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Today, the majority of the cosmic baryons in the Universe are not observed directly, leading to an issue of "missing baryons" at low redshift. Cosmological hydrodynamical simulations have indicated that a significant portion of them will be…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 A. Fresco , C. Péroux , A. Merloni , A. Hamanowicz , R. Szakacs

We present a detection of a broad Ly-alpha absorber (BLA) with a matching O VI line in the nearby universe. The BLA is detected at z = 0.01028 in the high S/N spectrum of Mrk 290 obtained using the Cosmic Origins Spectrograph. The Ly-alpha…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-19 Anand Narayanan , Bart P. Wakker , Blair D. Savage , Brian A. Keeney , J. Michael Shull , John T. Stocke , Kenneth R. Sembach

We present a survey for metal absorption systems traced by neutral oxygen over $3.2 < z < 6.5$. Our survey uses Keck/ESI and VLT/X-Shooter spectra of 199 QSOs with redshifts up to 6.6. In total we detect 74 O I absorbers, of which 57 are…

In a series of papers, Nicastro et al. have reported the detection of z>0 OVII absorption features in the spectrum of Mrk421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate this result in the…

We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width (Doppler $b$ parameter) and column density ($N$) for H I and O VI absorbers. Leveraging extensive…

Astrophysics of Galaxies · Physics 2026-02-25 Zhijie Qu , Hsiao-Wen Chen , Eliana Schiller , Jing Wang , Max Gronke

For low-redshift cosmology and galaxy formation rates, it is important to account for all the baryons synthesized in the Big Bang. Although galaxies and clusters contain 10% of the baryons, many more reside in the photoionized Lyman-alpha…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 J. Michael Shull , Britton D. Smith , Charles W. Danforth

We present FUSE and STIS observations of the IGM toward PG 0953+415 (z_em = 0.239). An O VI system at z = 0.06807 is detected in H I Lya, Lyb, Lyg, O VI N V, C IV, and C III. The observations are modeled as a low density intervening gas…

Astrophysics · Physics 2007-05-23 B. D. Savage , K. R. Sembach , T. M. Tripp , P. Richter

Galactic outflows regulate the amount of gas galaxies convert into stars. However, it is difficult to measure the mass outflows remove because they span a large range of temperatures and phases. Here, we study the rest-frame ultraviolet…

Astrophysics of Galaxies · Physics 2017-12-27 J. Chisholm , R. Bordoloi , J. R. Rigby , M. Bayliss

In this paper we review the current predictions of numerical simulations for the origin and observability of the warm hot intergalactic medium (WHIM), the diffuse gas that contains up to 50 per cent of the baryons at z~0. During structure…

Astrophysics · Physics 2009-11-13 S. Bertone , J. Schaye , K. Dolag

We report the detection of Ne VIII in a z_abs = 0.59961 absorber towards the QSO PG 1407+265 (z_em = 0.94). Besides Ne VIII, absorption from HI Lyman series lines (HI 1025 - 915), several other low (C II, N II, O II, and S II), intermediate…

We report on the detection of two Ne VIII absorbers, at z = 0.61907 and z = 0.57052 in the HST/COS spectrum of background quasars SDSS J 080908.13+461925.6 and SBS 1122+594 respectively. The Ne VIII 770 line is at $\sim 3\sigma$…

Astrophysics of Galaxies · Physics 2018-02-06 Sachin Pachat , Anand Narayanan , Vikram Khaire , Blair D. Savage , Sowgat Muzahid , Bart P. Wakker

We investigate the relationship between galaxies and metal-line absorption systems in a large-scale cosmological simulation with galaxy formation. Our detailed treatment of metal enrichment and non-equilibrium calculation of oxygen species…

Astrophysics · Physics 2009-11-13 Rajib Ganguly , Renyue Cen , Taotao Fang , Kenneth Sembach

We searched for absorption lines of highly ionized O and Ne in the energy spectra of two Low-mass X-ray binaries, 4U1820-303 in the globular cluster NGC6624 and Cyg X-2, observed with the Chandra LETG, and detected O VII, O VIII and Ne IX…

Astrophysics · Physics 2009-11-10 Kazuo Futamoto , Kazuhisa Mitsuda , Yoh Takei , Ryuichi Fujimoto , Noriko Yamasaki

Recent observations of Broad Absorption Line (BAL) quasars demonstrated that the soft X-ray emission of these objects is extremely weak and convincing evidence for very strong absorption by a high column density (~ 10^23.5 cm^-2) was…

Astrophysics · Physics 2009-10-31 T. G. Wang , W. Brinkmann , W. Yuan , J. X. Wang , Y. Y. Zhou

We find resolved interstellar O K, Ne K, and Fe L absorption spectra in the Chandra Low Energy Transmission Grating Spectrometer spectrum of the low mass X-ray binary X0614+091. We measure the column densities in O and Ne, and find direct…

We construct an analytic phenomenological model for extended warm/hot gaseous coronae of $L_*$ galaxies. We consider UV OVI COS-Halos absorption line data in combination with Milky Way X-ray OVII and OVIII absorption and emission. We fit…

Astrophysics of Galaxies · Physics 2017-01-25 Yakov Faerman , Amiel Sternberg , Christopher F. McKee

To gain insight into four highly ionized high-velocity clouds (HVCs) discovered by Sembach et al. (1999), we have analyzed data from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) for the PKS 2155-304 and…

Astrophysics · Physics 2009-11-10 J. A. Collins , J. M. Shull , M. L. Giroux

We have searched for evidence of soft X-ray absorption by hot metals in the vicinity of the Galaxy in the spectra of a small sample of fifteen Type I AGN observed with the high resolution X-ray gratings on board Chandra. This is an…

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

We present Goddard High Resolution Spectrograph and ORFEUS-II measurements of Si IV, CIV, N V, and O VI absorption in the interstellar medium of the Galactic disk and halo toward the nucleus of the Seyfert galaxy ESO141-055. The high…

Astrophysics · Physics 2009-10-31 Kenneth R. Sembach , Blair D. Savage , Mark Hurwitz

In a previous paper we reported a 3-sigma detection of an absorption line from the Warm-Hot Intergalactic Medium (WHIM) using the Chandra and XMM X-ray grating spectra of the blazar H2356-309, the sight-line of which intercepts the Sculptor…

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