Search Publications
The Broadband X-Ray Spectrum of the X-Ray-obscured Type 1 AGN 2MASX J193013.80+341049.5
Walton, Dominic J.; Stern, Daniel; Assef, Roberto J. +6 more
We present results from modeling the broadband X-ray spectrum of the Type 1 active galactic nucleus (AGN) 2MASX J193013.80+341049.5 using NuSTAR, Swift, and archival XMM-Newton observations. We find this source to be highly X-ray obscured, with column densities exceeding 1023 cm-2 across all epochs of X-ray observations, span…
Triangulum-Andromeda Overdensity: a Region with a Complex Stellar Population
Souto, Diogo; Cunha, K.; Majewski, S. R. +4 more
The Triangulum-Andromeda (TriAnd) overdensity is a distant structure of the Milky Way located in the second Galactic quadrant well below the Galactic plane. Since its discovery, its nature has been under discussion, whether it could be old perturbations of the Galactic disk or the remains of a disrupted former dwarf galaxy. In this study, we inves…
Magnetic Stability of Massive Star-forming Clumps in RCW 106
Kusune, Takayoshi; Nakamura, Fumitaka; Tamura, Motohide +6 more
The RCW 106 molecular cloud complex is an active massive star-forming region where a ministarburst is taking place. We examined its magnetic structure by near-IR polarimetric observations with the imaging polarimeter SIRPOL on the IRSF 1.4 m telescope. The global magnetic field is nearly parallel to the direction of the Galactic plane and the clou…
Asteroseismology of the Pre-main-sequence δ Scuti Pulsator IP Persei
Li, Yan; Chen, Xinghao
A grid of theoretical models are computed to fit the nine oscillation modes of IP Per detected earlier from a multi-site ground-based campaign. Fitting results show that there are two sets of theoretical models that could reproduce the observed frequencies more or less equally as well. In view of other available spectroscopic and photometric measu…
A Carbon-rich Hot Bubble in the Planetary Nebula NGC 5189
Karovska, Margarita; Toalá, Jesús A.; Montez, Rodolfo, Jr.
We present the discovery of extended X-ray emission from the planetary nebula (PN) NGC 5189 around the [WO1]-type WD 1330-657 with XMM-Newton. The X-ray-emitting gas fills the cavities detected in the Hubble Space Telescope [O III] narrowband image and presents a limb-brightened morphology toward the outer edges of the east and west lobes. The bul…
Testing Seismic Models of Hot B Subdwarfs with Gaia Data
Latour, M.; Green, E. M.; Fontaine, G. +5 more
We report the results of a study designed to test further the basic validity of the seismic models of hot pulsating B subdwarfs that have been developed over the last two decades. Given estimates of the effective temperature, surface gravity, and mass as obtained from a seismic analysis, and given an estimate of the He/H ratio as available from in…
The Central Star of NGC 2346 as a Clue to Binary Evolution through the Common Envelope Phase
Bianchi, L.; Manteiga, M.; Gómez-Muñoz, M. A. +2 more
We present an analysis of the binary central star of the planetary nebula NGC 2346 based on archival data from the International Ultraviolet Explorer, and new low- and high-resolution optical spectra (3700-7300 Å). By including in the spectral analysis the contribution of both stellar and nebular continuum, we reconciled long-time discrepant UV an…
Propagation of Solar Energetic Particles in the Outer Heliosphere: Interplay between Scattering and Adiabatic Focusing
Wan, W.; He, H. -Q.
The turbulence and spatial nonuniformity of the guide magnetic field cause two competitive effects, namely, the scattering effect and the adiabatic focusing effect, respectively. In this work, we numerically solve the five-dimensional Fokker-Planck transport equation to investigate the radial evolutions of these important effects undergone by the …
Constraining the Active Galactic Nucleus and Starburst Properties of the IR-luminous Quasar Host Galaxy APM08279+5255 at Redshift 4 with SOFIA
Casey, Caitlin M.; Staguhn, Johannes; Dowell, C. Darren +3 more
We present far-IR photometry and the infrared spectrum of the z = 3.9114 quasar/starburst composite system APM 08279+5255, obtained using the Stratospheric Observatory for Infrared Astronomy (SOFIA)/High-resolution Airborne Wideband Camera+ (HAWC+) and the Spitzer Space Telescope Infrared Spectrograph. We decompose the IR-to-radio spectral energy …
X-Ray Spectrum of RBS 315: Absorption or Intrinsic Curvature
Behar, Ehud; Mushotzky, Richard F.; Ben Haim, Sivan
X-ray absorption of high-redshift quasars is enigmatic, because it remains unclear where in the universe the absorbing gas is. If absorption occurs near the high-z host, it could help us understand early stages of galaxy formation. If it is in the intergalactic medium (IGM), it provides a unique way to probe this elusive baryon component. We repor…