Search Publications
Tidal-locking-induced Stellar Rotation Dichotomy in the Open Cluster NGC 2287?
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
Stars spend most of their lifetimes on the “main sequence” (MS) in the Hertzsprung-Russell diagram. The obvious double MSs seen in the equivalent color-magnitude diagrams characteristic of Milky Way open clusters (OCs) pose a fundamental challenge to our traditional understanding of star clusters as “single stellar populations.” The clear MS bifur…
AGN photoionization of gas in companion galaxies as a probe of AGN radiation in time and direction
Schawinski, Kevin; Keel, William C.; Moiseev, Alexei V. +9 more
We consider AGN photoionization of gas in companion galaxies (cross-ionization) as a way to sample the intensity of AGN radiation in both direction and time, independent of the gas properties of the AGN host galaxies. From an initial set of 212 AGN+companion systems, identified with the help of Galaxy Zoo participants, we obtained long-slit optica…
FUGIN: Molecular Gas in Spitzer Bubble N4—Possible Evidence for a Cloud-Cloud Collision as a Trigger of Massive Star Formations
Yamagishi, Mitsuyoshi; Kuno, Nario; Tachihara, Kengo +17 more
Herein, we present 12CO (J = 1-0) and 13CO (J = 1-0) emission-line observations via the FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN) toward Spitzer bubble N4. We observed clouds at three discrete velocities: 16, 19, and 25 km s-1. Their masses were 0.1 × 104 M
Variability studies and modelling of the blazar PKS 2155-304 in the light of a decade of multi-wavelength observations
Serpico, P. D.; Lenain, J. -P.; Maurin, G. +2 more
The variability of the high-frequency peaked BL Lac object PKS 2155-304 is studied using almost 10 years of optical, X-ray and γ-ray data. Publicly available data have been gathered and analysed with the aim to characterize the variability and to search for lognormality or periodic behaviour. The optical and X-ray range follow a lognormal process;…
Tidal disruption events from massive black hole binaries: predictions for ongoing and future surveys
Sesana, Alberto; Thorp, Stephen; Chadwick, Eli
We compute the expected cosmic rates of tidal disruption events (TDEs) induced by individual massive black holes (MBHs) and by MBH binaries (MBHBs) - with a specific focus on the latter class - to explore the potential of TDEs to probe the cosmic population of sub-pc MBHBs. Rates are computed by combining MBH and MBHB population models derived fro…
A Broadband Look at the Old and New ULXs of NGC 6946
Fürst, Felix; Walton, Dominic J.; Stern, Daniel +8 more
Two recent observations of the nearby galaxy NGC 6946 with NuSTAR, one simultaneous with an XMM-Newton observation, provide an opportunity to examine its population of bright accreting sources from a broadband perspective. We study the three known ultraluminous X-ray sources (ULXs) in the galaxy, and find that ULX-1 and ULX-2 have very steep power…
Isochrone-cloud fitting of the extended main-sequence turn-off of young clusters
Bastian, N.; Aerts, C.; Johnston, C. +1 more
Context. Extended main-sequence turn-offs (eMSTOs) are a commonly observed property of young clusters. A global theoretical interpretation for eMSTOs is still lacking, but stellar rotation is considered a necessary ingredient to explain eMSTOs.
Aims: We aim to assess the importance of core-boundary and envelope mixing in stellar interiors for…
VLT/SPHERE Multiwavelength High-contrast Imaging of the HD 115600 Debris Disk: New Constraints on the Dust Geometry and the Presence of Young Giant Planets
Currie, Thayne; Wagner, Kevin; Moór, Attila +5 more
Young and dynamically active planetary systems can form disks of debris that are easier to image than the planets themselves. The morphology and evolution of these disks can help to infer the properties of the putative planets responsible for generating and shaping the debris structures. We present integral field spectroscopy and dual-band imaging…
Testing the Kerr Metric with X-Ray Reflection Spectroscopy of Mrk 335 Suzaku Data
Abdikamalov, Askar B.; Ayzenberg, Dimitry; Bambi, Cosimo +4 more
Einstein’s gravity has undergone extensive tests in the weak field gravitational limit, with results in agreement with theoretical predictions. There exist theories beyond general relativity (GR) which modify gravity in the strong field regime but agree with GR in the weak field. Astrophysical black holes are believed to be described by the Kerr m…
Statistics on the Magnetosheath Properties Related to Magnetopause Magnetic Reconnection
Zhang, Hui; Liu, Libo; Wan, Weixing +5 more
Magnetosheath properties, particularly those related to magnetopause magnetic reconnection (MR), are investigated in this study. (1) Asymmetries are found to exist in the distributions of plasma and magnetic field parameters in the magnetosheath. These asymmetries are related to the interplanetary magnetic field (IMF) orientation, and they are pro…