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Past studies based on optical spectroscopy suggest that the five $\omega$ Cen pulsators form a rather homogeneous group of hydrogen-rich subdwarf O stars with effective temperatures of around 50 000 K. This places the stars below the red…

Solar and Stellar Astrophysics · Physics 2017-04-12 M. Latour , S. K. Randall , P. Chayer , G. Fontaine , A. Calamida , J. Ely , T. M. Brown , W. Landsman

The line ratios R and G of the three main lines of He-like ions (triplet: resonance, intercombination, forbidden lines) are calculated for CV, NVI, OVII, NeIX, MgXI, and SiXIII. These ratios can be used to derive electron density n_e and…

Astrophysics · Physics 2016-08-30 D. Porquet , R. Mewe , J. Dubau , A. J. J. Raassen , J. S. Kaastra

The presence of O VI ions can be indicative of plasma temperatures of a few times 10^5 K that is expected in heat conduction layers between the hot shocked stellar wind gas at several 10^6 K and the cooler (~10,000 K) nebular gas of…

Astrophysics of Galaxies · Physics 2015-06-15 N. Ruiz , Y. -H. Chu , R. A. Gruendl , M. A. Guerrero , R. Jacob , D. Schonberner , M. Steffen

We observed the Monoceros R2 molecular cloud with the ACIS-I array onboard the Chandra X-ray Observatory. From the central 3.2' x 3.2' region, we detect 154 sources above the detection limit of ~5x10^-16 ergs s^-1 cm^-2 with a 100…

Astrophysics · Physics 2016-08-30 M. Kohno , K. Koyama , K. Hamaguchi

Recent observations with the Chandra X-ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within the inner 10'' of the Galaxy. The hot…

Astrophysics · Physics 2009-11-10 Gabriel Rockefeller , Chris L. Fryer , Fulvio Melia , Michael S. Warren

In a previous paper we have described a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line…

Astrophysics · Physics 2009-11-10 Patrick S. Wojdowski , Norbert S. Schulz

We report X-ray observations of the powerful radio galaxy Cygnus A with the Chandra X-ray Observatory. This letter focuses on the radio hot spots, all four of which are detected in X-rays with a very similar morphology to their radio…

Astrophysics · Physics 2009-10-31 A. S. Wilson , A. J. Young , P. L. Shopbell

We present the analysis of the X-ray data of the young active star HD35850 obtained with ASCA and ROSAT. Our main goal was to see if there is a difference in the elemental abundances of active stars between young and more evolved objects. A…

Astrophysics · Physics 2007-05-23 G. Tagliaferri , S. Covino , T. A. Fleming , M. Gagnè , R. Pallavicini , F. Haardt , Y. Uchida

Strong electron cooling on the neutral gas in cometary comae has been predicted for a long time, but actual measurements of low electron temperature are scarce. We present in situ measurements of plasma density, electron temperature and…

Weakly collisional Ar-O2 electronegative plasmas are investigated in a dc multidipole chamber. An electronegative core and an electropositive halo are observed. The density ratio of negative ions to electrons ({\alpha}) in the nondrifting…

Plasma Physics · Physics 2015-06-04 Y. -C. Ghim , N. Hershkowitz

We present a systematic study of the putative hot gas corona around late-type galaxies (LTGs) residing in the Virgo cluster, based on archival Chandra observations. Our sample consists of 21 nearly edge-on galaxies representing a star…

Astrophysics of Galaxies · Physics 2023-12-08 Meicun Hou , Lin He , Zhensong Hu , Zhiyuan Li , Christine Jones , William Forman , Yuanyuan Su , Jing Wang , Luis C. Ho

Chandra X-ray observations of NGC4342, a low stellar mass (M_K=-22.79 mag) early-type galaxy, show luminous, diffuse X-ray emission originating from hot gas with temperature of kT~0.6 keV. The observed 0.5-2 keV band luminosity of the…

(abridged) We searched for evidence of soft X-ray absorption by hot gas in the vicinity of the Galaxy in a small sample of fifteen type I AGN observed with the high resolution X-ray gratings on board Chandra. We find that around half of the…

Astrophysics · Physics 2009-11-10 B. McKernan , T. Yaqoob , C. S. Reynolds

Using a sample of nearly half million galaxies, intersected by over 7 million lines of sight from the Sloan Digital Sky Survey Data Release 12, we trace H$\alpha$ + [N{\small II}] emission from a galactocentric projected radius, $r_p$, of 5…

Astrophysics of Galaxies · Physics 2016-12-28 Huanian Zhang , Dennis Zaritsky , Guangtun Zhu , Brice Ménard , David W. Hogg

We discovered an X-ray cluster in a Chandra observation of the compact steep spectrum (CSS) radio source 1321+045 (z=0.263). CSS sources are thought to be young radio objects at the beginning of their evolution and can potentially test the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 M. Kunert-Bajraszewska , A. Siemiginowska , A. Labiano

We present high resolution X-ray spectra of 14 putative cooling-flow clusters of galaxies obtained with the Reflection Grating Spectrometer on XMM-Newton. The clusters in the sample span a large range of temperatures and mass deposition…

The Chandra HETGS spectra of the Seyfert 1 galaxy MCG--6-30-15 show numerous narrow, unresolved (FWHM < 200 km/s) absorption lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and Fe. The initial analysis of these…

Astrophysics · Physics 2007-05-23 J. C. Lee , C. R. Canizares , H. L. Marshall , A. C. Fabian , R. Morales , N. S. Schulz , K. Iwasawa

Effects of radio-frequency power and driven frequency on the two-dimensional (axial and radial) distributions of electron density and temperature were experimentally investigated in low pressure capacitively coupled argon plasmas. The…

Plasma Physics · Physics 2020-10-22 Jidun Wu , Hao Zheng , Yanfei Wang , Fengzhu Zhou , Xiaojiang Huang

We report the X-ray population study in the giant molecular cloud Sagittarius B2 (SgrB2). More than a dozen of X-ray cloud members (and candidates) are discovered with Chandra. Two bright X-ray sources are located near Sgr B2 Main, the most…

Astrophysics · Physics 2009-11-07 S. Takagi , H. Murakami , K. Koyama

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…

Astrophysics · Physics 2009-11-07 B. Boroson , S. Vrtilek , T. Kallman , M. Corcoran
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