Search Publications
Blinker/macro-spicule activity in an off-limb polar region
Doyle, J. G.; Banerjee, D.; O'Shea, E.
Using measurements of O V 629.73 Å from the Coronal Diagnostic Spectrometer (CDS) on board SOHO we report on blinker activity in off-limb regions above the Northern pole of the Sun. The blinkers are found to be occurring above a region showing strong dynamic activity, with evidence for evacuation of plasma. The presence of blinkers is discussed in…
Thermal and Nonthermal Nature of the Soft Excess Emission from Sérsic 159-03 Observed with XMM-Newton
Kaastra, Jelle S.; Bonamente, Massimiliano; Lieu, Richard +2 more
Several nearby clusters exhibit an excess of soft X-ray radiation that cannot be attributed to the hot virialized intracluster medium. There is no consensus to date on the origin of the excess emission: it could be either of thermal origin or due to an inverse Compton scattering of the cosmic microwave background. Using high-resolution XMM-Newton …
Young Stars and Dust in AFGL 437: Hubble Space Telescope NICMOS Polarimetric Imaging of an Outflow Source
Hines, Dean C.; Meakin, Casey A.; Thompson, Roger I.
We present near-infrared broadband and polarimetric images of the compact star-forming cluster AFGL 437 obtained with the NICMOS instrument on board HST. Our high-resolution images reveal a well-collimated bipolar reflection nebulosity in the cluster and allow us to identify WK 34 as the illuminating source. The scattered light in the bipolar nebu…
Magnetic Twist of an Extreme-Ultraviolet Coronal Loop Inferred from Plasma Constriction
Moon, Yong-Jae; Chae, Jongchul
Magnetic twist is a very likely way of constricting coronal plasma into loops. An attempt is made to determine the magnetic twist that can explain the constriction of coronal loops indirectly from observations. We decompose the coronal magnetic field into a large-scale magnetic field and a small-scale magnetic field. The large-scale field is assum…
Constraints on the Luminosity of the Central Source in SNR 1987A
Gilfanov, M. R.; Sunyaev, R. A.; Lutovinov, A. A. +1 more
We obtained constraints on the luminosity of the central source in SNR 1987 A using XMM-Newton and INTEGRAL data. XMM-Newton yields an upper limit on the SNR luminosity in the 2 10 keV energy band, L X ≲ 5 × 1034 erg s-1. Since the optical depth of the envelope is still large in the XMM-Newton energy band, this constraint carries no useful informa…
The Trail of Discrete X-Ray Sources in the Early-Type Galaxy NGC 4261: Anisotropy in the Globular Cluster Distribution?
Trinchieri, Ginevra; Wolter, Anna; Cortese, Luca +4 more
Chandra images of the elliptical galaxy NGC 4261 have revealed an anisotropy in the spatial distribution of the off-nuclear X-ray sources, interpreted by Zezas et al. as evidence of an association with a young stellar population. Our independent analysis of archive X-ray (Chandra) and optical (INT and HST) observations confirms the anisotropy of t…
<sl>Chandra</sl> and RXTE spectroscopy of the accreting msec pulsar IGR J00291+5934
Nowak, M. A.; Rodriguez, J.; Wilms, J. +4 more
We report on an observation of the recently discovered accreting millisecond X-ray pulsar IGR J00291+5934 performed with the RXTE-Proportional Counter Array (PCA) and <sl>Chandra</sl>-High Energy Transmission Grating Spectrometer (HETGS). The RXTE data are from a two-week follow-up of the source, while the <sl>Chandra</sl> …
The Nature of Radio Continuum Emission at Very Low Metallicity: Very Large Array Observations of I Zw 18
Cannon, John M.; Skillman, Evan D.; Walter, Fabian +1 more
We present the first resolved study of the radio continuum properties of I Zw 18, the dwarf galaxy with the lowest known nebular metal abundance in the local universe. New Very Large Array radio continuum images at 20 and 3.6 cm are compared to various Hubble Space Telescope images, and we find a striking morphological similarity between high-reso…
Small rampart craters in an equatorial region on Mars: Implications for near-surface water or ice
Jaumann, R.; Neukum, G.; Hauber, E. +3 more
Small onset diameters (1 km) of rampart craters were identified in High Resolution Stereo Camera (HRSC) imagery in the equatorial region of the Valles Marineris plateaus. This is in contrast to previous global studies based on Viking imagery, which showed onset diameters in the range of 4 km to 7 km in equatorial regions. The observed small rampar…
Asymmetrical structure of ionization and kinematics in the Seyfert galaxy NGC 5033
Battaner, E.; Arribas, S.; García-Lorenzo, B. +5 more
We present integral field spectroscopy of NGC 5033, a low luminosity Seyfert galaxy. The observations were made with INTEGRAL, a fiber based system operating at the WHT. The intensity map of the Hβ emission line represents a spiral or ring-like pattern of HII regions. On the contrary, the [OIII] intensity map morphology is markedly anisotropic. Th…