Search Publications
Fe VII Emission Lines in the Wavelength Range 193-197 Å
Landi, Enrico; Young, Peter R.; Ryabtsev, Alexander N.
The identifications of Fe VII emission lines in the wavelength range 193-197 Å are discussed in the light of new measurements of laboratory spectra and atomic data calculations. This region is of importance to studies of solar spectra from the EUV Imaging Spectrometer (EIS) on board the Hinode spacecraft, which has its peak sensitivity at these wa…
Toward a More Complex Understanding of Natal Super Star Clusters with Multiwavelength Observations
Johnson, Kelsey E.; Indebetouw, Remy; Brogan, Crystal L. +3 more
Henize 2-10 (He 2-10) is a nearby (D = 9 Mpc) starbursting blue compact dwarf galaxy that boasts a high star formation rate and a low-luminosity active galactic nucleus. He 2-10 is also one of the first galaxies in which embedded super star clusters (SSCs) were discovered. SSCs are massive, compact star clusters that will impact their host galaxie…
Transient Formation of Loops in the Core of an Active Region
Tripathi, Durgesh
We study the formation of transient loops in the core of the AR 11890. For this purpose, we have used the observations recorded by the Atmospheric Imaging Assembly (AIA) and the Interface Region Imaging Spectrograph (IRIS). For photospheric field configuration, we have used the line-of-sight (LOS) magnetograms obtained from the Helioseismic and Ma…
Observing the Stellar Halo of Andromeda in Cosmological Simulations: The AURIGA2PANDAS Pipeline
Grand, Robert J. J.; Gómez, Facundo A.; Fattahi, Azadeh +10 more
We present a direct comparison of the Pan-Andromeda Archaeological Survey (PAndAS) observations of the stellar halo of M31 with the stellar halos of six galaxies from the Auriga simulations. We process the simulated halos through the AURIGA2PANDAS pipeline and create PAndAS-like mocks that fold in all observational limitations of the survey data (…
The X-Ray Outburst of PG 1553+113: A Precession Effect of Two Jets in the Supermassive Black Hole Binary System
Chen, Xu; Huang, Shifeng; Yin, Hongxing +4 more
Blazar PG 1553+113 is thought to be a host of supermassive black hole binary system. A 2.2 yr quasi-periodicity in the γ-ray light curve was detected, possibly a result of jet precession. Motivated by the previous studies based on the γ-ray data, we analyzed the X-ray light curve and spectra observed during 2012-2020. The 2.2 yr quasi-periodicity …
Magnetic Fields and Star Formation around H II Regions: The S235 Complex
Ray, T. P.; Dewangan, L. K.; Luna, A. +3 more
Magnetic fields are ubiquitous and essential in star formation. In particular, their role in regulating formation of stars across diverse environments like H II regions needs to be well understood. In this study, we present magnetic field properties toward the S235 complex using near-infrared (NIR) H-band polarimetric observations, obtained with t…
Predictions of Astrometric Jitter for Sun-like Stars. I. The Model and Its Application to the Sun as Seen from the Ecliptic
Solanki, Sami K.; Shapiro, Alexander I.; Krivova, Natalie A.
The advent of Gaia, capable of measuring stellar wobbles caused by orbiting planets, raised interest in the astrometric detection of exoplanets. Another source of such wobbles (often also called jitter) is stellar magnetic activity. A quantitative assessment of the stellar astrometric jitter is important for a more reliable astrometric detection a…
Strong Correlation between Fe II/Mg II Ratio and Eddington Ratio of Type 1 Active Galactic Nuclei
Kim, Minjin; Nagao, Tohru; Woo, Jong-Hak +2 more
The Fe II/Mg II line flux ratio has been used as an indicator of the Fe/Mg abundance ratio in the broad-line region (BLR) of active galactic nuclei (AGNs). On the basis of archival rest-frame UV spectra obtained via the Hubble Space Telescope and the Sloan Digital Sky Survey, we investigate the Fe II/Mg II ratios of type 1 AGNs at z < 2. Over w…
The Challenge to MOND from Ultra-faint Dwarf Galaxies
Loeb, Abraham; Safarzadeh, Mohammadtaher
Modified Newtonian dynamics (MOND) at low acceleration has been astonishingly powerful at explaining the rotation curve of galaxies and the relation between the baryonic content of the galaxies and their observed circular velocity, known as the baryonic TullyFisher relationship. It is known that MOND fails at explaining the observed velocity dispe…
The Transition from Diffuse Molecular Gas to Molecular Cloud Material in Taurus
Kim, Hwihyun; Federman, S. R.; Lambert, David L. +6 more
We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical conditions toward stars behind the Taurus Molecular Cloud (TMC). New high-resolution spectra at visible and near-IR w…