Search Publications
The Calibration of Polycyclic Aromatic Hydrocarbon Dust Emission as a Star Formation Rate Indicator in the AKARI NEP Survey
Goto, Tomotsugu; Kim, Seong Jin; Burgarella, Denis +9 more
Polycyclic aromatic hydrocarbon (PAH) dust emission has been proposed as an effective extinction-independent star formation rate (SFR) indicator in the mid-infrared, but this may depend on conditions in the interstellar medium. The coverage of the AKARI/Infrared Camera (IRC) allows us to study the effects of metallicity, starburst intensity, and a…
A Luminous X-Ray Active Galactic Nucleus in the Dwarf–Dwarf Galaxy Merger RGG 66
Reines, Amy E.; Kimbrell, Seth J.
We present the discovery of a luminous X-ray active galactic nucleus (AGN) in the dwarf galaxy merger RGG 66. The black hole is predicted to have a mass of M BH ∼ 105.4 M ⊙ and to be radiating close to its Eddington limit (L bol/L Edd ∼ 0.75). The AGN in RGG 66 is notable both for its presence…
A Wave-corrected Assessment of the Local Midplane
Hinkel, Austin; Yin, Ziyuan
As the number of known Galactic structures mounts thanks to the Gaia Space Telescope, it is now pertinent to study methods for disentangling structures occupying the same regions of the Milky Way. Indeed, understanding the precise form of each individual structure and the interactions between structures may aid in understanding their origins and c…
Test for Echo: X-Ray Reflection Variability in the Seyfert-2 Active Galactic Nucleus NGC 4388
Brandt, W. N.; Arzoumanian, Zaven; Gendreau, Keith +4 more
We report on a study of the narrow Fe Kα line and reflection spectrum in the well-known Seyfert-2 active galactic nucleus (AGN), NGC 4388. X-ray spectra summed from two extensive NICER monitoring campaigns, separated by years, show strong evidence of variation in the direct continuum and reflected emission, but only small variations in the obscuri…
Revealing the Impact of Critical Stellar Central Density on Galaxy Quenching through Cosmic Time
Xu, Bingxiao; Peng, Yingjie
In a previous work, we investigated the structural and environmental dependence on quenching in the nearby universe. In this work, we extend our investigations to higher redshifts by combining galaxies from the Sloan Digital Sky Survey and The FourStar Galaxy Evolution surveys. In low density, we find a characteristic Σ1 kpc above which…
How Does the Structure of Rarefaction Regions Develop?
Němeček, Zdeněk; Ďurovcová, Tereza; Šafránková, Jana
A rarefaction region (RR) occurs at the trailing edge of the fast solar wind stream. It comes from an area of small longitudinal extent on the solar surface and exhibits a fine and complex structure. In our study, we did a superposed epoch analysis of the proton and α parameters across the RR and observed their gradual evolution. We did not find a…
Comparison of Solar Multifrequency Microwave Data with Other Solar Indices for Understanding Solar and Stellar Microwave Data
Namekata, Kosuke; Shimojo, Masumi; Watanabe, Kyoko +2 more
Thermal microwave emissions detected from stellar atmospheres contain information on stellar activity. However, even for the Sun, the relationship between multifrequency microwave data and other activity indices remains unclear. We investigated the relationships among the thermal microwave fluxes with 1, 2, 3.75, and 9.4 GHz, their circular polari…
Discovery of Radial Spectral Hardening in the Hot Bubble of Planetary Nebula BD+30°3639 with Median Energy Imaging
Montez, Rodolfo
We apply an imaging analysis technique to study the spatial distribution of the X-ray spectral hardness across the hot bubble of planetary nebula BD+30°3639. Hot bubble emission is typically photon starved, thus limiting the methods for spatial–spectral analysis; however, this technique uses the statistics of photon energies across the nebula to i…
Mass-transfer Outbursts Reborn: Modeling the Light Curve of the Dwarf Nova EX Draconis
Baptista, Raymundo; Schlindwein, Wagner
EX Draconis is an eclipsing dwarf nova that shows outbursts with moderate amplitude (≃2 mag) and a recurrence timescale of ≃20–30 days. Dwarf novae outbursts are explained in terms of either a thermal-viscous instability in the disc or an instability in the mass-transfer rate of the donor star (MTIM). We developed simulations of the response of ac…
Radio Signature of the Strong Compression between a Streamer and a Coronal Hole Boundary
Aguilar-Rodriguez, E.; Vourlidas, A.; Corona-Romero, P. +8 more
We present evidence of the first detection of the radio signature at metric wavelengths of the strong compression between a helmet streamer (HS) and the boundary of a coronal hole (CH) using radio observations from the Callisto MEXICO-LANCE and ALASKA-HAARP systems and white-light observations obtained by the STEREO-A/COR1-COR2 coronagraphs. The e…