Search Publications
The Red Supergiant Progenitor of Supernova 2012aw (PTF12bvh) in Messier 95
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Cenko, S. Bradley +9 more
We report on the direct detection and characterization of the probable red supergiant (RSG) progenitor of the intermediate-luminosity Type II-Plateau (II-P) supernova (SN) 2012aw in the nearby (10.0 Mpc) spiral galaxy Messier 95 (M95; NGC 3351). We have identified the star in both Hubble Space Telescope images of the host galaxy, obtained 17-18 yr…
A Disk-wind Model for the Near-infrared Excess Emission in Protostars
Bans, Alissa; Königl, Arieh
Protostellar systems, ranging from low-luminosity classical T Tauri and Herbig Ae stars to high-luminosity Herbig Be stars, exhibit a near-infrared (NIR) excess in their spectra that is dominated by a bump in the monochromatic luminosity with a peak near 3 µm. The bump can be approximated by a thermal emission component of temperature ~1500 …
Resolving the Far-IR Line Deficit: Photoelectric Heating and Far-IR Line Cooling in NGC 1097 and NGC 4559
Helou, G.; Roussel, H.; Murphy, E. J. +30 more
The physical state of interstellar gas and dust is dependent on the processes which heat and cool this medium. To probe heating and cooling of the interstellar medium over a large range of infrared surface brightness, on sub-kiloparsec scales, we employ line maps of [C II] 158 µm, [O I] 63 µm, and [N II] 122 µm in NGC 1097 and NG…
The Swift Burst Alert Telescope Detected Seyfert 1 Galaxies: X-Ray Broadband Properties and Warm Absorbers
Veilleux, Sylvain; Kallman, T. R.; McKernan, Barry +1 more
We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy …
A HST/WFC3-IR Morphological Survey of Galaxies at z = 1.5-3.6. II. The Relation between Morphology and Gas-phase Kinematics
Erb, Dawn K.; Shapley, Alice E.; Steidel, Charles C. +3 more
We analyze rest-frame optical morphologies and gas-phase kinematics as traced by rest-frame far-UV and optical spectra for a sample of 204 star-forming galaxies in the redshift range z ~ 2-3 drawn from the Keck Baryonic Structure Survey. We find that spectroscopic properties and gas-phase kinematics are closely linked to morphology: compact galaxi…
Computer Vision for the Solar Dynamics Observatory (SDO)
Wiegelmann, T.; Hochedez, J. F.; Raouafi, N. -E. +22 more
In Fall 2008 NASA selected a large international consortium to produce a comprehensive automated feature-recognition system for the Solar Dynamics Observatory (SDO). The SDO data that we consider are all of the Atmospheric Imaging Assembly (AIA) images plus surface magnetic-field images from the Helioseismic and Magnetic Imager (HMI). We produce r…
Field Topology Analysis of a Long-lasting Coronal Sigmoid
van Ballegooijen, A. A.; DeLuca, E. E.; Savcheva, A. S.
We present the first field topology analysis based on nonlinear force-free field (NLFFF) models of a long-lasting coronal sigmoid observed in 2007 February with the X-Ray Telescope on Hinode. The NLFFF models are built with the flux rope insertion method and give the three-dimensional coronal magnetic field as constrained by observed coronal loop …
The Extended Hubble Space Telescope Supernova Survey: The Rate of Core Collapse Supernovae to z ~ 1
Mobasher, Bahram; Riess, Adam G.; Strolger, Louis-Gregory +3 more
We use a sample of 45 core collapse supernovae detected with the Advanced Camera for Surveys on board the Hubble Space Telescope to derive the core collapse supernova rate in the redshift range 0.1 < z < 1.3. In redshift bins centered on langzrang = 0.39, langzrang = 0.73, and langzrang = 1.11, we find rates of 3.00+1.28 - 0.…
The nature of the interstellar medium of the starburst low-metallicity galaxy Haro 11: a multi-phase model of the infrared emission
Cooray, A.; Lebouteiller, V.; Madden, S. C. +15 more
Context. The low-metallicity interstellar medium (ISM) is profoundly different from that of normal systems, being clumpy with low dust abundance and little CO-traced molecular gas. Yet many dwarf galaxies in the nearby universe are actively forming stars. As the complex ISM phases are spatially mixed with each other, detailed modeling is needed to…
Low-mass X-Ray Binaries Indicate a Top-heavy Stellar Initial Mass Function in Ultracompact Dwarf Galaxies
Mieske, Steffen; Kroupa, Pavel; Pflamm-Altenburg, Jan +1 more
It has been shown before that the high mass-to-light ratios of ultracompact dwarf galaxies (UCDs) can be explained if their stellar initial mass function (IMF) was top-heavy, i.e., that the IMF was skewed toward high-mass stars. In this case, neutron stars (NSs) and black holes would provide unseen mass in the UCDs. In order to test this scenario …