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The chemical compositions of accreted and in situ galactic globular clusters according to SDSS/APOGEE
Majewski, Steven R.; Beers, Timothy C.; Horta, Danny +16 more
Studies of the kinematics and chemical compositions of Galactic globular clusters (GCs) enable the reconstruction of the history of star formation, chemical evolution, and mass assembly of the Galaxy. Using the latest data release (DR16) of the SDSS/APOGEE survey, we identify 3090 stars associated with 46 GCs. Using a previously defined kinematic …
The Separation Distribution of Ultrawide Binaries across Galactic Populations
Tian, Hai-Jun; Rix, Hans-Walter; Gould, Andrew +1 more
We present an extensive and pure sample of ultrawide binary stars with separations of 0.01 ≲ s/pc ≲ 1 in the solar neighborhood. Using data from Gaia DR2, we define kinematic subpopulations via the systems’ tangential velocities, I.e., disk-like (V ⊥,tot ≤ 40 km s-1), intermediate (V ⊥,tot = 40-85 km s-1…
Timing the earliest quenching events with a robust sample of massive quiescent galaxies at 2 < z < 5
Cimatti, A.; Cullen, F.; McLure, R. J. +19 more
We present a sample of 151 massive (M* > 1010 M⊙) quiescent galaxies at 2 < z < 5, based on a sophisticated Bayesian spectral energy distribution fitting analysis of the CANDELS UDS and GOODS-South fields. Our sample includes a robust sub-sample of 61 objects for which we confidently exclude low-redshift a…
The `red supergiant problem': the upper luminosity boundary of Type II supernova progenitors
Beasor, Emma R.; Davies, Ben
By comparing the properties of red supergiant (RSG) supernova (SN) progenitors to those of field RSGs, it has been claimed that there is an absence of progenitors with luminosities L above log (L/L⊙) > 5.2. This is in tension with the empirical upper luminosity limit of RSGs at log (L/L⊙) = 5.5, a result known as the `RSG …
MIRACLES: atmospheric characterization of directly imaged planets and substellar companions at 4-5 µm. I. Photometric analysis of β Pic b, HIP 65426 b, PZ Tel B, and HD 206893 B
Quanz, S. P.; Todorov, K. O.; Stolker, T. +6 more
Context. Directly imaged planets and substellar companions are key targets for the characterization of self-luminous atmospheres. Their photometric appearance at 4-5 µm is sensitive to the chemical composition and cloud content of their atmosphere.
Aims: We aim to systematically characterize the atmospheres of directly imaged low-mass c…
Confirmation of WASP-107b's Extended Helium Atmosphere with Keck II/NIRSPEC
Kirk, James; López-Morales, Mercedes; Alam, Munazza K. +1 more
We present the detection of helium in the extended atmosphere of the sub-Saturn WASP-107b using high-resolution (R ≈ 25,000) near-infrared spectra from Keck II/Near Infrared Echelle Spectrograph (NIRSPEC). We find peak excess absorption of 7.26% ± 0.24% (30σ) centered on the He i triplet at 10833 Å. The amplitude and shape of the helium absorption…
Observations of galactic and extragalactic novae
Izzo, Luca; Della Valle, Massimo
The recent GAIA DR2 measurements of distances to galactic novae have allowed to re-analyse some properties of nova populations in the Milky Way and in external galaxies on new and more solid empirical bases. In some cases, we have been able to confirm results previously obtained, such as the concept of nova populations into two classes of objects,…
The MUSE Hubble Ultra Deep Field Survey. XIII. Spatially resolved spectral properties of Lyman α haloes around star-forming galaxies at z > 3
Bacon, Roland; Blaizot, Jérémy; Garel, Thibault +18 more
We present spatially resolved maps of six individually-detected Lyman α haloes (LAHs) as well as a first statistical analysis of the Lyman α (Lyα) spectral signature in the circum-galactic medium of high-redshift star-forming galaxies (-17.5 > MUV > -21.5) using the Multi-Unit Spectroscopic Explorer. Our resolved spectroscopic ana…
The Galactic radial abundance gradients of C, N, O, Ne, S, Cl, and Ar from deep spectra of H II regions
Méndez-Delgado, J. E.; Arellano-Córdova, K. Z.; García-Rojas, J. +1 more
We present a reassessment of the radial abundance gradients of C, N, O, Ne, S, Cl, and Ar in the Milky Way using deep spectra of 33 H II regions gathered from the literature, covering Galactocentric distances from 6 to 17 kpc. The distances of the objects have been revised using Gaia parallaxes. We recalculate the physical conditions and ionic abu…
The Ups and Downs of Accreting X-Ray Pulsars: Decade-long Observations with the Fermi Gamma-Ray Burst Monitor
Wilson-Hodge, C. A.; Roberts, O. J.; Malacaria, C. +4 more
We review more than 10 yr of continuous monitoring of accreting X-ray pulsars with the all-sky Gamma-ray Burst Monitor (GBM) aboard the Fermi Gamma-ray Space Telescope. Our work includes data from the start of GBM operations in 2008 August, through to 2019 November. Pulsations from 39 accreting pulsars are observed over an energy range of 10-50 ke…