Search Publications
Discovery of a Compact Companion to the Hot Subdwarf Star BD +37° 442
Mereghetti, Sandro; Esposito, Paolo; Tiengo, Andrea +1 more
We report the results of the first X-ray observation of the luminous and helium-rich O-type subdwarf BD +37° 442 carried out with the XMM-Newton satellite in 2011 August. X-ray emission is detected with a flux of about 3× 10-14 erg cm-2 s-1 (0.2-1 keV) and a very soft spectrum, well fit by the sum of a blackbody wi…
Multi-wavelength Spectroscopic Observation of Extreme-ultraviolet Jet in AR 10960
Kitagawa, N.; Yokoyama, T.; Imada, S. +1 more
We have studied the relationship between the velocity and temperature of a solar EUV jet. The highly accelerated jet occurred in the active region NOAA 10960 on 2007 June 5. Multi-wavelength spectral observations with EIS/Hinode allow us to investigate Doppler velocities at a wide temperature range. We analyzed the three-dimensional angle of the j…
The Relationship between Hard X-Ray Pulse Timings and the Locations of Footpoint Sources during Solar Flares
Dennis, B. R.; Inglis, A. R.
The cause of quasi-periodic pulsations in solar flares remains the subject of debate. Recently, Nakariakov & Zimovets proposed a new model suggesting that, in two-ribbon flares, such pulsations could be explained by propagating slow waves. These waves may travel obliquely to the magnetic field, reflect in the chromosphere, and constructively i…
A Comparison of Broad Iron Emission Lines in Archival Data of Neutron Star Low-mass X-Ray Binaries
Reis, Rubens C.; Fabian, Andrew C.; Miller, Jon M. +2 more
Relativistic X-ray disklines have been found in multiple neutron star low-mass X-ray binaries, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we…
HerMES: A Statistical Measurement of the Redshift Distribution of Herschel-SPIRE Sources Using the Cross-correlation Technique
Scott, D.; Béthermin, M.; Wang, L. +19 more
The wide-area imaging surveys with the Herschel Space Observatory at submillimeter (sub-mm) wavelengths have now resulted in catalogs of the order of one-hundred-thousand dusty, starburst galaxies. These galaxies capture an important phase of galaxy formation and evolution, but, unfortunately, the redshift distribution of these galaxies, N(z), is …
An Unexpected Discovery in the Rich Open Cluster NGC 6819 Using XMM-Newton
Ramirez-Ruiz, Enrico; Pooley, David; Kalirai, Jason +4 more
We present the first study of the X-ray population of the intermediate-age rich open cluster NGC 6819 using the XMM-Newton Observatory. In the past decade, Chandra X-ray observations have shown a relationship between the X-ray population of globular clusters and their internal dynamics and encounter frequency. We investigate the role dynamics poss…
Shocked and Scorched: The Tail of a Tadpole in an Interstellar Pond
Sahai, R.; Morris, M. R.; Claussen, M. J.
We report multi-wavelength observations of the far-infrared source IRAS 20324+4057, including high-resolution optical imaging with the Hubble Space Telescope, and ground-based near-infrared, millimeter-wave and radio observations. These data show an extended, limb-brightened, tadpole-shaped nebula with a bright, compact, cometary nebula located in…
The Central Region of the Barred Spiral Galaxy NGC 1097 Probed by AKARI Near-infrared Spectroscopy
Oyabu, Shinki; Onaka, Takashi; Yamagishi, Mitsuyoshi +6 more
With the Infrared Camera on board AKARI, we carried out near-infrared (2.5-5.0 µm) spectroscopy of the central kiloparsec region of the barred spiral galaxy, NGC 1097, categorized as Seyfert 1 with a circumnuclear starburst ring. Our observations mapped the area of ~50'' × 10'' with the resolution of ~5'', covering about a half of the ring a…
Multipolar Planetary Nebulae: Not as Geometrically Diversified as Thought
Kwok, Sun; Tafoya, D.; Imai, H. +2 more
Planetary nebulae (PNe) have diverse morphological shapes, including point-symmetric and multipolar structures. Many PNe also have complicated internal structures such as tori, lobes, knots, and ansae. A complete accounting of all the morphological structures through physical models is difficult. A first step toward such an understanding is to der…
Modeling the Accretion Structure of AU Mon
Peters, Geraldine J.; Miller, Brendan P.; Budaj, Ján +2 more
AU Mon is a long-period (11.113 days) Algol-type binary system with a persistent accretion disk that is apparent as double-peaked Hα emission. We present previously unpublished optical spectra of AU Mon which were obtained over 20 years from 1991-2011 with dense orbital phase coverage. We utilize these data, along with archival UV spectra, to mode…