Search Publications
Binary Red Supergiants: A New Method for Detecting B-type Companions
Massey, Philip; Levesque, Emily M.; Neugent, Kathryn F.
With the exception of a few well-known and studied systems, the binary population of red supergiants (RSGs) remains relatively uncharacterized. Famous systems such as VV Cep, 31 Cyg, and ζ Aur contain RSG + B star binaries, and here we explore whether B stars are the main type of companion we expect from an evolutionary point of view. Using the Ge…
Suzaku and NuSTAR X-ray spectroscopy of γ Cassiopeiae and HD 110432
Tsujimoto, Masahiro; Hayashi, Takayuki; Kitaguchi, Takao +1 more
γ Cas and its dozen analogs comprise a small but distinct class of X-ray sources. They are early Be-type stars with an exceptionally hard thermal X-ray emission. The X-ray production mechanism has been under intense debate. Two competing ideas are (i) the magnetic activities in the Be star and its disk, and (ii) the mass accretion onto the unident…
The Megaparsec-scale Gas-sloshing Spiral in the Remnant Cool Core Cluster Abell 1763
Clarke, T. E.; Randall, S. W.; Blanton, E. L. +4 more
We present a multiwavelength study of the massive galaxy cluster Abell 1763 at redshift z = 0.231. Image analysis of a 19.6 ks Chandra archival observation reveals a cluster-wide spiral of enhanced surface brightness in the intracluster medium (ICM). While such spirals are understood to form in clusters with sloshing strong cool cores (SCCs), the …
Measuring the hydrostatic mass bias in galaxy clusters by combining Sunyaev-Zel'dovich and CMB lensing data
Hurier, G.; Angulo, R. E.
The cosmological parameters preferred by the cosmic microwave background (CMB) primary anisotropies predict many more galaxy clusters than those that have been detected via the thermal Sunyaev-Zeldovich (tSZ) effect. This discrepancy has attracted considerable attention since it might be evidence of physics beyond the simplest ΛCDM model. However,…
Topographic Expressions of Large Thrust Faults on Mars
Klimczak, Christian; Kling, Corbin L.; Byrne, Paul K.
On planets with little erosion, thrust faults produce broad, asymmetric, positive-relief, linear to arcuate ridges—often referred to as lobate scarps—that remain largely unaltered, such that their topographic expressions are a measure of the structural uplift caused by the displacement and associated country rock deformation of the faults. Here we…
A Comparison of Maps and Power Spectra Determined from South Pole Telescope and Planck Data
Bleem, L. E.; Stark, A. A.; George, E. M. +43 more
We study the consistency of 150 GHz data from the South Pole Telescope (SPT) and 143 GHz data from the Planck satellite over the patch of sky covered by the SPT-SZ survey. We first visually compare the maps and find that the residuals appear consistent with noise after accounting for differences in angular resolution and filtering. We then calcula…
The blue straggler V106 in NGC 6791: a prototype progenitor of old single giants masquerading as young
Ryde, N.; Grundahl, F.; Stello, D. +18 more
We determine the properties of the binary star V106 in the old open cluster NGC 6791 . We identify the system to be a blue straggler cluster member by using a combination of ground-based and Kepler photometry and multi-epoch spectroscopy. The properties of the primary component are found to be M_p∼ 1.67 M_{⊙ }, more massive than the cluster turn-o…
Revisiting Stephan's Quintet with deep optical images
Cuillandre, Jean-Charles; Duc, Pierre-Alain; Renaud, Florent
Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As such, it has been subject to intensive multiwavelength observation campaigns. Yet, models lack constrains to …
Gaia GraL: Gaia DR2 gravitational lens systems. II. The known multiply imaged quasars
Djorgovski, S. G.; Surdej, J.; Ducourant, C. +12 more
Context. Thanks to its spatial resolution, the ESA/Gaia space mission offers a unique opportunity to discover new multiply imaged quasars and to study the already known lensed systems at sub-milliarcsecond astrometric precisions.
Aims: In this paper, we address the detection of the known multiply imaged quasars from the Gaia Data Release 2 (D…
Absorption and emission features of 7Be II in the outburst spectra of V838 Her (Nova Her 1991)
Molaro, P.; Izzo, L.; Selvelli, P.
High- and low-resolution International Ultraviolet Explorer (IUE) spectra of V838 Her in the early outburst stages exhibit a strong absorption feature shortward of λ3130. We discuss the nature of this spectral feature and provide convincing evidence that it corresponds to the blueshifted resonance doublet of singly ionized 7Be recently …