Search Publications
On the AGN Nature of Two UV-bright Sources at zspec ∼ 5.5 in the CANDELS Fields: An Update on the AGN Space Density at M1450 ∼ -22.5
Dickinson, M.; Fiore, F.; Grazian, A. +8 more
It is widespread opinion that hydrogen reionization is mainly driven by primeval star-forming galaxies, with high-z active galactic nuclei (AGNs) having a minor role. Recent observations, however, challenge this notion, indicating a number of issues related to a galaxy-driven reionization scenario. We provide here an updated assessment of the spac…
Delay Time Distributions of Type Ia Supernovae from Galaxy and Cosmic Star Formation Histories
Pacifici, Camilla; Graur, Or; Strolger, Louis-Gregory +2 more
We present analytical reconstructions of SN Ia delay time distributions (DTDs) by way of two independent methods: by a Markov Chain Monte Carlo best-fit technique comparing the volumetric SN Ia rate history to today's compendium cosmic star formation history, and second through a maximum likelihood analysis of the star formation rate histories of …
A Systematic Study of the Dust of Galactic Supernova Remnants. I. The Distance and the Extinction
Jiang, Biwei; Chen, Bingqiu; Zhao, He +3 more
By combining the photometric, spectroscopic, and astrometric information of the stars in the sightline of supernova remnants (SNRs), the distances to and the extinctions of 32 Galactic SNRs are investigated. The stellar atmospheric parameters are from the Sloan Digital Sky Survey-DR14/Apache Point Observatory Galaxy Evolution Experiment and Large …
Hot Dust-obscured Galaxies with Excess Blue Light
Stern, D.; Bauer, F. E.; Díaz-Santos, T. +10 more
Hot dust-obscured galaxies (Hot DOGs) are among the most luminous galaxies in the universe. Powered by highly obscured, possibly Compton-thick, active galactic nuclei (AGNs), Hot DOGs are characterized by spectral energy distributions that are very red in the mid-infrared yet dominated by the host galaxy stellar emission in the UV and optical. An …
Very Long Baseline Astrometry of PSR J1012+5307 and its Implications on Alternative Theories of Gravity
Deller, Adam T.; Kaplan, David L.; Lazio, T. Joseph W. +4 more
PSR J1012+5307, a millisecond pulsar in orbit with a helium white dwarf (WD), has been timed with high precision for about 25 yr. One of the main objectives of this long-term timing is to use the large asymmetry in gravitational binding energy between the neutron star and the WD to test gravitational theories. Such tests, however, will be eventual…
X-shooter Spectroscopy and HST Imaging of 15 Massive Quiescent Galaxies at z ≳ 2
Conselice, Christopher J.; Gallazzi, Anna; Zibetti, Stefano +23 more
We present a detailed analysis of a large sample of spectroscopically confirmed massive quiescent galaxies (MQGs; log(M */M ⊙) ∼ 11.5) at z ≳ 2. This sample comprises 15 galaxies selected in the COSMOS and UDS fields by their bright K-band magnitudes and followed up with Very Large Telescope (VLT) X-shooter spectroscopy and H…
Introducing the Search for Intermediate-mass Black Holes in Nearby Galaxies (SIBLING) Survey
Plotkin, Richard M.; Martínez-Palomera, Jorge; Lira, Paulina +2 more
Intermediate-mass black holes (IMBHs) have masses between 102 and 106 M⊙ and are key to our understanding of the formation of massive black holes. The known population of IMBHs remains small, with a few hundred candidates and only a handful of them confirmed as bona fide IMBHs. Until now, the most widely used selec…
Revisiting the Impact of Dust Production from Carbon-rich Wolf-Rayet Binaries
Sakon, Itsuki; Williams, Peredur M.; Lau, Ryan M. +3 more
We present a dust spectral energy distribution (SED) and binary stellar population analysis revisiting the dust production rates (DPRs) in the winds of carbon-rich Wolf-Rayet (WC) binaries and their impact on galactic dust budgets. DustEM SED models of 19 Galactic WC "dustars" reveal DPRs of ${\dot{M}}_{d}\sim {10}^{-10}\mbox{--}{10}^{-6}$ M⊙…
Discovery of Two Pulsating Extremely Low-mass Pre-white Dwarf Candidates in the TESS Eclipsing Binaries
Zhang, Xiaobin; Wang, Kun; Dai, Min
We report the discovery of two new pulsating extremely low-mass pre-white dwarf (pre-ELMV) candidates in the Transiting Exoplanet Survey Satellite (TESS) eclipsing binaries, TIC 149160359 and TIC 416264037. Their light curves show a typical feature of EL CVn-type binaries. The light-curve modeling indicates that they are both detached systems with…
Cosmological Insights into the Early Accretion of r-process-enhanced Stars. I. A Comprehensive Chemodynamical Analysis of LAMOST J1109+0754
Zhao, Gang; Beers, Timothy C.; Placco, Vinicius M. +11 more
This study presents a comprehensive chemodynamical analysis of LAMOST J1109+0754, a bright (V = 12.8), extremely metal-poor ([Fe/H] = -3.17) star, with a strong r-process enhancement ([Eu/Fe] = +0.94 ± 0.12). Our results are based on the 7D measurements supplied by Gaia and the chemical composition derived from a high-resolution (R ∼ 110,000), hig…