Muno, M. P., Bauer, F. E., Baganoff, F. K., Bandyopadhyay, R. M., Bower, G. C., Brandt, W. N., ...
We present a catalog of 9017 X-ray sources identified in Chandra observations of a 2 by 0.8 degree field around the Galactic center. We increase the number of known X-ray sources in the region by a...
A Search for the Near-Infrared Counterpart to GCRT J1745-3009 (2008)
Kaplan, D. L., Hyman, S. D., Roy, S., Bandyopadhyay, R. M., Chakrabarty, D., Kassim, N. E., ...
We present an optical/near-infrared search for a counterpart to the perplexing radio transient GCRT J1745-3009, a source located ~1 degree from the Galactic Center. Motivated by some similarities to...
Inverse-Compton emission from the lobes of 3C 353 (2008)
Goodger, J. L., Hardcastle, M. J., Croston, J. H., Kassim, N. E., Perley, R. A.
X-ray emission due to inverse-Compton scattering of microwave background photons by electrons in the lobes of powerful radio galaxies has now been seen in a large number of objects. Combining an...
Inverse-Compton emission from the lobes of 3C 353. (2008)
Goodger, J.L., Hardcastle, M.J., Croston, J.H., Kassim, N.E., Perley, R.A.
‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.13028.x
Radio Frequency Spectra of 388 Bright 74 MHz Sources (2007)
Helmboldt, J. F., Kassim, N. E., Cohen, A. S., Lane, W. M., Lazio, T. J.
As a service to the community, we have compiled radio frequency spectra from the literature for all sources within the VLA Low Frequency Sky Survey (VLSS) that are brighter than 15 Jy at 74 MHz. Over...
The VLA Low-frequency Sky Survey (2007)
Cohen, A. S., Lane, W. M., Cotton, W. D., Kassim, N. E., Lazio, T. J. W., Perley, R. A., ...
The Very Large Array (VLA) Low-frequency Sky Survey (VLSS) has imaged 95% of the 3*pi sr of sky north of declination = -30 degrees at a frequency of 74 MHz (4 meter wavelength). The resolution is 80"...
The 74MHz System on the Very Large Array (2007)
Kassim, N. E., Lazio, T. J. W., Erickson, W. C., Perley, R. A., Cotton, W. D., Greisen, E. W., ...
The Naval Research Laboratory and the National Radio Astronomy Observatory completed implementation of a low frequency capability on the VLA at 73.8 MHz in 1998. This frequency band offers...
Castelletti, G., Dubner, G., Brogan, C., Kassim, N. E.
We present new Very Large Array (VLA) radio images at 74 and 324 MHz of the SNR W44. The VLA images, obtained with unprecedented angular resolution and sensitivity for such low frequencies have been...
Monitoring the Bi-Directional Relativistic Jets of the Radio Galaxy 3C 338 (2006)
Gentile, G., Rodriguez, C., Taylor, G. B., Giovannini, G., Allen, S. W., Lane, W. M., ...
We present the analysis of VLA and VLBA observations of the radio source 3C 338, associated with the cD galaxy NGC 6166, the central dominant galaxy of the cluster Abell 2199. The VLBA observations...
Cygnus A: A Long Wavelength Resolution of the Hot Spots (2006)
Lazio, T. J. W., Cohen, A. S., Kassim, N. E., Perley, R. A., Erickson, W. C., Carilli, C. L., ...
This paper presents observations of Cygnus A at 74 and 327 MHz at angular resolutions of approximately 10" and 3", respectively. These observations are among the highest angular resolutions obtained...
Discovery of 35 New Supernova Remnants in the Inner Galaxy (2006)
Brogan, C. L., Gelfand, J. D., Gaensler, B. M., Kassim, N. E., Lazio, T. J.
We report the discovery of up to 35 new supernova remnants (SNRs) from a 42 arcsec resolution 90cm multi-configuration Very Large Array survey of the Galactic plane covering 4.5 deg< l
New results from the low-frequency counterpart of the XMM large scale structure survey (2006)
Tasse, C., Cohen, A.S., Röttgering, H.J.A., Kassim, N.E., Pierre, M., Perley, R., ...
New results from the low-frequency counterpart of the XMM large scale structure survey (2006)
Tasse, C., Cohen, A.S., Röttgering, H.J.A., Kassim, N.E., Pierre, M., Perley, R.A., ...
