Search Publications
Characterizing the Structure of Diffuse Emission in Hi-GAL Maps
Natoli, P.; Paladini, R.; Rygl, K. L. J. +18 more
We present a study of the structure of the Galactic interstellar medium (ISM) through the Δ-variance technique, related to the power spectrum and the fractal properties of infrared/submillimeter maps. Through this method, it is possible to provide quantitative parameters, which are useful for characterizing different morphological and physical con…
Formation and Decay of Rudimentary Penumbra around a Pore
Kitai, Reizaburo; Otsuji, Kenichi; Watanabe, Hiroko
We analyze the evolution of a pore in the active region NOAA 10940 using the data obtained by the Hinode satellite on 2007 February 3. The pore we analyzed showed the formation of a rudimentary penumbra structure, succeeded by an abrupt disappearance after about 5 hr. The pore had an approximate radius of 3.5 Mm and a total magnetic flux of 3.0 × …
Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and its Implications
Koyama, Katsuji; Uchida, Hiroyuki; Tsuru, Takeshi Go +3 more
We present deep observations of the Galactic supernova remnant IC 443 with the Suzaku X-ray satellite. We find prominent K-shell lines from iron and nickel, together with a triangle residual at 8-10 keV, which corresponds to the energy of the radiative recombination continuum (RRC) of He-like iron. In addition, the wavy residuals have been seen at…
Quantifying the Heating Sources for Mid-infrared Dust Emissions in Galaxies: The Case of M 81
Boquien, M.; Cooray, A.; Madden, S. C. +12 more
With the newly available photometric images at 250 and 500 µm from the Herschel Space Observatory, we study quantitative correlations over a sub-kiloparsec scale among three distinct emission components in the interstellar medium of the nearby spiral galaxy M 81 (NGC 3031): (1) I 8 or I 24, the surface brightness of the…
Constraining the Evolutionary Fate of Central Compact Objects: "Old" Radio Pulsars in Supernova Remnants
Kaspi, Victoria M.; Bogdanov, Slavko; Ng, C. -Y.
Central compact objects (CCOs) constitute a population of radio-quiet, slowly spinning (>=100 ms) young neutron stars with anomalously high thermal X-ray luminosities. Their spin-down properties imply weak dipole magnetic fields (~1010-11 G) and characteristic ages much greater than the ages of their host supernova remnants (SNRs). H…
A Multi-wavelength View of the Central Kiloparsec Region in the Luminous Infrared Galaxy NGC 1614
Colina, Luis; Alonso-Herrero, Almudena; Alberdi, Antxon +9 more
The Luminous Infrared Galaxy NGC 1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Paα, optical, and X-ray observations of NGC 1614, aimed at studying in detail both the ci…
An ALMA Survey of Sub-millimeter Galaxies in the Extended Chandra Deep Field South: Sub-millimeter Properties of Color-selected Galaxies
Smail, I.; Greve, T. R.; Walter, F. +16 more
We study the sub-millimeter properties of color-selected galaxies via a stacking analysis applied for the first time to interferometric data at sub-millimeter wavelengths. We base our study on 344 GHz ALMA continuum observations of ~20''-wide fields centered on 86 sub-millimeter sources detected in the LABOCA Extended Chandra Deep Field South (ECD…
Evidence for Two Separate Heliospheric Current Sheets of Cylindrical Shape During Mid-2012
Young, P. R.; Wang, Y. -M.; Muglach, K.
During the reversal of the Sun's polar fields at sunspot maximum, outward extrapolations of magnetograph measurements often predict the presence of two or more current sheets extending into the interplanetary medium, instead of the single heliospheric current sheet (HCS) that forms the basis of the standard "ballerina skirt" picture. By comparing …
HST-COS Spectroscopy of the Cooling Flow in A1795—Evidence for Inefficient Star Formation in Condensing Intracluster Gas
Veilleux, Sylvain; Roediger, Joel; McDonald, Michael +1 more
We present far-UV spectroscopy from the Cosmic Origins Spectrograph on the Hubble Space Telescope of a cool, star-forming filament in the core of A1795. These data, which span 1025 Å < λrest < 1700 Å, allow for the simultaneous modeling of the young stellar populations and the intermediate-temperature (105.5 K) gas in t…
Shocks and Star Formation in Stephan's Quintet. I. Gemini Spectroscopy of Hα-bright Knots
Bastian, N.; Appleton, P. N.; Smith, L. J. +8 more
We present a Gemini-GMOS spectroscopic study of Hubble Space Telescope (HST)-selected Hα-emitting regions in Stephan's Quintet (HCG 92), a nearby compact galaxy group, with the aim of disentangling the processes of shock-induced heating and star formation in its intra-group medium. The ≈40 sources are distributed across the system, but most densel…