Highly Ionized Envelopes of High Velocity Clouds (2009)
Zekis, Erin E., Shull, J. Michael
We present recent results on highly ionized gas in Galactic High-Velocity Clouds (HVCs), originally surveyed in OVI (Sembach et al. 2003). In a new FUSE/HST survey of SiII/III/IV (Shull et al. 2009)...
Shull, J. Michael, Jones, Jennifer R., Danforth, Charles W., Collins, Joseph A.
The low Galactic halo is enveloped by a sheath of ionized, low-metallicity gas, which can provide a substantial (1 M_sun/yr) cooling inflow to replenish star formation in the disk. Using absorption...
The Cosmic Origins Spectrograph and the Future of Ultraviolet Astronomy (2009)
I describe the capabilities of the Cosmic Origins Spectrograph, scheduled for May 2009 installation on the Hubble Space Telescope. With a factor-of-ten increase in far-UV throughput for moderate...
Molecular Hydrogen in the FUSE Translucent Lines of Sight: The Full Sample (2008)
Rachford, Brian L., Snow, Theodore P., Destree, Joshua D., Ross, Teresa L., Ferlet, Roger, Friedman, Scott D., ...
We report total abundances and related parameters for the full sample of the FUSE survey of molecular hydrogen in 38 translucent lines of sight. New results are presented for the "second half" of the...
Shull, J. Michael, Venkatesan, Aparna
We examine the constraints on high-redshift star formation, ultraviolet and X-ray pre-ionization, and the epoch of reionization at redshift z_r, inferred from the recent WMAP-5 measurement, tau_e =...
Dust sputtering by Reverse Shocks in Supernova Remnants (2008)
Nath, Biman B., Laskar, Tanmoy, Shull, J. Michael
We consider sputtering of dust grains, believed to be formed in cooling supernovae ejecta, under the influence of reverse shocks. In the regime of self-similar evolution of reverse shocks, we can...
Ricotti, Massimo, Gnedin, Nickolay Y., Shull, J. Michael
In two previous papers, we presented simulations of the first galaxies in a representative volume of the Universe. The simulations are unique because we model feedback-regulated galaxy formation,...
The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z (2007)
Danforth, Charles W., Shull, J. Michael
We conduct an ultraviolet (HST and FUSE) spectroscopic survey of HI (Lyman lines) and seven metal ions (OVI, NV, CIV, CIII, SiIV, SiIII, FeIII) in the low-redshift intergalactic medium (IGM) at z
The Metallicity of Intergalactic Gas in Cosmic Voids (2007)
Stocke, John T., Danforth, Charles W., Shull, J. Michael, Penton, Steven V., Giroux, Mark L.
We have used the Hubble/STIS and FUSE archives of ultraviolet spectra of bright AGN to identify intergalactic Lya absorbers in nearby (z < 0.1) voids. From a parent sample of 651 Lya absorbers, we...
Critical Metallicities for Second-Generation Stars (2007)
The first massive stars may influence the formation of second-generation stars, in part by their metal enrichment of the surrounding gas. We investigate the "critical metallicity", defined as the the...
What is the Total Deuterium Abundance in the Local Galactic Disk? (2007)
Linsky, Jeffrey L., Draine, Bruce T., Moos, H. W., Jenkins, Edward B., Wood, Brian E., Oliveira, Cristina, ...
Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together with spectra from the Copernicus and IMAPS instruments, reveal an unexplained very wide range...
What is the Total Deuterium Abundance in the Local Galactic Disk? (2006)
Linsky, Jeffrey L., Draine, Bruce T., Moos, H. W., Jenkins, Edward B., Wood, Brian E., Oliveira, Cristina, ...
Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together with spectra from the Copernicus and IMAPS instruments, reveal an unexplained very wide range...
Does the Milky Way Produce a Nuclear Galactic Wind? (2006)
Keeney, Brian A., Danforth, Charles W., Stocke, John T., Penton, Steven V., Shull, J. Michael, Sembach, Kenneth R.