Hewitt, J. W, Yusef-Zadeh, F, Wardle, M, Roberts, D. A, Kassim, N. E
We present spectral line observations of the ground-state transitions of hydroxyl (OH) toward supernova remnant (SNR) IC 443 carried out with the Green Bank Telescope. Weak, extended OH (1720 MHz)...
LaRosa, T. N., Brogan, C. L., Shore, S. N., Lazio, T. J., Kassim, N. E., Nord, M. E.
New low-frequency 74 and 330 MHz observations of the Galactic center (GC) region reveal the presence of a large-scale ($6\arcdeg\times 2\arcdeg$) diffuse source of nonthermal synchrotron emission. A...
Brogan, C. L., Gaensler, B. M., Gelfand, J. D., Lazendic, J. S., Lazio, T. J., Kassim, N. E., ...
We present the discovery of non-thermal radio and X-ray emission positionally coincident with the TeV $\gamma$-ray source HESS J1813--178. We demonstrate that the non-thermal radio emission is due to...
Clarke, T. E., Sarazin, C. L., Blanton, E. L., Neumann, D. M., Kassim, N. E.
A previous analysis of the Chandra X-ray image of the center of the cooling core cluster Abell 2597 showed two ``ghost holes'' in the X-ray emission to the west and northeast of the central radio...
A powerful bursting radio source towards the Galactic Centre (2005)
Hyman, S. D., Lazio, T. J. W., Kassim, N. E., Ray, P. S., Markwardt, C. B., Yusef-Zadeh, F.
Transient astronomical sources are typically powered by compact objects and usually signify highly explosive or dynamic events. While radio astronomy has an impressive record of obtaining high time...
Spatially Resolved Low Frequency VLA observations of the Supernova Remnant 3C 391 (2005)
Brogan, C. L., Lazio, T. J., Kassim, N. E., Dyer, K. K.
We present VLA images of the supernova remnant (SNR) 3C~391 at 74, 330, and 1465 MHz. This remnant has been known for some time to exhibit a turnover in its integrated radio continuum spectrum at...
Resolving the Steep Spectrum Emission in the Central Radio Source in ZwCl 0735.7+7421 (2005)
Cohen, A. S., Clarke, T. E., Feretti, L., Kassim, N. E.
It has long been know that an extremely steep spectrum radio source lies at the center of ZwCl 0735.7+7421, a galaxy cluster with high X-ray luminosity and a cooling core. In this Letter, we present...
First Results of the 74 MHz VLA-Pie Town Link. Hercules A at Low Frequencies (2005)
Gizani, Nectaria A. B., Cohen, A., Kassim, N. E.
We present the results of the first successful observations of the Pie Town link with the Very Large Array (VLA) at 74 MHz on Hercules A. The improvement in resolution from 25 arcsec to 10 arcsec...
The Astronomical Low-Frequency Array (2004)
Jones, D. L., Allen, R. J., Blume, W. H., Desch, M. M., Erickson, W. C., Kaiser, M. L., ...
An array of satellites is proposed to make astronomic observations in the low frequency range of a few tens of MHz down to roughly 100 kHz, a range that cannot be observed through the ionosphere. The...
A deep, high-resolution survey at 74MHz. (2004)
Cohen, A.S., Rottgering, H.J.A., Jarvis, M.J., Kassim, N.E., Lazio, T.J.W.
A Deep, High-Resolution Survey at 74 MHz (2003)
Cohen, A. S., Rottgering, H. J. A., Jarvis, M. J., Kassim, N. E., Lazio, T. J. W.
We present a 74 MHz survey of a 165 square degree region located near the north galactic pole. This survey has an unprecedented combination of both resolution (25'' FWHM) and sensitivity (RMS noise...
Brogan, C. L., Devine, K. E., Lazio, T. J., Kassim, N. E., Tam, C. R., Brisken, W. F., ...
We have imaged a 1 deg^2 field centered on the known Galactic supernova remnant (SNR) G11.2-0.3 at 74, 330, and 1465 MHz with the Very Large Array radio telescope (VLA) and 235 MHz with the Giant...
Hydra A at Low Radio Frequencies (2003)
Lane, W. M., Clarke, T. E., Taylor, G. B., Perley, R. A., Kassim, N. E.
