Search Publications
A phase-variable absorption feature in the X-ray spectrum of the magnetar SGR 0418+5729
Bignami, G. F.; Tiengo, A.; Götz, D. +9 more
An absorption feature, the properties of which strongly depend on the pulse phase, has been recently discovered in the X-ray spectrum of the soft gamma repeater SGR 0418+5729. If interpreted as a proton cyclotron line, its energy implies a magnetic field ranging from 2×1014 G to more than 1015 G, which confirms the magnetar i…
Long-term X-ray timing of the double pulsar PSR J0737-3039
Pellizzoni, A.; Egron, E.; Iacolina , M. N.
The relativistic double neutron star binary PSR
Results from HOPS: A multiwavelength census of Orion protostars
Megeath, S. T.; Osorio, M.; Stanke, T. +7 more
Surveys with the Spitzer and Herschel space observatories are now enabling the discovery and characterization of large samples of protostars in nearby molecular clouds, providing the observational basis for a detailed understanding of star formation in diverse environments. We are pursuing this goal with the Herschel Orion Protostar Survey (HOPS),…
Merger shocks in Abell 3667 and the Cygnus A cluster
Finoguenov, A.; Wik, D. R.; Sarazin, C. L.
We present new XMM-Newton observations of the northwest (NW) radio relic region in the cluster Abell 3667. We detect a jump in the X-ray surface brightness and X-ray temperature at the sharp outer edge of the radio relic which indicate that this is the location of a merger shock with a Mach number of about 2. Comparing the radio emission to the sh…
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…
A multiwavelength view of star-disk interaction in NGC 2264
Baglin, A.; Micela, G.; Stauffer, J. R. +2 more
Variability is a signature property of cool young stars, particularly for those surrounded by disks. Traditional single-band time series display complex features associated with accretion, disk structure, and accompanying stellar activity, but these processes are challenging to model. To make progress in connecting observed time domain properties …
The M 4 Core Project with HST: I. Overview and first epoch
van den Berg, M.; Anderson, J.; Milone, A. P. +13 more
We present an overview of the ongoing Hubble Space Telescope large program GO-12911. The program is focused on the core of M 4, the nearest Galactic globular cluster, and the observations are designed to constrain the number of binaries with massive companions (black holes, neutron stars, or white dwarfs) by measuring the ``wobble'' of the luminou…
Advanced Spectral Library (ASTRAL): Cool stars edition
Ayres, T. R.
ASTRAL is a project to create high-resolution, high-S/N UV (1150-3200 Å) atlases of bright stars utilizing {HST}/STIS. During Cycle 18 (2010-2011), eight cool star targets were observed, including key objects like Procyon and Betelgeuse, churning through 146 orbits in the process. The new spectral atlases are publically available through the proje…
Metal jumps across sloshing cold fronts: The case of A 496
Molendi, S.; De Grandi, S.; Ghizzardi, S.
Cold-fronts in cool-core clusters are thought to be induced by minor mergers and to develop through a sloshing mechanism. While temperature and surface-brightness jumps have been detected and measured in many systems, a detailed characterization of the metal abundance across the discontinuity is only available for a handful of objects. Within the …
X-ray observations of the merging cluster CIZA J2242.8+5301
Simionescu, A.; Croston, J. H.; van Weeren, R. J. +4 more
Multiwavelength studies of radio relics at merger shocks set powerful constraints on the relics origin and formation mechanism. However, for X-ray observations, a main difficulty is represented by the low X-ray surface brightness far out in the cluster outskirts, where relics are typically found. Here, we present XMM-Newton results from a 130-ks o…