Adi Foord
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View article: Evidence for Supermassive Black Hole Binaries
Evidence for Supermassive Black Hole Binaries Open
We review the state of the evidence for the existence and observational appearance of supermassive black hole binaries. Such objects are expected from standard hierarchical galaxy evolution to form after two galaxies, each containing a sup…
View article: Chandra Discovery of a Candidate Hyperluminous X-Ray Source in MCG+11-11-032
Chandra Discovery of a Candidate Hyperluminous X-Ray Source in MCG+11-11-032 Open
We present a multiwavelength analysis of MCG+11-11-032, a nearby active galactic nucleus (AGN), with a unique classification as being both a binary and a dual AGN candidate. With new Chandra observations, we aim to resolve any dual AGN sys…
View article: Evidence for supermassive black hole binaries
Evidence for supermassive black hole binaries Open
We review the state of the evidence for the existence and observational appearance of supermassive black hole binaries. Such objects are expected from standard hierarchical galaxy evolution to form after two galaxies, each containing a sup…
View article: Large-scale dual AGN in large-scale cosmological hydrodynamical simulations
Large-scale dual AGN in large-scale cosmological hydrodynamical simulations Open
Detecting dual active galactic nuclei (DAGNs) in observations and understanding theoretically which massive black holes (MBHs) compose them and in which galactic and large-scale environment they reside are becoming increasingly important q…
View article: Large-scale dual AGN in large-scale cosmological hydrodynamical simulations
Large-scale dual AGN in large-scale cosmological hydrodynamical simulations Open
Detecting dual active galactic nuclei (DAGN) in observations and understanding theoretically which massive black holes (MBHs) compose them and in which galactic and large-scale environment they reside are becoming increasingly important qu…
View article: Searching for the Highest-z Dual Active Galactic Nuclei in the Deepest Chandra Surveys
Searching for the Highest-z Dual Active Galactic Nuclei in the Deepest Chandra Surveys Open
We present an analysis searching for dual active galactic nuclei (AGN) among 62 high-redshift (2.5 < z < 3.5) X-ray sources selected from the X-UDS, AEGIS-XD, CDF-S, and COSMOS-Legacy Chandra surveys. We aim to quantify the frequency of du…
View article: A Multiwavelength Portrait of the 3C 220.3 Lensed System
A Multiwavelength Portrait of the 3C 220.3 Lensed System Open
The 3C 220.3 system is a rare case of a foreground narrow-line radio galaxy (“galaxy A,” z A = 0.6850) lensing a background submillimeter galaxy ( z SMG = 2.221). New spectra from MMT/Binospec confirm that the companion galaxy (“galaxy B”)…
View article: The Black Hole Mass and Photometric Components of NGC 4826
The Black Hole Mass and Photometric Components of NGC 4826 Open
We present infrared photometry and Hubble Space Telescope imaging and spectroscopy of the Sab galaxy NGC 4826. Schwarzschild dynamical modeling is used to measure its central black hole mass M . Photometric decomposition is used to enable …
View article: The Black Hole Mass and Photometric Components of NGC 4826
The Black Hole Mass and Photometric Components of NGC 4826 Open
We present IR photometry and HST imaging and spectroscopy of Sab galaxy NGC 4826. Schwarzschild dynamical modeling is used to measure its central black hole mass $M$. Photometric decomposition is used to enable a comparison of $M$ to publi…
View article: Chandra Discovery of a Candidate Hyper-Luminous X-ray Source in MCG+11-11-032
Chandra Discovery of a Candidate Hyper-Luminous X-ray Source in MCG+11-11-032 Open
We present a multi-wavelength analysis of MCG+11-11-032, a nearby AGN with the unique classification of both a binary and a dual AGN candidate. With new Chandra observations we aim to resolve any dual AGN system via imaging data, and searc…
View article: A Multiwavelength Portrait of the 3C 220.3 Lensed System
A Multiwavelength Portrait of the 3C 220.3 Lensed System Open
The 3C 220.3 system is a rare case of a foreground narrow-line radio galaxy (“galaxy A,” zA = 0.6850) lensing a background submillimeter galaxy (zSMG = 2.221). New spectra from MMT/Binospec confirm that the companion galaxy (“galaxy B”) is…
View article: Prospects for AGN Studies with AXIS: AGN Fueling—Resolving Hot Gas inside Bondi Radius of SMBHs
Prospects for AGN Studies with AXIS: AGN Fueling—Resolving Hot Gas inside Bondi Radius of SMBHs Open
Hot gas around a supermassive black hole (SMBH) should be captured within the gravitational “sphere of influence”, characterized by the Bondi radius. Deep Chandra observations have spatially resolved the Bondi radii of five nearby SMBHs th…
View article: Surveying the Onset and Evolution of Supermassive Black Holes at High-z with AXIS
Surveying the Onset and Evolution of Supermassive Black Holes at High-z with AXIS Open
The nature and origin of supermassive black holes (SMBHs) remain an open matter of debate within the scientific community. While various theoretical scenarios have been proposed, each with specific observational signatures, the lack of suf…
View article: Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945
Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945 Open
We analyze 330 ks of Chandra X-ray imaging and spectra of the nearby, edge-on starburst and Seyfert type 2 galaxy NGC 4945 to measure the hot gas properties along the galactic outflows. We extract and model spectra from 15 regions extendin…
View article: X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys
X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys Open
This study presents the capabilities of the AXIS telescope in estimating redshifts from X-ray spectra alone (X-ray redshifts, XZs). Through extensive simulations, we establish that AXIS observations enable reliable XZ estimates for more th…