We present new, low-frequency images of the powerful FR I radio galaxy Hydra A (3C 218). Images were made with the Very Large Array (VLA) at frequencies of 1415, 330, and 74 MHz, with resolutions on...
The Low Frequency Radio Counterpart of the XMM Large Scale Structure Survey (2003)
Cohen, A. S., Röttgering, H. J. A., Kassim, N. E., Cotton, W. D., Perley, R. A., Wilman, R., ...
The XMM Large Scale Structure Survey (XMM-LSS) is a major project to map the large scale structure of the universe out to cosmological distances. An 8 degree by 8 degree region will be surveyed by...
3C 129 at 90cm: Evidence for a Radio Relic? (2002)
Lane, W. M., Kassim, N. E., Ensslin, T. A., Harris, D. E., Perley, R. A.
We present a new wide-field map of the radio galaxy 3C 129 and its companion galaxy 3C 129.1 at lambda=90 cm. We see a distinct steep-spectrum feature near the head of 3C 129, extending in a...
3C 129 at 90 centimeters: Evidence for a radio relic? (2002)
Perley, R. A., Harris, D. E., Enßlin, Torsten A., Kassim, N. E., Lane, W. M.
We present a new wide-field map of the radio galaxy 3C 129 and its companion galaxy 3C 129.1 at lambda = 90 cm. We see a distinct steep-spectrum feature near the head of 3C 129, extending in a...
VLA observations of the Galactic Centre at 74 MHz (2002)
Anantharamaiah, K. R., Kassim, N. E., Lazio, T. J. W., Goss, W. M., Falcke, H.
Extended extragalactic radio emission (2002)
Owen, F.N., Ledlow, M.J., Eilek, J.A., Kassim, N.E., Miller, N.A., Dwarakanath, K.S., ...
Restricted Access. The Universe at Low Radio Frequencies, Proceedings of IAU Symposium 199, held 30 Nov - 4 Dec 1999, Pune, India. Eds. A. Pramesh Rao, G. Swarup, and Gopal-Krishna, 2002.
VLA observations of the galactic center at 74 MHz (2002)
Anantharamaiah, K.R., Kassim, N.E., Lazio, T.J.W., Goss, W.M., Falcke, H.
Restricted Access. The Universe at Low Radio Frequencies, Proceedings of IAU Symposium 199, held 30 Nov - 4 Dec 1999, Pune, India. Eds. A. Pramesh Rao, G. Swarup, and Gopal-Krishna, 2002.
The properties of the X-ray holes in the intracluster medium of the Perseus cluster (2001)
Fabian, A. C., Celotti, A., Blundell, K. M., Kassim, N. E., Perley, R. A.
High resolution X-ray and low frequency radio imaging now allow us to examine in detail the interaction and physical properties of the radio source 3C84 and the surrounding thermal gas. The radiative...
Radio Spectral Index and Expansion of 3C58 (2001)
Bietenholz, M. F., Kassim, N. E., Weiler, K. W.
We present new observations of the plerionic supernova remnant 3C58 with the VLA at 74 and 327 MHz. In addition, we re-reduced earlier observations at 1.4 and 4.9 GHz taken in 1973 and 1984....
Kassim, N. E., Clarke, T. E., Enßlin, T. A., Cohen, A. S., Neumann, D. M.
We present 74 MHz and 330 MHz VLA observations of Abell 754. Diffuse, halo-like emission is detected from the center of the cluster at both frequencies. At 330 MHz the resolution of 90''...
Extended Extragalactic Radio Emission (2000)
Owen, F. N., Ledlow, M. J., Eilek, J. A., Kassim, N. E., Miller, N. A., Dwarakanath, K. S., ...
Extended radio emission and its relation to parent galaxy properties is briefly reviewed. Our current understanding of the relation between absolute radio and optical luminosity, radio morphology and...
M87 at 90cm: A Different Picture (2000)
Owen, F. N., Eilek, J. A, Kassim, N. E.
We report new radio imaging of the large scale radio structure of M87 with the VLA at 90 cm. These new images show the complex structure of the radio emission more clearly than previous attempts,...
Lang, Cornelia C., Anantharamaiah, K.R., Kassim, N.E., Lazio, T.J.W.
We report the discovery of a new nonthermal filament, G358.85+0.47, the ``Pelican,'' located ~225 pc in projection from Sagittarius A and oriented parallel to the Galactic plane. VLA continuum...
