Search Publications
Missions
Journals
Publication Years
Discovery of an Intermediate-luminosity Red Transient in M51 and Its Likely Dust-obscured, Infrared-variable Progenitor
Williams, Robert E.; Kulkarni, S. R.; Tinyanont, Samaporn +49 more
We present the discovery of an optical transient (OT) in Messier 51, designated M51 OT2019-1 (also ZTF 19aadyppr, AT 2019abn, ATLAS19bzl), by the Zwicky Transient Facility (ZTF). The OT rose over 15 days to an observed luminosity of M r = -13 (νL ν = 9 × 106 L ⊙), in the luminosity gap between novae …
X-Ray Reprocessing: Through the Eclipse Spectra of High-mass X-Ray Binaries with XMM-Newton
Paul, Biswajit; Kretschmar, Peter; Aftab, Nafisa
The study of X-ray reprocessing is one of the key diagnostic tools to probe the environment in X-ray binary systems. One difficult aspect of studying X-ray reprocessing is the presence of much brighter primary radiation from the compact star together with the reprocessed radiation. In contrast, for eclipsing systems, the X-rays we receive during e…
Metal-poor Stars Observed with the Automated Planet Finder Telescope. II. Chemodynamical Analysis of Six Low-metallicity Stars in the Halo System of the Milky Way
Zhao, Gang; Placco, Vinicius M.; Li, Haining +2 more
In this work, we study the chemical compositions and kinematic properties of six metal-poor stars with [Fe/H] < -2.5 in the Galactic halo. From high-resolution (R ∼ 110,000) spectroscopic observations obtained with the Lick/Automated Planet Finder, we determined individual abundances for up to 23 elements, to quantitatively evaluate our sample.…
Transition from Circular-ribbon to Parallel-ribbon Flares Associated with a Bifurcated Magnetic Flux Rope
Ding, M. D.; Guo, Y.; Zhong, Z. +2 more
Magnetic flux ropes play a key role in triggering solar flares in the solar atmosphere. In this paper, we investigate the evolution of NOAA Active Region 12268 within 36 hr from 2015 January 29 to 30, during which a flux rope was formed and three M-class and three C-class flares were triggered without coronal mass ejections. During the evolution o…
Constraining Compact Object Formation with 2M0521
Breivik, Katelyn; Andrews, Jeff J.; Chatterjee, Sourav
We show that the recently discovered binary 2M05215658+4359220 (2M0521), comprising a giant star (GS) orbiting a suspected black hole (BH) in an ∼80 day orbit, may be instrumental in shedding light on uncertain BH-formation physics and can be a test case for studying wind accretion models. Using binary population synthesis with a realistic prescri…
Temperature stability in the sub-milliHertz band with LISA Pathfinder
Mendes, L.; Russano, G.; Lloro, I. +79 more
LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milliHertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferomet…
CG X-1: An Eclipsing Wolf-Rayet ULX in the Circinus Galaxy
Soria, Roberto; Liu, Jifeng; Walton, Dominic J. +7 more
We investigated the time-variability and spectral properties of the eclipsing X-ray source Circinus Galaxy X-1 (GG X-1), using Chandra, XMM-Newton and ROSAT. We phase-connected the light curves observed over 20 yr, and we obtained a best-fitting period P = (25,970.0 ± 0.1) s ≈ 7.2 hr, and a period derivative \dot{P}/P=(10.2+/- 4.6)× {10}-7
Multi-wavelength variability of the young solar analog ι Horologii. X-ray cycle, star spots, flares, and UV emission
Sanz-Forcada, J.; Stelzer, B.; Raetz, S. +2 more
Context. Chromospheric activity cycles are common in late-type stars; however, only a handful of coronal activity cycles have been discovered. ι Hor is the most active and youngest star with known coronal cycles. It is also a young solar analog, and we are likely facing the earliest cycles in the evolution of solar-like stars, at an age ( 600 Myr)…
Using ALMA to resolve the nature of the early star-forming large-scale structure PLCK G073.4-57.5
Frye, Brenda; Hill, Ryley; Béthermin, Matthieu +10 more
Galaxy clusters at high redshift are key targets for understanding matter assembly in the early Universe, yet they are challenging to locate. A sample of more than 2000 high-z candidate structures has been found using Planck's all-sky submillimetre maps, and a sub-set of 234 have been followed up with Herschel-SPIRE, which showed that the emission…
Single-spacecraft Identification of Flux Tubes and Current Sheets in the Solar Wind
Servidio, Sergio; Pecora, Francesco; Greco, Antonella +3 more
A novel technique is presented for describing and visualizing the local topology of the magnetic field using single-spacecraft data in the solar wind. The approach merges two established techniques: the Grad-Shafranov (GS) reconstruction method, which provides a plausible regional two-dimensional magnetic field surrounding the spacecraft trajector…