Search Publications
Dynamical Fragmentation of the T Pyxidis Nova Shell During Recurrent Eruptions
Zurek, David R.; Shara, Michael M.; Mac Low, Mordecai-Mark +1 more
Hubble Space Telescope images of the ejecta surrounding the nova T Pyxidis resolve the emission into more than 2000 bright knots. We simulate the dynamical evolution of the ejecta from T Pyxidis during its multiple eruptions over the last 150 years using the adaptive mesh refinement code Ramses. We demonstrate that the observed knots are the resul…
Keck-I MOSFIRE Spectroscopy of the z ~ 12 Candidate Galaxy UDFj-39546284
Capak, P.; Scoville, N. Z.; Vieira, J. D. +3 more
We report the results of deep (4.6 hr) H-band spectroscopy of the well studied z ~ 12 H-band dropout galaxy candidate UDFj-39546284 with MOSFIRE on Keck-I. These data reach a sensitivity of 5-10 × 10-19 erg s-1 cm-2 per 4.4 Å resolution element between sky lines. Previous papers have argued that this source could e…
Synoptic Mapping of Chromospheric Magnetic Flux
Pietarila, A.; Harvey, J. W.; Jin, C. L.
We used daily full-disk Ca II 854.2 nm magnetograms from the Synoptic Optical Long Term Investigations of the Sun (SOLIS) facility to study the chromospheric magnetic field from 2006 April through 2009 November. We determined and corrected previously unidentified zero offsets in the SOLIS magnetograms. By tracking the disk passages of stable unipo…
On the Nature of the mHz X-Ray Quasi-periodic Oscillations from Ultraluminous X-Ray Source M82 X-1: Search for Timing-Spectral Correlations
Pasham, Dheeraj R.; Strohmayer, Tod E.
Using all the archival XMM-Newton X-ray (3-10 keV) observations of the ultraluminous X-ray source (ULX) M82 X-1, we searched for a correlation between its variable mHz quasi-periodic oscillation (QPO) frequency and its hardness ratio (5-10 keV/3-5 keV), an indicator of the energy spectral power-law index. When stellar-mass black holes (StMBHs) exh…
The Nearby, Young, Isolated, Dusty Star HD 166191
Hinkley, Sasha; Zuckerman, B.; Song, Inseok +4 more
We report an in-depth study of the F8-type star HD 166191, identified in an ongoing survey for stars exhibiting infrared emission above their expected photospheres in the Wide-field Infrared Survey Explorer all-sky catalog. The fractional IR luminosity measured from 3.5 to 70 µm is exceptionally high (L IR/L bol ~ 10%).…
About the Linearity of the Color-Magnitude Relation of Early-type Galaxies in the Virgo Cluster
Forte, Juan Carlos; Faifer, Favio R.; González, Nélida M. +1 more
We revisit the color-magnitude relation of Virgo Cluster early-type galaxies in order to explore its alleged nonlinearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster Survey of the Hubble Space Telescope and perform our own photometry and analysis of the images of 100 early-type galaxies…
Uncertainties in Atomic Data and their Propagation through Spectral Models. I.
Quinet, P.; Gull, T. R.; Kallman, T. R. +4 more
We present a method for computing uncertainties in spectral models, i.e., level populations, line emissivities, and emission line ratios, based upon the propagation of uncertainties originating from atomic data. We provide analytic expressions, in the form of linear sets of algebraic equations, for the coupled uncertainties among all levels. These…
Waiting Times of Quasi-homologous Coronal Mass Ejections from Super Active Regions
Wang, Yuming; Shen, Chenglong; Wang, S. +3 more
Why and how do some active regions (ARs) frequently produce coronal mass ejections (CMEs)? These are key questions for deepening our understanding of the mechanisms and processes of energy accumulation and sudden release in ARs and for improving our space weather prediction capability. Although some case studies have been performed, these question…
Large-area [Fe II] Line Mapping of the Supernova Remnant IC 443 with the IRSF/SIRIUS
Onaka, Takashi; Lee, Ho-Gyu; Kaneda, Hidehiro +3 more
We present the results of near-infrared (near-IR) [Fe II] line mapping of the supernova remnant IC 443 with IRSF/SIRIUS, using the two narrow-band filters tuned for the [Fe II] 1.257 µm and [Fe II] 1.644 µm lines. Covering a large area of 30' × 35', our observations reveal that [Fe II] filamentary structures exist all over the remnant,…
HerMES: A Deficit in the Surface Brightness of the Cosmic Infrared Background due to Galaxy Cluster Gravitational Lensing
Kneib, J. -P.; Valtchanov, I.; Clements, D. L. +25 more
We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estim…