Publications (107)
A quasar-galaxy merger at : rapid host growth via accretion of two massive satellite galaxies
Roberto Decarli, Federica Loiacono, Emanuele Paolo Farina +38
We present JWST/NIRSpec Integral Field Spectroscopy in the rest-frame optical bands of the system PJ308-21, a quasar at caught as its host galaxy interacts with companio…
A 13-Billion-Year View of Galaxy Growth: Metallicity Gradient Evolution from the Local Universe to with JWST and Archival Surveys
Zihao Li, Zheng Cai, Xin Wang +25
The galaxy gas-phase metallicity gradients have been extensively studied over the past four decades, both in the local and high-redshift universe, as they trace the baryon cycle an…
Galaxy Pairs in the Sloan Digital Sky Survey XV: Properties of Ionised Outflows
William Matzko, Shobita Satyapal, Sara L. Ellison +6
Powerful outflows are thought to play a critical role in galaxy evolution and black hole growth. We present the first large-scale systematic study of ionised outflows in paired gal…
Supermassive black hole fueling in IllustrisTNG: Impact of environment
Aklant K. Bhowmick, Laura Blecha, July Thomas
We study the association between active galactic nuclei (AGN) and environment at scales of Mpc in the IllustrisTNG (TNG100) simulated universe. We identify supermas…
Recoiling Black Holes in Merging Galaxies
Laura Blecha, Thomas J. Cox, Abraham Loeb +1
Gravitational-wave (GW) recoil of merging supermassive black holes (SMBHs) may influence the co-evolution of SMBHs and their host galaxies. We examine this possibility using SPH/N-…
Toward Complete Merger Identification at Cosmic Noon with Deep Learning
Aimee Schechter, Aleksandra Ciprijanovic, Rebecca Nevin +4
As we enter the era of large imaging surveys such as , Rubin, and , a deeper understanding of potential biases and selection effects in optical ast…
Introducing the BRAHMA simulation suite: Signatures of low mass black hole seeding models in cosmological simulations
Aklant K. Bhowmick, Laura Blecha, Paul Torrey +6
The first "seeds" of supermassive black holes (BH) can range from . However, the lowest mass seeds () are inaccessible to most cosm…
Multi-wavelength observations of SDSS J105621.45+313822.1, a broad-line, low-metallicity AGN
Jenna M. Cann, Shobita Satyapal, Thomas Bohn +8
In contrast to massive galaxies with Solar or super-Solar gas phase metallicities, very few Active Galactic Nuclei (AGN) are found in low-metallicity dwarf galaxies. Such a populat…
Core Scouring Dynamics and Gravitational Wave Consequences: Constraints on Supermassive Black Hole Binary Hardening
C. J. Harris, Kayhan Gültekin, Laura Blecha
In this paper we perform a multi-messenger investigation of the efficiency of stellar scattering in tightening supermassive black hole binaries by jointly comparing models to the o…
Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?
Nathan J. Secrest, Henrique R. Schmitt, Laura Blecha +2
We present a combined morphological and X-ray analysis of Was 49, an isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in the disk of the primary galaxy…
NuSTAR Observations of Four Mid-IR Selected Dual AGN Candidates in Galaxy Mergers
Ryan W. Pfeifle, Kimberly Weaver, Shobita Satyapal +5
Mergers of galaxies are a ubiquitous phenomenon in the Universe and represent a natural consequence of the ``bottom-up'' mass accumulation and galaxy evolution cosmological paradig…
Local Analogs of Primordial Galaxies: In Search of Intermediate Mass Black Holes with JWST NIRSpec
Sara Doan, Shobita Satyapal, William Matzko +15
Local low metallicity galaxies with signatures of possible accretion activity are ideal laboratories in which to search for the lowest mass black holes and study their impact on th…
A Triple AGN in a Mid-Infrared Selected Late Stage Galaxy Merger
Ryan W. Pfeifle, Shobita Satyapal, Christina Manzano-King +11
The co-evolution of galaxies and the supermassive black holes (SMBHs) at their centers via hierarchical galaxy mergers is a key prediction of CDM cosmology. As gas and dust are…
The Illustris Simulation: Public Data Release
Dylan Nelson, Annalisa Pillepich, Shy Genel +12
We present the full public release of all data from the Illustris simulation project. Illustris is a suite of large volume, cosmological hydrodynamical simulations run with the mov…
Signatures of black hole seeding in the local Universe: Predictions from the BRAHMA cosmological simulations
Aklant K Bhowmick, Laura Blecha, Paul Torrey +8
