A5003192059- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Advanced Optical Sensing Technologies
- Advanced X-ray Imaging Techniques
- Astrophysics and Star Formation Studies
- Superconducting and THz Device Technology
- Stellar, planetary, and galactic studies
- Particle Detector Development and Performance
- Terahertz technology and applications
- Black Holes and Theoretical Physics
- Satellite Image Processing and Photogrammetry
- Cosmology and Gravitation Theories
- Relativity and Gravitational Theory
- Photoreceptor and optogenetics research
- Power Systems and Technologies
- Calibration and Measurement Techniques
- Photocathodes and Microchannel Plates
California Institute of Technology
2017-2022
We present final Spitzer trigonometric parallaxes for 361 L, T, and Y dwarfs. combine these with prior studies to build a list of 525 known dwarfs within 20 pc the Sun, 38 which are presented here first time. Using published photometry spectroscopy as well our own follow-up, we an array color-magnitude color-color diagrams further characterize census members, provide polynomial fits bulk trends. characterizations, assign each object $T_{\rm eff}$ value judge sample completeness over bins...
Abstract We present the active galactic nucleus (AGN) catalog and optical spectroscopy for second data release of Swift BAT AGN Spectroscopic Survey (BASS DR2). With this DR2 we provide 1449 spectra, which 1182 are released first time, 858 hard-X-ray-selected AGNs in 70-month sample. The majority spectra (801/1449, 55%) newly obtained from Very Large Telescope (VLT)/X-shooter or Palomar/Doublespec. Many have both higher resolution ( R > 2500, N ∼ 450) and/or very wide wavelength coverage...
Abstract We present detailed submillimeter- through centimeter-wave observations of the extraordinary extragalactic transient AT2018cow. The apparent characteristics—the high radio luminosity, rise and long-lived emission plateau at millimeter bands, sub-relativistic velocity—have no precedent. A basic interpretation data suggests coupled to a fast but ( ) shock in dense medium. find that X-ray is not naturally explained by an extension radio-submm synchrotron spectrum, nor inverse Compton...
Abstract We present measurements of broad emission lines and virial estimates supermassive black hole masses ( M BH ) for a large sample ultrahard X-ray-selected active galactic nuclei (AGNs) as part the second data release BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes total 689 AGNs, determined from H α , β Mg ii λ 2798, and/or C iv 1549 lines. The core 512 AGNs drawn 70 month Swift/BAT all-sky catalog. also provide 177 additional that are deeper survey data. study links...
Broadband X-ray spectroscopy of the emission produced in coronae active galactic nuclei (AGN) can provide important insights into physical conditions very close to their central supermassive black holes. The temperature Comptonizing plasma that forms corona is manifested through a high-energy cutoff has been difficult directly constrain even brightest AGN because it requires high-quality data at energies above 10 keV. In this paper we present large collection coronal constraints for obscured...
Abstract The corona is an integral component of active galactic nuclei (AGNs) which produces the bulk X-ray emission above 1–2 keV. However, many its physical properties and mechanisms powering this remain a mystery. In particular, temperature coronal plasma has been difficult to constrain for large samples AGNs, as constraints require high-quality broadband spectral coverage extending 10 keV in order measure high-energy cutoff, provides on combination optical depth temperature. We present...
The NuSTAR observatory, with its high sensitivity in hard X-rays, has enabled detailed broadband modeling of the X-ray spectra Active Galactic Nuclei (AGN), thereby allowing constraints to be placed on high-energy cutoff coronal continuum. We investigate spectral properties a sample 46 NuSTAR-observed Seyfert 1 AGN selected from Swift/BAT 70-month survey. Our measurements continuum are used map out temperature - compactness ($\theta-l$) plane for coronae. find that most coronae lie clustered...
We present ongoing work on the spectral energy distributions (SEDs) of active galactic nuclei (AGNs), derived from X-ray, ultraviolet, optical, infrared and radio photometry spectroscopy. Our is motivated by new wide-field imaging surveys that will identify vast numbers AGNs, need to benchmark AGN SED fitting codes. have constructed 41 SEDs individual AGNs 80 additional mimic Seyfert spectra. All our span 0.09 30 microns, while some extend into X-ray and/or radio. tested utility using them...
Abstract We present results from modeling the broadband X-ray spectrum of Type 1 active galactic nucleus (AGN) 2MASX J193013.80+341049.5 using NuSTAR , Swift and archival XMM-Newton observations. find this source to be highly obscured, with column densities exceeding 10 23 cm −2 across all epochs observations, spanning an 8 yr period. However, exhibits prominent broad optical emission lines, consistent unobscured AGN classification. fit spectra both phenomenological reflection models...
Over the last decades X-ray spectroscopy has proven to be a powerful tool for estimation of black hole spin and several other key parameters in dozens AGN binaries. In this White Paper, we discuss observational theoretical challenges expected exploration, discovery, study astrophysical holes next decade. We focus on case accreting their electromagnetic signatures, with particular emphasis measurement relativistic reflection component spectra.
We present analysis of NuSTAR X-ray observations in the 3-79 keV energy band Seyfert 2 galaxy NGC 4388, taken 2013. The broadband sensitivity NuSTAR, covering Fe K$\alpha$ line and Compton reflection hump, enables tight constraints to be placed on features AGN spectra, thereby providing insight into geometry circumnuclear material. In this observation, we found spectrum 4388 well described by a moderately absorbed power law with non-relativistic reflection. fit phenomenological models...
The corona is a key component of most luminous accreting black holes, carrying 5 - 30 % the power and in non-jetted Active Galactic Nuclei (AGN), creating all X-ray emission above $\simeq 1-2$ keV. Its illuminates inner accretion disc, atomic line-rich reflection spectrum used to diagnose map flow measure hole spin. likely powered magnetically by strong differential rotation disc it may be intimately related relativistic jets. Recent work shows that many coronae dominated electron-positron...
Abstarct We present ongoing work on the spectral energy distributions (SEDs) of active galactic nuclei (AGNs), derived from X-ray, ultraviolet, optical, infrared and radio photometry spectroscopy. Our is motivated by new wide-field imaging surveys that will identify vast numbers AGNs, need to benchmark AGN SED fitting codes. have constructed 41 SEDs individual AGNs 80 additional mimic Seyfert spectra. All our span 0.09 30 μm , while some extend into X-ray and/or radio. tested utility using...