B. Carpenter
A5101737539- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Neutrino Physics Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Radio Wave Propagation Studies
- Radiation Detection and Scintillator Technologies
- Gyrotron and Vacuum Electronics Research
- Earth Systems and Cosmic Evolution
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Magnetic confinement fusion research
- Spacecraft and Cryogenic Technologies
- Computational Physics and Python Applications
- SAS software applications and methods
Goddard Space Flight Center
2015-2020
Catholic University of America
2013-2020
University of Maryland, Baltimore County
2017-2020
University of America
2013-2020
Deleted Institution
2015-2017
Max Planck Institute for Radio Astronomy
2016
University of Würzburg
2016
Universitat de València
2016
Sonneberg Observatory
2016
Radboud University Nijmegen
2015
The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It based on (3FGL) sources between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, 2008 August 4 2012 July 31. 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10{\deg}), 71% increase over second 2 years data. There are 28 duplicate associations, thus 1563 2192 high-latitude gamma-ray 3FGL AGNs. Most them (98%) blazars. About half newly blazars unknown type, i.e.,...
Centaurus A is the closest radio-loud active galaxy. Very Long Baseline Interferometry (VLBI) enables us to study jet-counterjet system on milliarcsecond (mas) scales, providing essential information for jet emission and propagation models. We evolution of central parsec structure Cen over 3.5 years. The proper motion analysis individual components allows constrain formation test proposed correlation increased high energy flux with ejection events. an exceptional laboratory such detailed as...
The IceCube Collaboration has announced the discovery of a neutrino flux in excess atmospheric background. Owing to steeply falling background spectrum, events at PeV energies most likely have an extraterrestrial origin. We present multiwavelength properties six radio-brightest blazars that are positionally coincident with these using contemporaneous data TANAMI blazar sample, including high-resolution images and spectral energy distributions. Assuming X-ray γ-ray emission originates...
Gamma-ray detected radio-loud narrow-line Seyfert 1 (g-NLS1) galaxies constitute a small but interesting sample of the gamma-ray loud AGN. The radio-loudest g-NLS1 known, PKS 2004-447, is located in southern hemisphere and monitored radio regime by multiwavelength monitoring program TANAMI. We aim for first detailed study morphology long-term spectral evolution which are essential to understand diversity properties g-NLS1s. TANAMI VLBI uses Australian Long Baseline Array (LBA) telescopes...
Aims . In the framework of multi-wavelength and very long baseline interferometry (VLBI) monitoring program TANAMI (Tracking Active Nuclei with Austral Milliarcsecond Interferometry), we study evolution parsec-scale radio emission in galaxies southern hemisphere their relationship to γ -ray properties sources. Our investigates systematically, for first time, between two energy regimes galaxies. this paper, focus on Fermi -LAT-detected Methods The monitors a large sample radio-loud AGN at 8.4...
As part of the TANAMI multiwavelength progam, we discuss new X-ray observations γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004−447. The active is a member small sample NLS1s detected in γ-rays by Fermi Large Area Telescope. It stands out for being radio-loudest only southern-hemisphere source this sample. We present results from our monitoring program comprised Swift snapshot 2012 through 2014 two with XMM-Newton 2012. Supplemented archival data 2004 2011, set allows...
We investigate the nature and classification of PMNJ1603-4904, a bright radio source close to Galactic plane, which is associated with one brightest hard-spectrum gamma-ray sources detected by Fermi/LAT. It has previously been classified as low-peaked BL Lac object based on its broadband emission absence optical lines. Optical measurements, however, suffer strongly from extinction pronounced short-time variability over years monitoring unusual for blazar. are combining new archival...
Context. Simultaneous broadband spectral and temporal studies of blazars are an important tool for investigating active galactic nuclei (AGN) jet physics.
