Search Publications
Optical counterparts of two ULXs in NGC 5474 and NGC 3627 (M 66)
Akyuz, A.; Aksaker, N.; Avdan, S. +6 more
We identified two optical counterparts of brightest ultraluminous X-ray sources (ULXs) in galaxies NGC 5474 and NGC 3627 (M66). The counterparts in Hubble Space Telescope images are very faint, their V magnitudes are 24.7 (MV ≈ -4.5) and 25.9 (MV ≈ -4.2), respectively. NGC 5474 X-1 changes the X-ray flux more than two orders …
The Short Rotation Period of Hi’iaka, Haumea’s Largest Satellite
Margot, Jean-Luc; Brown, Michael E.; Fabrycky, Daniel C. +5 more
Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ∼9.8 hr (double peaked). This is ∼120 times faster than its orbital period, creating new questions about the f…
An Analysis of Interplanetary Solar Radio Emissions Associated with a Coronal Mass Ejection
Magdalenić, J.; Eastwood, J. P.; Davies, J. A. +13 more
Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma that may cause severe geomagnetic storms if Earth directed. Here, we report a rare instance with comprehensive in situ and remote sensing observations of a CME combining white-light, radio, and plasma measurements from four different vantage points. For the first time, we…
Interpreting the ionization sequence in star-forming galaxy emission-line spectra
Ferland, Gary J.; Hewett, Paul C.; Baldwin, Jack A. +4 more
High-ionization star-forming (SF) galaxies are easily identified with strong emission-line techniques such as the BPT diagram, and form an obvious ionization sequence on such diagrams. We use a locally optimally emitting cloud model to fit emission-line ratios that constrain the excitation mechanism, spectral energy distribution, abundances and ph…
Cloud clearing in the wake of Saturn's Great Storm of 2010-2011 and suggested new constraints on Saturn's He/H2 ratio
Baines, K. H.; Sromovsky, L. A.; Momary, T. W. +1 more
Saturn's Great Storm of 2010-2011 produced a planet-encircling wake that slowly transitioned from a region that was mainly dark at 5 µm in February 2011 to a region that was almost entirely bright and remarkably uniform by December of 2012. The uniformity and high emission levels suggested that the entire wake region had been cleared not onl…
Aggregate particles in the plumes of Enceladus
Ingersoll, Andrew P.; Zhang, Xi; Gao, Peter +1 more
Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll and Ewald (Ingersoll, A.P., Ewald, S.P. [2011]. Icarus 216(2), 492-506), who estimated the particulate mass of the Enceladu…
The nuclear and integrated far-infrared emission of nearby Seyfert galaxies
Esquej, P.; Hernán-Caballero, A.; Acosta-Pulido, J. A. +11 more
We present far-infrared (FIR) 70-500 µm imaging observations obtained with Herschel/Photodetector Array Camera (PACS) and Spectral and Photometric Imaging REceiver (SPIRE) of 33 nearby (median distance of 30 Mpc) Seyfert galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR nuclear (r = 1 kpc and r = 2 kpc) and integrated…
New identification of the mixed-morphology supernova remnant G298.6-0.0 with possible gamma-ray association
Petre, Robert; Terada, Yukikatsu; Bamba, Aya +4 more
We present an X-ray analysis on the Galactic supernova remnant (SNR) G298.6-0.0 observed with Suzaku. The X-ray image shows a center-filled structure inside a radio shell, implying that this SNR can be categorized as a mixed-morphology (MM) SNR. The spectrum is well reproduced by a single-temperature plasma model in ionization equilibrium, with a …
Evidence for a binary origin of a central compact object
Klochkov, Dmitry; Kavanagh, Patrick; Doroshenko, Victor +3 more
Central compact objects (CCOs) are thought to be young thermally emitting isolated neutron stars that were born during the preceding core-collapse supernova explosion. Here, we present evidence that at least in one case the CCO could have been formed within a binary system. We show that the highly reddened optical source IRAS 17287-3443, located 2…
Star Cluster Formation and Destruction in the Merging Galaxy NGC 3256
Whitmore, B. C.; Chandar, R.; Mulia, A. J.
We use the Advanced Camera for Surveys on the Hubble Space Telescope to study the rich population of young massive star clusters in the main body of NGC 3256, a merging pair of galaxies with a high star formation rate (SFR) and SFR per unit area (ΣSFR). These clusters have luminosity and mass functions that follow power laws, dN/dL ∝ L …