D. M. Alexander
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View article: Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. IV. Broad Emission-line Evolution Sequence among H <i>α</i> , Mg <scp>ii</scp> , and H <i>β</i>
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. IV. Broad Emission-line Evolution Sequence among H <i>α</i> , Mg <span>ii</span> , and H <i>β</i> Open
From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by W.-J. Guo et al., we investigate the evolutionary sequence of broad emission lines using a redshift-selected subset (0.35 < z < 0.45) of 54 CL-AGNs w…
View article: Using active learning to improve quasar identification for the DESI spectra processing pipeline
Using active learning to improve quasar identification for the DESI spectra processing pipeline Open
The Dark Energy Spectroscopic Instrument (DESI) survey uses an automatic spectral classification pipeline to classify spectra. QuasarNET is a convolutional neural network used as part of this pipeline originally trained using data from the…
View article: DESI 2024 V: Full-Shape galaxy clustering from galaxies and quasars
DESI 2024 V: Full-Shape galaxy clustering from galaxies and quasars Open
We present the measurements and cosmological implications of the galaxy two-point clustering using over 4.7 million unique galaxy and quasar redshifts in the range 0.1 < z < 2.1 divided into six redshift bins over a ∼ 7,500 square degree f…
View article: Euclid Quick Data Release (Q1). The active galaxies of Euclid
Euclid Quick Data Release (Q1). The active galaxies of Euclid Open
We present three catalogues of candidate active galactic nuclei (AGN) in the Euclid Quick Release (Q1) fields. For each Euclid source, we collected multi-wavelength photometric and spectroscopic information from surveys such as the Galaxy …
View article: DESI 2024 VII: cosmological constraints from the full-shape modeling of clustering measurements
DESI 2024 VII: cosmological constraints from the full-shape modeling of clustering measurements Open
We present cosmological results from the measurement of clustering of galaxy, quasar and Lyman-α forest tracers from the first year of observations with the Dark Energy Spectroscopic Instrument (DESI Data Release 1). We adopt the full-shap…
View article: DESI 2024 II: sample definitions, characteristics, and two-point clustering statistics
DESI 2024 II: sample definitions, characteristics, and two-point clustering statistics Open
We present the samples of galaxies and quasars used for DESI 2024 cosmological analyses, drawn from the DESI Data Release 1 (DR1). We describe the construction of large-scale structure (LSS) catalogs from these samples, which include match…
View article: The Compton-thick AGN population and the <i>N</i>H distribution of low-mass AGN in our cosmic backyard
The Compton-thick AGN population and the <i>N</i>H distribution of low-mass AGN in our cosmic backyard Open
We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density ($N_{\rm {H}}$) distribution of AGN in our cosmic backyard using a mid-infrared selected AGN sample within 15 Mpc. The column den…
View article: The Compton-thick AGN Population and the $N_{\rm H}$ Distribution of Low-mass AGN in our Cosmic Backyard
The Compton-thick AGN Population and the $N_{\rm H}$ Distribution of Low-mass AGN in our Cosmic Backyard Open
We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density ($N_{\rm{H}}$) distribution of AGN in our cosmic backyard using a mid-infrared selected AGN sample within 15 Mpc. The column dens…
View article: Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. II. Statistical Properties from the First Data Release
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. II. Statistical Properties from the First Data Release Open
We present the identification of changing-look active galactic nuclei (CL-AGNs) from the Dark Energy Spectroscopic Instrument First Data Release and Sloan Digital Sky Survey Data Release 16 at z ≤ 0.9. To confirm the CL-AGNs, we utilize sp…
View article: An obscured quasar census with the 4MOST IR AGN survey: design, predicted properties, and scientific goals
An obscured quasar census with the 4MOST IR AGN survey: design, predicted properties, and scientific goals Open
We present the 4MOST (4-metre Multi-Object Spectroscopic Telescope) infrared (IR) AGN survey, the first large-scale optical spectroscopic survey characterizing mid-infrared (MIR) selected obscured active galactic nuclei (AGNs). The survey …
View article: DESI 2024 III: baryon acoustic oscillations from galaxies and quasars
DESI 2024 III: baryon acoustic oscillations from galaxies and quasars Open
We present the DESI 2024 galaxy and quasar baryon acoustic oscillations (BAO) measurements using over 5.7 million unique galaxy and quasar redshifts in the range 0.1 < z < 2.1. Divided by tracer type, we utilize 300,017 galaxies from the m…
View article: Euclid Quick Data Release (Q1). The active galaxies of Euclid
Euclid Quick Data Release (Q1). The active galaxies of Euclid Open
We present a catalogue of candidate active galactic nuclei (AGN) in the $Euclid$ Quick Release (Q1) fields. For each $Euclid$ source we collect multi-wavelength photometry and spectroscopy information from Galaxy Evolution Explorer (GALEX)…
View article: Data Release 1 of the Dark Energy Spectroscopic Instrument
Data Release 1 of the Dark Energy Spectroscopic Instrument Open
In 2021 May the Dark Energy Spectroscopic Instrument (DESI) collaboration began a 5-year spectroscopic redshift survey to produce a detailed map of the evolving three-dimensional structure of the universe between $z=0$ and $z\approx4$. DES…