We detect high-velocity absorbing gas using Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer medium resolution spectroscopy along two high-latitude AGN sight lines (Mrk 1383 and PKS...
The radiative transport of dust in primordial galaxies and second-generation star formation (2006)
Venkatesan, Aparna, Nath, Biman B., Shull, J. Michael
Restricted Access till March 2009 (3 year embargo). Open access version available at arXiv.org
Finkelstein, Steven L., Morse, Jon A., Green, James C., Linsky, Jeffrey L., Shull, J. Michael, Snow, Theodore P., ...
We present new optical emission-line images of the young SNR 1E 0102-7219 (E0102) in the SMC obtained with the HST Advanced Camera for Surveys (ACS). E0102 is a member of the oxygen-rich class of...
The Galaxy Environment of O VI Absorption Systems (2005)
Stocke, John T., Penton, Steven V., Danforth, Charles W, Shull, J. Michael, Tumlinson, Jason, McLin, Kevin M.
We combine a FUSE sample of OVI absorbers (z < 0.15) with a database of 1.07 million galaxy redshifts to explore the relationship between absorbers and galaxy environments. All 37 absorbers with...
Santoro, Fernando, Shull, J. Michael
The influence of the first stars on the formation of second-generation objects at high redshift may be determined, in part, by their metal enrichment of surrounding gas. At a critical metallicity,...
The Low-z Intergalactic Medium. II. LyB, OVI, and CIII Forest (2005)
Danforth, Charles W., Shull, J. Michael, Rosenberg, Jessica L., Stocke, John T.
We present the results of a large survey of HI, OVI, and CIII absorption lines in the low-redshift (z80 mA) in 31 AGN sight lines studied with the Hubble Space Telescope and measure corresponding...
The Radiative Transport of Dust in Primordial Galaxies and Second-Generation Star Formation (2005)
Venkatesan, Aparna, Nath, Biman B., Shull, J. Michael
We investigate the radiative transport of dust in primordial galaxies in the presence of the UV radiation field from the first metal-free stars. We find that dust created in the first supernova (SN)...
A FUSE Survey of Interstellar Molecular Hydrogen toward High-Latitude AGN (2005)
Gillmon, Kristen, Shull, J. Michael, Tumlinson, Jason, Danforth, Charles
We report results from a FUSE survey of interstellar molecular hydrogen (H2) along 45 sight lines to AGN at high Galactic latitudes (|b| > 20 degrees). Most (39 of 45) of the sight lines show...
Molecular Hydrogen in Infrared Cirrus (2005)
Gillmon, Kristen, Shull, J. Michael
We combine data from our recent FUSE survey of interstellar molecular hydrogen absorption toward 50 high-latitude AGN with COBE-corrected IRAS 100 micron emission maps to study the correlation of...
An OVI Baryon Census of the Low-z Warm-Hot Intergalactic Medium (2005)
Danforth, Charles W., Shull, J. Michael
Intergalactic absorbers along lines of sight to distant quasars are a powerful diagnostic for the evolution and content of the intergalactic medium (IGM). In this study, we use the FUSE satellite to...
Tumlinson, Jason, Shull, J. Michael, Giroux, Mark L., Stocke, John T.
We present HST/STIS and FUSE spectra of the QSO PG 1211+143 (z_em = 0.081) and a galaxy survey of the surrounding field. This sightline shows two strong intergalactic absorption systems at cz ~...
He II Reionization and Sources of Metagalactic Ionization (2004)
Intergalactic Ly-alpha opacity suggests that H I was reionized at z ~ 6, while He II reionization was delayed to z ~ 3. Both epochs are in conflict with inferences from CMB optical depth (WMAP) which...
The LyB and OVI Forest in the Local Universe (2004)
Danforth, Charles W., Shull, J. Michael
Intergalactic absorbers along lines of sight to distant quasars are a powerful diagnostic for the evolution and content of the IGM. In this study, we search known low-z Ly-alpha absorption systems...
