Search Publications
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. VI. Evidence for the Long-lived Nonsteady Warp of Nongravitational Scenarios
Wang, H. -F.; López-Corredoira, M.; Huang, Y. +6 more
By combining LAMOST DR4 and Gaia DR2 common red clump stars with age and proper motion, we analyze the amplitude evolution of the stellar warp independently of any assumption with a simple model. The greatest height of the warp disk increases with galactocentric distance in different populations and is dependent on age: the younger stellar populat…
The Mass-Size Relation and the Constancy of GMC Surface Densities in the Milky Way
Lada, Charles J.; Dame, T. M.
We use two existing molecular cloud catalogs derived from the same CO survey and two catalogs derived from local dust extinction surveys to investigate the nature of the giant molecular cloud (GMC) mass-size relation in the Galaxy. We find that the four surveys are well described by MGMC ∼ R2, implying a constant mean surface…
Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation
Martin, Crystal L.; Chevallard, Jacopo; Shapley, Alice E. +5 more
Strong [O III]λλ4959,5007 + Hβ emission appears to be typical in star-forming galaxies at z > 6.5. As likely contributors to cosmic reionization, these galaxies and the physical conditions within them are of great interest. At z > 6.5, where Lyα is greatly attenuated by the intergalactic medium, rest-UV metal emission lines provide an altern…
The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2
Amarante, João A. S.; Smith, Martin C.; Boeche, Corrado
Although the stellar halo accounts for just ∼1 per cent of the total stellar mass of the Milky Way, the kinematics of halo stars encode valuable information about the origins and evolution of our Galaxy. It has been shown that the high transverse velocity stars in Gaia DR2 reveal a double sequence in the Hertzsprung-Russell (HR) diagram, indicatin…
ISPY-NACO Imaging Survey for Planets around Young stars. Survey description and results from the first 2.5 years of observations
Queloz, D.; Quanz, S. P.; Avenhaus, H. +21 more
Context. The occurrence rate of long-period (a ≳ 50 au) giant planets around young stars is highly uncertain since it is not only governed by the protoplanetary disc structure and planet formation process, but also reflects both dynamical re-structuring processes after planet formation as well as possible capture of planets not formed in situ. Dir…
Rapid late-time X-ray brightening of the tidal disruption event OGLE16aaa
Kajava, Jari J. E.; Miniutti, Giovanni; Giustini, Margherita +1 more
Stars that pass too close to a super-massive black hole may be disrupted by strong tidal forces. OGLE16aaa is one such tidal disruption event (TDE) which rapidly brightened and peaked in the optical/UV bands in early 2016 and subsequently decayed over the rest of the year. OGLE16aaa was detected in an XMM-Newton X-ray observation on June 9, 2016 w…
Constraining churning and blurring in the Milky Way using large spectroscopic surveys - an exploratory study
Bowers, J. Bradley; Feltzing, Sofia; Agertz, Oscar
We have investigated the possibilities to quantify how much stars move in the Milky Way disc due to diffuse processes (blurring) and due to influences from spiral arms and the bar (churning). We assume that the formation radius of a star can be inferred if we know its elemental abundances and age and the metallicity profile of the interstellar med…
Seeing above the clouds with high-resolution spectroscopy
Gandhi, Siddharth; Brogi, Matteo; Webb, Rebecca K.
In the last decade, ground-based high-resolution Doppler spectroscopy (HRS) has detected numerous species in transiting and non-transiting hot Jupiters, and is ideally placed for atmospheric characterization of warm Neptunes and super Earths. Many of these cooler and smaller exoplanets have shown cloudy atmospheres from low-resolution near-infrare…
Gamma-Ray Emission of 60Fe and 26Al Radioactivity in Our Galaxy
Greiner, J.; Wang, W.; Siegert, T. +7 more
The isotopes 60Fe and 26Al originate from massive stars and their supernovae, reflecting ongoing nucleosynthesis in the Galaxy. We studied the gamma-ray emission from these isotopes at characteristic energies 1173, 1332, and 1809 keV with over 15 yr of SPI data, finding a line flux in 60Fe combined lines of $(0.31\…
The Formation of a Stellar Association in the NGC 7000/IC 5070 Complex: Results from Kinematic Analysis of Stars and Gas
Hillenbrand, Lynne A.; Carpenter, John M.; Kuhn, Michael A. +1 more
We examine the clustering and kinematics of young stellar objects (YSOs) in the North America/Pelican Nebulae, as revealed by Gaia astrometry, in relation to the structure and motions of the molecular gas, as indicated in molecular-line maps. The Gaia parallaxes and proper motions allow us to significantly refine previously published lists of YSOs…