Search Publications
Discovery of "Warm Dust" Galaxies in Clusters at z ~ 0.3: Evidence for Stripping of Cool Dust in the Dense Environment?
Smail, I.; Altieri, B.; Valtchanov, I. +15 more
Using far-infrared imaging from the "Herschel Lensing Survey," we derive dust properties of spectroscopically confirmed cluster member galaxies within two massive systems at z ~ 0.3: the merging Bullet Cluster and the more relaxed MS2137.3-2353. Most star-forming cluster sources (~90%) have characteristic dust temperatures similar to local field g…
Helioseismology of a Realistic Magnetoconvective Sunspot Simulation
Birch, A. C.; Braun, D. C.; Rempel, M. +1 more
We compare helioseismic travel-time shifts measured from a realistic magnetoconvective sunspot simulation using both helioseismic holography and time-distance helioseismology, and measured from real sunspots observed with the Helioseismic and Magnetic Imager instrument on board the Solar Dynamics Observatory and the Michelson Doppler Imager instru…
The Road to the Red Sequence: A Detailed View of the Formation of a Massive Galaxy at z ~ 2
Hathi, Nimish P.; Pirzkal, Nor; Cohen, Seth +11 more
Over half of the census of massive galaxies at z ~ 2 are dominated by quiescent stellar populations. The formation mechanism for these galaxies is still under debate, with models relying either on massive and early mergers or cold accretion. It is therefore imperative to understand in detail the properties of these galaxies. We present here a deta…
Evolution of the Symbiotic Nova PU Vul—Outbursting White Dwarf, Nebulae, and Pulsating Red Giant Companion
Kato, Mariko; Hachisu, Izumi; Mikołajewska, Joanna
We present a composite light-curve model of the symbiotic nova PU Vul (Nova Vulpeculae 1979) that shows a long-lasting flat optical peak followed by a slow decline. Our model light curve consists of three components of emission, i.e., an outbursting white dwarf (WD), its M-giant companion, and the nebulae. The WD component dominates in the flat pe…
The relative and absolute timing accuracy of the EPIC-pn camera on XMM-Newton, from X-ray pulsations of the Crab and other pulsars
Guainazzi, M.; Freyberg, M. J.; Wellbrock, A. +13 more
Aims: Reliable timing calibration is essential for the accurate comparison of XMM-Newton light curves with those from other observatories, to ultimately use them to derive precise physical quantities. The XMM-Newton timing calibration is based on pulsar analysis. However, because pulsars show both timing noise and glitches, it is essential to…
The Chandra HRC View of the Subarcsecond Structures in the Nuclear Region of NGC 1068
Elvis, Martin; Risaliti, Guido; Karovska, Margarita +2 more
We have obtained a high spatial resolution X-ray image of the nucleus of NGC 1068 using the High Resolution Camera (HRC-I) on board the Chandra X-ray Observatory, which provides an unprecedented view of the innermost 1 arcsec radius region of this galaxy. The HRC image resolves the narrow-line region into X-ray emission clumps matching bright emis…
Characteristic Size of Flare Kernels in the Visible and Near-infrared Continua
Xu, Yan; Cao, Wenda; Jing, Ju +1 more
In this Letter, we present a new approach to estimate the formation height of visible and near-infrared emission of an X10 flare. The sizes of flare emission cores in three wavelengths are accurately measured during the peak of the flare. The source size is the largest in the G band at 4308 Å and shrinks toward longer wavelengths, namely the green…
How the inclination of Earth's orbit affects incoming solar irradiance
Cheung, M. C. M.; Kretzschmar, M.; Dudok de Wit, T. +3 more
The variability in solar irradiance, the main external energy source of the Earth's system, must be critically studied in order to place the effects of human-driven climate change into perspective and allow plausible predictions of the evolution of climate. Accurate measurements of total solar irradiance (TSI) variability by instruments onboard sp…
Rest-frame stacking of 2XMM catalog sources. Properties of the Fe Kα line
Nandra, K.; Merloni, A.; Comastri, A. +3 more
Aims: The aim of this work is to characterize the average Fe K emission properties of active galactic nuclei (AGNs) in the source rest-frame.
Methods: We selected a sample of 248 AGNs from the 2XMM catalog, covering a wide redshift range 0 < z < 5 and with the EPIC-PN net 2-10 keV rest-frame counts ≥ 200 and power law photon indice…
Properties of Umbral Dots from Stray Light Corrected Hinode Filtergrams
Ichimoto, Kiyoshi; Ravindra, B.; Mathew, Shibu K. +3 more
High-resolution blue continuum filtergrams from Hinode are employed to study the umbral fine structure of a regular unipolar sunspot. The removal of scattered light from the images increases the rms contrast by a factor of 1.45 on average. Improvement in image contrast renders identification of short filamentary structures resembling penumbrae tha…