Ryan W. Pfeifle
A5045714248- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Astrophysics and Star Formation Studies
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Statistics Education and Methodologies
- Relativity and Gravitational Theory
- Atomic and Subatomic Physics Research
- Advanced X-ray Imaging Techniques
- Superconducting Materials and Applications
- Environmental Monitoring and Data Management
- X-ray Spectroscopy and Fluorescence Analysis
- Cosmology and Gravitation Theories
Goddard Space Flight Center
2015-2024
Oak Ridge Associated Universities
2023-2024
National Aeronautics and Space Administration
2024
George Mason University
2019-2023
We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm relative proper motion prediction due to light curve signal observed this event. This (and companion Keck result) provide first confirmation a signal, deviation was only 2%. The follow-up determine flux host star in multiple passbands remove model ambiguity caused by sparse sampling part curve. leads precise...
The Line Emission Mapper (LEM) is an X-ray Probe for the 2030s that will answer outstanding questions of Universe's structure formation. It also provide transformative new observing capabilities every area astrophysics, and to heliophysics planetary physics as well. LEM's main goal a comprehensive look at galaxy formation, including stellar black-hole feedback flows baryonic matter into out galaxies. These processes are best studied in X-rays, emission-line mapping pressing need this area....
The BAT AGN Spectroscopic Survey (BASS) is designed to provide a highly complete census of the key physical parameters supermassive black holes (SMBHs) that power local active galactic nuclei (AGN) (z<0.3), including their bolometric luminosity, hole mass, accretion rates, and line-of-sight gas obscuration, distinctive properties host galaxies (e.g., star formation masses, fractions). We present an overview BASS data release 2 (DR2), unprecedented spectroscopic survey in spectral range,...
The merger of two or more galaxies can enhance the inflow material from galactic scales into close environments Active Galactic Nuclei (AGN), obscuring and feeding supermassive black hole (SMBH). Both recent simulations observations AGN in mergers have confirmed that are related to strong nuclear obscuration. However, it is still unclear how obscuration evolves last phases process. We study a sample 60 Luminous Ultra-luminous IR (U/LIRGs) GOALS observed by NuSTAR. find fraction Compton-thick...
Abstract To understand the origin of nuclear (≲100 pc) millimeter-wave (mm-wave) continuum emission in active galactic nuclei (AGNs), we systematically analyzed subarcsecond resolution Band-6 (211–275 GHz) Atacama Large Millimeter/submillimeter Array data 98 nearby AGNs ( z < 0.05) from 70 month Swift/BAT catalog. The sample, almost unbiased for obscured systems, provides largest number to date with high mm-wave spatial sampling (∼1–200 pc), and spans broad ranges 14–150 keV luminosity {...
Ever since the discovery of first active galactic nuclei (AGN), substantial observational and theoretical effort has been invested into understanding how massive black holes have evolved across cosmic time. Circum-nuclear obscuration is now established as a crucial component, with almost every AGN observed known to display signatures some level in their X-ray spectra. However, despite more than six decades effort, open questions remain: does accretion power impact structure circum-nuclear...
Since the discovery of cosmic X-ray background (CXB), astronomers have strived to understand accreting supermassive black holes (SMBHs) contributing its peak in 10–40 keV band. Existing soft telescopes could study this population up only 10 keV, and, while NuSTAR (focusing on 3–24 keV) made great progress, it also left significant uncertainties characterizing hard population, crucial for calibrating current synthesis models. This paper presents an in-depth analysis simulations two...
A fundamental goal of modern-day astrophysics is to understand the connection between supermassive black hole (SMBH) growth and galaxy evolution. Merging galaxies offer one most dramatic channels for evolution known, capable driving inflows gas into galactic nuclei, potentially fueling both star formation central SMBH activity. Dual active nuclei (dual AGNs) in late-stage mergers with nuclear pair separations <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Abstract Observations and theoretical simulations suggest that a significant fraction of merger-triggered accretion onto supermassive black holes is highly obscured, particularly in late-stage galaxy mergers, when the hole expected to grow most rapidly. Starting with Wide-Field Infrared Survey Explorer all-sky survey, we identified population galaxies whose morphologies ongoing interaction which exhibit red mid-infrared colors often associated powerful active galactic nuclei (AGNs). In...
Abstract One of the primary outstanding questions in extragalactic astronomy is formation and early evolution supermassive black holes that are seen nearly every massive galaxy. Low-metallicity dwarf galaxies may offer most representative local analogs to pristine galaxies, making them a vital tool probing hole seed models through study intermediate-mass (IMBHs) possibly hosted therein; though these IMBHs they host, typically not as well-studied this context their higher-metallicity...
Abstract The coevolution of galaxies and the supermassive black holes (SMBHs) at their centers via hierarchical galaxy mergers is a key prediction ΛCDM cosmology. As gas dust are funneled to SMBHs during merger, light up as active galactic nuclei (AGNs). In some cases, merger two can encounter third galaxy, leading triple which would manifest AGN if all three simultaneously accreting. Using high spatial resolution X-ray, near-IR, optical spectroscopic diagnostics, we report here compelling...
Abstract NGC 4945 contains a well-known heavily obscured active galactic nucleus (AGN) at its core, with prior reports of strong nuclear and off-nuclear neutral Fe K α emission due to the AGN activity. We report discovery very extended XMM-Newton EPIC pn in ∼5 kpc by ∼10 region that is misaligned plane inclined optical disk ∼60° projection. After careful consideration crowded center galaxy numerous unresolved hard X-ray sources present, we estimate ∼15% on kiloparsec-sized scales. The...