Ensslin, T. A., Perley, R. A., Kassim, N. E.
We report on an ongoing project to map a 15 degree x 15 degree region in Coma Berenices with the new 74 MHz receiver system of the VLA. The field is centered on the Coma cluster of galaxies. Coma...
Lang, Cornelia C., Anantharamaiah, K. R., Kassim, N. E., Lazio, T. J. W.
We report the discovery of a new non-thermal filament, G358.85+0.47, the ``Pelican'', located ~225 pc in projection from SgrA, and oriented parallel to the Galactic plane. VLA continuum observations...
Lazio, T.J.W., Anantharamaiah, K.R., Goss, W.M., Kassim, N.E., Cordes, J.M.
G359.87+0.18 is an enigmatic object located 15' from Sgr A*. It has been variously classified as an extragalactic source, a Galactic jet source, and a young supernova remnant. We present new...
Discovery of a New Filamentary Structure near the Galactic Center: G358.85+0.47 - The Pelican (1999)
Anantharamaiah, K. R., Lang, C. C., Kassim, N. E., Lazio, T. J. W., Goss, W. M.
We report the discovery of a new filamentary structure, G358.85+0.47, consisting of at least three mutually parallel but bent `strands', located about 1.5 degrees SW of the Sgr A complex. Unlike all...
Discovery of a new filamentary structure G358.85+0.47 -- The Pelican (1999)
Anantharamaiah, K.R., Lang, C.C., Kassim, N.E., Lazio, T.J.W., Goss, W.M.
Restricted Access. The Central Parsecs of the Galaxy, ASP Conference Series, Vol. 186. Eds. Heino Falcke, Angela Cotera, Wolfgang J. Duschl, Fulvio Melia, and Marcia J. Rieke, 1999.
Hyperstrong radio-wave scattering and free electrons in the galactic center (1999)
Lazio, T.J.W., Cordes, J.M., Anantharamaiah, K.R., Goss, W.M., Kassim, N.E.
Restricted Access. The Central Parsecs of the Galaxy, ASP Conference Series, Vol. 186. Eds. Heino Falcke, Angela Cotera, Wolfgang J. Duschl, Fulvio Melia, and Marcia J. Rieke, 1999.
Evidence for thermal absorption inside Cassiopeia A (1995)
Kassim, N.E., Perley, R.A., Dwarakanath, K.S., Erickson, W.C.
Subarcminute resolution images of Cas A at 74 and 333 MHz are presented. Comparison with each other and with higher frequency observations indicates that the spectral index of its nonthermal emission...
Does the Crab Have a Shell? (1995)
Frail, D. A., Kassim, N. E., Cornwell, T. J., Goss, W. M.
We present deep images of a region around the Crab nebula made with the VLA, utilizing new imaging and deconvolution algorithms in a search for a faint radio shell. The existence of a high-velocity,...
The Radio Nebula of the Soft Gamma Ray Repeater SGR 1806-20 (1994)
Kulkarni, S. R., Frail, D. A., Kassim, N. E., Murakami, T., Vasisht, G.
Earlier we had suggested that G10.0-0.3, a non-thermal nebula, most likely an old supernova remnant (SNR), was associated with the soft gamma repeater (SGR) SGR 1806-20. Here we present new radio...
Subarcminute resolution imaging of radio sources at 74 MHz with the Very Large Array (1993)
Kassim, N.E., Perley, R.A., Erickson, W.C., Dwarakanath, K.S.
A new observing system operating at 74 MHz and providing an angular resolution of 20 sec is currently being tested at the Very Large Array (VLA). The system comprises a prime-focus dipole feed and...
The ALFA medium explorer mission
Jones, D.L., Allen, R.J., Basart, J.P., Bastian, T., Blume, W.H., Bougeret, J.L., ...
The frequency range below a few tens of MHz is unexplored with high angular resolution due to the opacity of Earth's ionosphere. An interferometer array in space providing arcminute angular...
The ALFA medium explorer mission
Jones, D.L., Allen, R.J., Basart, J.P., Bastian, T., Blume, W.H., Bougeret, J.L., ...
The frequency range below a few tens of MHz is unexplored with high angular resolution due to the opacity of Earth's ionosphere. An interferometer array in space providing arcminute angular...