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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Astrophysics and Astronomy

Aerospace, Physics, and Space Science Faculty Publications

Series

2010

Galaxies: Active

Articles 1 - 5 of 5

Full-Text Articles in Physical Sciences and Mathematics

A Flare In The Jet Of Pictor A, Herman L. Marshall, Eric S. Perlman May 2010

A Flare In The Jet Of Pictor A, Herman L. Marshall, Eric S. Perlman

Aerospace, Physics, and Space Science Faculty Publications

A Chandra X-ray imaging observation of the jet in Pictor A showed a feature that appears to be a flare that faded between 2000 and 2002. The feature was not detected in a follow-up observation in 2009. The jet itself is over 150kpc long and about 1 kpc wide, so finding year-long variability is surprising. Assuming a synchrotron origin of the observed high-energy photons and a minimum energy condition for the outflow, the synchrotron loss time of the X-ray emitting electrons is of order 1200 years, which is much longer than the observed variability timescale. This leads to the possibility …


Hubble Space Telescope Near-Infrared Snapshot Survey Of 3cr Radio Source Counterparts. Iii. Radio Galaxies And Quasars In Context, David J.E. Floyd, David Axon, Stefi Baum, Alessandro Capetti, Marco Chiaberge, Juan P. Madrid, Christopher P. O'Dea, Eric S. Perlman, William B. Sparks Apr 2010

Hubble Space Telescope Near-Infrared Snapshot Survey Of 3cr Radio Source Counterparts. Iii. Radio Galaxies And Quasars In Context, David J.E. Floyd, David Axon, Stefi Baum, Alessandro Capetti, Marco Chiaberge, Juan P. Madrid, Christopher P. O'Dea, Eric S. Perlman, William B. Sparks

Aerospace, Physics, and Space Science Faculty Publications

We compare the near-infrared (NIR) H-band photometric and morphological properties of low-z (z < 0.3) 3CR radio galaxies with samples of BL Lac objects and quasar host galaxies, merger remnants, quiescent elliptical galaxies, and brightest cluster galaxies drawn from the literature. In general, the 3CR host galaxies are consistent with luminous (~Lsstarf) elliptical galaxies. The vast majority of FR II's (~80%) occupy the most massive ellipticals and form a homogeneous population that is comparable to the population of radio-loud quasar (RLQ) host galaxies in the literature. However, a significant minority (~20%) of the 3CR FR II's appears under-luminous with respect to quasar host galaxies. All FR II objects in this faint tail are either unusually red, or appear to be the brightest objects within a group. We discuss the apparent differences between the radio galaxy and RLQ host galaxy populations. RLQs appear to require gsim1011 M☉ host galaxies (and ~109 M☉ black holes), whereas radio galaxies and radio-quiet quasars can exist in galaxies down to ~3 × 1010 M☉. This may be due to biases in the measured quasar host galaxy luminosities or populations studied, or due to a genuine difference in host galaxy. If due to a genuine difference, it would support the idea that radio and optical active galactic nuclei are two separate populations with a significant overlap.


Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Deosthenes Kazanas Jan 2010

Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Deosthenes Kazanas

Aerospace, Physics, and Space Science Faculty Publications

We present new Chandra observations of the radio galaxy 3C 445, centered on its southern radio hot spot. Our observations detect X-ray emission displaced upstream and to the west of the radio-optical hot spot. Attempting to reproduce both the observed spectral energy distribution and the displacement excludes all one-zone models. Modeling of the radio-optical hot spot spectrum suggests that the electron distribution has a low-energy cutoff or break approximately at the proton rest mass energy. The X-rays could be due to external Compton scattering of the cosmic microwave background coming from the fast (Lorentz factor Γ ≈ 4) part of …


Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Demosthenes Kazanas Jan 2010

Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Demosthenes Kazanas

Aerospace, Physics, and Space Science Faculty Publications

We present new Chandra observations of the radio galaxy 3C 445, centered on its southern radio hot spot. Our observations detect X-ray emission displaced upstream and to the west of the radio-optical hot spot. Attempting to reproduce both the observed spectral energy distribution and the displacement excludes all one-zone models. Modeling of the radio-optical hot spot spectrum suggests that the electron distribution has a low-energy cutoff or break approximately at the proton rest mass energy. The X-rays could be due to external Compton scattering of the cosmic microwave background coming from the fast (Lorentz factor Γ ≈ 4) part of …


A Multi-Wavelength Spectral And Polarimetric Study Of The Jet Of 3c 264, Eric S. Perlman Jan 2010

A Multi-Wavelength Spectral And Polarimetric Study Of The Jet Of 3c 264, Eric S. Perlman

Aerospace, Physics, and Space Science Faculty Publications

We present a comprehensive multi-band spectral and polarimetric study of the jet of 3C 264 (NGC 3862). Included in this study are three Hubble Space Telescope (HST) optical and ultraviolet polarimetry data sets, along with new and archival Very Large Array radio imaging and polarimetry, a re-analysis of numerous HST broadband data sets from the near infrared to the far ultraviolet, and a Chandra ACIS-S observation. We investigate similarities and differences between optical and radio polarimetry, in both degree of polarization and projected magnetic field direction. We also examine the broadband spectral energy distribution of both the nucleus and jet …