brownsberger, Sasha
We report on a survey for Hα bow shock emission around nearby γ-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around Fermi pulsar PSR J1741-2054, we now report Hα structures around two additional γ-ray pulsars, PSR J2030+4415 and PSR J1…
Detection of White Dwarf Companions to Blue Stragglers in the Open Cluster NGC 188: Direct Evidence for Recent Mass Transfer
Sills, Alison; Knigge, Christian; Leigh, Nathan +3 more
Several possible formation pathways for blue straggler stars have been developed recently, but no one pathway has yet been observationally confirmed for a specific blue straggler. Here we report the first findings from a Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel far-UV photometric program to search for white dwarf comp…
Molecular Gas Heating Mechanisms, and Star Formation Feedback in Merger/Starbursts: NGC 6240 and Arp 193 as Case Studies
Greve, T. R.; van der Werf, Paul; Zhang, Zhi-Yu +6 more
We used the SPIRE/FTS instrument aboard the Herschel Space Observatory to obtain the Spectral Line Energy Distributions (SLEDs) of CO from J = 4-3 to J = 13-12 of Arp 193 and NGC 6240, two classical merger/starbursts selected from our molecular line survey of local Luminous Infrared Galaxies (L IR >= 1011 L ⊙). …
Three Ancient Halo Subgiants: Precise Parallaxes, Compositions, Ages, and Implications for Globular Clusters
Schaefer, Gail H.; Nelan, Edmund P.; Bond, Howard E. +3 more
The most accurate ages for the oldest stars are those obtained for nearby halo subgiants because they depend almost entirely on just the measured parallaxes and absolute oxygen abundances. In this study, we have used the Fine Guidance Sensors on the Hubble Space Telescope to determine trigonometric parallaxes, with precisions of 2.1% or better, fo…
Hubble Space Telescope/Advanced Camera for Surveys Confirmation of the Dark Substructure in A520
Hoekstra, H.; Jee, M. J.; Mahdavi, A. +1 more
We present a weak-lensing study of the cluster A520 based on Advanced Camera for Surveys (ACS) data. The excellent data quality provides a mean source density of ~109 arcmin-2, which improves both resolution and significance of the mass reconstruction compared to a previous study based on Wide Field Planetary Camera 2 (WFPC2) images. We…
3XMM J185246.6+003317: Another Low Magnetic Field Magnetar
Rea, N.; Torres, D. F.; Israel, G. L. +2 more
We study the outburst of the newly discovered X-ray transient 3XMM J185246.6+003317, re-analyzing all available XMM-Newton observations of the source to perform a phase-coherent timing analysis, and derive updated values of the period and period derivative. We find the source rotating at P = 11.55871346(6) s (90% confidence level; at epoch MJD 547…
A Survey of the Molecular ISM Properties of Nearby Galaxies Using the Herschel FTS
Conley, A.; Glenn, J.; Kamenetzky, J. +2 more
The 12CO J = 4 → 3 to J = 13 → 12 lines of the interstellar medium from nearby galaxies, newly observable with the Herschel SPIRE Fourier transform spectrometer, offer an opportunity to study warmer, more luminous molecular gas than that traced by 12CO J = 1 → 0. Here we present a survey of 17 nearby infrared-luminous galaxy …
A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds: First Results
Massey, Philip; Hillier, D. John; Morrell, Nidia +1 more
Over the years, directed surveys and incidental spectroscopy have identified 12 Wolf-Rayet (WR) stars in the Small Magellanic Cloud (SMC) and 139 in the Large Magellanic Cloud (LMC), numbers which are often described as "essentially complete." Yet, new WRs are discovered in the LMC almost yearly. We have therefore initiated a new survey of both Ma…