The first "seeds" of supermassive black holes (BHs) continue to be an outstanding puzzle, and it is currently unclear whether the imprints of early seed formation survive today. He…
Concordance between observations and simulations in the evolution of the mass relation between supermassive black holes and their host galaxies
Xuheng Ding, John D. Silverman, Tommaso Treu +7
We carry out a comparative analysis of the relation between the mass of supermassive black holes (BHs) and the stellar mass of their host galaxies at using well-matched…
The NANOGrav 15 yr Data Set: Targeted Searches for Supermassive Black Hole Binaries
Nikita Agarwal, Gabriella Agazie, Akash Anumarlapudi +116
We present the first targeted searches for continuous gravitational waves (CWs) from 114 active galactic nuclei (AGN) that may host supermassive black hole binaries, using the NANO…
The NANOGrav 15 yr data set: Posterior predictive checks for gravitational-wave detection with pulsar timing arrays
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +99
Pulsar-timing-array experiments have reported evidence for a stochastic background of nanohertz gravitational waves consistent with the signal expected from a population of superma…
Impact of gas spin and Lyman-Werner flux on black hole seed formation in cosmological simulations: implications for direct collapse
Aklant K. Bhowmick, Laura Blecha, Paul Torrey +5
Direct collapse black holes~(BH) are promising candidates for producing massive quasars, but their formation requires fine-tuned conditions. In this work, we use cosmo…
Cosmic evolution of supermassive black holes: A view into the next two decades
Francesca Civano, Nico Cappelluti, Ryan Hickox +38
The discoveries made over the past 20 years by Chandra and XMM-Newton surveys in conjunction with multiwavelength imaging and spectroscopic data available in the same fields have s…
The power of infrared AGN selection in mergers: a theoretical study
Laura Blecha, Gregory F. Snyder, Shobita Satyapal +1
The role of galaxy mergers in fueling active galactic nuclei (AGN) is still debated, owing partly to selection effects inherent to studies of the merger/AGN connection. In particul…
Probing the quasars in a universe with IllustrisTNG physics: Impact of gas-based black hole seeding models
Aklant Kumar Bhowmick, Laura Blecha, Yueying Ni +6
We explore implications of a range of black hole (BH) seeding prescriptions on the formation of the brightest quasars in cosmological hydrodynamic simulations. The unde…
Electromagnetic Counterparts to Massive Black Hole Mergers
Tamara Bogdanovic, M. Coleman Miller, Laura Blecha
The next two decades are expected to open the door to the first coincident detections of electromagnetic (EM) and gravitational wave (GW) signatures associated with massive black h…
Double-peaked Narrow-Line Signatures of Dual Supermassive Black Holes in Galaxy Merger Simulations
Laura Blecha, Abraham Loeb, Ramesh Narayan
We present a first attempt to model the narrow-line (NL) region of active galactic nuclei (AGN) in hydrodynamic simulations of galaxy mergers, using a novel physical prescription.…
Buried AGNs in Advanced Mergers:Mid-infrared color selection as a dual AGN finder
Shobita Satyapal, Nathan J. Secrest, Claudio Ricci +7
A direct consequence of hierarchical galaxy formation is the existence of dual supermassive black holes (SMBHs), which may be preferentially triggered as active galactic nuclei (AG…
Recoiling Black Holes in Merging Galaxies: Relationship to AGN Lifetimes, Starbursts, and the M-sigma Relation
Laura Blecha, Thomas J. Cox, Abraham Loeb +1
Gravitational-wave (GW) recoil of merging supermassive black holes (SMBHs) may influence the co-evolution of SMBHs and their host galaxies. We examine this possibility using SPH/N-…
Astrophysics with the Laser Interferometer Space Antenna
Pau Amaro Seoane, Jeff Andrews, Manuel Arca Sedda +156
The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it will offer unique opportunities to address many…
The Limitations of Optical Spectroscopic Diagnostics in Identifying AGNs in the Low Mass Regime
Jenna M. Cann, Shobita Satyapal, Nicholas P. Abel +4
Intermediate-mass black holes (IMBHs) with masses between are crucial to our understanding of black hole seed formation and are the prime targets for LISA, ye…
Massive Black Hole Binary Mergers in Dynamical Galactic Environments
Luke Zoltan Kelley, Laura Blecha, Lars Hernquist
Gravitational Waves (GW) have now been detected from stellar-mass black hole binaries, and the first observations of GW from Massive Black Hole (MBH) Binaries are expected within t…
