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The Heating of Mid-infrared Dust in the Nearby Galaxy M33: A Testbed for Tracing Galaxy Evolution
Calzetti, Daniela; Boquien, Médéric; van der Werf, Paul +10 more
Infrared emission is an invaluable tool for quantifying star formation in galaxies. Because the 8 µm polycyclic aromatic hydrocarbon (PAH) emission has been found to correlate with other well-known star formation tracers, it has widely been used as a star formation rate (SFR) tracer. There are, however, studies that challenge the accuracy an…
Quiescent Reconnection Rate Between Emerging Active Regions and Preexisting Field, with Associated Heating: NOAA AR 11112
Longcope, Dana W.; McKenzie, David E.; Yoshimura, Keiji +1 more
When magnetic flux emerges from beneath the photosphere, it displaces the preexisting field in the corona, and a current sheet generally forms at the boundary between the old and new magnetic domains. Reconnection in the current sheet relaxes this highly stressed configuration to a lower energy state. This scenario is most familiar and most often …
Ionizing stellar population in the disc of NGC 3310 - I. The impact of a minor merger on galaxy evolution
Pérez-Montero, E.; Sánchez, S. F.; Díaz, A. I. +2 more
Numerical simulations of minor mergers predict little enhancement in the global star formation activity. However, it is still unclear the impact they have on the chemical state of the whole galaxy and on the mass build-up in the galaxy bulge and disc. We present a two-dimensional analysis of NCG 3310, currently undergoing an intense starburst like…
Metal Distributions out to 0.5 r 180 in the Intracluster Medium of Four Galaxy Groups Observed with Suzaku
Sato, Kosuke; Matsushita, Kyoko; Sasaki, Toru
We studied the distributions of metal abundances and metal-mass-to-light ratios in the intracluster medium (ICM) of four galaxy groups, MKW 4, HCG 62, the NGC 1550 group, and the NGC 5044 group, out to ~0.5 r 180 observed with Suzaku. The iron abundance decreases with radius and is about 0.2-0.4 solar beyond 0.1 r 180. At a g…
Wind collisions in three massive stars of Cygnus OB2
Nazé, Yaël; Rauw, Gregor; Cazorla, Constantin
Aims: We wish to study the origin of the X-ray emission of three massive stars in the Cyg OB2 association: Cyg OB2 #5, Cyg OB2 #8A, and Cyg OB2 #12.
Methods: To this aim, dedicated X-ray observations from XMM-Newton and Swift are used, as well as archival ROSAT and Suzaku data.
Results: Our results on Cyg OB2 #8A improve the phase c…
High-speed photospheric material flow observed at the polarity inversion line of a δ-type sunspot producing an X5.4 flare on 2012 March 7
Shimizu, Toshifumi; Lites, Bruce W.; Bamba, Yumi
Solar flares abruptly release the free energy stored as a non-potential magnetic field in the corona and may be accompanied by eruptions of the coronal plasma. Formation of a non-potential magnetic field and the mechanisms for triggering the onset of flares are still poorly understood. In particular, photospheric dynamics observed near those polar…
Automatic detection of impact craters on Mars using a modified adaboosting method
Jin, Shuanggen; Zhang, Tengyu
The accurate recognition of impact craters is important to analyze and understand the relative dating of Martian surface. Since manually identifying small craters in a deluge of high-resolution Martian images is a tremendous task, a robust automatic detection algorithm of the crater is needed, but subject to lots of uncertainties and low successfu…
Developing a self-consistent description of Titan's upper atmosphere without hydrodynamic escape
Bougher, Stephen W.; Hunter Waite, J.; Bell, Jared M. +4 more
In this study, we develop a best fit description of Titan's upper atmosphere between 500 km and 1500 km, using a one-dimensional (1-D) version of the three-dimensional (3-D) Titan Global Ionosphere-Thermosphere Model. For this modeling, we use constraints from several lower atmospheric Cassini-Huygens investigations and validate our simulation res…
Running with BICEP2: implications for small-scale problems in CDM
Kaplinghat, Manoj; Bullock, James S.; Garrison-Kimmel, Shea +2 more
The BICEP2 results, when interpreted as a gravitational wave signal and combined with other cosmic microwave background data, suggest a roll-off in power towards small scales in the primordial matter power spectrum. Among the simplest possibilities is a running of the spectral index. Here we show that the preferred level of running alleviates smal…
The puzzling source IGR J17361-4441 in NGC 6388: a possible planetary tidal disruption event
Lodato, G.; Segreto, A.; De Cesare, G. +5 more
On 2011 August 11, INTEGRAL discovered the hard X-ray source IGR J17361-4441 near the centre of the globular cluster NGC 6388. Follow-up observations with Chandra showed the position of the transient was inconsistent with the cluster dynamical centre, and thus not related to its possible intermediate mass black hole. The source showed a peculiar h…