Related papers: Spectral Analysis of the Chandra Comet Survey

We report on archival data from the Chandra X-ray Observatory for the radio jet of 3C120. We consider the emission process responsible for the X-rays from 4 knots using spectra constructed from radio, optical, and X-ray intensities. While a…

We report on Chandra and XMM-Newton observations of a sample of 13 quasars at z~4.7-5.4 mostly taken from the Sloan Digital Sky Survey (SDSS). The present sample complements previous X-ray studies of z>4 quasars, in which the majority of…

High-mass gamma-ray binaries are powerful nonthermal galactic sources, some of them hosting a pulsar whose relativistic wind interacts with a likely inhomogeneous stellar wind. So far, modeling these sources including stellar wind…

We report the detection at X-rays of the radio/optical jet of 3C 371, from a short (10 ks) Chandra exposure in March 2000. We also present a new MERLIN observation at 1.4 GHz together with a renalysis of the archival HST WFPC2 F555W image.…

Since 1950 when Oort published his paper on the structure of the cloud of comets it is believed that stars passing near this hypothetical cometary reservoir play an important role in the dynamical evolution of long period comets and…

We present an extended analysis of deep Chandra HETG observations of the WR+OB binary system WR 147 that was resolved into a double X-ray source (Zhekov & Park, 2010, ApJ, 709, L119). Our analysis of the profiles of strong emission lines…

We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey (SDSS) that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project…

We report the discovery of eight X-ray sources with periodic variability in 487 ks of observations of the Galactic center with Chandra. The sources are identified from a sample of 285 objects detected with 100-4200 net counts. Their periods…

We analyze the ASCA spectrum of the Cen X-3 X-ray binary system in eclipse using atomic models appropriate to recombination-dominated level population kinetics in an overionized plasma. In order to estimate the wind characteristics, we…

We present an overview of four phase-constrained Chandra HETGS X-ray observations of Delta Ori A. Delta Ori A is actually a triple system which includes the nearest massive eclipsing spectroscopic binary, Delta Ori Aa, the only such object…

We explore the relationship among three coronal mass ejections (CMEs), observed on 28 October 2003, 7 November 2004, and 20 January 2005, the type II burst-associated shock waves in the corona and solar wind, as well as the arrival of their…

We report on the results of a spectroscopic survey of 130 comets that was conducted at McDonald observatory from 1980 through 2008. Some of the comets were observed on only one night, while others were observed repeatedly. For 20 of these…

We present three new Chandra X-ray epochs along with new ground-based optical-UV observations as the third installment in a time-series analysis of four high-redshift ($z\sim4.1-4.4$) radio-quiet quasars (RQQs). In total, we present nine…

We present observations of SS 433 using the Chandra High Energy Transmission Grating Spectrometer. Many emission lines of highly ionized elements are detected with the relativistic blue and red Doppler shifts. The lines are measurably…

Strong outflows from active galactic nuclei are frequently observed in objects with lower coronal X-ray luminosity. This intrinsic X-ray weakness is considered a requirement for the formation of radiatively driven winds. To obtain an…

We discuss a probe of the contribution of wind-related shocks to the radio emission in otherwise radio-quiet quasars. Given 1) the non-linear correlation between UV and X-ray luminosity in quasars, 2) that such correlation leads to higher…

Photometric and spectroscopic observations of five nearly parabolic comets with eccentricity larger than 0.99 at heliocentric distances greater than 4 AU were performed. No molecular emission was observed for any studied comet and the…

High-resolution radio observations have revealed that non-thermal radio emission in WR stars arises where the stellar wind of the WR star collides with that of a binary companion. These colliding-wind binary (CWB) systems offer an important…

We discuss the effects of particle acceleration at the bow shocks expected in the binary pulsar system J0737-3039, due to the wind from pulsar A interacting with both the interstellar medium (ISM), and with the magnetosphere of pulsar B. In…

Chandra X-ray Observatory grating spectra of the supergiant X-ray Binary 4U 1700-37 reveal emission lines from hydrogen and helium-like S, Si, Mg, and Ne in the 4-13 A range. The spectrum also shows fluorescent lines from S, Si, and a…