How to Detect an Astrophysical Nanohertz Gravitational-Wave Background
Bence Bécsy, Neil J. Cornish, Patrick M. Meyers +93
Analysis of pulsar timing data have provided evidence for a stochastic gravitational wave background in the nHz frequency band. The most plausible source of such a background is th…
The NANOGrav 15-year Data Set: Search for Gravitational Wave Memory
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
We present the results of a search for nonlinear gravitational wave memory in the NANOGrav 15-year data set. We find no significant evidence for memory signals in the dataset, with…
The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +111
We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15-year pulsar-timing data set collected by the North American Nanohertz O…
Recoiling Black Holes in Merging Galaxies: Relationship to AGN Lifetimes and Merger Remnant Properties
Laura Blecha, Thomas J. Cox, Abraham Loeb +1
Central supermassive black holes (SMBHs) are a ubiquitous feature of locally-observed galaxies, and ample evidence suggests that the growth of SMBHs and their host galaxies is clos…
Simulations of black hole fueling in isolated and merging galaxies with an explicit, multiphase ISM
Aneesh Sivasankaran, Laura Blecha, Paul Torrey +9
We study gas inflows onto supermassive black holes using hydrodynamics simulations of isolated galaxies and idealized galaxy mergers with an explicit, multiphase interstellar mediu…
The Next-Generation Very Large Array: Supermassive Black Hole Pairs and Binaries
Sarah Burke-Spolaor, Laura Blecha, Tamara Bogdanovic +7
The Next-Generation Very Large Array (ngVLA) has the potential to be a workhorse for the discovery and study of paired supermassive black holes either at large separations (dual) o…
Signatures of the M31-M32 Galactic Collision
Marion Dierickx, Laura Blecha, Abraham Loeb
The unusual morphologies of the Andromeda spiral galaxy (M31) and its dwarf companion M32 have been characterized observationally in great detail. The two galaxies' apparent proxim…
Inferring Mbh-Mbulge Evolution from the Gravitational Wave Background
Cayenne Matt, Kayhan Gultekin, Luke Kelley +104
We test the impact of an evolving supermassive black hole (SMBH) mass scaling relation (Mbh-Mbulge) on the predictions for the gravitational wave background (GWB). The observed GWB…
Heavy seeds and the first black holes: Insights from the BRAHMA simulations
Aklant K. Bhowmick, Laura Blecha, Paul Torrey +9
From the luminous quasars at to the recent AGNs revealed by JWST, observations of the earliest black hole (BH) populations can provide unique constraints o…
Mergers and Recoil in Triple Massive Black Hole Systems from Illustris
Pranav Satheesh, Laura Blecha, Luke Zoltan Kelley
Massive black hole binaries (MBHBs) form through galaxy mergers and are among the loudest sources of gravitational waves (GWs) in the universe. If the binary inspiral time is long,…
Signatures of BH seeding on the relation: Predictions from the BRAHMA simulations
Jonathan Kho, Aklant K. Bhowmick, Paul Torrey +4
The James Webb Space Telescope (JWST) has identified a large population of supermassive (-) black holes (BHs) in the early universe (-). C…
From ASTRID to BRAHMA -- The role of overmassive black holes in little red dots in cosmological simulations
Patrick LaChance, Aklant Kumar Bhowmick, Rupert A. C. Croft +8
We leverage the overmassive black holes () present in a realization of the BRAHMA cosmological hydrodynamic simulation suite to investigate their ro…
The NANOGrav 15-year data set: Search for Transverse Polarization Modes in the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96
Recently we found compelling evidence for a gravitational wave background with Hellings and Downs (HD) correlations in our 15-year data set. These correlations describe gravitation…
The NANOGrav 15-year Data Set: Search for Anisotropy in the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +90
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has reported evidence for the presence of an isotropic nanohertz gravitational wave background (GWB) in…
Relics of Supermassive Black Hole Seeds: The Discovery of an Accreting Black Hole in an Optically Normal, Low Metallicity Dwarf Galaxy
Jenna M. Cann, Shobita Satyapal, Barry Rothberg +11
The detection and characterization of supermassive black holes (SMBHs) in local low mass galaxies is crucial to our understanding of the origins of SMBHs. This statement assumes th…
