Search Results - "Xavier Prochaska, J."
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A cold, massive, rotating disk galaxy 1.5 billion years after the Big Bang
Published in Nature (London) (01-05-2020)“…Massive disk galaxies like the Milky Way are expected to form at late times in traditional models of galaxy formation 1 , 2 , but recent numerical simulations…”
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The PHLEK Survey: A New Determination of the Primordial Helium Abundance
Published in The Astrophysical journal (01-06-2020)“…We present Keck NIRSPEC and Keck NIRES spectroscopy of sixteen metal-poor galaxies that have pre-existing optical observations. The near-infrared (NIR)…”
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3
Correcting C iv-based virial black hole masses
Published in Monthly notices of the Royal Astronomical Society (01-02-2017)“…The C IV...1498,1501 broad emission line is visible in optical spectra to redshifts exceeding z ~ 5. C IV has long been known to exhibit significant…”
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The physical properties of z > 2 Lyman limit systems: new constraints for feedback and accretion models
Published in Monthly notices of the Royal Astronomical Society (01-02-2016)“…We study the physical properties of a homogeneous sample of 157 optically thick absorption line systems at redshifts ~1.8-4.4, selected from a high-dispersion…”
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A semisupervised machine learning search for never-seen gravitational-wave sources
Published in Monthly notices of the Royal Astronomical Society (01-02-2021)“…ABSTRACT By now, tens of gravitational-wave (GW) events have been detected by the LIGO and Virgo detectors. These GWs have all been emitted by compact binary…”
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EARLY AND EXTENDED HELIUM REIONIZATION OVER MORE THAN 600 MILLION YEARS OF COSMIC TIME
Published in The Astrophysical journal (10-07-2016)“…ABSTRACT We measure the effective optical depth of He ii Ly α absorption at in 17 UV-transmitting quasars observed with UV spectrographs on the Hubble Space…”
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Detection of Pristine Gas Two Billion Years After the Big Bang
Published in Science (American Association for the Advancement of Science) (02-12-2011)“…In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced…”
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Characterizing the Fast Radio Burst Host Galaxy Population and its Connection to Transients in the Local and Extragalactic Universe
Published in The Astronomical journal (01-02-2022)“…Abstract We present the localization and host galaxies of one repeating and two apparently nonrepeating fast radio bursts (FRBs). FRB 20180301A was detected…”
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Multiphase outflows in post-starburst E+A galaxies - II. A direct connection between the neutral and ionized outflow phases
Published in Monthly notices of the Royal Astronomical Society (01-06-2020)“…ABSTRACT Post-starburst E+A galaxies are systems that hosted a powerful starburst that was quenched abruptly. Simulations suggest that these systems provide…”
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Quasar quartet embedded in giant nebula reveals rare massive structure in distant universe
Published in Science (American Association for the Advancement of Science) (15-05-2015)“…All galaxies once passed through a hyperluminous quasar phase powered by accretion onto a supermassive black hole. But because these episodes are brief,…”
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MUSE Analysis of Gas around Galaxies (MAGG) – II: metal-enriched halo gas around z ∼ 1 galaxies
Published in Monthly notices of the Royal Astronomical Society (01-12-2020)“…ABSTRACT We present a study of the metal-enriched cool halo gas traced by Mg ii absorption around 228 galaxies at z ∼ 0.8–1.5 within 28 quasar fields from the…”
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12
A UNIVERSAL DENSITY STRUCTURE FOR CIRCUMGALACTIC GAS
Published in The Astrophysical journal (20-10-2016)“…ABSTRACT We develop a new method to constrain the physical conditions in the cool (∼104 K) circumgalactic medium (CGM) from measurements of ionic column…”
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The low density and magnetization of a massive galaxy halo exposed by a fast radio burst
Published in Science (American Association for the Advancement of Science) (11-10-2019)“…Present-day galaxies are surrounded by cool and enriched halo gas extending for hundreds of kiloparsecs. This halo gas is thought to be the dominant reservoir…”
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High time resolution and polarization properties of ASKAP-localized fast radio bursts
Published in Monthly notices of the Royal Astronomical Society (01-09-2020)“…ABSTRACT Combining high time and frequency resolution full-polarization spectra of fast radio bursts (FRBs) with knowledge of their host galaxy properties…”
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THE COS-HALOS SURVEY: ORIGINS OF THE HIGHLY IONIZED CIRCUMGALACTIC MEDIUM OF STAR-FORMING GALAXIES
Published in The Astrophysical journal (10-12-2016)“…ABSTRACT The total contribution of diffuse halo gas to the galaxy baryon budget strongly depends on its dominant ionization state. In this paper, we address…”
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The COS-Halos Survey: Metallicities in the Low-redshift Circumgalactic Medium
Published in The Astrophysical journal (10-03-2017)“…Abstract We analyze new far-ultraviolet spectra of 13 quasars from the COS-Halos survey that cover the H i Lyman limit of 14 circumgalactic medium (CGM)…”
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Implications of z ∼ 6 Quasar Proximity Zones for the Epoch of Reionization and Quasar Lifetimes
Published in The Astrophysical journal (01-05-2017)“…We study quasar proximity zones in the redshift range 5.77 ≤ z ≤ 6.54 by homogeneously analyzing 34 medium-resolution spectra, encompassing both archival and…”
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Simple Models of Metal-line Absorption and Emission from Cool Gas Outflows
Published in The Astrophysical journal (10-06-2011)“…We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We…”
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QUASARS PROBING QUASARS. IV. JOINT CONSTRAINTS ON THE CIRCUMGALACTIC MEDIUM FROM ABSORPTION AND EMISSION
Published in The Astrophysical journal (20-03-2013)“…We have constructed a sample of 29 close projected quasar pairs where the background quasar spectrum reveals absorption from optically thick Hi gas associated…”
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THE H i CONTENT OF THE UNIVERSE OVER THE PAST 10 GYR
Published in The Astrophysical journal (20-02-2016)“…ABSTRACT We use the Hubble Space Telescope (HST) archive of ultraviolet (UV) quasar spectroscopy to conduct the first blind survey for damped Ly absorbers…”
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