Search Publications
The Variable Relativistic Outflow of IRAS 13224-3809
Chartas, George; Canas, Manuel H.
The discovery of an ultrafast outflow has been reported in the z = 0.0658 narrow-line Seyfert galaxy IRAS 13224-3809. The ultrafast outflow was first inferred through the detection of highly blueshifted absorption lines and then confirmed with a principal component analysis. Two of the reported properties of this outflow differed from those typica…
A critical re-evaluation of the Thorne-Żytkow object candidate HV 2112
Beasor, Emma R.; Davies, Ben; Cabrera-Ziri, Ivan +1 more
It has been argued in the literature that the star HV 2112 in the Small Magellanic Cloud (SMC) is the first known example of a Thorne-Żytkow object (TŻO), a red supergiant with a degenerate neutron core. This claim is based on the star having a high luminosity (log (L/L⊙) ≳ 5), an extremely cool effective temperature, and a surface enri…
Ultra-deep Large Binocular Camera U-band Imaging of the GOODS-North Field: Depth Versus Resolution
Fontana, Adriano; Grazian, Andrea; Rutkowski, Michael J. +13 more
We present a study of the trade-off between depth and resolution using a large number of U-band imaging observations in the GOODS-North field from the Large Binocular Camera (LBC) on the Large Binocular Telescope (LBT). Having acquired over 30 hr of data (315 images with 5-6 minutes exposures), we generated multiple image mosaics, starting with th…
The Type IIn Supernova SN 2010bt: The Explosion of a Star in Outburst
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Smith, Nathan +12 more
It is well known that massive stars (M > 8 M ⊙) evolve up to the collapse of the stellar core, resulting in most cases in a supernova (SN) explosion. Their heterogeneity is related mainly to different configurations of the progenitor star at the moment of the explosion and to their immediate environments. We present photometry and sp…
The AGN luminosity fraction in merging galaxies
Smith, Howard A.; Zezas, Andreas; Hayward, Christopher C. +7 more
Galaxy mergers are key events in galaxy evolution, often causing massive starbursts and fueling active galactic nuclei (AGNs). In these highly dynamic systems, it is not yet precisely known how much starbursts and AGNs, respectively, contribute to the total luminosity, at what interaction stages they occur, and how long they persist. Here we estim…
A radial velocity survey of the Carina Nebula's O-type stars
Smith, Nathan; Kiminki, Megan M.
We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1-2 km s-1 precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile…
Unraveling the Links among Sympathetic Eruptions
Wang, Yuming; Liu, Rui; Gou, Tingyu +4 more
Solar eruptions occurring at different places within a relatively short time interval are considered to be sympathetic. However, it is difficult to determine whether there exists a cause and effect between them. Here we study a failed and a successful filament eruption following an X1.8-class flare on 2014 December 20, in which slipping-like magne…
Field-Aligned Currents in Saturn's Magnetosphere: Observations From the F-Ring Orbits
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +3 more
We investigate the azimuthal magnetic field signatures associated with high-latitude field-aligned currents observed during Cassini's F-ring orbits (October 2016-April 2017). The overall ionospheric meridional current profiles in the northern and southern hemispheres, that is, the regions poleward and equatorward of the field-aligned currents, dif…
The Near-infrared CO Absorption Band as a Probe to the Innermost Part of an AGN-obscuring Material
Nakagawa, Takao; Baba, Shunsuke; Isobe, Naoki +1 more
We performed a systematic analysis of the 4.67 µm CO ro-vibrational absorption band toward nearby active galactic nuclei (AGNs) and analyzed the absorption profiles of 10 nearby galaxies collected from the AKARI and Spitzer spectroscopic observations that show the CO absorption feature by fitting a plane-parallel local thermal equilibrium ga…
The Enigmatic (Almost) Dark Galaxy Coma P: The Atomic Interstellar Medium
McQuinn, Kristen B. W.; Cannon, John M.; Salzer, John J. +12 more
We present new high-resolution H I spectral line imaging of Coma P, the brightest H I source in the system HI 1232+20. This galaxy with extremely low surface brightness was first identified in the ALFALFA survey as an “(Almost) Dark” object: a clearly extragalactic H I source with no obvious optical counterpart in existing optical survey data (alt…