Supermassive Black Hole Assembly from Heavy Seeds with Dynamical Friction in the BRAHMA Simulations: Implications for JWST, LISA, and the Local Universe
Aklant K. Bhowmick, Laura Blecha, Paul Torrey +8
The JWST discoveries of supermassive black holes (BHs) at may provide key insights into their seeding origins. Using new BRAHMA cosmological sim…
The NANOGrav 15 Yr Data Set: Removing Pulsars One by One from the Pulsar Timing Array
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +102
Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15-year pulsar-timing data set compiled by the NANOGrav collaboration. Similar signals have been…
Key Science Goals for the Next Generation Very Large Array (ngVLA): Update from the ngVLA Science Advisory Council (2024)
David J. Wilner, Brenda C. Matthews, Brett McGuire +32
In 2017, the next generation Very Large Array (ngVLA) Science Advisory Council, together with the international astronomy community, developed a set of five Key Science Goals (KSGs…
A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of Quasars Using JWST
Jinyi Yang, Feige Wang, Xiaohui Fan +53
Studies of rest-frame optical emission in quasars at have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (…
An "inside-out" approach to modeling supermassive black hole binary inspiral
Laura Blecha
The inspiral and merger of two supermassive black holes (SMBHs) releases immense energy in low-frequency gravitational waves (GWs). Recent pulsar timing array (PTA) observations of…
The X-ray View of Merger-Induced AGN Activity at Low Redshift
Nathan Secrest, Sara Ellison, Shobita Satyapal +1
Galaxy mergers are predicted to trigger accretion onto the central supermassive black holes, with the highest rates occurring during final coalescence. Previously, we have shown el…
2MASX J00423991+3017515: An offset active galactic nucleus in an interacting system
J. Drew Hogg, Laura Blecha, Christopher S. Reynolds +2
We present a spectroscopic and imaging study of an abnormal active galactic nucleus (AGN), 2MASX J00423991+3017515. This AGN is newly identified in the hard X-rays by the Swift BAT…
Effects of gravitational-wave recoil on the dynamics and growth of supermassive black holes
Laura Blecha, Abraham Loeb
Simulations of binary black hole mergers indicate that asymmetrical gravitational wave (GW) emission can cause black holes to recoil at speeds up to thousands of km/s. These GW rec…
The LISA Astrophysics MBHcatalogues Project: A comparison of predictions of simulated massive black hole binaries
David Izquierdo-Villalba, Melanie Habouzit, Matteo Bonetti +67
In the hierarchical paradigm of galaxy formation, central massive black holes (MBHs) are expected to coalesce after the merger of their host galaxies. One of the main goals of the…
Massive black hole binary inspiral and spin evolution in a cosmological framework
Mohammad Sayeb, Laura Blecha, Luke Zoltan Kelley +3
Massive black hole (MBH) binary inspiral time scales are uncertain, and their spins are even more poorly constrained. Spin misalignment, along with unequal mass ratios and spin mag…
ASPIRE: The Environments and Dark Matter Halos of Luminous Quasars in the Epoch of Reionization
Feige Wang, Jaclyn B. Champagne, Jiamu Huang +42
We present a systematic study of the environments of 25 luminous quasars at from the ASPIRE program. Using JWST/NIRCam WFSS data, we identified 487 galaxies at $5.3 \less…
The NANOGrav 15 yr Data Set: Piecewise Power-Law Reconstruction of the Gravitational-Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +108
The NANOGrav 15-year (NG15) data set provides evidence for a gravitational-wave background (GWB) signal at nanohertz frequencies, which is expected to originate either from a cosmi…
The NANOGrav 15 yr Data Set: Looking for Signs of Discreteness in the Gravitational-wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +97
The cosmic merger history of supermassive black hole binaries (SMBHBs) is expected to produce a low-frequency gravitational wave background (GWB). Here we investigate how signs of…
Single Sources in the Low-Frequency Gravitational Wave Sky: properties and time to detection by pulsar timing arrays
Luke Zoltan Kelley, Laura Blecha, Lars Hernquist +2
We calculate the properties, occurrence rates and detection prospects of individually resolvable 'single sources' in the low frequency gravitational wave (GW) spectrum. Our simulat…
Astro2020 Science White Paper: Black Hole Growth in Mergers and Dual AGN
Michael Koss, Vivian U, Edmund Hodges-Kluck +13