Multiwavelength observations have revealed the highly unusual properties of gamma-ray source PMN J1603-4904, which are difficult to reconcile with any other well established class. The object is either a very atypical blazar or compact jet seen at larger angle line sight. In order determine physical origin high-energy emission processes in we study X-ray spectrum detail. We performed quasi-simultaneous XMM-Newton and Suzaku 2013 September, resulting first high signal-to-noise this source....
Using high-resolution radio imaging with VLBI techniques, the TANAMI program has been observing parsec-scale jets of southern (declination south -30{\deg}) gamma-ray bright AGN simultaneously Fermi/LAT monitoring their emission. We present and properties sources based on one year contemporaneous data. A large fraction (72%) sample can be associated for this time range. Association rates differ different optical classes all BL Lacs, 76% quasars just 17% galaxies detected by LAT. Upper limits...
Abstract We report on Fermi Large Area Telescope (LAT) and multi-wavelength results the recently discovered very-high-energy (VHE, E > 100 GeV) blazar S4 0954+65 (z = 0.368) during an exceptionally bright optical flare in 2015 February. During time period (2015 February 13/14, or MJD 57067) when MAGIC telescope detected VHE γ-ray emission from source, Fermi-LAT data indicated a significant spectral hardening at GeV energies, with power-law photon index of 1.8 ± 0.1—compared 3FGL (The...
The Southern Hemisphere VLBI monitoring program TANAMI provides dual-frequency (8 GHz and 22 GHz), milliarcsecond of extragalactic jets south -30 degrees declination. sample consists a combined radio gamma-ray selected subsample currently 80 AGN jets, with new bright sources being added upon detections by Fermi/LAT. Supporting programs provide simultaneous multiwavelength coverage all sources, in order to construct broadband spectral energy distributions (SEDs) flaring quiescence source...
Abstract Quasi-simultaneous observations of the Flat Spectrum Radio Quasar PKS 2326−502 were carried out in γ -ray, X-ray, UV, optical, near-infrared, and radio bands. Using these observations, we are able to characterize spectral energy distribution (SED) source during two flaring one quiescent -ray states. These data used constrain one-zone leptonic models SEDs each flare investigate physical conditions giving rise them. While modeling required only changes electron spectrum compared...
TANAMI is a multiwavelength program monitoring active galactic nuclei (AGN) south of -30deg declination including high-resolution Very Long Baseline Interferometry (VLBI) imaging, radio, optical/UV, X-ray and gamma-ray studies. We have previously published first-epoch 8.4GHz VLBI images the parsec-scale structure initial sample. In this paper, we present 39 additional sources. The full sample comprises most radio- brightest AGN in southern quarter sky, overlapping with region from which...
Following our study of the radio and high-energy properties $\gamma$-ray-emitting galaxies, here we investigate kinematic spectral parsec-scale jets galaxies that have not yet been detected by Fermi-LAT. We take advantage regular VLBI observations provided TANAMI monitoring program, explore six $\gamma$-ray-faint galaxies. include publicly available kinematics $\gamma$-ray-quiet monitored MOJAVE program perform a Fermi-LAT analysis, deriving upper limits. combine these results with those...
declination. TheTANAMI sample consists of a combined radio and g-ray selected subsample currently ˘ 80AGN jets, with new bright sources being added upon detections by Fermi/LAT. Supportingprograms provide simultaneous multiwavelength coverage all sources, in order to constructbroadband spectral energy distributions (SEDs) flaring quiescence source states, as wellas rapid follow-up high-energy flares. This setup allows us continuously studythe structural evolution highly energetic extragalactic...
We present results from a multiwavelength study of the blazar PKS 1954-388 at radio, UV, X-ray, and gamma-ray energies. A RadioAstron observation 1.66 GHz in June 2012 resulted detection interferometric fringes on baselines 6.2 Earth-diameters. This suggests source frame brightness temperature greater than 2x10^12 K, well excess both equipartition inverse Compton limits implying existence Doppler boosting core. An 8.4 TANAMI VLBI image, made less month after observations, is consistent with...
and the TANAMI