Search Publications
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…
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…
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…
A Comparison of Star-forming Clumps and Tidal Tails in Local Mergers and High-redshift Galaxies
Calzetti, Daniela; Whitmore, Bradley C.; Chandar, Rupali +8 more
The Clusters, Clumps, Dust, and Gas in Extreme Star-forming Galaxies (CCDG) survey with the Hubble Space Telescope includes multiwavelength imaging of 13 galaxies less than 100 Mpc away, spanning a range of morphologies and sizes, from blue compact dwarfs to luminous infrared galaxies, all with star formation rates in excess of hundreds of solar m…
Forbidden Line Emission from Type Ia Supernova Remnants Containing Balmer-dominated Shells
Leibundgut, Bruno; Raymond, John C.; Chu, You-Hua +3 more
Balmer-dominated shells in supernova remnants (SNRs) are produced by collisionless shocks advancing into a partially neutral medium and are most frequently associated with Type Ia supernovae. We have analyzed Hubble Space Telescope (HST) images and Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) or AAT/Wide Field Integral Spect…
Statistics of the Chemical Composition of Solar Analog Stars and Links to Planet Formation
Beaton, Rachael L.; Jain, Bhuvnesh; Teske, Johanna K. +3 more
The Sun has been found to be depleted in refractory (rock-forming) elements relative to nearby solar analogs, suggesting a potential indicator of planet formation. Given the small amplitude of the depletion, previous analyses have primarily relied on high signal-to-noise stellar spectra and a strictly differential approach to determine elemental a…
Interplanetary Coronal Mass Ejections from MAVEN Orbital Observations at Mars
Feng, Xueshang; Wang, Yang; Liu, Libo +9 more
The measurements from the Mars Atmosphere and Volatile EvolutioN spacecraft, in orbit around Mars, are utilized to investigate interplanetary coronal mass ejections (ICMEs) near 1.52 au. We identify 24 ICMEs from 2014 December 6 to 2019 February 21. The ICME list is used to examine the statistical properties of ICMEs. On average, the magnetic fiel…