Hierarchical models of galaxy formation predict that galaxy mergers represent a significant transitional stage of rapid supermassive black hole (SMBH) growth. Yet, the connection b…
The NANOGrav 15-year Gravitational-Wave Background Methods
Aaron D. Johnson, Patrick M. Meyers, Paul T. Baker +93
Pulsar timing arrays (PTAs) use an array of millisecond pulsars to search for gravitational waves in the nanohertz regime in pulse time of arrival data. This paper presents rigorou…
The NANOGrav 15-year Data Set: Constraints on Supermassive Black Hole Binaries from the Gravitational Wave Background
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +111
The NANOGrav 15-year data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such low-frequency gr…
Gravitational Wave Measurement of the - Intrinsic Scatter at High Redshift
Cayenne Matt, Kayhan Gültekin, Gabriella Agazie +109
The observed GWB spectrum is higher in amplitude than model predictions by a factor of 2-3. Using a semi-analytic model, we evaluate the effect of a high-scatter supermassive black…
A quasar-galaxy merger at : black hole mass and quasar properties from the NIRSpec spectrum
Federica Loiacono, Roberto Decarli, Marco Mignoli +31
We present JWST/NIRSpec integral field data of the quasar PJ308-21 at . As shown by previous ALMA and HST imaging, the quasar has two companion sources, interacting with…
First results of AMBRA: Abundant Seeds and Early Mergers as a Pathway to the First Massive Black Holes
Yihao Zhou, Aklant Kumar Bhowmick, Tiziana Di Matteo +6
AMBRA combines the large cosmological volume and statistical power of ASTRID with the physically motivated gas-based black hole seeding models from BRAHMA. Motivated by JWST's disc…
Detecting Offset Active Galactic Nuclei
Laura Blecha, Walter Brisken, Sarah Burke-Spolaor +5
Gravitational wave (GW) and gravitational slingshot recoil kicks, which are natural products of SMBH evolution in merging galaxies, can produce active galactic "nuclei" that are of…
The Gravitational Wave Background from Massive Black Holes in the ASTRID Simulation
Nianyi Chen, Tiziana Di Matteo, Yihao Zhou +6
Recent pulsar timing array (PTA) observations have detected nanohertz gravitational waves, likely originating from massive black hole binaries (MBHBs). The detected amplitude is un…
Dynamics of low-mass black hole seeds in the BRAHMA simulations using subgrid-dynamical friction: Impact on merger-driven black hole growth in the high redshift Universe
Aklant K. Bhowmick, Laura Blecha, Luke Z. Kelley +7
We analyze the dynamics of low-mass black hole (BH) seeds in the high-redshift () Universe using a suite of and BRAHMA cosmol…
The NANOGrav 15-year Data Set: Search for Signals from New Physics
Adeela Afzal, Gabriella Agazie, Akash Anumarlapudi +120
The 15-year pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence for the presence of a low-freque…
AGN feedback in merging galaxies with a SMUGGLE multiphase ISM
Aneesh Sivasankaran, Laura Blecha, Paul Torrey +6
We study fast nuclear winds driven by Active Galactic Nucleus (AGN) feedback in merging galaxies using high-resolution hydrodynamics simulations. We use Stars and MUltiphase Gas in…
The NANOGrav 15-year Data Set: Observations and Timing of 68 Millisecond Pulsars
Gabriella Agazie, Md Faisal Alam, Akash Anumarlapudi +97
We present observations and timing analyses of 68 millisecond pulsars (MSPs) comprising the 15-year data set of the North American Nanohertz Observatory for Gravitational Waves (NA…
Buried Black Hole Growth in IR-selected Mergers: New Results from Chandra
Ryan W. Pfeifle, Shobita Satyapal, Nathan J. Secrest +8
Observations and theoretical simulations suggest that a significant fraction of merger-triggered accretion onto supermassive black holes is highly obscured, particularly in late-st…
The NANOGrav 12.5-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
Zaven Arzoumanian, Paul T. Baker, Laura Blecha +75
Pulsar timing array collaborations, such as the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), are seeking to detect nanohertz gravitational waves emitted…
The NANOGrav 15 yr Data Set: Impacts of Customized Chromatic Noise Models on Gravitational Wave Analyses
Nikita Agarwal, Gabriella Agazie, Alessandra Amosso +120
We report updated nHz gravitational wave (GW) significance, characterization, and interpretations using the customized chromatic-noise models (CNMs) developed in Larsen, Baier et a…
JWST Reveals Compact Nuclear Starbursts Masquerading as AGNs in Metal-Poor Dwarfs: Where Are the Accreting Intermediate-Mass Black Holes?
