Optical Spectroscopy of Bright Fermi LAT Blazars (2009)
Shaw, Michael S., Romani, Roger W., Healey, Stephen E., Cotter, Garret, Michelson, Peter F., Readhead, Anthony C. S.
We report on Hobby-Eberly Telescope and Palomar 5 m spectroscopy of recently identified γ-ray blazars in the Fermi LAT Bright Source List. These data provide identifications for 10 newly discovered...
Filling in the Gaps in the 4.85 GHz Sky (2009)
Healey, Stephen E., Fuhrmann, Lars, Taylor, Gregory B., Romani , Roger W., Readhead, Anthony C. S.
We describe a 4.85 GHz survey of bright, flat-spectrum radio sources conducted with the Effelsberg 100 m telescope in an attempt to improve the completeness of existing surveys, such as CRATES. We...
Optical Spectroscopy of Bright Fermi LAT Blazars (2009)
Shaw, Michael S., Romani, Roger W., Healey, Stephen E., Cotter, Garret, Michelson, Peter F., Readhead, Anthony C. S.
We report on HET and Palomar 5 m spectroscopy of recently identified $\gamma$-ray blazars in the {\it Fermi} LAT Bright Source List. These data provide identifications for 10 newly discovered...
Filling in the Gaps in the 4.85 GHz Sky (2009)
Healey, Stephen E., Fuhrmann, Lars, Taylor, Gregory B., Romani, Roger W., Readhead, Anthony C. S.
We describe a 4.85 GHz survey of bright, flat-spectrum radio sources conducted with the Effelsberg 100 m telescope in an attempt to improve the completeness of existing surveys, such as CRATES. We...
An Atlas For Interpreting Gamma-Ray Pulsar Light Curves (2008)
Watters, Kyle P., Romani, Roger W., Weltevrede, Patrick, Johnston, Simon
We have simulated a population of young spin-powered pulsars and computed the beaming pattern and lightcurves for the three main geometrical models: polar cap emission, two-pole caustic ("slot gap")...
CGRaBS : an all-sky survey of gamma-ray blazar candidates (2008)
Healey, Stephen E., Romani, Roger W., Cotter, Garret, Michelson, Peter F., Schlafly, Edward F., Readhead, Anthony C. S., ...
We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely γ-ray active galactic nuclei (AGNs). The...
Rings and Jets around PSR J2021+3651: the `Dragonfly Nebula' (2008)
Van Etten, Adam, Romani, Roger W.
We describe recent Chandra ACIS observations of the Vela-like pulsar PSR J2021+3651 and its pulsar wind nebula (PWN). This `Dragonfly Nebula' displays an axisymmetric morphology, with bright inner...
First-Year Spectroscopy for the SDSS-II Supernova Survey (2008)
Zheng, Chen, Romani, Roger W., Sako, Masao, Marriner, John, Bassett, Bruce, Becker, Andrew, ...
This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of...
γ-Ray Pulsars: Emission Zones and Viewing Geometries (2008)
There are now a half dozen young pulsars detected in high energy photons by the Compton GRO, showing a variety of emission efficiencies and pulse profiles. We present here a calculation of the...
First-year spectroscopy for the sloan digital sky survey - II. Supernova survey (2008)
Zheng, Chen, Romani, Roger W., Sako, Masao, Marriner, John, Bassett, Bruce, Becker, Andrew, ...
γ-Ray Pulsars: Beaming Evolution, Statistics and Unidentified EGRET Sources (2007)
We compute the variation of the beaming fraction with the efficiency of high energy fl-ray production in the outer gap pulsar model of Romani and Yadigaroglu. This allows us to correct the fluxes...
Fitting Pulsar Wind Tori. II. Error Analysis and Applications (2007)
We have applied the torus fitting procedure described in Ng & Romani (2004) to PWNe observations in the Chandra data archive. This study provides quantitative measurement of the PWN geometry and we...
CGRaBS: An All-Sky Survey of Gamma-Ray Blazar Candidates (2007)
Healey, Stephen E., Romani, Roger W., Cotter, Garret, Michelson, Peter F., Schlafly, Edward F., Readhead, Anthony C. S., ...