View article: ADF22-WEB: A giant barred spiral starburst galaxy in the <i>z</i> = 3.1 SSA22 protocluster core
ADF22-WEB: A giant barred spiral starburst galaxy in the <i>z</i> = 3.1 SSA22 protocluster core Open
In the present-day universe, the most massive galaxies are ellipticals located in the cores of galaxy clusters, harboring the heaviest super-massive black holes (SMBHs). However, the mechanisms that drive the early growth phase and subsequ…
View article: Tripling the Census of Dwarf AGN Candidates Using DESI Early Data
Tripling the Census of Dwarf AGN Candidates Using DESI Early Data Open
Using early data from the Dark Energy Spectroscopic Instrument (DESI) survey, we search for active galactic nuclei (AGN) signatures in 410,757 line-emitting galaxies. By employing the BPT emission-line ratio diagnostic diagram, we identify…
View article: Identifying Missing Quasars from the DESI Bright Galaxy Survey
Identifying Missing Quasars from the DESI Bright Galaxy Survey Open
The Dark Energy Spectroscopic Instrument (DESI) cosmology survey includes a Bright Galaxy Survey (BGS), which will yield spectra for over 10 million bright galaxies ( r < 20.2 AB mag). The resulting sample will be valuable for both cosmolo…
View article: DESI 2024 VI: cosmological constraints from the measurements of baryon acoustic oscillations
DESI 2024 VI: cosmological constraints from the measurements of baryon acoustic oscillations Open
We present cosmological results from the measurement of baryon acoustic oscillations (BAO) in galaxy, quasar and Lyman- α forest tracers from the first year of observations from the Dark Energy Spectroscopic Instrument (DESI), to be releas…
View article: ALMA/SCUBA-2 COSMOS Survey: Properties of X-Ray- and SED-selected Active Galactic Nuclei in Bright Submillimeter Galaxies
ALMA/SCUBA-2 COSMOS Survey: Properties of X-Ray- and SED-selected Active Galactic Nuclei in Bright Submillimeter Galaxies Open
We investigate the properties of active galactic nuclei (AGNs) in the brightest submillimeter galaxies (SMGs) in the COSMOS field. We utilize the bright sample of the ALMA/SCUBA-2 COSMOS Survey (AS2COSMOS), which consists of 260 SMGs with …
View article: Connection between steep radio spectral slopes and dust extinction in QSOs: evidence for outflow-driven shocks in dusty QSOs
Connection between steep radio spectral slopes and dust extinction in QSOs: evidence for outflow-driven shocks in dusty QSOs Open
Recent studies have found a striking positive correlation between the amount of dust obscuration and enhanced radio emission in quasi-stellar objects (QSOs). However, what causes this connection remains unclear. In this paper we analyse uG…
View article: Connection between steep radio spectral slopes and dust extinction in QSOs: evidence for outflow-driven shocks in dusty QSO
Connection between steep radio spectral slopes and dust extinction in QSOs: evidence for outflow-driven shocks in dusty QSO Open
Recent studies have found a striking positive correlation between the amount of dust obscuration and enhanced radio emission in quasi-stellar objects (QSOs). However, what causes this connection remains unclear. In this paper we analyse uG…
View article: DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman alpha forest
DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman alpha forest Open
We present the measurement of Baryon Acoustic Oscillations (BAO) from the Lyman- α (Ly α ) forest of high-redshift quasars with the first-year dataset of the Dark Energy Spectroscopic Instrument (DESI). Our analysis uses over 420 000 Ly α …
View article: The NuSTAR Local AGN N <sub>H</sub> Distribution Survey (NuLANDS). I. Toward a Truly Representative Column Density Distribution in the Local Universe
The NuSTAR Local AGN N <sub>H</sub> Distribution Survey (NuLANDS). I. Toward a Truly Representative Column Density Distribution in the Local Universe Open
Hard X-ray-selected samples of active galactic nuclei (AGN) provide one of the cleanest views of supermassive black hole accretion but are biased against objects obscured by Compton-thick gas column densities of N H > 10 24 cm −2 . To tack…
View article: ALMA/SCUBA-2 COSMOS Survey: Properties of X-ray- and SED-selected AGNs in Bright Submillimeter Galaxies
ALMA/SCUBA-2 COSMOS Survey: Properties of X-ray- and SED-selected AGNs in Bright Submillimeter Galaxies Open
We investigate the properties of active galactic nuclei (AGNs) in the brightest submillimeter galaxies (SMGs) in the COSMOS field. We utilize the bright sample of ALMA/SCUBA-2 COSMOS Survey (AS2COSMOS), which consists of 260 SMGs with $S_{…
View article: Unveiling AGN Outflows: [O iii] Outflow Detection Rates and Correlation with Low-Frequency Radio Emission
Unveiling AGN Outflows: [O iii] Outflow Detection Rates and Correlation with Low-Frequency Radio Emission Open
Some Active Galactic Nuclei (AGN) host outflows which have the potential to alter the host galaxy's evolution (AGN feedback). These outflows have been linked to enhanced radio emission. Here we investigate the connection between low-freque…
View article: Unveiling AGN outflows: [O <scp>iii</scp>] outflow detection rates and correlation with low-frequency radio emission
Unveiling AGN outflows: [O <span>iii</span>] outflow detection rates and correlation with low-frequency radio emission Open
Some active galactic nuclei (AGN) host outflows which have the potential to alter the host galaxy’s evolution (AGN feedback). These outflows have been linked to enhanced radio emission. Here, we investigate the connection between low-frequ…