William Matzko, Shobita Satyapal, Jeffrey D. Mckaig +19
We present JWST/NIRSpec spectroscopy of the low-mass, metal-poor galaxy SDSS~J160135.95+311353.7 (J1601), selected for its extreme mid-infrared colors and compact nuclear emission,…
The Hunt for Intermediate Mass Black Holes in the JWST Era
Jenna M. Cann, Shobita Satyapal, Nicholas P. Abel +4
Intermediate mass black holes (IMBHs), with masses between 100 to 10^5 M_\odot, represent the link between stellar mass black holes and the supermassive black holes that reside in…
The NANOGrav 15-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +96
Evidence for a low-frequency stochastic gravitational wave background has recently been reported based on analyses of pulsar timing array data. The most likely source of such a bac…
MBH binary intruders: triple systems from cosmological simulations
Mohammad Sayeb, Laura Blecha, Luke Zoltan Kelley
Massive black hole (MBH) binaries can form following a galaxy merger, but this may not always lead to a MBH binary merger within a Hubble time. The merger timescale depends on how…
Reliable Identification of Binary Supermassive Black Holes from Rubin Observatory Time-Domain Monitoring
Megan C. Davis, Kaylee E. Grace, Jonathan R. Trump +7
Periodic signatures in time-domain observations of quasars have been used to search for binary supermassive black holes. These searches, across existing time-domain surveys, have p…
Representing low mass black hole seeds in cosmological simulations: A new sub-grid stochastic seed model
Aklant K Bhowmick, Laura Blecha, Paul Torrey +5
The nature of the first seeds of supermassive black holes (SMBHs) is currently unknown, with postulated initial masses ranging from to as low as $\sim10^2~M_{\…
Probing Massive Black Hole Binary Populations with LISA
Michael L. Katz, Luke Zoltan Kelley, Fani Dosopoulou +3
ESA and NASA are moving forward with plans to launch LISA around 2034. With data from the Illustris cosmological simulation, we provide analysis of LISA detection rates accompanied…
Growth of high redshift supermassive black holes from heavy seeds in the BRAHMA cosmological simulations: Implications of overmassive black holes
Aklant K Bhowmick, Laura Blecha, Paul Torrey +6
JWST has recently revealed a large population of accreting black holes (BHs) in the early Universe. Even after accounting for possible systematic biases, the high-z $M_*-M_{\rm \rm…
Building Semi-Analytic Black Hole Seeding Models Using IllustrisTNG Host Galaxies
Analis Eolyn Evans, Laura Blecha, Aklant Kumar Bhowmick
Because early black holes (BHs) grew to in less than 1 Gyr of cosmic time, BH seeding models face stringent constraints. To efficiently constrain the paramete…
UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation
Michael J. Koss, Ezequiel Treister, Darshan Kakkad +23
We present multi-wavelength high-spatial resolution (~0.1'', 70 pc) observations of UGC 4211 at z=0.03474, a late-stage major galaxy merger at the closest nuclear separation yet fo…
Inference on inner galaxy structure via gravitational waves from supermassive binaries
Yifan Chen, Matthias Daniel, Daniel J. D'Orazio +107
The detection of a stochastic gravitational wave background by pulsar-timing arrays indicates the presence of a population of supermassive black hole binaries. Although the observe…
BEES: Quasar lifetime measurements from extended rest-optical emission line nebulae at
Dominika ÄurovÄÃková, Anna-Christina Eilers, Yuzo Ishikawa +13
Measurements of quasar lifetimes at high redshift indicate that the earliest billion-solar-mass supermassive black holes (SMBHs) have only been active as luminous quasars for less…
A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Reveals a Filamentary Structure around a z=6.61 Quasar
Feige Wang, Jinyi Yang, Joseph F. Hennawi +56
We present the first results from the JWST ASPIRE program (A SPectroscopic survey of biased halos In the Reionization Era). This program represents an imaging and spectroscopic sur…
Learning the Universe at High Redshifts: Impact of Accretion Modeling on Early Black Hole Growth
Jonathan Kho, Aklant K. Bhowmick, Rainer Weinberger +8
JWST discoveries of the earliest () supermassive black holes (BHs, ) challenge the BH seeding and accretion models of most cosmol…
