Search Publications
The origin of the chemical elements in cluster cores
de Plaa, J.
Metals play a fundamental role in ICM cooling processes in cluster cores through the emission of spectral lines. But when and how were these metals formed and distributed through the ICM? The X-ray band has the unique property of containing emission lines from all elements from carbon to zinc within the 0.1-10 keV band. Using XMM-Newton, the abund…
X-ray activity cycle on the active ultra-fast rotator AB Doradus A?. Implication of correlated coronal and photometric variability
Schmitt, J. H. M. M.; Lalitha, S.
Context. Although chromospheric activity cycles have been studied in a larger number of late-type stars for quite some time, very little is known about coronal activity-cycles in other stars and their similarities or dissimilarities with the solar activity cycle.
Aims: While it is usually assumed that cyclic activity is present only in stars …
Evidence of Multiple Slow Acoustic Oscillations in the Stellar Flaring Loops of Proxima Centauri
Srivastava, A. K.; Pandey, J. C.; Lalitha, S.
We present the first observational evidence of multiple slow acoustic oscillations in the post-flaring loops of the corona of Proxima Centauri using XMM-Newton observations. We find the signature of periodic oscillations localized in the decay phase of the flare in its soft (0.3-10.0 keV) X-ray emissions. Using the standard wavelet tool, we find m…
Observation of SN2011fe with INTEGRAL. I. Pre-maximum phase
Zhang, X.; Hernanz, M.; Jordi, C. +19 more
Context. SN2011fe was detected by the Palomar Transient Factory in M101 on August 24, 2011, a few hours after the explosion. From the early optical spectra it was immediately realized that it was a Type Ia supernova, thus making this event the brightest one discovered in the past twenty years.
Aims: The distance of the event offered the rare …
A multi-epoch spectroscopic study of the BAL quasar APM 08279+5255. I. C IV absorption variability
Perna, M.; Trevese, D.; Vagnetti, F. +3 more
Context. Broad absorption lines indicate gas outflows with velocities from thousands of km s-1 to about 0.2 the speed of light, which may be present in all quasars and may play a major role in the evolution of the host galaxy. The variability of absorption patterns can provide information on changes in the density and velocity distribut…
Reconciling main belt asteroid spectral flux density measurements with a self-consistent thermophysical model
Choukroun, Mathieu; Janssen, Michael; Keihm, Stephen +4 more
Thermophysical models consistent with Earth’s Moon and infrared and submillimeter measurements obtained during the Rosetta fly-by of Asteroid (21) Lutetia have been applied to computations of thermal fluxes from Asteroids (4) Vesta, (1) Ceres, (2) Pallas, and (10) Hygiea. Comparisons are made with Earth- and space-based flux measurements that cove…
A Low-metallicity Molecular Cloud in the Lower Galactic Halo
Lockman, Felix J.; Wakker, Bart P.; Benjamin, Robert A. +5 more
We find evidence for the impact of infalling, low-metallicity gas on the Galactic disk. This is based on FUV absorption line spectra, 21 cm emission line spectra, and far-infrared (FIR) mapping to estimate the abundance and physical properties of IV21 (IVC135+54-45), a galactic intermediate-velocity molecular cloud that lies ~300 pc above the disk…
Determining olivine composition of basaltic dunes in Gale Crater, Mars, from orbit: Awaiting ground truth from Curiosity
Christensen, Philip R.; Lane, Melissa D.
successful landing of the Mars Science Laboratory Curiosity rover in Gale Crater, Mars, presents a rare opportunity for validation of a spectral index developed for determining olivine chemistry from orbital midinfrared remote-sensing data. Here, a spectral index is developed using laboratory emissivity data of 13 synthetic Mg-Fe olivines. Utilizi…
The origin of Phobos grooves from ejecta launched from impact craters on Mars: Tests of the hypothesis
Head, James W.; Ramsley, Kenneth R.
The surface of the martian moon Phobos is characterized by parallel and intersecting grooves that bear resemblance to secondary crater chains observed on planetary surfaces. Murray (2011) has hypothesized that the main groove-forming process on Phobos is the intersection of Phobos with ejecta from primary impact events on Mars to produce chains of…
The 9 and 18 Micrometer Luminosity Functions of Various Types of Galaxies with AKARI: Implication for the Dust Torus Structure of AGN
Oyabu, Shinki; Ohyama, Youichi; Takita, Satoshi +6 more
We present the 9 and 18 µm luminosity functions (LFs) of galaxies at 0.006 ≤ z ≤ 0.8 (with an average redshift of ∼ 0.04) using the AKARI mid-infrared all-sky survey catalog. We selected 243 galaxies at 9 µm and 255 galaxies at 18 µm from the Sloan Digital Sky Survey (SDSS) spectroscopy region. These galaxies were then classified…