Search Publications
Spectropolarimetric Inversions of the Ca II 8542 Å Line in an M-class Solar Flare
Mathioudakis, M.; Rouppe van der Voort, L.; Carlsson, M. +3 more
We study the M1.9-class solar flare SOL2015-09-27T10:40 UT using high-resolution full Stokes imaging spectropolarimetry of the Ca II 8542 Å line obtained with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope. Spectropolarimetric inversions using the non-LTE code NICOLE are used to construct semiempirical models of the flarin…
Rotating Stars from Kepler Observed with Gaia DR2
Davenport, James R. A.; Covey, Kevin R.
We have matched the astrometric data from Gaia Data Release 2 to the sample of stars with measured rotation periods from Kepler. Using 30,305 stars with good distance estimates, we select 16,248 as being likely main-sequence single stars centered within a 0.5 mag region about a 1 Gyr isochrone, removing many subgiants and unresolved binary stars f…
The AGN Ionization Cones of NGC 5728. I. Excitation and Nuclear Structure
Durré, Mark; Mould, Jeremy
We explore the gas morphology and excitation mechanisms of the ionization cones of the Type II Seyfert galaxy NGC 5728. Near-IR and optical data from the SINFONI and MUSE integral field units on the Very Large Telescope are combined with Hubble Space Telescope optical images, Chandra X-ray data, and Very Large Array radio observations. The complex…
The Far-infrared Emission of the First Massive Galaxies
Shivaei, Irene; Lyu, Jianwei; Rieke, George H. +2 more
Massive Population II galaxies undergoing the first phase of vigorous star formation after the initial Population III stage should have high energy densities and silicate-rich interstellar dust. We have modeled the resulting far-infrared spectral energy distributions (SEDs), demonstrating that they are shifted substantially to bluer (“warmer”) wav…
An Evaluation of 10 Lensing Models of the Frontier Fields Cluster MACS J0416.1-2403
Sharon, K.; Mahler, G.; Remolina González, J. D.
Galaxy clusters can act as gravitational lenses and magnify the universe behind them, allowing us to see deep into the early universe. The Hubble Space Telescope Frontier Fields program uses six galaxy clusters imaged by Hubble to discover and study galaxies at z ∼ 5-10. Seven independent teams developed lens models and derived magnifications for …
Metallicity Variations in the Type II Globular Cluster NGC 6934
Milone, A. P.; Marino, A. F.; Bedin, L. R. +7 more
The Hubble Space Telescope photometric survey of Galactic globular clusters (GCs) has revealed a peculiar “chromosome map” for NGC 6934. In addition to a typical sequence, similar to that observed in Type I GCs, NGC 6934 displays additional stars on the red side, analogous to the anomalous Type II GCs, as defined in our previous work. We present a…
Storm in a Teacup: X-Ray View of an Obscured Quasar and Superbubble
Mullaney, James R.; Edge, Alastair C.; Alexander, David M. +5 more
We present the X-ray properties of the “Teacup AGN” (SDSS J1430+1339), a z = 0.085 type 2 quasar that is interacting dramatically with its host galaxy. Spectral modeling of the central quasar reveals a powerful, highly obscured active galactic nucleus (AGN) with a column density of N H = (4.2-6.5) × 1023 cm-2 and a…
Toward Understanding the B[e] Phenomenon. VII. AS 386, a Single-lined Binary with a Candidate Black Hole Component
Reichart, D. E.; Miroshnichenko, A. S.; Manset, N. +24 more
We report the results of spectroscopic and photometric observations of the emission-line object AS 386. For the first time we found that it exhibits the B[e] phenomenon and fits the definition of an FS CMa type object. The optical spectrum shows the presence of a B-type star with the following properties: T eff = 11,000 ± 500 K, log L/L…
Microlensing and Intrinsic Variability of the Broad Emission Lines of Lensed Quasars
Hanslmeier, A.; Muñoz, J. A.; Falco, E. E. +5 more
We study the broad emission lines in a sample of 11 gravitationally lensed quasars with at least two epochs of observation to identify intrinsic variability and to disentangle it from microlensing. To improve our statistical significance and emphasize trends, we also include 15 lens systems with single-epoch spectra. Mg II and C III] emission line…
Mass and Light of Abell 370: A Strong and Weak Lensing Analysis
Schrabback, T.; Vulcani, B.; Hoag, A. +13 more
We present a new gravitational lens model of the Hubble Frontier Fields cluster Abell 370 (z = 0.375) using imaging and spectroscopy from Hubble Space Telescope and ground-based spectroscopy. We combine constraints from a catalog of 909 weakly lensed galaxies and 39 multiply imaged sources comprised of 114 multiple images, including a system of mu…