Search Publications
Cool Transition Region Loops Observed by the Interface Region Imaging Spectrograph
Madjarska, Maria S.; Li, Bo; Xia, Lidong +1 more
We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops, a class of loops that has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si iv 1402.8 Å spectral raster and 1400 Å slit-jaw images. We divide the loops in…
Missing cosmic metals revealed by X-ray absorption towards distant sources
Ferrara, Andrea; Pallottini, Andrea; Salvaterra, Ruben +1 more
The census of heavy elements (metals) produced by all stars through cosmic times up to present-day is limited to ≲ 50%; of these only half are still found within their parent galaxy. The majority of metals is expelled from galaxies into the circumgalactic (or even more distant, intergalactic) space by powerful galactic winds, leaving unpleasant un…
A new view on the solar wind interaction with the Moon
Barabash, Stas; Holmström, Mats; Futaana, Yoshifumi +9 more
Characterised by a surface bound exosphere and localised crustal magnetic fields, the Moon was considered as a passive object when solar wind interacts with it. However, the neutral particle and plasma measurements around the Moon by recent dedicated lunar missions, such as Chandrayaan-1, Kaguya, Chang'E-1, LRO, and ARTEMIS, as well as IBEX have r…
Peculiar Velocities of Galaxies in the Leo Spur
Tully, R. Brent; Karachentsev, Igor D.; Makarov, Dmitry I. +2 more
The Hubble Space Telescope Advanced Camera for Surveys has been used to determine accurate distances for the spiral galaxy NGC 2683 and 12 other galaxies in a zone of the “local velocity anomaly” from luminosity measurements of the brightest red giant branch stars. These galaxies lie in the Leo Spur, the nearest filament beyond our Local Sheet. Th…
Analysis of a coronal mass ejection and corotating interaction region as they travel from the Sun passing Venus, Earth, Mars, and Saturn
Harra, L. K.; Arridge, C. S.; Matthews, S. A. +2 more
During June 2010 a good alignment in the solar system between Venus, STEREO-B, Mars, and Saturn provided an excellent opportunity to study the propagation of a coronal mass ejection (CME) and closely occurring corotating interaction region (CIR) from the Sun to Saturn. The CME erupted from the Sun at 01:30 UT on 20 June 2010,with v≈ 600 km s-…
Dust attenuation up to z ≃ 2 in the AKARI North Ecliptic Pole Deep Field
Ciesla, L.; Buat, V.; Burgarella, D. +13 more
Aims: We aim to study the evolution of dust attenuation in galaxies selected in the infrared (IR) in the redshift range in which they are known to dominate the star formation activity in the universe. The comparison with other measurements of dust attenuation in samples selected using different criteria will give us a global picture of the at…
X-ray bright active galactic nuclei in massive galaxy clusters - III. New insights into the triggering mechanisms of cluster AGN
Brandt, W. N.; von der Linden, A.; Xue, Y. Q. +6 more
We present the results of a new analysis of the X-ray selected active galactic nuclei (AGN) population residing in and behind 135 of the most massive galaxy clusters in the redshift range of 0.2 < z < 0.9 observed with Chandra. With a sample of more than 11 000 X-ray point sources, we are able to measure, for the first time, evidence for evo…
A Global Star-forming Episode in M31 2-4 Gyr Ago
Bell, Eric F.; Monachesi, Antonela; Dolphin, Andrew E. +9 more
We have identified a major global enhancement of star formation in the inner M31 disk that occurred between 2-4 Gyr ago, producing ∼60% of the stellar mass formed in the past 5 Gyr. The presence of this episode in the inner disk was discovered by modeling the optical resolved star color-magnitude diagrams of low extinction regions in the main disk…
Understanding the Mg II and Hα Spectra in a Highly Dynamical Solar Prominence
Heinzel, P.; Schmieder, B.; Gunár, S. +1 more
Mg ii h and k and Hα spectra in a dynamical prominence have been obtained along the slit of the Interface Region Imaging Spectrograph (IRIS) and with the Meudon Multi-channel Subtractive Double Pass spectrograph on 2013 September 24, respectively. Single Mg ii line profiles are not much reversed, while at some positions along the IRIS slit the pro…
Predicting dust extinction properties of star-forming galaxies from Hα/UV ratio
Yamamura, Issei; Takita, Satoshi; Koyama, Yusei +8 more
Using star-forming galaxies sample in the nearby Universe (0.02 < z < 0.10) selected from the Sloan Digital Sky Survey (DR7) and Galaxy Evolution Explorer all-sky survey (GR5), we present a new empirical calibration for predicting dust extinction of galaxies from the Hα-to-FUV flux ratio. We find that the Hα dust extinction (AHα) …