Search Publications
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…
Measurements of Outflow Velocities in on-disk Plumes from EIS/Hinode Observations
Fu, Hui; Li, Bo; Xia, Lidong +3 more
The contribution of plumes to the solar wind has been subject to hot debate in the past decades. The EUV Imaging Spectrometer (EIS) on board Hinode provides a unique means to deduce outflow velocities at coronal heights via direct Doppler shift measurements of coronal emission lines. Such direct Doppler shift measurements were not possible with pr…
A Wind Accretion Model for HLX-1
Maccarone, Thomas J.; Farrell, Sean A.; Miller, M. Coleman
The brightest ultraluminous X-ray source currently known, HLX-1, has been observed to undergo five outburst cycles. The periodicity of these outbursts, and their high inferred maximum accretion rates of ~few × 10-4 M ⊙ yr-1, naturally suggest Roche lobe overflow at the pericenter of an eccentric orbit. It is, howev…
On Magnetic Activity Band Overlap, Interaction, and the Formation of Complex Solar Active Regions
McIntosh, Scott W.; Leamon, Robert J.
Recent work has revealed a phenomenological picture of the how the ~11 yr sunspot cycle of the Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22 yr magnetic activity cycle and are rooted deep in the Sun's convective…