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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Observations Of The Gas Reservoir Around A Star Forming Galaxy In The Early Universe, Brenda L. Frye, David V. Bowen, Mairead Hurley, Todd M. Tripp, Xiaohui Fan, Bradley Holden, Puragra Guhathakurta, Dan Coe, Tom Broadhurst, Eiichi Egami, G. Meylan
Observations Of The Gas Reservoir Around A Star Forming Galaxy In The Early Universe, Brenda L. Frye, David V. Bowen, Mairead Hurley, Todd M. Tripp, Xiaohui Fan, Bradley Holden, Puragra Guhathakurta, Dan Coe, Tom Broadhurst, Eiichi Egami, G. Meylan
Todd M. Tripp
We present a high signal-to-noise spectrum of a bright galaxy at z = 4.9 in 14 h of integration on VLT FORS2. This galaxy is extremely bright, i_850 = 23.10 +/- 0.01, and is strongly-lensed by the foreground massive galaxy cluster Abell 1689 (z=0.18). Stellar continuum is seen longward of the Ly-alpha emission line at ~7100 \AA, while intergalactic H I produces strong absorption shortward of Ly-alpha. Two transmission spikes at ~6800 Angstroms (A) and ~7040 A are also visible, along with other structures at shorter wavelengths. Although fainter than a QSO, the absence of a strong central ultraviolet flux …
Discovery Of A Primitive Damped Lyman Alpha Absorber Near An X-Ray Bright Galaxy Group In The Virgo Cluster, Todd M. Tripp, Edward B. Jenkins, David V. Bowen, Jason X. Prochaska, Bastien Aracil, Rajib Ganguly
Discovery Of A Primitive Damped Lyman Alpha Absorber Near An X-Ray Bright Galaxy Group In The Virgo Cluster, Todd M. Tripp, Edward B. Jenkins, David V. Bowen, Jason X. Prochaska, Bastien Aracil, Rajib Ganguly
Todd M. Tripp
We report the discovery of a low-redshift, sub-damped Ly_ absorber (DLA) in the outer periphery of the Virgo cluster near the X-ray bright NGC4261 galaxy group, in the direction of PG1216+069. We have obtained a new spectrum of PG1216+069 (zQSO = 0.3313) with the E140M echelle mode of the Space Telescope Imaging Spectrograph (STIS), and this spectrum reveals damped Ly_ absorption as well as O I, C II, Si II, and Fe II absorption lines at zabs = 0.00632. Notably, the absorber shows no evidence of highly-ionized gas: Si IV, C IV, and O VI are not signi_cantly detected at …
The Connections Between Qso Absorption Systems And Galaxies: Low-Redshift Observations, Todd M. Tripp, David V. Bowen
The Connections Between Qso Absorption Systems And Galaxies: Low-Redshift Observations, Todd M. Tripp, David V. Bowen
Todd M. Tripp
Quasar absorption lines have long been recognised to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be studied by any other means. While some pre-Hubble Space Telescope (HST) observations indicated that Mg II absorption lines arise in gaseous galactic halos with a large covering factor, many early QSO absorber studies were hampered by a lack of information about the context of the absorbers and their connections with galaxies. By providing access to crucial ultraviolet resonance lines at low redshifts, deployment of HST …
Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk
Evidence For Correlated Titanium And Deuterium Depletion In The Galactic Ism, Jason X. Prochaska, Todd M. Tripp, Christopher Howk
Todd M. Tripp
Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high resolution profiles of the refractory ion Ti II along seven Galactic sightlines with D/H ranging from 0.65 to 2.1 × 10−5. These measurements, acquired with the recently upgraded Keck/HIRES spectrometer, indicate a correlation between Ti/H and D/H at the > 95% c.l. Therefore, our observations support the interpretation that D/H scatter …
The O Vi Absorbers Toward Pg 0953+415: High-Metallicity, Cosmic-Web Gas Far From Luminous Galaxies, Todd M. Tripp, Bastien Aracil, David V. Bowen, Edward B. Jenkins
The O Vi Absorbers Toward Pg 0953+415: High-Metallicity, Cosmic-Web Gas Far From Luminous Galaxies, Todd M. Tripp, Bastien Aracil, David V. Bowen, Edward B. Jenkins
Todd M. Tripp
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 survey in the 5' x 5' field centered on the QSO. This survey is fully complete for r' < 19.7 and is 73% complete for r' < 21.0. We find three galaxies at the redshift of the higher-z O VI system (z = 0.14232) including a galaxy at projected distance rho = 155 kpc. We find no galaxies in the Gemini field at the redshift of the lower-z O VI absorber (z = 0.06807), which indicates that the nearest galaxy is more than 195 kpc away or has L < 0.04 L*. Previous shallower surveys covering a larger field have shown that the z = 0.06807 O VI absorber is affiliated with a group/filament of galaxies, but the nearest known galaxy has rho = 736 kpc. The z = 0.06807 absorber is notable for several reasons. The absorption profiles reveal simple kinematics indicative of quiescent material. The H I line widths and good alignment of the H I and metal lines favor photoionization and, moreover, the column density ratios imply a high metallicity: [M/H] = -0.3 +/- 0.12. The z = 0.14232 O VI system is more complex and less constrained but also indicates a relatively high metallicity. Using galaxy redshifts from SDSS, we show that both of the PG0953+415 O VI absorbers are located in large-scale filaments of the cosmic web. Evidently, some regions of the web filaments are highly metal enriched. We discuss the origin of the high-metallicity gas and suggest that the enrichment might have occurred long ago (at high z).
Complex C: A Low-Metallicity High-Velocity Cloud Plunging Into The Milky Way, Todd M. Tripp, Bart P. Wakker, Edward B. Jenkins, C. W. Bowers, A. C. Danks, R. F. Green, S. R. Heap, C. L. Joseph, M. E. Kaiser, J. L. Linsky, B. E. Woodgate
Complex C: A Low-Metallicity High-Velocity Cloud Plunging Into The Milky Way, Todd M. Tripp, Bart P. Wakker, Edward B. Jenkins, C. W. Bowers, A. C. Danks, R. F. Green, S. R. Heap, C. L. Joseph, M. E. Kaiser, J. L. Linsky, B. E. Woodgate
Todd M. Tripp
We present evidence that high-velocity cloud (HVC) complex C is a low-metallicity gas cloud that is plunging toward the disk and beginning to interact with the ambient gas that surrounds the Milky Way. This evidence begins with a new high-resolution (7 km s-1 FWHM) echelle spectrum of 3C 351 obtained with the Space Telescope Imaging Spectrograph (STIS). 3C 351 lies behind the low-latitude edge of complex C, and the new spectrum provides accurate measurements of O I, Si II, Al II, Fe II, and Si III absorption lines at the velocity of complex C; N I, S II, Si IV, …