Publications (34)
A QPO in Mkn 421 from Archival RXTE Data
Evan Smith, Lani Oramas, Eric Perlman
We report a 325(-7, +8) day quasi-periodic oscillation (QPO) in the X-ray emission of the blazar Mkn 421, based on data obtained with the Rossi X-ray Timing Explorer (RXTE). The QP…
The Open Connectome Project Data Cluster: Scalable Analysis and Vision for High-Throughput Neuroscience
Randal Burns, William Gray Roncal, Dean Kleissas +17
We describe a scalable database cluster for the spatial analysis and annotation of high-throughput brain imaging data, initially for 3-d electron microscopy image stacks, but for t…
A public turbulence database cluster and applications to study Lagrangian evolution of velocity increments in turbulence
Yi Li, Eric Perlman, Minping Wan +6
A public database system archiving a direct numerical simulation (DNS) data set of isotropic, forced turbulence is described in this paper. The data set consists of the DNS output…
Differences between CO- and calcium triplet-derived velocity dispersions in spiral galaxies: evidence for central star formation?
Rogemar A. Riffel, Luis C. Ho, Rachel Mason +16
We examine the stellar velocity dispersions (sigma) of a sample of 48 galaxies, 35 of which are spirals, from the Palomar nearby galaxy survey. It is known that for ultra-luminous…
A Community-Developed Open-Source Computational Ecosystem for Big Neuro Data
Randal Burns, Eric Perlman, Alex Baden +27
Big imaging data is becoming more prominent in brain sciences across spatiotemporal scales and phylogenies. We have developed a computational ecosystem that enables storage, visual…
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 +6
We compare the near-infrared (NIR) H band photometric and morphological properties of low-redshift (z<0.3) 3CR radio galaxies with samples of BL Lac object and quasar host galaxies…
Hubble Space Telescope Near-Infrared Snapshot Survey of 3CR radio source counterparts at low redshift
Juan P. Madrid, Marco Chiaberge, David Floyd +9
We present newly acquired images of the near-infrared counterpart of 3CR radio sources. All the sources were selected to have a redshift of less than 0.3 to allow us to obtain the…
How is the blazar GeV emission really produced?
Markos Georganopoulos, Eric Perlman, Demosthenes Kazanas +1
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 characte…
CHANG-ES V: Nuclear Radio Outflow in a Virgo Cluster Spiral after a Tidal Disruption Event
Judith A. Irwin, Richard N. Henriksen, Marita Krause +5
We have observed the Virgo Cluster spiral galaxy, NGC~4845, at 1.6 and 6 GHz using the Karl G. Jansky Very Large Array, as part of the `Continuum Halos in Nearby Galaxies -- an EVL…
Optical Structure and Physics of the M87 Jet
Eric Perlman, William Sparks, John Biretta +2
We summarize HST observations of the M87 jet, concentrating on polarimetry and spectral index maps, and compare its optical and radio structures. The evidence now supports a strati…
A QPO in NGC 4945 from Archival RXTE Data
Evan Smith, Rebecca Robles, Eric Perlman
We report the discovery of a ~6-week quasi-periodic oscillation (QPO) in archival NGC 4945 data observed by the Rossi X-ray Timing Explorer (RXTE) satellite. QPOs are an important…
On the Origins of "Hostless'' Supernovae: Testing the Faint-end Galaxy Luminosity Function and Supernova Progenitors with Events in Dwarf Galaxies
Louis-Gregory Strolger, Mia Sauda Bovill, Eric Perlman +3
We present arguments on the likely origins of supernovae without associated host galaxies from open field, non-clustered, environments. We show why it is unlikely these ``hostless'…
Near- to Mid- Infrared Imaging and Spectroscopy of Two Buried AGNs of the Nearby Merging Galaxy NGC 6240 with Subaru/IRCS+AO and GTC/CanariCam
Tamami I. Mori, Masatoshi Imanishi, Almudena Alonso-Herrero +7
We report near-infrared K', L', and M' band imaging observations of the nearby merging galaxy NGC 6240 with the Infrared Camera and Spectrograph on the Subaru telescope. The observ…
A diagnostic test for determining the location of the GeV emission in powerful blazars
Amanda Dotson, Markos Georganopoulos, Demosthenes Kazanas +1
An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a clear diagnostic…
A Multi-band Study of the remarkable Jet in Quasar 4C+19.44
Daniel Harris, Nicholas Lee, Dan Schwartz +14
We present arc-second-resolution data in the radio, IR, optical and X-ray for 4C+19.44 (=PKS 1354+195), the longest and straightest quasar jet with deep X-ray observations. We repo…
Gemini Imaging of Mid-IR Emission from the Nuclear Region of Centaurus A
James T. Radomski, Christopher Packham, N. A. Levenson +7
We present high spatial resolution mid-IR images of the nuclear region of NGC 5128 (Centaurus A). Images were obtained at 8.8 micron, N-band (10.4 micron), and 18.3 micron using th…
An HST Proper-Motion Study of the Large-scale Jet of 3C273
Eileen T. Meyer, William B. Sparks, Markos Georganopoulos +7