We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray AGN. The defined sample has...
CRATES: An All-Sky Survey of Flat-Spectrum Radio Sources (2007)
Healey, Stephen E., Romani, Roger W., Taylor, Gregory B., Sadler, Elaine M., Ricci, Roberto, Murphy, Tara, ...
We have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b|>10 deg) coverage for sources brighter than S_{4.8 GHz} = 65 mJy. The...
Birth Kick Distributions and the Spin-Kick Correlation of Young Pulsars (2007)
Evidence from pulsar wind nebula symmetry axes and radio polarization observations suggests that pulsar motions correlate with the spin directions. We assemble this evidence for young isolated...
The Origin and Motion of PSR J0538+2817 in S147 (2006)
Romani, Roger W., Brisken, Walter F., Chatterjee, Shami, Kramer, Michael
We report on VLBA astrometry and CXO imaging of PSR J0538+2817 in the supernova remnant S147. We measure a parallax distance of $1.47^{+0.42}_{-0.27}$kpc along with a high-precision proper motion,...
The Spectral Energy Distribution of the High-Z Blazar Q0906+693 (2006)
We describe further observations of QSO J0906+6930, a z=5.48 blazar likely to be detected in gamma-rays. New radio and X-ray data place significant constraints on any kpc-scale extension of the...
Proper Motion of the Crab Pulsar Revisited (2006)
It has been suggested that the Crab pulsar's proper motion is well aligned with the symmetry axis of the pulsar wind nebula. We have re-visited this question, examining over 6 years of F547M WFPC2...
The Complex Wind Torus and Jets of PSR B1706-44 (2005)
Romani, Roger W., Dodson, Richard, Brisken, Walter
We report on Chandra ACIS imaging of the pulsar wind nebula (PWN) of the young Vela-like PSR B1706-44, which shows the now common pattern of an equatorial wind and polar jets. The structure is...
Two Pulsar Wind Nebulae: Chandra/XMM-Newton Imaging of GeV J1417-6100 (2005)
Roberts, Mallory S. E., Romani, Roger W.
We report on Chandra ACIS and XMM-Newton MOS/PN imaging observations of two pulsar wind nebulae (K3/PSR J1420-6048 and G313.3+0.1=`the rabbit') associated with the Galactic unidentified gamma-ray...
The Vela Pulsar in the Ultraviolet (2005)
Romani, Roger W., Kargaltsev, Oleg, Pavlov, George G.
We describe time-tagged observations of the Vela pulsar (PSR B0833-45) with the HST STIS MAMA-UV detectors. Using an optimal extraction technique, we obtain a NUV light curve and crude FUV...
A Northern Survey of Gamma-Ray Blazar Candidates (2005)
Sowards-Emmerd, David, Romani, Roger W., Michelson, Peter F., Healey, Stephen E., Nolan, Patrick L.
In preparation for GLAST, we have compiled a sample of blazar candidates to increase the pool of well studied AGN from which GLAST counterparts will be drawn. Sources were selected with our Figure of...
Pulsar Wind Nebulae in EGRET Error Boxes (2004)
Roberts, Mallory S. E., Brogan, Crystal L., Gaensler, Bryan M., Hessels, Jason W. T., Romani, Roger W.
A remarkable number of pulsar wind nebulae (PWN) are coincident with EGRET gamma-ray sources. X-ray and radio imaging studies of unidentified EGRET sources have resulted in the discovery of at least...
Roberts, Mallory S. E., Lyutikov, Maxim, Gaensler, Bryan M., Brogan, Crystal, Tam, Cindy R., Romani, Roger W.
The traditional view of radio pulsar wind nebulae (PWN), encouraged by the Crab nebula's X-ray and radio morphologies, is that they are a result of the integrated history of their pulsars' wind. The...
