A5066428326- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Relativity and Gravitational Theory
- Black Holes and Theoretical Physics
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- History and Developments in Astronomy
- Photocathodes and Microchannel Plates
- Child Therapy and Development
- Inorganic and Organometallic Chemistry
- Medical Imaging Techniques and Applications
- Terrorism, Counterterrorism, and Political Violence
- Geological Modeling and Analysis
- Nuclear Physics and Applications
- Error Correcting Code Techniques
- Satellite Communication Systems
University of Colorado Boulder
2015-2024
University of Colorado System
2021-2022
Laboratory for Atmospheric and Space Physics
2014-2015
University of Arkansas at Fayetteville
2009-2013
Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on C iv, Hα, Hβ broad emission lines. Our is upon that Greene, Peng, & Ludwig, expanded new near-IR spectroscopic observations, consistently analyzed high signal-to-noise ratio (S/N) consistent continuum luminosity at 5100 Å. We find BH full width...
Dual active galactic nuclei (AGNs) and offset AGNs are kpc-scale separation supermassive black holes pairs created during galaxy mergers, where both or one of the AGNs, respectively. These dual valuable probes link between mergers but challenging to identify. Here we present Chandra/ACIS observations 12 optically selected AGN candidates at , use X-rays identify AGNs. We also Hubble Space Telescope/Wide Field Camera 3 10 these candidates, which reveal any stellar bulges accompanying discover...
We have examined a subset of 18 active galactic nuclei (AGNs) drawn from sample 81 galaxies that possess double-peaked narrow optical emission line spectra in the Sloan Digital Sky Survey, two AGN components separated by >0.2", and are detected Faint Images Radio at Twenty-centimeters survey. Without follow-up observations, sources lines uncertain, may be produced kpc-scale separation dual supermassive black holes, outflows, or disk rotation. In this work, we propose new methodology to...
Merger-remnant galaxies with kpc-scale separation dual active galactic nuclei (AGNs) should be widespread as a consequence of galaxy mergers and triggered gas accretion onto supermassive black holes, yet very few AGNs have been observed. Galaxies double-peaked narrow AGN emission lines in the Sloan Digital Sky Survey are plausible candidates, but their profiles could also result kinematics or AGN-driven outflows jets on small large scales. To help distinguish between these scenarios, we...
Abstract To facilitate new studies of galaxy-merger-driven fueling active galactic nuclei (AGNs), we present a catalog 387 AGNs that have identified in the final population over 10,000 z < 0.15 galaxies observed by Sloan Digital Sky Survey-IV (SDSS-IV) integral field spectroscopy survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA). We selected via mid-infrared Wide-field Infrared Survey Explorer colors, Swift/Burst Alert Telescope ultra-hard X-ray detections, NRAO Very...
Abstract Hydrated chlorine salts are expected to exist on a variety of planetary bodies, including inner planets such as Mars and outer planet satellites Europa. However, detection by remote sensing has been limited due lack comparison data in spectral libraries. In addition, at low temperatures features many H 2 O‐bearing species deviate from their room temperature behavior. Thus, we acquired spectra NaCl, NaClO 4 · n O, MgCl Mg(ClO ) ·6H 3 O 0.35 2.5 µm both 298 80 K observe the effects...
Abstract Accurate active galactic nucleus (AGN) identifications and spatially resolved host galaxy properties are a powerful combination for studies of the role AGNs AGN feedback in coevolution galaxies their central supermassive black holes. Here, we present robust 406 first 6261 observed by integral field spectroscopy survey Mapping Nearby Galaxies at Apache Point Observatory. Instead using optical line flux ratios, which can be difficult to interpret light effects shocks metallicity,...
Abstract During galaxy mergers, gas and dust are driven toward the centers of merging galaxies, triggering enhanced star formation supermassive black hole (SMBH) growth. Theory predicts that this heightened activity peaks at SMBH separations <20 kpc; if sufficient material accretes onto one or both SMBHs for them to become observable as active galactic nuclei (AGNs) during phase, they known offset dual AGNs, respectively. To better study these systems, we have built ACS-AGN Merger...
We present a sample of 131 quasars from the Sloan Digital Sky Survey at redshifts 0.8 < z 1.6 with double peaks in either high-ionization narrow emission lines [Ne v] λ3426 or iii] λ3869. These sources were selected intention identifying high-redshift analogs active galactic nuclei (AGNs) double-peaked [O λ5007 lines, which might represent AGN outflows dual AGNs. Lines high ionization potential are believed to originate inner, highly photoionized portion line region, and we exploit this...
We present optical longslit observations of the complete sample 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at $z < 0.1$ in Sloan Digital Sky Survey. Double-peaked are produced by a variety mechanisms including disk rotation, kpc-scale dual AGNs, and NLR kinematics (outflows or inflows). develop novel kinematic classification technique to determine nature these objects using spectroscopy alone. that 86% profiles moderate luminosity AGN outflows, 6% 8%...
We present a sample of 18 optically-selected and X-ray detected spatially offset active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). In 9 systems, AGN is stellar core that located within 3'' diameter SDSS spectroscopic fiber. 11 outside fiber, with an overlap 2. To build sample, we cross-matched Type II selected galaxy catalogue archival Chandra imaging employed our custom astrometric registration procedure. The projected angular (physical) offsets span range 0."6 (0.8...
