Search Publications
The Nature of Radio Continuum Emission in the Dwarf Starburst Galaxy NGC 625
Cannon, John M.; Skillman, Evan D.
We present new multifrequency radio continuum imaging of the dwarf starburst galaxy NGC 625 obtained with the Very Large Array. Data at 20, 6, and 3.6 cm reveal global continuum emission dominated by free-free emission, with only mild synchrotron components. Each of the major H II regions is detected; the individual spectral indices are thermal fo…
A Chandra View of the Normal S0 Galaxy NGC 1332. I. An Unbroken, Steep Power-Law Luminosity Function for the Low-Mass X-Ray Binary Population
Humphrey, Philip J.; Buote, David A.
Chandra ACIS -S3 observations of the nearby S0 galaxy NGC 1332 resolve much of the X-ray emission into 73 point sources, of which 37 lie within the D25 isophote. The remaining galaxy emission comprises hot, diffuse gas and unresolved sources and is discussed in two companion papers. The point-source X-ray luminosity function (XLF) shows…
Some Like It Hot: The X-Ray Emission of the Giant Star YY Mensae
Skinner, Stephen L.; Güdel, Manuel; Audard, Marc +3 more
We present an analysis of the X-ray emission of the rapidly rotating giant star YY Mensae observed by Chandra HETGS and XMM-Newton. The high-resolution spectra display numerous emission lines of highly ionized species; Fe XVII to Fe XXV lines are detected, together with H-like and He-like transitions of lower Z elements. Although no obvious flare …
Clean Optical Spectrum of the Radio Jet of 3C 120
Christensen, L.; Mediavilla, E.; Sánchez, S. F. +2 more
We present integral field spectroscopy (IFS) of the central region of 3C 120. We have modeled the nuclear and host galaxy three-dimensional spectra using techniques normally applied to imaging, decoupling both components and obtaining a residual data cube. Using this residual data cube, we detected the extended emission line region associated with…
Observations Indicating That ~1 × 107 K Solar Flare Plasmas May Be Produced in Situ from ~1 × 106 K Coronal Plasma
Landi, E.; Doschek, G. A.; Feldman, U. +1 more
We discuss a set of flare observations obtained at a position of 0.10 Rsolar above the solar northwest limb. The data were acquired by the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO). We derive time-dependent comparisons of physical properties, such as electron…
Lower Mass Black Holes in the Great Observatories Origins Deep Survey? Off-nuclear X-Ray Sources
Hornschemeier, A. E.; Chary, R.; Alexander, D. M. +9 more
We have identified a sample of 10 highly reliable off-nuclear (>~2 kpc) X-ray sources at z=0.03-0.25 in late-type host galaxies within the two Great Observatories Origins Deep Survey (GOODS) fields (i.e., the two Chandra Deep Fields). The combination of the superb spatial resolution and great depth of the Hubble Space Telescope Advanced Camera …
Chandra ACIS and XMM-Newton EPIC Observations of the X-Ray-Luminous SN 1978K in NGC 1313
Kaaret, Philip; Schlegel, Eric M.; Kong, Albert +2 more
We describe an observation of the X-ray-luminous SN 1978K in NGC 1313 using the ACIS detector on board Chandra and an archival XMM-Newton EPIC observation. The models that provided good fits to the ASCA SIS and GIS and the ROSAT PSPC spectra no longer do so for the ACIS and EPIC spectra. The best-fit models to the ACIS and EPIC spectra are dual ho…
Phase Variation in the Pulse Profile of SMC X-1
Neilsen, J.; Hickox, R. C.; Vrtilek, S. D.
We present the results of the timing and spectral analysis of X-ray high-state observations of the high-mass X-ray pulsar SMC X-1 with Chandra, XMM-Newton, and ROSAT, taken between 1991 and 2001. The source has LX~(3-5)×1038 ergs s-1, and the spectra can be modeled as a power law plus blackbody with kTBB…
Densities and Velocities in Fast Coronal Mass Ejections: Radiative Pumping of the O VI Doublet
Raymond, J. C.; Ciaravella, A.
In very fast coronal mass ejections (CMEs), it is possible for O VI ions to scatter Lyβ photons that originate in the solar chromosphere and for the λ1037 transition of O VI to scatter λ1032 photons from the solar transition region. This scattering process can be identified by departures of the O VI I1032/I1037 intensity rati…
Very High Iron Abundance of the Hot Gas around the cD Galaxy of the MKW 4 Cluster
Fukazawa, Yasushi; Kawano, Naomi; Kawashima, Kengo
We observed a nearby X-ray-bright poor cluster MKW 4 with Chandra. The iron abundance is found to increase dramatically from 0.3 to 1.3 solar within 150" of the cD galaxy NGC 4073. Then MKW 4 is the second cluster to exhibit a significantly high metallicity of greater than 1 solar, after the Centaurus Cluster. Weakness of the central cool componen…