Search Publications
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…
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…
A Suzaku Observation of Mkn 590 Reveals a Vanishing Soft Excess
Rivers, Elizabeth; Markowitz, Alex; Rothschild, Richard +1 more
We have analyzed a long-look Suzaku observation of the Seyfert 1.2 Mkn 590. We aimed to measure the Compton reflection strength, Fe K complex properties, and soft excess emission as had been observed previously in this source. The Compton reflection strength was measured to be in the range 0.2-1.0 depending on the model used. A moderately strong F…
Active Region Moss: Doppler Shifts from Hinode/Extreme-ultraviolet Imaging Spectrometer Observations
Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.
Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper, we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode on 2007 December 12 to measure the Doppl…
First Science Results from SOFIA/FORCAST: The Mid-infrared View of the Compact H II Region W3A
Schoenwald, J.; Zinnecker, H.; Tielens, A. G. G. M. +10 more
The massive star-forming region W3 was observed with the faint object infrared camera for the SOFIA telescope as part of the Short Science program. The 6.4, 6.6, 7.7, 19.7, 24.2, 31.5, and 37.1 µm bandpasses were used to observe the emission of polycyclic aromatic hydrocarbon (PAH) molecules, very small grains, and big grains. Optical depth …
Are Large, Cometary-shaped Proplyds Really (Free-floating) Evaporating Gas Globules?
Sahai, R.; Morris, M. R.; Güsten, R.
We report the detection of strong and compact molecular line emission (in the CO J = 3-2, 4-3, 6-5, 7-6, 13CO J = 3-2, HCN, and HCO+ J = 4-3 transitions) from a cometary-shaped object (Carina-frEGG1) in the Carina star-forming region (SFR) previously classified as a photoevaporating protoplanetary disk (proplyd). We derive a …
Prospect of Studying Hard X- and Gamma-Rays from Type Ia Supernovae
Yamaguchi, H.; Diehl, R.; Tamagawa, T. +9 more
We perform multi-dimensional, time-dependent radiation transfer simulations for hard X-ray and γ-ray emissions, following radioactive decays of 56Ni and 56Co, for two-dimensional delayed-detonation models of Type Ia supernovae (SNe Ia). The synthetic spectra and light curves are compared with the sensitivities of current and …
The Atacama Cosmology Telescope: High-resolution Sunyaev-Zel'dovich Array Observations of ACT SZE-selected Clusters from the Equatorial Strip
Hilton, Matt; Hasselfield, Matthew; Sifón, Cristóbal +41 more
We present follow-up observations with the Sunyaev-Zel'dovich Array (SZA) of optically confirmed galaxy clusters found in the equatorial survey region of the Atacama Cosmology Telescope (ACT): ACT-CL J0022-0036, ACT-CL J2051+0057, and ACT-CL J2337+0016. ACT-CL J0022-0036 is a newly discovered, massive (sime 1015 M ⊙), high-re…
A Direct Measurement of the Total Gas Column Density in Orion KL
Comito, C.; Schilke, P.; Lis, D. C. +7 more
The large number of high-J lines of C18O available via the Herschel Space Observatory provide an unprecedented ability to model the total CO column density in hot cores. Using the emission from all the observed lines (up to J = 15-14), we sum the column densities in each individual level to obtain the total column after correcting for t…