Search Publications
The IGRINS YSO Survey. III. Stellar Parameters of Pre-main-sequence Stars in Ophiuchus and Upper Scorpius
Johns-Krull, Christopher M.; Lee, Jae-Joon; Prato, L. +9 more
We used the Immersion GRating Infrared Spectrometer (IGRINS) to determine fundamental parameters for 61 K- and M-type young stellar objects (YSOs) located in the Ophiuchus and Upper Scorpius star-forming regions. We employed synthetic spectra and a Markov chain Monte Carlo approach to fit specific K-band spectral regions and determine the photosph…
Calibrating X-Ray Binary Luminosity Functions via Optical Reconnaissance. II. The High-mass XLF and Globular Cluster Population of X-Ray Binaries in the Low Star-forming Spiral M81
Chandar, Rupali; Mok, Angus; Gallo, Elena +2 more
We characterize the optical counterparts to the compact X-ray source population within the nearby spiral galaxy M81 using multiband Hubble Space Telescope (HST) imaging data. By comparing the optical luminosities and colors measured for candidate donor stars and host clusters to stellar and cluster evolutionary models, respectively, we estimate th…
The Baryonic Content of Galaxies Mapped by MaNGA and the Gas Around Them
Bershady, Matthew A.; Wake, David A.; Lundgren, Britt +4 more
We analyze the cool gas in and around 14 nearby galaxies (at z < 0.1) mapped with the Sloan Digital Sky Survey IV MaNGA survey by measuring absorption lines produced by gas in spectra of background quasars/active galactic nuclei at impact parameters of 0-25 effective radii from the galactic centers. Using Hubble Space Telescope/Cosmic Origins S…
Constraining the Binarity of Black Hole Candidates: A Proof-of-concept Study of Gaia BH1 and Gaia BH2
Trani, Alessandro A.; Suto, Yasushi; Hayashi, Toshinori
Nearly a hundred binary black holes (BBHs) have been discovered with gravitational-wave signals emitted at their merging events. Thus, it is quite natural to expect that significantly more abundant BBHs with wider separations remain undetected in the Universe or even in our Galaxy. We consider a possibility that star-BH binary candidates may indee…
Rapid Variability of the Accretion Disk Wind in the Narrow-line Seyfert 1, PG 1448+273
Porquet, D.; Reeves, J. N.; Braito, V. +3 more
PG 1448+273 is a luminous, nearby (z = 0.0645), narrow-line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. XMM-Newton observations of PG 1448+273 in 2017 revealed the presence of an ultrafast outflow, as seen through its blueshifted iron K absorption profile, with an outflow velocity of about 0.1 c. Here, the first NuSTAR ob…
Formulating Mass-loss Rates for Sun-like Stars: A Hybrid Model Approach
Toriumi, Shin; Cranmer, Steven R.; Shoda, Munehito
We observe an enhanced stellar wind mass-loss rate from low-mass stars exhibiting higher X-ray flux. This trend, however, does not align with the Sun, where no evident correlation between X-ray flux and mass-loss rate is present. To reconcile these observations, we propose a hybrid model for the stellar wind from solar-type stars, incorporating bo…
An XMM-Newton View of the Symbiotic Stars HM Sge, NQ Gem, and PU Vul
Toalá, Jesús A.; Sabin, Laurence; Botello, Marissa K.
We present the analysis of archival XMM-Newton observations of the symbiotic stars HM Sge, NQ Gem, and PU Vul. The EPIC-pn spectra hint at the presence of emission lines, which are further confirmed in the first-order RGS spectra of the three sources. Spectral modeling of the EPIC-pn data discloses unprecedented characteristics; for instance, the …
Further Evidence for the 9 s Pulsation in LS 5039 from NuSTAR and ASCA
Enoto, Teruaki; Makishima, Kazuo; Takahashi, Tadayuki +2 more
The present study aims to reinforce the evidence for the ~9 s pulsation in the gamma-ray binary LS 5039, derived from a Suzaku observation in 2007 and a NuSTAR observation in 2016. Through a reanalysis of the NuSTAR data incorporating the orbital Doppler correction, the 9.0538 s pulsation was confirmed successfully even in the 3-10 keV range, wher…
X-Ray, Near-ultraviolet, and Optical Flares Produced by Colliding Magnetospheres in the Young High-eccentricity Binary DQ Tau
Kóspál, Ágnes; Arulanantham, Nicole; Getman, Konstantin V. +3 more
DQ Tau is a unique young high-eccentricity binary system that exhibits regular magnetic reconnection flares and pulsed accretion near periastron. We conducted NuSTAR, Swift, and Chandra observations during the 2022 July 30 periastron to characterize X-ray, near-ultraviolet (NUV), and optical flaring emissions. Our findings confirm the presence of …
Turbulence Properties of Interplanetary Coronal Mass Ejections in the Inner Heliosphere: Dependence on Proton Beta and Flux Rope Structure
Möstl, C.; Kilpua, E. K. J.; Chen, C. H. K. +3 more
Interplanetary coronal mass ejections (ICMEs) have low proton beta across a broad range of heliocentric distances and a magnetic flux rope structure at large scales, making them a unique environment for studying solar wind fluctuations. Power spectra of magnetic field fluctuations in 28 ICMEs observed between 0.25 and 0.95 au by Solar Orbiter and …