A Multiwavelength Spectral and Polarimetric Study of the Jet of 3C 264 (2009)
Perlman, Eric S., Padgett, C. Alex, Georganopoulos, Markos, Worrall, Diana M., Kastner, Joel H., Franz, Geoffrey, ...
We present a comprehensive multiband spectral and polarimetric study of the jet of 3C 264 (NGC 3862). Included in this study are three HST optical and ultraviolet polarimetry data sets, along with...
Chandra Observations of the Radio Galaxy 3C 445 and the Hotspot X-ray Emission Mechanism (2009)
Perlman, Eric S., Georganopoulos, Markos, May, Emily M., Kazanas, Demosthenes
We present new {\it Chandra} observations of the radio galaxy 3C 445, centered on its southern radio hotspot. Our observations detect X-ray emission displaced upstream and to the west of the...
Mehta, Kushal T., Georganopoulos, Markos, Perlman, Eric S., Padgett, Charles A., Chartas, George
We present new NICMOS and ACS observations of the quasar jet PKS 0637-752, and we use them, together with existing multiwavelength observations, to produce the most complete spectral coverage of the...
Georganopoulos, Markos, Sambruna, Rita M., Kazanas, Demosthenes, Cillis, Analia N., Cheung, Chi C., Perlman, Eric S., ...
We describe a new method for measuring the extragalactic background light (EBL) through the detection of $\gamma$-ray inverse Compton (IC) emission due to scattering of the EBL photons off...
A multi-zone model for simulating the high energy variability of TeV blazars (2008)
Graff, Philip B., Georganopoulos, Markos, Perlman, Eric S., Kazanas, Demosthenes
We present a time-dependent multi-zone code for simulating the variability of Synchrotron-Self Compton (SSC) sources. The code adopts a multi-zone pipe geometry for the emission region, appropriate...
Thermal AGN Signatures in Blazars (2008)
Perlman, Eric S., Addison, Brett, Georganopoulos, Markos, Wingert, Brian, Graff, Philip
Long ignored in blazars because of the dominance of the beamed radiation from the jet, the topic of thermal emissions in these objects is just beginning to be explored. While this emission is weak in...
Graff, Philip B., Georganopoulos, Markos, Perlman, Eric S., Kazanas, Demosthenes
With the anticipated launch of GLAST, the existing X-ray telescopes, and the enhanced capabilities of the new generation of TeV telescopes, developing tools for modeling the variability of high...
The "Supercritical Pile" GRB Model: Afterglows and GRB, XRR, XRF Unification (2006)
Kazanas, Demosthenes, Mastichiadis, Apostolos, Georganopoulos, Markos
We present the general notions and observational consequences of the "Supercritical Pile" GRB model; the fundamental feature of this model is a detailed process for the conversion of the energy...
Georganopoulos, Markos, Perlman, Eric S., Kazanas, Demosthenes, McEnery, Julie
The process responsible for the Chandra-detected X-ray emission from the large scale jets of powerful quasars is a matter of ongoing debate. The two main contenders are external Compton (EC)...
Optical Polarimetry of the Jets of Nearby Radio Galaxies: I. The Data (2006)
Perlman, Eric S., Padgett, C. A., Georganopoulos, Markos, Sparks, William B., Biretta, John A., O'Dea, Christopher P., ...
We present an overview of new HST imaging polarimetry of six nearby radio galaxies with optical jets. These observations triple the number of extragalactic jets with subarcsecond-resolution optical...
Optical polarimetry of the jets of nearby radio galaxies: I. The Data (2006)
Perlman, Eric, Padgett, Alex, Georganopoulos, Markos, Sparks, William, Biretta, John, O'Dea, Christopher, ...
Archived in: arXiv:astro-ph/0606119 v1 6 Jun 2006
Optical polarimetry of the jets of nearby radio galaxies: I. The data (2006)
Perlman, Eric, Padgett, Alex, Georganopoulos, Markos, Sparks, William, Biretta, John, O'Dea, Christopher, ...
Archived in: arXiv:astro-ph/0606119 v1 6 Jun 2006
Optical polarimetry of the jets of nearby radio galaxies. I. The data (2006)
Perlman, Eric S., Padgett, C. A., Georganopoulos, Markos, Sparks, William B., Biretta, John A., O'Dea, Christopher P., ...
We present an overview of new HST imaging polarimetry of six nearby radio galaxies with optical jets. These observations triple the number of extragalactic jets with subarcsecond-resolution optical...
Is the core of M87 the source of its TeV emission? Implications for unified schemes (2005)
Georganopoulos, Markos, Perlman, Eric S., Kazanas, Demosthenes
M87 has been recently shown to be a TeV source which is likely to be variable. Based on this, and on contemporaneous optical and X-ray monitoring, we argue that the source of the TeV emission is the...
How is the blazar GeV emission really produced? (2005)
Georganopoulos, Markos, Perlman, Eric, Kazanas, Demosthenes, Wingert, Brian
We show that the external Compton (EC) model for the production of the GeV emission in blazars makes specific predictions for the spectrum and variability of those blazars characterized by a high...
