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Measuring the vertical response of the Galactic disc to an infalling satellite
Laporte, Chervin F. P.; Drimmel, Ronald; Johnston, Kathryn V. +3 more
Using N-body simulations of the Milky Way interacting with a satellite similar to the Sagittarius dwarf galaxy, we quantitatively analyse the vertical response of the Galactic disc to the satellite's repeated impacts. We approximate the vertical distortion of the Galactic disc as the sum of the first three Fourier azimuthal terms m = 0, 1, and 2, …
HAZMAT. VII. The Evolution of Ultraviolet Emission with Age and Rotation for Early M Dwarf Stars
Loyd, R. O. Parke; Jackman, James A. G.; Peacock, Sarah +6 more
The ultraviolet (UV) emission from the most numerous stars in the universe, M dwarfs, impacts the formation, chemistry, atmospheric stability, and surface habitability of their planets. We have analyzed the spectral evolution of UV emission from M0-M2.5 (0.3-0.6 M⊙) stars as a function of age, rotation, and Rossby number using Hubble Sp…
Supervirial Temperature or Neon Overabundance? Suzaku Observations of the Milky Way Circumgalactic Medium
Nicastro, Fabrizio; Mathur, Smita; Gupta, Anjali +4 more
We analyzed Suzaku and Chandra observations of the soft diffuse X-ray background toward four sight lines with the goal of characterizing the X-ray emission from the Milky Way circumgalactic medium (CGM). We identified two thermal components of the CGM, one at a uniform temperature of kT = 0.176 ± 0.008 keV and the other at temperatures in the rang…
SLITRONOMY: Towards a fully wavelet-based strong lensing inversion technique
Starck, J. -L.; Courbin, F.; Joseph, R. +2 more
Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content of galaxies. It also serves as a valuable cosmological probe by allowing us to measure the Hubble constant independently of other methods. These applications all require the difficult task of inverting the lens equation and simultane…
Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code - III. ω Cen
Brownstein, Joel R.; Cunha, Katia; Smith, Verne V. +18 more
We study the multiple populations of ω Cen by using the abundances of Fe, C, N, O, Mg, Al, Si, K, Ca, and Ce from the high-resolution, high signal-to-noise (S/N > 70) spectra of 982 red giant stars observed by the SDSS-IV/APOGEE-2 survey. We find that the shape of the Al-Mg and N-C anticorrelations changes as a function of metallicity, continuo…
Location and energetics of the ultra-fast outflow in PG 1448+273
Piconcelli, E.; Tombesi, F.; Middei, R. +3 more
Context. Ultra-fast outflows (UFOs) are the most powerful disk-driven winds in active galactic nuclei (AGNs). Theoretical and observational evidence shows that UFOs play a key role in the AGN feedback mechanism. The mechanical power of the strongest UFOs may be enough to propagate the feedback to the host galaxies and ultimately shape the AGN-gala…
X-ray-induced chemistry of water and related molecules in low-mass protostellar envelopes
Walsh, Catherine; Bosman, Arthur D.; Nomura, Hideko +2 more
Context. Water is a key molecule in star- and planet-forming regions. Recent water line observations toward several low-mass protostars suggest low water gas fractional abundances (<10−6 with respect to total hydrogen density) in the inner warm envelopes (r < 102 au). Water destruction by X-rays is thought to influence …
The Flattening Metallicity Gradient in the Milky Way's Thin Disk
Shen, Juntai; Li, Zhao-Yu; Vickers, John J.
We calculate the ages, orbits and phase-space coordinates for a sample of ~4 million LAMOST and Gaia stars. The ages are cross-matched and compared with values from two other popular age catalogs, which derive the ages using different methods. Of these ~4 million stars, we select a sample of 1.3 million stars and investigate their radial metallici…
The dynamics of the globular cluster NGC 3201 out to the Jacobi radius
Lewis, Geraint F.; de Boer, Thomas; Mackey, Dougal +7 more
As part of a chemodynamical survey of five nearby globular clusters with 2dF/AAOmega on the Anglo-Australian Telescope (AAT), we have obtained kinematic information for the globular cluster NGC 3201. Our new observations confirm the presence of a significant velocity gradient across the cluster which can almost entirely be explained by the high pr…
APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge
Piatti, Andrés E.; Beers, Timothy C.; Placco, Vinicius M. +26 more
The central (`bulge') region of the Milky Way is teeming with a significant fraction of mildly metal-deficient stars with atmospheres that are strongly enriched in cyanogen (12C14N). Some of these objects, which are also known as nitrogen-enhanced stars, are hypothesised to be relics of the ancient assembly history of the Mil…