The radio galaxy 3C 273 hosts one of the nearest and best-studied powerful quasar jets. Having been imaged repeatedly by the Hubble Space Telescope (HST) over the past twenty years…
The infrared-dominated jet of 3C401
Marco Chiaberge, William. B. Sparks, F. Duccio Macchetto +6
We present a Hubble Space Telescope image of the FRII radio galaxy 3C 401, obtained at 1.6 microns with the NICMOS camera in which we identify the infrared counterpart of the brigh…
The Jet and Circumnuclear Environment of 3C 293
David J. E. Floyd, Eric Perlman, J. Patrick Leahy +5
We present the new HST near-infrared polarimetry, broad and narrow-band imaging, and MERLIN 4.5GHz Multi-Frequency Synthesis radio imaging of 3C 293, a unique radio galaxy whose ho…
Ruling out IC/CMB X-rays in PKS 0637-752 and the Implications for TeV Emission from Large-Scale Quasar Jets
Eileen T. Meyer, Markos Georganopoulos, William B. Sparks +3
The Chandra X-ray observatory has discovered dozens of resolved, kiloparsec-scale jets associated with powerful quasars in which the X-ray fluxes are observed to be much higher tha…
The Deep X-ray Radio Blazar Survey (DXRBS)
Paolo Padovani, Eric Perlman, Paolo Giommi +4
We have undertaken a survey for blazars by correlating the ROSAT WGACAT database with publicly available radio catalogs, restricting our candidate list to serendipitous flat-spectr…
Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of their Matter Content
Markos Georganopoulos, Demosthenes Kazanas, Eric Perlman +1
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…
NeuroStorm: Accelerating Brain Science Discovery in the Cloud
Gregory Kiar, Robert J. Anderson, Alex Baden +24
Neuroscientists are now able to acquire data at staggering rates across spatiotemporal scales. However, our ability to capitalize on existing datasets, tools, and intellectual capa…
Hubble Space Telescope far-ultraviolet imaging of the jet in 3C273: a common emission component from optical to X-rays
Sebastian Jester, Klaus Meisenheimer, Andre' Martel +2
We present far-ultraviolet (UV) observations at 150 nm of the jet of the quasar 3C 273 obtained with the Advanced Camera for Survey's Solar Blind Channel (ACS/SBC) on board the Hub…
A survey of X-ray emission from 100 kpc radio jets
Daniel A Schwartz, Herman L Marshall, Diana M Worrall +8
We have completed a Chandra snapshot survey of 54 radio jets that are extended on arcsec scales. These are associated with flat spectrum radio quasars spanning a redshift range z=0…
Missing Gamma-Rays from kpc-scale AGN Jets: A Test of the IC/CMB Model
Eileen T. Meyer, Markos Georganopoulos, William B. Sparks +2
The physical origin of the X-ray emission in powerful quasar jets has been a long-standing mystery. Though these jets start out on the sub-pc scale as highly relativistic flows, we…
Determining the location of the GeV emission in powerful blazars
Amanda Dotson, Markos Georganopoulos, Demosthenes Kazanas +1
An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a diagnostic tool f…
Proper Motions of Jets on the Kiloparsec Scale: New Results with HST
Eileen T. Meyer, William B. Sparks, Markos Georganopoulos +7
The Hubble Space Telescope recently celebrated 25 years of operation. Some of the first images of extragalactic optical jets were taken by HST in the mid-1990s; with time baselines…
Far-UV Emission Properties of FR1 Radio Galaxies
Charles W. Danforth, John T. Stocke, Kevin France +2
The power mechanism and accretion geometry for low-power FR1 radio galaxies is poorly understood in comparison to Seyfert galaxies and QSOs. In this paper we use the diagnostic pow…
Variability of extragalactic X-ray jets on kiloparsec scales
Eileen T. Meyer, Aamil Shaik, Yanbo Tang +10
Unexpectedly strong X-ray emission from extragalactic radio jets on kiloparsec scales has been one of the major discoveries of Chandra, the only X-ray observatory capable of sub-ar…
An optical-IR jet in 3C133
David J. E. Floyd, Robert Laing, Marco Chiaberge +10
We report the discovery of a new optical-IR synchrotron jet in the radio galaxy 3C133 from our HST/NICMOS snapshot survey. The jet and eastern hotspot are well resolved, and visibl…
The Warped Nuclear Disk of Radio Galaxy 3C 449
Grant R. Tremblay, Alice C. Quillen, David J. E. Floyd +11
Among radio galaxies containing nuclear dust disks, the bipolar jet axis is generally observed to be perpendicular to the disk major axis. The FR I radio source 3C 449 is an outlie…
HST NIR Snapshot Survey of 3CR Radio Source Counterparts II: An Atlas and Inventory of the Host Galaxies, Mergers and Companions
David J. E. Floyd, David Axon, Stefi Baum +10
We present the second part of an H-band (1.6 microns) atlas of z<0.3 3CR radio galaxies, using the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer (HST NI…
The Deep X-ray Radio Blazar Survey (DXRBS). I. Methods and First Results
Eric Perlman, Paolo Padovani, Paolo Giommi +4
We have undertaken a survey of archived, pointed ROSAT PSPC data for blazars by correlating the ROSAT WGACAT database with several publicly available radio catalogs, restricting ou…