Search Publications
Discovery of a Radio-loud Narrow-line Seyfert 1 Galaxy at z = 0.9 Reddened with a Strong 2175 Å Bump
Jin, Chichuan; Hao, Lei; Ji, Tuo +12 more
We present a broadband spectrophotometric analysis of an unusual quasar, SDSS J160558.86+474300.1, at z = 0.9, found in a systematic search for reddened radio-loud narrow-line Seyfert 1 galaxies (NLS1s). J1605+4743 qualifies for the conventional definition of an NLS1 in its permitted emission line widths and Hβ/[O III] flux ratio. It also shows st…
A Systematic Study of the Short-term X-Ray Variability of Seyfert Galaxies. I. Diversity of the X-Ray rms Spectra
Jin, Chichuan; Yuan, Weimin; Hu, Jingwei +1 more
The X-ray variability of active galactic nuclei (AGN) carries crucial information about the X-ray radiation mechanism. We performed a systematic study of the X-ray short-term (1-100 ks timescale) variability for a large sample of 78 Seyferts with 426 deep XMM-Newton observations. In this paper, we present the time-averaged spectra and rms spectra …
MAXI J1535-571 2017 Outburst Seen by INTEGRAL/SPI and Investigating the Origin of Its Hard Tail
Jourdain, E.; Roques, J. P.; Rodi, James
On 2017 September 2 MAXI J1535-571 went into outburst and peaked at ~5 Crab in the 2-20 keV energy range. Early in the flare, the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) performed target of opportunity pointings and monitored the source as it transitioned from the hard state to the soft state. Using quasi-simultaneous observatio…
Decoding the Bifurcated Red Giant Branch as a Tracer of Multiple Stellar Populations in the Young Large Magellanic Cloud Cluster NGC 2173
Zucker, Daniel B.; de Grijs, Richard; Kamath, Devika +1 more
Multiple stellar populations (MPs) representing star-to-star light-element abundance variations are common in nearly all ancient Galactic globular clusters (GCs). Here we provide the strongest evidence yet that the populous, ~1.7 Gyr old Large Magellanic Cloud cluster NGC 2173 also exhibits light-element abundance variations. Thus, our results sug…
Adsorption-driven Gas Trapping in Cometary Ice Analogs
Yokochi, Reika
Icy planetary bodies carry volatiles in abundances that should reflect the conditions of their formation. However, the interpretation of volatile abundance data from comets is complicated by the fact that the governing parameters and underlying mechanism of volatile trapping are poorly constrained. To unravel the mechanism of gas trapping in water…
Testing Model-determined Temperatures in the Hyades: A Bayesian Approach
Joner, Michael D.; Jeffery, Elizabeth J.; Taylor, Benjamin J.
Gains in our understanding of stellar evolution over the last century are largely due to improvements in stellar models. One key aspect in the use of these models is a reliable transformation between theoretical values (such as luminosity and temperature) to observable quantities (such as magnitude and color). To assess the current state of this t…
RXTE Observation of the Nonthermal Emission from the Early Stage Merger in A1750
Henriksen, Mark J.
We make the first observation-based calculation of the energy that goes into cosmic ray protons versus cosmic ray electrons in shock acceleration during structure formation. We find a ratio of energy in cosmic ray protons to energy in cosmic ray electrons of 0.86. This value, calculated from the nonthermal X-ray component reported here from RTXE a…
Erratum: "Identification of Faint Chandra X-Ray Sources in the Core-collapsed Globular Cluster NGC 6397: Evidence for a Bimodal Cataclysmic Variable Population" (2010, ApJ, 722, 20)
Anderson, Jay; Bogdanov, Slavko; Heinke, Craig O. +6 more
Near-infrared Spectroscopy of Ultracompact H II Regions in W51A with NIFS/ALTAIR
Damineli, Augusto; Navarete, Felipe; Conti, Peter S. +2 more
W51A is the most active star formation region of the giant H II region W51. It harbors the two massive protoclusters W51e and W51 IRS2, which are very rare in the Galaxy. We aim to identify the newborn massive stars and ultracompact H II regions to derive its distance and age. We performed Integral Field Unit observations with NIFS+ALTAIR of nine …
Infrared Line Emissions from Atoms and Atomic Ions in NGC 7027: Improved Wavelength Determinations for Infrared Metal Lines and a Probable Detection of Zn5+
Neufeld, David A.
An infrared L- and M-band spectral survey, performed toward the young planetary nebula NGC 7027 with the iSHELL instrument on NASA's Infrared Telescope Facility (IRTF), has revealed more than 20 vibrational lines of the molecules HeH+, H2, and CH+ and more than 50 spectral lines of atoms and atomic ions. The presen…