Q0906+6930: The Highest-Redshift Blazar (2004)
Romani, Roger W., Sowards-Emmerd, David, Greenhill, Lincoln, Michelson, Peter
We report the discovery of a radio-loud flat-spectrum QSO at z=5.47 with properties similar to those of the EGRET gamma-ray blazars. This source is the brightest radio QSO at z>5, with a pc-scale...
Pulsar Kicks: Spin and Kinematic Constraints (2004)
It has been noted that the Crab and Vela pulsar proper motions lie along the symmetry axes of their wind nebulae. In an effort to promote this observation to a serious test of kick physics, we are...
Fitting Pulsar Wind Tori (2003)
CXO imaging has shown that equatorial tori, often with polar jets, are very common in young pulsar wind nebulae (PWNe). These structures are interesting both for what they reveal about the...
Giant Pulses from PSR B0540-69 in the Large Magellanic Cloud (2003)
Johnston, Simon, Romani, Roger W.
We report the discovery of the first giant pulses from an extragalactic radio pulsar. Observations of PSR B0540-69 in the Large Magellanic Cloud made with the Parkes radio telescope at 1.38 GHz show...
The PWN torus of PSR J0538+2817 and the Origin of Pulsar Velocities (2003)
We find evidence for a faint wind nebula surrounding PSR J0538+2817 in CXO-ACIS imaging. This object is particularly interesting, as the pulsar spindown age is largest for any such X-ray PWN. If...
The Gamma-Ray Blazar Content of the Northern Sky (2002)
Sowards-Emmerd, David, Romani, Roger W., Michelson, Peter F.
Using survey data, we have re-evaluated the correlation of flat spectrum radio sources with EGRET sources in the Northern sky. A likelihood analysis incorporating the radio and X-ray properties and...
The Rest of the Story: Radio Pulsars and IR through Gamma-Ray Emission (2002)
Recent observations have detected a number of young pulsars from the power peak in the gamma-ray band to the incoherent photon peak in the optical/IR. We have made progress on the multiwavelength...
RX J1856-3754: Evidence for a Stiff EOS (2002)
Braje, Timothy M., Romani, Roger W.
We have examined the soft X-ray plus optical/UV spectrum of the nearby isolated neutron star RX J1856-3754, comparing with detailed models of a thermally emitting surface. Like previous...
A search for giant pulses in Vela-like pulsars (2002)
Johnston, Simon, Romani, Roger W.
We have carried out a survey for `giant pulses' in 6 young, Vela-like pulsars. In no cases did we find single pulses with flux densities more than 10 times the mean flux density. However, in PSR...
Chandra Imaging of the Gamma-Ray Source GeV J1809-2327 (2002)
Braje, Timothy M., Romani, Roger W., Roberts, Mallory S. E., Kawai, Nobuyuki
We report on Chandra imaging observations of the Galactic Unidentified $\gamma$-ray source GEV J1809-2327, comparing the X-ray images with new VLA 1.46 GHz and 4.86 GHz maps. The X-ray images reveal...
Pulsar Wind Nebulae as High Energy Gamma-Ray Emitters (2001)
Roberts, Mallory S. E., Gaensler, Bryan M., Romani, Roger W.
There is growing evidence that some variable high-energy gamma-ray sources are associated with pulsar wind nebulae. We review the current status of X-ray and radio studies of the sources most likely...
Multiwavelength Studies of PSR J1420-6048, a Young Pulsar in the Kookaburra (2001)
Roberts, Mallory S. E., Romani, Roger W., Johnston, Simon
We present X-ray, radio, and infrared observations of the 68 ms pulsar PSR J1420-6048 and its surrounding nebula, a possible counterpart of the gamma-ray source GeV J1417-6100/3EG J1420-6038. Pulsed...
Phase-resolved Crab Studies with a Cryogenic TES Spectrophotometer (2001)
Romani, Roger W., Miller, A. J., Cabrera, B., Nam, S. W., Martinis, John M.
We are developing time- and energy-resolved near-IR/optical/UV photon detectors based on sharp superconducting-normal transition edges in thin films. We report observations of the Crab pulsar made...