Intrinsic Curvature in the X-ray Spectra of BL Lacertae Objects (2005)
Perlman, Eric S., Madejski, Greg, Georganopoulos, Markos, Andersson, Karl, Dougherty, Timothy, Krolik, Julian, ...
We report results from {\it XMM-Newton} observations of thirteen X-ray bright BL Lacertae objects, selected from the {\it Einstein} Slew Survey sample. The survey was designed to look for evidence of...
Georganopoulos, Markos, Kazanas, Demosthenes, Perlman, Eric, Stecker, Floyd
We propose a method for estimating the composition, i.e. the relative amounts of leptons and protons, of extragalactic jets which exhibit X-ray bright knots in their kpc scale jets. The method relies...
Georganopoulos, Markos, Kazanas, Demosthenes
A puzzling feature of the {\it Chandra}--detected quasar jets is that their X-ray emission decreases faster along the jet than their radio emission, resulting to an outward increasing radio to X-ray...
The "Supercritical Pile" Model of GRB: Thresholds, Polarization, Time Lags (2003)
Kazanas, Demosthenes, Georganopoulos, Markos, Mastichiadis, Apostolos
The essence of the ``Supercritical Pile'' model is a process for converting the energy stored in the relativistic protons of a Relativistic Blast Wave (RBW) of Lorentz factor $\Gamma$ into electron...
I present here a short personal view of our understanding of the Chandra detected knots and hot spots of powerful Fanaroff Rilley (FR) II radio galaxies and quasars in the context of leptonic models....
Decelerating Flows in TeV Blazars: A Resolution to the BL Lac -- FR I Unification Problem (2003)
Georganopoulos, Markos, Kazanas, Demosthenes
TeV emission from BL Lacertae (BL) objects is commonly modeled as Synchrotron-Self Compton (SSC) radiation from relativistically moving homogeneous plasma blobs. In the context of these models, the...
Decelerating Flows in TeV Blazars (2003)
Georganopoulos, Markos, Kazanas, Demosthenes
The peak of the de-absorbed energy distribution of the TeV emitting BLs can reach values up to ~10 TeV. In the context of SSC models of relativistic uniformly moving blobs of plasma, such high energy...
Georganopoulos, Markos, Kazanas, Demosthenes
Pairs of radio emitting jets with lengths up to several hundred kiloparsecs emanate from the central region (the `core') of radio loud active galaxies. In the most powerful of them, these jets...
Relativistic Flows at the Hotspots of Radio Galaxies and Quasars? (2003)
Georganopoulos, Markos, Kazanas, Demosthenes
We review the broad band properties of X-ray detected hotspots in radio galaxies and quasars. We show that their collective properties can be unified in a framework involving frequency dependent...
Chandra Detection of Hotspot and Knots of 3C 303 (2002)
Kataoka, Jun, Edwards, Philip, Georganopoulos, Markos, Takahara, Fumio, Wagner, Stefan
We report the detection at X-rays of the radio/optical hotspot and knots of 3C 303 from a short (15 ksec) Chandra exposure in 2001 March. The X-ray morphology is similar to that of the radio/optical...
The "Supercritical Pile" Model for GRB: Getting the nu F_{nu} peak at 1 MeV (2002)
Kazanas, Demosthenes, Georganopoulos, Markos, Mastichiadis, Apostolos
We propose that the internal energy of the GRB blast waves, thought to be stored in the form of relativistic protons co-moving with the blast wave, is converted explosively (i.e. on light crossing...
Size-Luminosity scaling and Inverse Compton Seed Photons in Blazars (2000)
Georganopoulos, Markos, Kirk, John G., Mastichiadis, Apostolos
We present preliminary results of our work on blazar unification. We assume that all blazars have a broad line region (BLR) and that the size of the BLR scales with the power of the source in a...
Blue Quasars and Blazar Unification Schemes (2000)
Blue quasars (BQs) are sources with strong broad emission lines and flat hard X-ray spectra, properties that resemble classical flat spectrum radio quasars (FSRQs), and high peak frequencies and...
Modeling the variability of the BL Lacertae object PKS 2155-304 (1998)
Georganopoulos, Markos, Marscher, Alan P.
The bright X-ray selected BL Lacertae object PKS 2155-304 has been the target of two intense multiwavelength campaigns, in November 1991 and in May 1994. Although the spectral energy distributions at...
A Viewing Angle - Kinetic Luminosity Unification Scheme For BL Lacertae Objects (1998)
Georganopoulos, Markos, Marscher, Alan P.
We propose a unified classification for BL Lac objects (BLs), focusing on the synchrotron peak frequency of the spectral energy distribution. The unification scheme is based on the angle Theta that...
A new classification and a two-parameter unification of BL Lacertae objects (1997)
Georganopoulos, Markos, Marscher, Alan P.
A new continuous classification system for BL Lacertae (BL Lac) objects is proposed. The peak frequency of the synchrotron component in the $\nu L_{\nu}$ spectrum is used as a classifying parameter....