The NANOGrav 15-Year Data Set: Detector Characterization and Noise Budget
Gabriella Agazie, Akash Anumarlapudi, Anne M. Archibald +88
Pulsar timing arrays (PTAs) are galactic-scale gravitational wave detectors. Each individual arm, composed of a millisecond pulsar, a radio telescope, and a kiloparsecs-long path,…
Science with an ngVLA: Offset Active Galactic Nuclei
Laura Blecha, Walter Brisken, Sarah Burke-Spolaor +5
Gravitational-wave (GW) and gravitational slingshot recoil kicks, which are natural products of SMBH evolution in merging galaxies, can produce active galactic "nuclei" that are of…
The NANOGrav 15 yr Data Set: Harmonic Analysis of the Pulsar Angular Correlations
Gabriella Agazie, Jeremy G. Baier, Paul T. Baker +86
Pulsar timing array observations have found evidence for an isotropic gravitational wave background with the Hellings-Downs angular correlations, expected from general relativity.…
The Gravitational Wave Background from Massive Black Hole Binaries in Illustris: spectral features and time to detection with pulsar timing arrays
Luke Zoltan Kelley, Laura Blecha, Lars Hernquist +2
Pulsar Timing Arrays (PTA) around the world are using the incredible consistency of millisecond pulsars to measure low frequency gravitational waves from (super)Massive Black Hole…
Multi-Messenger Astrophysics with Pulsar Timing Arrays
Luke Zoltan Kelley, Maria Charisi, Sarah Burke-Spolaor +29
Pulsar timing arrays (PTAs) are on the verge of detecting low-frequency gravitational waves (GWs) from supermassive black hole binaries (SMBHBs). With continued observations of a l…
On the Use of Letters of Recommendation in Astronomy and Astrophysics Graduate Admissions
Darcy Barron, Rachel Bezanson, Laura Blecha +8
Letters of recommendation are a common tool used in graduate admissions. Most admissions systems require three letters for each applicant, burdening both letter writers and admissi…
Constraints on the Nature of CID-42: Recoil Kick or Supermassive Black Hole Pair?
Laura Blecha, Francesca Civano, Martin Elvis +1
The galaxy CXOC J100043.1+020637, also known as CID-42, is a highly unusual object. An apparent galaxy merger remnant, it displays signatures of both an inspiraling, kiloparsec-sca…
Molecular Gas in Major Mergers Hosting Dual and Single AGN at <10 kpc Nuclear Separations
Makoto A. Johnstone, Ezequiel Treister, Franz E. Bauer +24
We present high-resolution (50100 pc) Atacama Large Millimeter Array (ALMA) observations of CO(2-1) or CO(1-0) emission in seven local ( 0.05)…
Impact of gas based seeding on supermassive black hole populations at
Aklant K. Bhowmick, Laura Blecha, Paul Torrey +6
Deciphering the formation of supermassive black holes~(SMBHs) is a key science goal for upcoming observational facilities. In most theoretical channels proposed so far, the seed fo…
Beyond the Brightest: A Deep Learning Approach to Identifying Major and Minor Galaxy Mergers in CANDELS at
Aimee L. Schechter, Aleksandra ÄiprijanoviÄ, Xuejian Shen +5
Galaxy mergers play an important role in galaxy evolution. Therefore, accurate merger identifications are paramount for achieving a complete understanding of how galaxies evolve. A…
The NANOGrav 12.5-year data set: A computationally efficient eccentric binary search pipeline and constraints on an eccentric supermassive binary candidate in 3C 66B
Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker +85
The radio galaxy 3C 66B has been hypothesized to host a supermassive black hole binary (SMBHB) at its center based on electromagnetic observations. Its apparent 1.05-year period an…
The NANOGrav 12.5-year Data Set: Search for Gravitational Wave Memory
Gabriella Agazie, Zaven Arzoumanian, Paul T. Baker +87
We present the results of a Bayesian search for gravitational wave (GW) memory in the NANOGrav 12.5-yr data set. We find no convincing evidence for any gravitational wave memory si…
Recoiling black holes: prospects for detection and implications of spin alignment
Laura Blecha, Debora Sijacki, Luke Zoltan Kelley +6
Supermassive black hole (BH) mergers produce powerful gravitational wave (GW) emission. Asymmetry in this emission imparts a recoil kick to the merged BH, which can eject the BH fr…