Giant Pulses from the Millisecond Pulsar B1821-24 (2001)
Romani, Roger W., Johnston, Simon
We have carried out a survey for `giant pulses' in 5 millisecond pulsars. We detect individual pulses from the high Edot pulsar PSR B1821-24 with energies exceeding 50x the mean pulse energy. These...
X-Ray and Radio Observations of Bright GeV Sources (2001)
Roberts, Mallory S. E., Romani, Roger W., Kawai, Nobuyuki, Gaensler, Bryan M., Johnston, Simon
We present X-ray and radio studies of sources which are brightabove 1 GeV (F_{>1GeV} > 4e-8 ph/cm^2/s. Only 11 out of ~30 of these gamma-ray sources have been identified with lower energy...
The ASCA Catalog of Potential X-Ray Counterparts of GeV Sources (2000)
Roberts, Mallory S. E., Romani, Roger W., Kawai, Nobuyuki
We present a catalog of 2-10 keV ASCA Gas Imaging Spectrometer images of fields containing bright sources of GeV emission. The images cover $\sim 85%$ of the 95% confidence position contour for 28 of...
Magnetospheric Scattering and Emission in Millisecond Pulsars (2000)
Braje, Timothy M., Romani, Roger W.
We model the formation of magnetospheric components of millisecond pulsar light curves, deriving an approximate model for the curved space, `swept-back' dipole field and following photon emission,...
Light Curves of Rapidly Rotating Neutron Stars (2000)
Braje, Timothy M., Romani, Roger W., Rauch, Kevin P.
We consider the effect of rapid rotation on the light curves of neutron stars with hot polar caps. For $P \approx 3$ms spin periods, the pulse fractions can be as much as an order of magnitude larger...
The `Rabbit': A Potential Radio Counterpart of GeV J1417-6100 (1998)
Roberts, Mallory S. E., Romani, Roger W., Johnston, Simon, Green, Anne J.
We have mapped the radio emission in the error ellipse of GeV J1417-6100 (2EGS J1418-6049) at 13cm and 20cm using the Australia Telescope Compact Array. We find a large shell with extended wings, at...
X-ray Emission from the Guitar Nebula (1997)
Romani, Roger W., Cordes, James M.
We have detected weak soft X-ray emission from the Pulsar Wind Nebula trailing the high velocity star PSR 2224+65 (the `Guitar Nebula'). This X-ray flux gives evidence of \gamma~10^7 eV particles in...
Gamma-Ray Pulsars and Massive Stars in the Solar Neighborhood (1996)
We revisit the association of unidentified Galactic plane EGRET sources with tracers of recent massive star formation and death. Up-to-date catalogs of OB associations, SNRs, young pulsars, HII...
Magnetized Iron Atmospheres for Neutron Stars (1996)
Rajagopal, Mohan, Romani, Roger W., Miller, M. Coleman
Using a Hartree-Fock formalism, we estimate energy levels and photon cross sections for atomic iron in magnetic fields B ~ 10^13 G. Computing ionization equilibrium and normal mode opacities with...
Ultra-Low Frequency Gravitational Radiation from Massive Black Hole Binaries (1994)
Rajagopal, Mohan, Romani, Roger W.
For massive black hole binaries produced in galactic mergers, we examine the possibility of inspiral induced by interaction with field stars. We model the evolution of such binaries for a range of...
Gamma-Ray Pulsars: Beaming Evolution, Stats and Unident. EGRET Sources (1994)
We compute the variation of the beaming fraction with the efficiency of high energy gamma-ray production in the outer gap pulsar model of Romani and Yadigaroglu. This allows us to correct the fluxes...
$\gamma$-Ray Pulsars: Emission Zones and Viewing Geometries, A Computer Animation (1994)
The computer animation illustrates the geometries described in a paper by the same authors. The preprint is available as number 9401045. The opening scene shows dipole field lines emanating from the...
$\gamma$-Ray Pulsars: Emission Zones and Viewing Geometries (1994)
There are now a half dozen young pulsars detected in high energy photons by the Compton GRO, showing a variety of emission efficiencies and pulse profiles. We present here a calculation of the...