View article: Tracking Supermassive Black Hole Mergers from kpc to sub-pc Scales with AXIS
Tracking Supermassive Black Hole Mergers from kpc to sub-pc Scales with AXIS Open
We present an analysis showcasing how the Advanced X-ray Imaging Satellite (AXIS), a proposed NASA Probe-class mission, will significantly increase our understanding of supermassive black holes undergoing mergers—from kpc to sub-pc scales.…
View article: Uncovering the First AGN Jets with AXIS
Uncovering the First AGN Jets with AXIS Open
Jets powered by AGN in the early Universe (z≳6) have the potential to not only define the evolutionary trajectories of the first-forming massive galaxies but to enable the accelerated growth of their associated SMBHs. Under typical assumpt…
View article: Detecting Wandering Intermediate-Mass Black Holes with AXIS in the Milky Way and Local Massive Galaxies
Detecting Wandering Intermediate-Mass Black Holes with AXIS in the Milky Way and Local Massive Galaxies Open
This white paper explores the detectability of intermediate-mass black holes (IMBHs) wandering in the Milky Way (MW) and massive local galaxies, with a particular emphasis on the role of AXIS. IMBHs, ranging within 103−6M⊙, are commonly fo…
View article: The Seoul National University AGN Monitoring Project. III. Hβ Lag Measurements of 32 Luminous Active Galactic Nuclei and the High-luminosity End of the Size–Luminosity Relation
The Seoul National University AGN Monitoring Project. III. Hβ Lag Measurements of 32 Luminous Active Galactic Nuclei and the High-luminosity End of the Size–Luminosity Relation Open
We present the main results from a long-term reverberation mapping campaign carried out for the Seoul National University AGN Monitoring Project (SAMP). High-quality data were obtained during 2015–2021 for 32 luminous active galactic nucle…
View article: Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945
Hot Gas Outflow Properties of the Starburst Galaxy NGC 4945 Open
We analyze 330 ks of {\it Chandra} X-ray imaging and spectra of the nearby, edge-on starburst and Seyfert Type 2 galaxy NGC 4945 to measure the hot gas properties along the galactic outflows. We extract and model spectra from 15 regions ex…
View article: Searching for the Highest-z Dual AGN in the Deepest Chandra Surveys
Searching for the Highest-z Dual AGN in the Deepest Chandra Surveys Open
We present an analysis searching for dual AGN among 62 high-redshift ($2.5 < z < 3.5$) X-ray sources selected from publicly available deep Chandra fields. We aim to quantify the frequency of dual AGN in the high-redshift Universe, which ho…
View article: The Seoul National University AGN Monitoring Project III: H$β$ lag measurements of 32 luminous AGNs and the high-luminosity end of the size--luminosity relation
The Seoul National University AGN Monitoring Project III: H$β$ lag measurements of 32 luminous AGNs and the high-luminosity end of the size--luminosity relation Open
We present the main results from a long-term reverberation mapping campaign carried out for the Seoul National University Active Galactic Nuclei (AGN) Monitoring Project. High-quality data were obtained during 2015-2021 for 32 luminous AGN…
View article: Prospects for AGN Studies with AXIS: AGN Fueling -- Resolving Hot Gas inside Bondi Radius of SMBHs
Prospects for AGN Studies with AXIS: AGN Fueling -- Resolving Hot Gas inside Bondi Radius of SMBHs Open
Hot gas around a supermassive black hole (SMBH) should be captured within the gravitational "sphere of influence", characterized by the Bondi radius. Deep Chandra observations have spatially resolved the Bondi radii of five nearby SMBHs th…
View article: X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys
X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys Open
This study presents the capabilities of the AXIS telescope in estimating redshifts from X-ray spectra alone (X-ray redshifts, XZs). Through extensive simulations, we establish that AXIS observations enable reliable XZ estimates for more th…
View article: Uncovering the First AGN Jets with AXIS
Uncovering the First AGN Jets with AXIS Open
Jets powered by AGN in the early Universe ($z \gtrsim 6$) have the potential to not only define the trajectories of the first-forming massive galaxies but to enable the accelerated growth of their associated SMBHs. Under typical assumption…
View article: Detecting Wandering Intermediate-Mass Black Holes with AXIS in the Milky Way and Local Massive Galaxies
Detecting Wandering Intermediate-Mass Black Holes with AXIS in the Milky Way and Local Massive Galaxies Open
This white paper explores the detectability of intermediate-mass black holes (IMBHs) wandering in the Milky Way (MW) and massive local galaxies, with a particular emphasis on the role of AXIS. IMBHs, ranging within $10^{3-6} \, M_\odot$, a…
View article: AGN in overdense environments at high-$z$ with AXIS
AGN in overdense environments at high-$z$ with AXIS Open
Overdense regions at high redshift ($z \gtrsim 2$) are perfect laboratories to study the relations between environment and SMBH growth, and the AGN feedback processes on the surrounding galaxies and diffuse gas. In this white paper, we dis…
View article: Tracking Supermassive Black Hole Mergers from kpc to sub-pc Scales with AXIS
Tracking Supermassive Black Hole Mergers from kpc to sub-pc Scales with AXIS Open
We present an analysis showcasing how the Advanced X-ray Imaging Satellite (AXIS), a proposed NASA Probe-class mission, will significantly increase our understanding of supermassive black holes undergoing mergers -- from kpc to sub-pc scal…
View article: Surveying the onset and evolution of supermassive black holes at high-z with AXIS
Surveying the onset and evolution of supermassive black holes at high-z with AXIS Open
The nature and origin of supermassive black holes (SMBHs) remain an open matter of debate within the scientific community. While various theoretical scenarios have been proposed, each with specific observational signatures, the lack of suf…