Search Publications
Suzaku Monitoring of the Iron K Emission Line in the Type 1 Active Galactic Nucleus NGC 5548
Elvis, Martin; Wilkes, Belinda J.; Nicastro, Fabrizio +10 more
We present seven sequential weekly observations of NGC 5548 conducted in 2007 with the Suzaku X-ray Imaging Spectrometer (XIS) in the 0.2-12 keV band and Hard X-ray Detector (HXD) in the 10-600 keV band. The iron Kα line is well detected in all seven observations and Kβ line is also detected in four observations. In this paper, we investigate the …
Long-term Multi-wavelength Studies of GRS 1915+105. I. A High-energy and Mid-infrared Focus with RXTE/INTEGRAL and Spitzer
Chaty, S.; Rahoui, F.; Rodriguez, J. +3 more
To date, mid-infrared properties of Galactic black hole binaries have barely been investigated in the framework of multi-wavelength campaigns. Yet, studies in this spectral domain are crucial to get complementary information on the presence of dust and/or on the physical processes such as dust heating and thermal bremsstrahlung. Here, we report a …
Spectroscopy of M81 Globular Clusters
Nantais, Julie B.; Huchra, John P.
We obtained spectra of 74 globular clusters (GCs) in M81. These GCs had been identified as candidates in a Hubble Space Telescope (HST) Advanced Camera for Surveys I-band survey. Sixty-eight of these 74 clusters lie within 7' of the M81 nucleus. Sixty-two of these clusters are newly spectroscopically confirmed, more than doubling the number of con…
Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies
Menten, K. M.; Martin, P. G.; Murphy, J. A. +54 more
Aims: To investigate the accretion and feedback processes in massive star formation, we analyze the shapes of emission lines from hot molecular cores, whose asymmetries trace infall and expansion motions.
Methods: The high-mass star forming region SgrB2(M) was observed with Herschel/HIFI (HEXOS key project) in various lines of HCN and it…
Rift zone volcanism and associated cinder cone field in Utopia Planitia, Mars
Neukum, G.; Wagner, R.; Lanz, J. K. +2 more
We analyzed a small cone field in SW Utopia Planitia that shows striking similarities to volcanic rift zones on Earth. This is of particular interest as the study area lies off any of the volcanic centers of Mars in the northern hemisphere lowlands and is surrounded by material of the Amazonian aged Vastitas Borealis Formation (VBF). We believe th…
Coronal Mass Ejections and Sunspots—Solar Cycle Perspective
Ramesh, K. B.
Recent studies have indicated that the occurrence of the maxima of coronal mass ejection (CME) rate and sunspot number (SSN) were nearly two years apart. We find that the two-year lag of CME rate manifests only when the SSN index is considered and the lag is minimal (two-three months) when the sunspot area is considered. CMEs with speeds greater t…
Dune morphology, sand transport pathways and possible source areas in east Thaumasia Region (Mars)
Silvestro, S.; Di Achille, G.; Ori, G. G.
An aeolian system located in Aonia Terra (eastern Thaumasia region) consists of six dark dune fields. The dune pattern suggests an organized extended sand transport system, which is characterized by the presence of long sand corridors. The latter connects the different ergs with potential sources. The sand stored in the ergs is provided by layered…
The radius and effective temperature of the binary Ap star β CrB from CHARA/FLUOR and VLT/NACO observations
Kervella, P.; Kiss, L. L.; Tuthill, P. G. +14 more
Context. The prospects for using the asteroseismology of rapidly oscillating Ap (roAp) stars are hampered by the large uncertainty in fundamental stellar parameters. Results in the literature for the effective temperature (Teff) often span a range of 1000 K.
Aims: Our goal is to reduce systematic errors and improve the Teff
A Hemispheric Helicity Sign Rule Indicated by Large-scale Photospheric Magnetic Fields at Three Phases of Solar Cycle 23
Zhang, Mei; Wang, Chuanyu
The hemispheric sign rule of current helicity is examined for large-scale magnetic fields, extending to 60° high in solar latitudes, at three different phases of solar cycle 23 and using three different instruments. The current helicity is calculated from the vector magnetic fields derived respectively from the longitudinal full-disk magnetograms …
Far-infrared line imaging of the starburst ring in NGC 1097 with the Herschel/PACS spectrometer
Helou, G.; Roussel, H.; Murphy, E. J. +38 more
NGC 1097 is a nearby SBb galaxy with a Seyfert nucleus and a bright starburst ring. We study the physical properties of the interstellar medium (ISM) in the ring using spatially resolved far-infrared spectral maps of the circumnuclear starburst ring of NGC 1097, obtained with the PACS spectrometer on board the Herschel Space Observatory. In partic…