Search Publications
Swift/BAT Detection of Hard X-Rays from Tycho's Supernova Remnant: Evidence for Titanium-44
Troja, E.; Cusumano, G.; Gehrels, N. +6 more
We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10σ) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchro…
Joint XMM-Newton and Chandra Observations of the NGC 1407/1400 Complex: A Tail of an Early-Type Galaxy and a Tale of a Nearby Merging Group
Gu, Liyi; White, Raymond E., III; Su, Yuanyuan +1 more
The nearby group centered on its bright central galaxy NGC 1407 has been suggested by previous kinematic studies to be an unusually dark system. It is also known for hosting a bright galaxy, NGC 1400, with a large radial velocity (1200 km s-1) with respect to the group center. Previous ROSAT X-ray observations revealed an extended regio…
NuSTAR and INTEGRAL Observations of a Low/Hard State of 1E1740.7-2942
Hailey, Charles J.; Fürst, Felix; Pottschmidt, Katja +19 more
The microquasar 1E1740.7-2942, also known as the "Great Annihilator," was observed by NuSTAR in the summer of 2012. We have analyzed in detail two observations taken ~2 weeks apart, for which we measure hard and smooth spectra typical of the low/hard state. A few weeks later the source flux declined significantly. Nearly simultaneous coverage by I…
Recombining Plasma in the Gamma-Ray-emitting Mixed-morphology Supernova Remnant 3C 391
Ercan, E. N.; Chatterjee, A.; Majumdar, P. +4 more
A group of middle-aged mixed-morphology (MM) supernova remnants (SNRs) interacting with molecular clouds (MCs) has been discovered to be strong GeV gamma-ray emitters by the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope (Fermi-LAT). The recent observations of the Suzaku X-ray satellite have revealed that some of these int…
The Mid-infrared Appearance of the Galactic Mini-starburst W49A
Peeters, E.; Stock, D. J.; Shannon, M. J. +1 more
The massive star-forming region W49A represents one of the largest complexes of massive star formation present in the Milky Way and contains at least 50 young massive stars still enshrouded in their natal molecular cloud. We employ Spitzer/Infrared Spectrometer spectral mapping observations of the northern part of W49A to investigate the mid-infra…
On the Puzzling High-Energy Pulsations of the Energetic Radio-Quiet γ-Ray Pulsar J1813-1246
Marelli, M.; Saz Parkinson, P. M.; Wood, K. S. +6 more
We have analyzed the new deep XMM-Newton and Chandra observations of the energetic, radio-quiet pulsar J1813-1246. The X-ray spectrum is nonthermal, very hard, and absorbed. Based on spectral considerations, we propose that J1813 is located at a distance further than 2.5 kpc. J1813 is highly pulsed in the X-ray domain, with a light curve character…
A Hubble Space Telescope Search for a Sub-Earth-sized Exoplanet in the GJ 436 System
Stevenson, Kevin B.; Kreidberg, Laura; Bean, Jacob L. +1 more
The detection of small planets orbiting nearby stars is an important step toward the identification of Earth twins. In previous work using the Spitzer Space Telescope, we found evidence to support at least one sub-Earth-sized exoplanet orbiting the nearby mid-M dwarf star GJ 436. As a follow up, here we used the Hubble Space Telescope (HST) to inv…
Hydrogen Fluoride toward Luminous Nearby Galaxies: NGC 253 and NGC 4945
Falgarone, E.; Lis, D. C.; Phillips, T. G. +4 more
We present the detection of hydrogen fluoride (HF) in two luminous nearby galaxies, NGC 253 and NGC 4945 using the Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory. The HF line toward NGC 253 has a P-Cygni profile, while an asymmetric absorption profile is seen toward NGC 4945. The P-Cygni profile in NGC 253 sugge…
Tracking the Evolution of Quasi-periodic Oscillation in RE J1034+396 Using the Hilbert-Huang Transform
Hu, Chin-Ping; Chou, Yi; Yang, Ting-Chang +1 more
RE J1034+396, a narrow-line Seyfert 1 active galactic nucleus (AGN), is the first example of AGNs that exhibited a nearly coherent quasi-periodic oscillation (QPO) for the data collected by XMM-Newton in 2007. The spectral behaviors and timing properties of the QPO have been studied since its discovery. We present an analysis of the QPO in RE J103…
AMUSE-Field. II. Nucleation of Early-type Galaxies in the Field versus Cluster Environment
Treu, Tommaso; Baldassare, Vivienne F.; Plotkin, Richard M. +4 more
The optical light profiles of nearby early-type galaxies are known to exhibit a smooth transition from nuclear light deficits to nuclear light excesses with decreasing galaxy mass, with as much as 80% of the galaxies with stellar masses below 1010 M ⊙ hosting a massive nuclear star cluster (NSC). At the same time, while all m…