Search Publications
Theoretical Clues to the Ultraviolet Diversity of Type Ia Supernovae
Baron, E.; Wang, Lifan; Milne, Peter +2 more
The effect of metallicity on the observed light of Type Ia supernovae (SNe Ia) could lead to systematic errors as the absolute magnitudes of local and distant SNe Ia are compared to measure luminosity distances and determine cosmological parameters. The UV light may be especially sensitive to metallicity, though different modeling methods disagree…
A Chandra Search for a Pulsar Wind Nebula around PSR B1055-52
Pavlov, G. G.; Posselt, B.; Spence, G.
The nearby, middle-aged PSR B1055-52 has many properties in common with the Geminga pulsar. Motivated by the Geminga's enigmatic and prominent pulsar wind nebula (PWN), we searched for extended emission around PSR B1055-52 with Chandra ACIS. For an energy range 0.3-1 keV, we found a 4σ flux enhancement in a 4\buildrel{\prime\prime}\over{.} 9-20
The Grism Lens-Amplified Survey from Space (GLASS). V. Extent and Spatial Distribution of Star Formation in z ~ 0.5 Cluster Galaxies
Fontana, Adriano; Pentericci, Laura; Schmidt, Kasper B. +14 more
We present the first study of the spatial distribution of star formation in z ∼ 0.5 cluster galaxies. The analysis is based on data taken with the Wide Field Camera 3 as part of the Grism Lens-Amplified Survey from Space (GLASS). We illustrate the methodology by focusing on two clusters (MACS 0717.5+3745 and MACS 1423.8+2404) with different morpho…
Physical Conditions in the X-Ray Emission-line Gas in NGC 1068
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. Michael +2 more
We present a detailed, photoionization modeling analysis of XMM-Newton/Reflection Grating Spectrometer observations of the Seyfert 2 galaxy NGC 1068. The spectrum, previously analyzed by Kinkhabwala et al., reveals a myriad of soft X-ray emission lines, including those from H- and He-like carbon, nitrogen, oxygen, and neon, and M- and L-shell iron…
Temperature and Electron Density Diagnostics of a Candle-flame-shaped Flare
Longcope, D. W.; McKenzie, D. E.; Plowman, J. E. +2 more
Candle-flame-shaped flares are archetypical structures that provide indirect evidence of magnetic reconnection. A flare resembling Tsuneta's famous 1992 candle-flame flare occurred on 2011 January 28; we present its temperature and electron density diagnostics. This flare was observed with Solar Dynamics Observatory/Atmospheric Imaging Assembly (S…
Enhancement of the 6.4 keV Line in the Inner Galactic Ridge: Proton-induced Fluorescence?
Koyama, K.; Tanaka, T.; Fukui, Y. +7 more
A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius…
The Three-dimensional Evolution of Ion-scale Current Sheets: Tearing and Drift-kink Instabilities in the Presence of Proton Temperature Anisotropy
Matteini, L.; Burgess, D.; Gingell, P. W.
We present the first three-dimensional (3D) hybrid simulations of the evolution of ion-scale current sheets, with an investigation of the role of temperature anisotropy and associated kinetic instabilities on the growth of the tearing instability and particle heating. We confirm the ability of the ion cyclotron and firehose instabilities to enhanc…
X-Ray Spectral Residuals in NGC 5408 X-1: Diffuse Emission from Star Formation, or the Signature of a Super-Eddington Wind?
Middleton, Matthew J.; Sutton, Andrew D.; Roberts, Timothy P.
If ultraluminous X-ray sources (ULXs) are powered by accretion onto stellar remnant black holes, then many must be accreting at super-Eddington rates. It is predicted that such high accretion rates should give rise to massive, radiatively driven winds. However, observational evidence of a wind, in the form of absorption or emission features, has r…
Evidence for (and Against) Progenitor Bias in the Size Growth of Compact Red Galaxies
Newman, Jeffrey; Graves, Genevieve; Abraham, Roberto G. +5 more
Most massive, passive galaxies are compact at high redshifts, but similarly compact massive galaxies are rare in the local universe. The most common interpretation of this phenomenon is that massive galaxies have grown in size by a factor of about five since redshift z = 2. An alternative explanation is that recently quenched massive galaxies are …
X-Ray Emission from J1446--4701, J1311--3430, and Other Black Widow Pulsars
Pavlov, George G.; Garmire, Gordon P.; Arumugasamy, Prakash
We present the results of detailed X-ray analysis of two black-widow pulsars (BWPs), J1446-4701 and J1311-3430. PSR J1446-4701 is a BWP with orbital parameters near the median values of the sample of known BWPs. Its X-ray emission that was detected by XMM-Newton is well characterized by a soft power-law (PL) spectrum (photon index Γ ≈ 3), and it s…