Search Publications
The Physical Parameters of Four WC-type Wolf-Rayet Stars in the Large Magellanic Cloud: Evidence of Evolution
Aadland, Erin; Massey, Philip; Hillier, D. John +1 more
We present a spectral analysis of four Large Magellanic Cloud (LMC) WC-type Wolf-Rayet (WR) stars (BAT99-8, BAT99-9, BAT99-11, and BAT99-52) to shed light on two evolutionary questions surrounding massive stars. The first is: are WO-type WR stars more oxygen enriched than WC-type stars, indicating further chemical evolution, or are the strong high…
[C II] Map of the Molecular Ring and Arms of the Spiral Galaxy NGC 7331
Fadda, Dario; Sutter, Jessica
We present the [C II] 157.7 µm map of galaxy NGC 7331 obtained with the Field-Imaging Far-Infrared Line Spectrometer on board the Stratospheric Observatory for Infrared Astronomy (SOFIA). This map extends an existent Herschel/Photodetector Array Camera and Spectrometer observation of the central strip of the galaxy to encompass the entire mo…
Joint Survey Processing. I. Compact Oddballs in the COSMOS Field-Low-luminosity Quasars at z > 6?
Koekemoer, Anton M.; Brammer, Gabriel; Miyatake, Hironao +8 more
The faint-end slope of the quasar luminosity function at z ~ 6 and its implication on the role of quasars in reionizing the intergalactic medium at early times has been an outstanding problem for some time. The identification of faint high-redshift quasars with luminosities of <1044.5 erg s-1 is challenging. They are rare …
Observations of Instability-driven Nanojets in Coronal Loops
Antolin, Patrick; McLaughlin, James A.; Sukarmadji, A. Ramada C.
The recent discovery of nanojets by Antolin et al. represents magnetic reconnection in a braided field, thus clearly identifying reconnection-driven nanoflares. Due to their small scale (500 km in width, 1500 km in length) and short timescales (<15 s), it is unclear how pervasive nanojets are in the solar corona. In this paper, we present Inter…
Long-term Photometric and Low-resolution Spectroscopic Analysis of Five Contact Binaries
Joshi, Y. C.; Panchal, A.; De Cat, Peter +1 more
A photometric and spectroscopic investigation is performed on five W Ursae Majoris eclipsing binaries J015818.6+260247 (hereinafter as J0158b), J073248.4+405538 (hereinafter as J0732), J101330.8+494846 (hereinafter as J1013), J132439.8+130747 (hereinafter as J1324), and J152450.7+245943 (hereinafter as J1524). The photometric data are collected wi…
Multiwavelength Observations of the Obscuring Wind in the Radio-quiet Quasar MR 2251-178
Kaastra, J. S.; Djorgovski, S. G.; Stern, D. +11 more
Obscuring winds driven away from active supermassive black holes are rarely seen due to their transient nature. They have been observed with multiwavelength observations in a few Seyfert 1 galaxies and one broad absorption line radio-quiet quasar so far. An X-ray obscuration event in MR 2251-178 was caught in late-2020, which triggered multiwavele…
Solar Wind Charge Exchange Soft X-Ray Emissions in the Magnetosphere during an Interplanetary Coronal Mass Ejection Compared to Its Driven Sheath
Liu, Ying D.; Sun, Wei; Ji, Li +9 more
Soft X-ray emissions from solar wind charge exchange (SWCX) are applied in a recently developed approach to study the magnetosphere using panoramic soft X-ray imaging. This study represents the first attempt to distinguish magnetospheric SWCX emissions observed by XMM-Newton during the impact of an interplanetary coronal mass ejection (ICME) and i…
An Electric-field-driven Global Coronal Magnetohydrodynamics Simulation Model Using Helioseismic and Magnetic Imager Vector-magnetic-field Synoptic Map Data
Hayashi, Keiji; Wu, Chin-Chun; Liou, Kan
We present the simulation methodology and results of our new data-driven global coronal magnetohydrodynamics (MHD) simulation model. In this model, the solar-surface electric field is first calculated such that the curl will satisfy both the induction equation and the given temporal variations of the solar-surface magnetic field. We use the synopt…
New Theoretical Period-Luminosity-Metallicity Relations for RR Lyrae in the Rubin-LSST Filters
Marconi, Marcella; Molinaro, Roberto; Dall'Ora, Massimo +8 more
The revolutionary power of future Rubin-LSST observations will allow us to significantly improve the physics of pulsating stars, including RR Lyrae. In this context, an updated theoretical scenario predicting all the relevant pulsation observables in the corresponding photometric filters is mandatory. The bolometric light curves are based on a rec…
The Extended Tidal Tails of NGC 7089 (M2)
Grillmair, Carl J.
Using photometry and proper motions from Gaia Early Data Release 3, we detect a 45° long trailing stellar debris stream associated with the old, metal-poor globular cluster NGC 7089. With a width on the order of 100 pc, the extended stream appears to be as dynamically cold as the coldest known streams found to date. There is some evidence for an e…