Abstract Hyper-luminous X-ray sources (HLXs; L X > 10 41 erg s −1 ) are off-nuclear in galaxies and strong candidates for intermediate-mass black holes (IMBHs). We have constructed a sample of 169 HLX by combining detections from the Chandra Source Catalog (Version 2) with Sloan Digital Sky Survey registering individual images improved relative astrometric accuracy. The spatial resolution allows to extend out z ∼ 0.9. Optical counterparts detected among one-fourth sample, one-third which...
The X-ray source CXOXBJ142607.6+353351 (CXOJ1426+35), which was identified in a 172 ks Chandra image the Boötes field, shows double-peaked rest-frame optical/UV emission lines, separated by 069 (5.5 kpc) spatial dimension and 690 km s−1 velocity dimension. high excitation lines line ratios indicate both systems are ionized an active galactic nucleus (AGN) continuum, profile resembles that of candidate dual AGNs. At redshift z = 1.175, this is highest AGN yet identified. However, many sources...
We present new and stronger evidence for a previously reported relationship between galactic spiral arm pitch angle P (a measure of the tightness structure) mass M_BH disk galaxy's nuclear supermassive black hole (SMBH). use an improved method to accurately in galaxies generate quantitative data on this morphological feature 34 with directly measured masses. find relation log(M/M_sun) = (8.21 +/- 0.16) - (0.062 0.009)P. This is compared other means estimating determine its effectiveness...
Abstract We present an analysis of 12 optically selected dual active galactic nucleus (AGN) candidates at z < 0.34. Each candidate was originally identified via double-peaked [O iii ] λ 5007 emission lines and received follow-up Chandra Hubble Space Telescope ( HST ) observations. Because the X-ray data are low-count (<100 counts) with small separations (<1″), a robust is necessary for classifying each source. Pairing long-slit observations existing observations, we re-analyze...
ABSTRACT It is difficult to accurately identify galaxy mergers and it an even larger challenge classify them by their mass ratio or merger stage. In previous work we used a suite of simulated create classification technique that uses linear discriminant analysis major minor mergers. Here, apply this 1.3 million galaxies from the SDSS DR16 photometric catalogue present probability each merger, splitting classifications stages (early, late, post-coalescence). We publicly available imaging...
Abstract We present a catalog of physical properties for galaxies hosting active galactic nuclei (AGN) detected by the Wide-field Infrared Survey Explorer (WISE). By fitting broadband spectral energy distributions sources in WISE AGN Catalog with empirical galaxy and templates, we derive photometric redshifts, bolometric luminosities, measures obscuration, host stellar masses, star formation rates (SFRs) 695,273 AGN. The wide-area nature this significantly augments known number obscured out...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCondensation Reactions of IsoquinaldaldehydeRobert S. Barrows and H. G. LindwallCite this: J. Am. Chem. Soc. 1942, 64, 10, 2430–2432Publication Date (Print):October 1, 1942Publication History Published online1 May 2002Published inissue 1 October 1942https://doi.org/10.1021/ja01262a058RIGHTS & PERMISSIONSArticle Views181Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text article downloads since...
Abstract The presence and distribution of oxychlorine salts (e.g., chlorates perchlorates) on Mars have implications for the stability water, most notably, that they lower freezing temperature. To date, elemental chlorine has been measured by all lander missions, with perchlorate ion identified at both Phoenix Curiosity landing sites, but detection near‐infrared (NIR) mid‐infrared (MIR) remote sensing limited to deposits anhydrous chlorides. Given can form numerous hydrated phases, we their...
Abstract Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs poorly understood. In Paper I, we constructed sample of spatially offset X-ray AGNs that represent galaxy hosting single AGN. paper, use our AGN constrain parameters affect observability mergers. We also construct dual-AGN samples with similar selection properties for comparison. find fraction shows no evidence dependence on luminosity, while...
Low-mass compact galaxies (ultracompact dwarfs [UCDs] and ellipticals [cEs]) populate the stellar size-mass plane between globular clusters early-type galaxies. Known to be formed either in-situ with an intrinsically low mass or resulting from stripping of a more massive galaxy, presence supermassive intermediate-mass black hole (BH) could help discriminate these possible scenarios. With this aim, we have performed multiwavelength search active BH activity, i.e. galactic nuclei (AGN), in...
Pairs of galaxies hosting active galactic nuclei (AGN) are powerful probes merger-driven supermassive black hole (SMBH) growth as they can resolve individual AGN and trace mergers over a large range physical separations. To exploit this on scale for the first time both obscured unobscured AGN, we use photometric redshifts selected by Wide-field Infrared Survey Explorer (WISE) to find probabilistic pairs (<100 kpc separations) across sky, along with comparison sample inactive galaxy pairs....
Abstract Galaxy mergers are capable of triggering both star formation and active galactic nuclei (AGNs) therefore may represent an important pathway in the co-evolution galaxies supermassive black holes (SMBHs). However, correlated enhancements merger-induced AGN be hidden by variable conditions timescales during which they occur. In Paper I, we presented evidence merger-triggered a sample six late-stage galaxy ( <?CDATA $2\mbox{--}8\,\mathrm{kpc}$?> <mml:math...
Abstract We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in z = 0.06 galaxy SDSS J1354+1327. This episodic nuclear activity result discrete accretion events could have been triggered by a past interaction with companion currently located 12.5 kpc away. originally targeted J1354+1327 because its Sloan Digital Sky Survey spectrum has narrow AGN emission lines exhibit velocity offset 69 km s −1 relative to systemic. To determine nature...