In this study, we use the SWIFT/BAT AGN sample, which has received extensive multiwavelength follow-up analysis as a result of BAT Spectroscopic Survey (BASS), to develop diagnostic for nuclear obscuration by examining relationship between line-of-sight column densities ($N_{\rm{H}}$), 2-10 keV-to-$12\,\rm{\mu m}$ luminosity ratio, and WISE mid-infrared colors. We demonstrate that heavily obscured AGNs tend exhibit both preferentially ''redder'' colors lower values...
Abstract In contrast to massive galaxies with solar or super-solar gas phase metallicities, very few active galactic nuclei (AGNs) are found in low-metallicity dwarf galaxies. Such a population could provide insight into the origins of supermassive black holes. Here we report near-IR spectroscopic and X-ray observations SDSS J105621.45+313822.1, low-mass, galaxy optical narrow line ratios consistent star-forming but broad H α mid-infrared colors an AGN. We detect [Si vi ] 1.96 μ m coronal Pa...
Abstract We present a catalog of the millimeter-wave (mm-wave) continuum properties 98 nearby ( z < 0.05) active galactic nuclei (AGNs) selected from 70 month Swift/BAT hard-X-ray that have precisely determined X-ray spectral and subarcsecond-resolution Atacama Large Millimeter/submillimeter Array Band 6 (211–275 GHz) observations as 2021 April. Due to (>10 keV) selection, sample is nearly unbiased for obscured systems at least up Compton-thick-level obscuration, provides largest...
Local low metallicity dwarf galaxies are relics of the early universe and hold clues into origins supermassive black holes (SMBHs). In recent work, coronal lines have been used to unveil a population candidate accreting in with gas phase metallicities stellar masses well below host any previously known AGNs. Using MUSE/VLT observations, we report detection [Fe X] $\lambda$6374 line emission broad H$\alpha$ nucleus SDSS J094401.87$-$003832.1, nearby ($z=0.0049$) metal poor galaxy almost 500...
Abstract Accreting supermassive black holes (SMBHs) located at the centers of galaxies are typically surrounded by large quantities gas and dust. The structure evolution this circumnuclear material can be studied different wavelengths, from submillimeter to X-ray. Recent X-ray studies have shown that covering factor obscuring tends decrease with increasing Eddington ratio, likely due radiative feedback on dusty gas. Here we study a sample 549 nearby ( z ≲ 0.1) hard (14–195 keV) selected...
Abstract Binary and dual active galactic nuclei (AGNs) are an important observational tool for studying the formation dynamical evolution of galaxies supermassive black holes. An entirely new method identifying possible AGN pairs makes use exquisite positional accuracy Gaia to detect astrometrically variable quasars, in tandem with high spatial resolution Karl G. Jansky Very Large Array (VLA). We present a pilot study radio observations 18 quasars (0.8 ≤ z 2.9), selected from Sloan Digital...
This white paper discusses the breadth of science related to active galactic nuclei (AGN) and associated phenomena be enabled by a mission with microcalorimeter energy resolution in soft X-ray band, large collecting area, wide-field imaging. Such mission, Line Emission Mapper (LEM), has been proposed NASA's 2023 Astrophysics Probe Explorer call. While pillars PI-led part focus on galaxy evolution, LEM All-Sky Survey (LASS) General Observer/Investigator opportunities will enable vital...
The Line Emission Mapper (LEM) is a Probe mission concept developed in response to NASA's Astrophysics Explorer (APEX) Announcement of Opportunity. LEM has single science instrument composed large-area, wide-field X-ray optic and microcalorimeter imaging spectrometer the focal plane. optimized observe low-surface-brightness diffuse emission over 30′ equivalent diameter field view with 1.3 2.5 eV spectral resolution 0.2−2.0 keV band. Our primary scientific objective map thermal, kinetic,...
To answer NASA’s call for a sensitive X-ray observatory in the 2030s, we present High Energy Probe (HEX-P) mission concept. HEX-P is designed to provide required capabilities explore current scientific questions and make new discoveries with broadband that simultaneously measures sources from 0.2 80 keV. HEX-P’s main goals include: 1) understand growth of supermassive black holes how they drive galaxy evolution; 2) lower mass populations white dwarfs, neutron stars, stellar-mass nearby...
Since the discovery of cosmic X-ray background (CXB), astronomers have strived to understand accreting supermassive black holes (SMBHs) contributing its peak in 10-40 keV band. Existing soft telescopes could study this population up only 10 keV, and, while NuSTAR (focusing on 3--24 keV) made great progress, it also left significant uncertainties characterizing hard population, crucial for calibrating current synthesis models. This paper presents an in-depth analysis simulations two...
Ever since the discovery of first Active Galactic Nuclei (AGN), substantial observational and theoretical effort has been invested into understanding how massive black holes have evolved across cosmic time. Circum-nuclear obscuration is now established as a crucial component, with almost every AGN observed known to display signatures some level in their X-ray spectra. But despite more than six decades effort, open questions remain: How does accretion power impact structure circum-nuclear...
A fundamental goal of modern-day astrophysics is to understand the connection between supermassive black hole (SMBH) growth and galaxy evolution. Merging galaxies offer one most dramatic channels for evolution known, capable driving inflows gas into galactic nuclei, potentially fueling both star formation central SMBH activity. Dual active nuclei (dual AGNs) in late-stage mergers with nuclear pair separations $<10$ kpc are thus ideal candidates study along merger sequence since they coincide...
Context. In the hierarchical structure formation model, galaxies grow through various merging events. Numerical simulations indicate that mergers can enhance activity of central supermassive black holes in galaxies. Aims. A system three interacting galaxies, called J0849+1114, has recently been identified and multi-wavelength evidence all containing active galactic nuclei found. The substantial radio emission; we aim to investigate origin this emission with a high-resolution interferometric...