Search Publications
Sun-as-a-Star Observation of Flares in Lyman α by the PROBA2/LYRA Radiometer
Kretzschmar, M.; Dammasch, I. E.; Dominique, M.
There are very few reports of flare signatures in the solar irradiance at H I Lyman α at 121.5 nm, i.e. the strongest line of the solar spectrum. The LYRA radiometer onboard PROBA2 has observed several flares for which unambiguous signatures have been found in its Lyman-α channel. Here we present a brief overview of these observations followed by …
Redistribution of lunar polar water to mid-latitudes and its role in forming an OH veneer
Delory, G. T.; Halekas, J. S.; Farrell, W. M. +4 more
We suggest that energization processes like ion sputtering and impact vaporization can eject/release polar water molecules residing within cold trapped regions with sufficient velocity to allow their redistribution to mid-latitudes. We consider the possibility that these polar-ejected molecules can contribution to the water/OH veneer observed as a…
Discovering a 5.72-d period in the supergiant fast X-ray transient AX J1845.0-0433
Hill, A. B.; Sidoli, L.; Bird, A. J. +5 more
Temporal analysis of INTEGRAL/IBIS data has revealed a 5.7195 ± 0.0007 d periodicity in the supergiant fast X-ray transient source AX J1845.0-0433, which we interpret as the orbital period of the system. The new-found knowledge of the orbital period is utilized to investigate the geometry of the system by means of estimating an upper limit for the…
Fermi-LAT and Suzaku observations of the radio galaxy Centaurus B
Cheung, C. C.; Funk, S.; Kataoka, J. +8 more
Centaurus B is a nearby radio galaxy positioned in the southern hemisphere close to the Galactic plane. Here we present a detailed analysis of about 43 months of accumulated Fermi-LAT data of the γ-ray counterpart of the source initially reported in the 2nd Fermi-LAT catalog, and of newly acquired Suzaku X-ray data. We confirm its detection at GeV…
Probing the Shallow Convection Zone: Rising Motion of Subsurface Magnetic Fields in the Solar Active Region
Toriumi, Shin; Yokoyama, Takaaki; Sekii, Takashi +1 more
In this Letter, we present a seismological detection of a rising motion of magnetic flux in the shallow convection zone of the Sun, and show estimates of the emerging speed and its decelerating nature. In order to evaluate the speed of subsurface flux that creates an active region, we apply six Fourier filters to the Doppler data of NOAA AR 10488,…
HST/WFC3 Observations of Low-mass Globular Clusters AM 4 and Palomar 13: Physical Properties and Implications for Mass Loss
Dolphin, Andrew E.; Smith, Graeme H.; Grillmair, Carl J. +4 more
We investigate the loss of low-mass stars in two of the faintest globular clusters known, AM 4 and Palomar 13 (Pal 13), using HST/WFC3 F606W and F814W photometry. To determine the physical properties of each cluster—age, mass, metallicity, extinction, and present day mass function (MF)—we use the maximum likelihood color-magnitude diagram (CMD) fi…
The Herschel/PACS view of disks around low-mass stars in Chamaleon-I
Pascucci, I.; Henning, Th.; Olofsson, J. +3 more
Context. Circumstellar disks are expected to be planet birthplaces. The potential for forming one or more planets of various masses is essentially driven by the initial mass of the disks, a crucial parameter for any planet formation theory. Constraining the masses of disks is of great interest for low-mass stars, which are expected to harbor less …
The shape of the cutoff in the synchrotron emission of SN 1006 observed with XMM-Newton
Miceli, M.; Bocchino, F.; Decourchelle, A. +3 more
Context. Synchrotron X-ray emission from the rims of young supernova remnants allows us to study the high-energy tail of the electrons accelerated at the shock front.
Aims: The analysis of X-ray spectra can provide information on the physical mechanisms that limit the energy achieved by the electrons in the acceleration process. We aim at ver…
Deeper by the Dozen: Understanding the Cross-field Temperature Distributions of Coronal Loops
Schmelz, J. T.; Pathak, S.; Jenkins, B. S. +1 more
Spectroscopic analysis of coronal loops has revealed a variety of cross-field temperature distributions. Some loops appear to be isothermal while others require multithermal plasma. The EUV Imaging Spectrometer on Hinode has the spatial resolution and temperature coverage required for differential emission measure (DEM) analysis of coronal loops. …
Fueling the central engine of radio galaxies. II. The footprints of AGN feedback on the ISM of 3C 236
Morganti, R.; Combes, F.; García-Burillo, S. +7 more
Context. There is growing observational evidence of active galactic nuclei (AGN) feedback on the interstellar medium (ISM) of radio-quiet and radio-loud galaxies. While AGN feedback is expected to be more common at high-redshift objects, studying local universe galaxies helps to better characterize the different manifestations of AGN feedback.