Search Publications
Probing the mass and anisotropy of the Milky Way gaseous halo: sight-lines toward Mrk 421 and PKS 2155-304
Krongold, Y.; Mathur, S.; Gupta, A. +1 more
We recently found that the halo of the Milky Way contains a large reservoir of warm-hot gas that accounts for large fraction of the missing baryons from the Galaxy. The average physical properties of this circumgalactic medium (CGM) are determined by combining average absorption and emission measurements along several extragalactic sightlines. How…
Spectroscopy of BL Lacertae objects of extraordinary luminosity
Sbarufatti, B.; Falomo, R.; Treves, A. +1 more
Aims: We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs objects.
Methods: We secured optical and near-infrared medium-resolution spectra of four bright BL Lac objects of unknown redshift using the spectrograph X-Shooter at the ESO-VLT.
Results: In spite of the high quality of the spectra and …
The circumnuclear environment of NGC 613: a nuclear starburst caught in the act?
Schinnerer, E.; Knapen, J. H.; Böker, T. +4 more
We present near-infrared (H- and K-band) integral-field observations of the inner ∼700 pc of the active spiral galaxy NGC 613, obtained with SINFONI on the Very Large Telescope. We use emission-line ratios to determine the dominant excitation mechanisms in different regions within our field of view, in particular, the active nucleus and the star-f…
Linking the X-ray and infrared properties of star-forming galaxies at z < 1.5
Magnelli, B.; Lutz, D.; Pannella, M. +16 more
We present the most complete study to date of the X-ray emission from star formation in high-redshift (median z = 0.7; z < 1.5), IR-luminous (LIR = 1010-1013 L⊙) galaxies detected by Herschel's PACS and SPIRE instruments. For our purpose, we take advantage of the deepest X-ray data to date, the Chandr…
CHARA/MIRC Observations of Two M Supergiants in Perseus OB1: Temperature, Bayesian Modeling, and Compressed Sensing Imaging
Kiss, L. L.; Baron, F.; McAlister, H. A. +12 more
Two red supergiants (RSGs) of the Per OB1 association, RS Per and T Per, have been observed in the H band using the Michigan Infra-Red Combiner (MIRC) instrument at the CHARA array. The data show clear evidence of a departure from circular symmetry. We present here new techniques specially developed to analyze such cases, based on state-of-the-art…
Quiescent state and outburst evolution of SGR 0501+4516
Tiengo, A.; Götz, D.; Mereghetti, S. +9 more
We report on the quiescent state of the soft gamma repeater SGR 0501+4516 observed by XMM-Newton on 2009 August 30. The source exhibits an absorbed flux ∼75 times lower than that measured at the peak of the 2008 outburst, and a rather soft spectrum, with the same value of the blackbody temperature observed with ROSAT back in 1992. This new observa…
Direct calculation of the ring current distribution and magnetic structure seen by Cluster during geomagnetic storms
Baker, D. N.; Dunlop, M.; Liu, Z. X. +8 more
Magnetic disturbances caused by the Earth's ring current, particularly during storm time activity, have a dominant effect on the geomagnetic field. Strong currents and large kinetic and magnetic energies can change considerably local field geometry and depress the ground geomagnetic field. The multispacecraft magnetic measurements of Cluster allow…
Electric fields associated with dipolarization fronts
Parks, George K.; Zong, Qiu-Gang; Yao, Zhonghua +6 more
Electric fields associated with dipolarization fronts (DFs) have been investigated in the magnetotail plasma sheet using Cluster observations. We have studied each term in the generalized Ohm's law using data obtained from the multispacecraft Cluster. Our results show that in the plasma flow frame, electric fields are directed normal to the DF in …
A cold hydrological system in Gale crater, Mars
McKay, Christopher P.; Squyres, Steven W.; Clifford, Stephen M. +9 more
Gale crater is a ~154-km-diameter impact crater formed during the Late Noachian/Early Hesperian at the dichotomy boundary on Mars. Here we describe potential evidence for ancient glacial, periglacial and fluvial (including glacio-fluvial) activity within Gale crater, and the former presence of ground ice and lakes. Our interpretations are derived …
NuSTAR Observations of X-Ray Bursts from the Magnetar 1E 1048.1-5937
An, Hongjun; Hailey, Charles J.; Mori, Kaya +13 more
We report the detection of eight bright X-ray bursts from the 6.5 s magnetar 1E 1048.1-5937, during a 2013 July observation campaign with the Nuclear Spectroscopic Telescope Array. We study the morphological and spectral properties of these bursts and their evolution with time. The bursts resulted in count rate increases by orders of magnitude, so…