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The stellar halo of isolated central galaxies in the Hyper Suprime-Cam imaging survey
Sonnenfeld, Alessandro; Wang, Wenting; Han, Jiaxin +14 more
We study the faint stellar halo of isolated central galaxies, by stacking galaxy images in the HSC survey and accounting for the residual sky background sampled with random points. The surface brightness profiles in HSC r band are measured for a wide range of galaxy stellar masses (9.2 < log10M∗/M⊙ < 11.4) an…
Detection of Superluminal Motion in the X-Ray Jet of M87
Cheung, C. C.; Jones, Christine; Meyer, Eileen T. +5 more
Chandra HRC observations are investigated for evidence of proper motion and brightness changes in the X-ray jet of the nearby radio galaxy M87. Using images spanning 5 yr, proper motion is measured in the X-ray knot HST-1, with a superluminal apparent speed of 6.3 ± 0.4c, or 24.1 ± 1.6 mas yr-1, and in Knot D, with a speed of 2.4 ± 0.6c…
The Relation between Galaxy ISM and Circumgalactic O VI Gas Kinematics Derived from Observations and ΛCDM Simulations
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +8 more
We present the first galaxy-O VI absorption kinematic study for 20 absorption systems (EW > 0.1 Å) associated with isolated galaxies (0.15 ≤ z ≤ 0.55) that have accurate redshifts and rotation curves obtained using Keck/ESI. Our sample is split into two azimuthal angle bins: major axis (Φ < 25°) and minor axis (Φ > 33°). O VI absorption a…
CHANG-ES. XX. High-resolution Radio Continuum Images of Edge-on Galaxies and Their AGNs: Data Release 3
Saikia, D. J.; Wang, Q. Daniel; Irwin, Judith +17 more
The CHANG-ES galaxy sample consists of 35 nearby edge-on galaxies that have been observed using the VLA at 1.6 and 6.0 GHz. Here we present the third data release of our sample, namely, the B configuration 1.6 GHz sample. In addition, we make available the band-to-band spectral index maps between 1.6 and 6.0 GHz, the latter taken in the matching r…
Observational evidence for a dry dust-wind origin of Mars seasonal dark flows
Vincendon, Mathieu; Carter, John; Stcherbinine, Aurélien +1 more
Seasonal flows on warm slopes, or recurring slope lineae ("RSL"), have been presented as strong evidence for currently flowing water on Mars. This assumption was supported by a correlation between activity and warm temperatures, and by the spectral identification of hydrated salts. Here we first demonstrate that salts spectral identification is no…
Hypervelocity Stars from a Supermassive Black Hole-Intermediate-mass Black Hole Binary
Tagawa, Hiromichi; Rossi, Elena Maria; Fragione, Giacomo +4 more
In this paper we consider a scenario in which the currently observed hypervelocity stars in our Galaxy have been ejected from the Galactic center as a result of dynamical interactions with an intermediate-mass black hole (IMBH) orbiting the central supermassive black hole (SMBH). By performing three-body scattering experiments, we calculate the di…
The sdA problem - III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry
Kepler, S. O.; Bell, Keaton J.; Pelisoli, Ingrid +1 more
The physical nature of the sdA stars - cool hydrogen-rich objects with spectroscopic surface gravities intermediate between main-sequence and canonical-mass white dwarfs - has been elusive since they were found in Sloan Digital Sky Survey Data Release 12 spectra. The population is likely dominated by metal-poor A/F stars in the halo with overestim…
Properties of Magnetic Reconnection and FTEs on the Dayside Magnetopause With and Without Positive IMF Bx Component During Southward IMF
Kilpua, E. K. J.; Fear, R. C.; Palmroth, M. +11 more
This paper describes properties and behavior of magnetic reconnection and flux transfer events (FTEs) on the dayside magnetopause using the global hybrid-Vlasov code Vlasiator. We investigate two simulation runs with and without a sunward (positive) Bx component of the interplanetary magnetic field (IMF) when the IMF is southward. The r…
The Quintuplet Cluster: Extended Structure and Tidal Radius
Rui, Nicholas Z.; Hosek, Matthew W., Jr.; Lu, Jessica R. +4 more
The Quintuplet star cluster is one of only three known young (<10 Myr) massive (M > 104 M ⊙) clusters within ∼100 pc of the Galactic center (GC). In order to explore star cluster formation and evolution in this extreme environment, we analyze the Quintuplet’s dynamical structure. Using the HST WFC3-IR instrument, we tak…
Mass function and dynamical study of the open clusters Berkeley 24 and Czernik 27 using ground based imaging and Gaia astrometry
Bisht, D.; Yadav, R. K. S.; Fynbo, J. P. U. +3 more
We present a UBVI photometric study of the open clusters Berkeley 24 (Be 24) and Czernik 27 (Cz 27). The radii of the clusters are determined as 2{^'.}7 and 2{^'.}3 for Be 24 and Cz 27, respectively. We use the Gaia Data Release 2 (GDR2) catalogue to estimate the mean proper motions for the clusters. We found the mean proper …