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Two Populations of Carbon-enhanced Metal-poor Stars in the Disk System of the Milky Way
Yoon, Jinmi; Beers, Timothy C.; Lee, Young Sun +2 more
We present a chemodynamical analysis of low-resolution (R ~ 1300) spectroscopy of ~50,000 stars from the AAOmega Evolution of Galactic Structure survey, focusing on two key populations of (in total) 650 carbon-enhanced metal-poor (CEMP) stars within the disk system of the Milky Way: a mildly prograde population (Lz < 1000 kpc km s
Improved Measurements of Molecular Cloud Distances Based on Global Search
Wang, Hongchi; Xu, Ye; Su, Yang +5 more
The principle of the background-eliminated extinction-parallax (BEEP) method is examining the extinction difference between on- and off-cloud regions to reveal the extinction jump caused by molecular clouds, thereby revealing the distance in complex dust environments. The BEEP method requires high-quality images of molecular clouds and high-precis…
Chandra Observations of Excess Fe Kα Line Emission in Galaxies with High Star Formation Rates: X-Ray Reflection on Galaxy Scales?
Ricci, Claudio; Bauer, Franz E.; Hickox, Ryan C. +4 more
In active galactic nuclei (AGNs), fluorescent Fe Kα (iron) line emission is generally interpreted as originating from obscuring material around a supermassive black hole on the scale of a few parsecs. However, recent Chandra studies indicate the existence of iron line emission extending to kiloparsec scales in the host galaxy. The connection betwe…
First Observation of the Oxygen 630 nm Emission in the Martian Dayglow
Aoki, S.; Vandaele, A. C.; Daerden, F. +13 more
Following the recent detection of the oxygen green line airglow on Mars, we have improved the statistical analysis of the data recorded by the NOMAD/UVIS instrument on board the ExoMars Trace Gas Orbiter mission by summing up hundreds of spectra to increase the signal to noise ratio. This led to the observation of the OI 630 nm emission, the first…
Daily dust variation from the PFS MEx observations
Giuranna, Marco; Wolkenberg, Paulina
We collected over 7 Martian years (MY) of data observed by the Planetary Fourier Spectrometer (PFS) to present a daily variation of dust content in the Martian atmosphere. We found three typical behaviors of dust opacities with LT (local time). The most peculiar variation was observed when global dust storms (MYs 28 and 34) or particularly strong …
Variation in the Stellar Initial Mass Function from the Chromospheric Activity of M Dwarfs in Early-type Galaxies
van Dokkum, Pieter; Conroy, Charlie
Mass measurements and absorption-line studies indicate that the stellar initial mass function (IMF) is bottom-heavy in the central regions of many early-type galaxies, with an excess of low-mass stars compared to the IMF of the Milky Way. Here we test this hypothesis using a method that is independent of previous techniques. Low-mass stars have st…
A Massive, Clumpy Molecular Gas Distribution and Displaced AGN in Zw 3146
Fabian, A. C.; Combes, F.; McDonald, M. +8 more
We present a recent Atacama Large Millimeter/submillimeter Array observation of the CO(1-0) line emission in the central galaxy of the Zw 3146 galaxy cluster (z = 0.2906). We also present updated X-ray cavity measurements from archival Chandra observations. The 5 × 1010 M⊙ supply of molecular gas, which is confined to the cen…
Potential asteroid discoveries by the ESA Gaia mission. Results from follow-up observations
Mignard, F.; Panem, C.; Tanga, P. +42 more
Context. Since July 2014, the Gaia mission of the European Space Agency has been surveying the entire sky down to magnitude 20.7 in the visible. In addition to the millions of daily observations of stars, thousands of Solar System objects (SSOs) are observed. By comparing their positions, as measured by Gaia, to those of known objects, a daily pro…
Hunting for the elusive methylene radical
Menten, K. M.; Gong, Y.; Bergman, P. +4 more
Context. The NKaKc = 404-313 transitions of ortho-CH2 between 68 and 71 GHz were first detected toward the Orion-KL and W51 Main star-forming regions. Given their high upper level energies (225 K) above the ground state, they were naturally thought to arise in dense, hot molecular c…
Testing Photoevaporation and MHD Disk Wind Models through Future High-angular Resolution Radio Observations: The Case of TW Hydrae
Ricci, Luca; Weber, Michael; Ercolano, Barbara +1 more
We present theoretical predictions for the free-free emission at centimeter wavelengths obtained from photoevaporation and magnetohydrodynamic (MHD) wind disk models adjusted to the case of the TW Hydrae young stellar object. For this system, disk photoevaporation with heating due to the high-energy photons from the star has been proposed as a pos…