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We present analysis of two O VI absorbers at redshift z_{abs} = 0.227, detected in the spectra of two closely spaced QSO sightlines (Q 0107-025 A and B), observed with the Cosmic Origins Spectrograph (COS) on board the Hubble Space…

Astrophysics of Galaxies · Physics 2014-03-03 Sowgat Muzahid

We report on detailed Monte Carlo inversion analysis of five OVI systems from the spectrum of the bright quasar HE 0515-4414 (z_e = 1.71). The associated system at z_a = 1.697 with the neutral hydrogen column density N(HI)= 4.4 10^{13}…

Astrophysics · Physics 2009-11-07 S. A. Levshakov , I. I. Agafonova , D. Reimers , R. Baade

We use high-resolution UV spectra of the radio-quiet QSO H1821+643 (z_em = 0.297), obtained with STIS and FUSE, to study the ionization and metallicity of an intervening O VI absorption line system at z(abs) = 0.1212. This absorber has the…

We report on the detection of two O VI absorbers separated in velocity by 710 km/s at z ~ 0.4 towards the background quasar SBS0957+599. Both absorbers are multiphase systems tracing substantial reservoirs of warm baryons. The low and…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-13 Sachin Pachat , Anand Narayanan , Sowgat Muzahid , Vikram Khaire , Raghunathan Srianand , Bart P. Wakker , Blair D. Savage

We present a high resolution (R~500) X-ray spectrum of the bright quasar H1821+643 (z=0.297), obtained in a 470 ksec Chandra observation. We search for X-ray absorption by highly ionized metal species, OVII and OVIII in particular, at the…

Astrophysics · Physics 2008-11-26 Smita Mathur , David Weinberg , Xuelei Chen , .

High resolution optical (HIRES/Keck) and UV (STIS/HST) spectra, covering a large range of chemical transitions, are analyzed for three single-cloud weak MgII absorption systems along the line of sight toward the quasar PG 1634+706. Weak…

Astrophysics · Physics 2008-11-26 J. C. Charlton , J. Ding , S. G. Zonak , C. W. Churchill , N. A. Bond , J. R. Rigby

Using $HST$/COS observations of the twin quasar lines of sight Q$0107-025$A $\&$ Q$0107-025$B, we report on the physical properties, chemical abundances and transverse sizes of gas in a multiple galaxy environment at $z = 0.399$ across a…

Astrophysics of Galaxies · Physics 2021-02-24 Pratyush Anshul , Anand Narayanan , Sowgat Muzahid , Alexander Beckett , Simon L. Morris

We present HST/COS high S/N observations of the z = 0.32566 multi-phase absorber towards 3C263. The COS data shows absorption from H I, O VI, C III, N III, Si III and C II. The Ne VIII in this absorber is detected in the FUSE spectrum. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Anand Narayanan , Blair D. Savage , Bart P. Wakker

We have obtained new observations of the partial Lyman limit absorber at \zabs$=0.93$ towards quasar PG~1206+459, and revisit its chemical and physical conditions. The absorber, with $ N(HI) \sim 10^{17.0}$ ~\sqcm\ and absorption lines…

We present a census of z(abs) < 2, intrinsic (those showing partial coverage) and associated [z(abs) ~ z(em)] quasar absorption-line systems detected in the Hubble Space Telescope archive of Space Telescope Imaging Spectrograph echelle…

High resolution FUSE and STIS observations of the bright QSO HE 0226-4110 (zem = 0.495) reveal the presence of a multi-phase absorption line system at zabs(O VI) = 0.20701 containing absorption from H I (Ly alpha to Ly theta), C III, O III,…

We present analyses of the physical conditions in the z=0.22496 and z=0.22638 multi-phase O VI absorption systems detected in the ultraviolet HST/STIS and FUSE spectra of the quasar H1821+643. Both absorbers are likely associated with the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Anand Narayanan , Blair D. Savage , Bart P. Wakker

The spectrum of the low-redshift QSO PG0953+415 shows two strong, intervening O VI absorption systems. To study the nature of these absorbers, we have used the Gemini Multiobject Spectrograph to conduct a deep spectroscopic galaxy redshift…

Astrophysics · Physics 2009-11-11 Todd M. Tripp , Bastien Aracil , David V. Bowen , Edward B. Jenkins

We present a comprehensive catalog of ultraviolet HST/STIS and FUSE absorbers in the low-redshift IGM at z<0.4. The catalog draws from the extensive literature on IGM absorption, and it reconciles discrepancies among previous catalogs…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Evan M. Tilton , Charles W. Danforth , J. Michael Shull , Teresa L. Ross

High resolution X-ray absorption spectroscopy is a powerful diagnostic tool for probing chemical and physical properties of the interstellar medium (ISM) at various phases. We present detections of K transition absorption lines from the low…

Astrophysics of Galaxies · Physics 2011-02-11 Yangsen Yao , Norbert S. Schulz , Ming F. Gu , Michael A. Nowak , Claude R. Canizares

(Abridged) With the goal of investigating the nature of OVI absorbers at high redshifts, we study the effects of proximity to the background quasar. In a sample of sixteen quasars at z(QSO) between 2.14 and 2.87 observed at 6.6 km/s…

Astrophysics · Physics 2009-11-13 Andrew J. Fox , Jacqueline Bergeron , Patrick Petitjean

We present a physically-based absorption-line model for the spectroscopic study of the intergalactic medium (IGM). This model adopts results from Cloudy simulations and theoretical calculations by Gnat and Sternberg (2007) to examine the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Yangsen Yao , J. Michael Shull , Charles W. Danforth , Brian A. Keeney , John T. Stocke

We present results from the analysis of a multiphase O VI - broad Ly-alpha absorber at z = 0.19236 in the HST/COS spectrum of PG 1121+422. The low and intermediate ionization metal lines in this absorber have a single narrow component,…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-24 Anand Narayanan , Blair D. Savage , Preetish K. Mishra , Bart P. Wakker , Vikram Khaire , Yogesh Wadadekar

We present a search for O I in the spectra of nine 4.9 < z_qso < 6.4 QSOs taken with Keck/HIRES. We detect six systems with N(O I) > 10^13.7 cm^{-2} in the redshift intervals where O I 1302 falls redward of the Ly-alpha forest. Four of…

Astrophysics · Physics 2009-11-13 George D. Becker , Wallace L. W. Sargent , Michael Rauch , Robert A. Simcoe

We present results from an analysis of FUSE and HST/STIS spectroscopy of the z_em=0.57 quasar PKS0405-123. We focus on the intervening metal-line systems identified along the sightline and investigate their ionization mechanism, ionization…