The Baryon Content of the Local Intergalactic Medium (2004)
Stocke, John T., Shull, J. Michael, Penton, Steven V.
We describe our surveys of low column density Lyman-alpha absorbers [N(HI) = 10^(12.5-16.0) cm^-2], which show that the warm photoionized IGM contains 30% of all baryons at z < 0.1. This fraction is...
A Composite Extreme Ultraviolet QSO Spectrum from the Far Ultraviolet Spectroscopic Explorer (2004)
Scott, Jennifer E., Kriss, Gerard A., Brotherton, Michael, Green, Richard F., Hutchings, John, Shull, J. Michael, ...
The Far Ultraviolet Spectroscopic Explorer (FUSE) has surveyed a large sample (> 100) of active galactic nuclei in the low-redshift universe (z < 1). Its response at short wavelengths makes it...
A Composite Extreme Ultraviolet QSO Spectrum from FUSE (2004)
Scott, Jennifer E., Kriss, Gerard A., Brotherton, Michael, Green, Richard F., Hutchings, John, Shull, J. Michael, ...
The Far Ultraviolet Spectroscopic Explorer (FUSE) has surveyed a large sample (> 100) of active galactic nuclei in the low redshift universe (z < 1). Its response at short wavelengths makes it...
OVI, NV, and CIV in the Galactic Halo: I. Velocity-Dependent Ionization Models (2004)
Indebetouw, Remy, Shull, J. Michael
We explore theoretical models of the ionization ratios of the Li-like absorbers NV, OVI, and CIV, in the Galactic halo. These ions are believed to form in nonequilibrium processes such as shocks,...
OVI, NV and CIV in the Galactic Halo: II. Velocity-Resolved Observations with Hubble and FUSE (2004)
Indebetouw, Remy, Shull, J. Michael
We present a survey of NV and OVI (and where available CIV) in the Galactic halo, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST) along 34...
Nucleosynthesis, Reionization, and the Mass Function of the First Stars (2004)
Tumlinson, Jason, Venkatesan, Aparna, Shull, J. Michael
We critique the hypothesis that the first stars were very massive stars (VMS; M > 140 Msun). We review the two major lines of evidence for the existence of VMS: (1) that the relative metal abundances...
Penton, Steven V., Stocke, John T., Shull, J. Michael
We present HST STIS/G140M spectra of 15 extragalactic targets, which we combine with GHRS/G160M data to examine the statistical properties of the low-z Ly-alpha forest. We evaluate the physical...
Shull, J. Michael, Tumlinson, Jason, Giroux, Mark L., Kriss, Gerard A., Reimers, Dieter
We provide an in-depth analysis of the He II and H I absorption in the intergalactic medium (IGM) at redshifts z = 2.3-2.9 toward HE 2347-4342, using spectra from the Far Ultraviolet Spectroscopic...
The Multiphase Intergalactic Medium towards PKS 2155-304 (2003)
Shull, J. Michael, Tumlinson, Jason, Giroux, Mark
We study the cluster of H I and O VI absorption systems and the claimed detection of O VIII absorption from the intergalactic medium at z ~ 0.0567, associated with a group of galaxies toward the BL...
Inferring physical conditions in interstellar clouds of H_2 (2002)
Browning, Matthew K., Tumlinson, Jason, Shull, J. Michael
We have developed a code that models the formation, destruction, radiative transfer, and vibrational/rotational excitation of H_2 in a detailed fashion. We discuss how such codes, together with FUSE...
Cosmological Effects of the First Stars: Evolving Spectra of Population III (2002)
Tumlinson, Jason, Shull, J. Michael, Venkatesan, Aparna
The first stars hold intrinsic interest for their uniqueness and for their potential importance to galaxy formation, chemical enrichment, and feedback on the intergalactic medium (IGM). The...
Evolving Spectra of Pop III Stars: Consequences for Cosmological Reionization (2002)
Venkatesan, Aparna, Tumlinson, Jason, Shull, J. Michael
We examine the significance of the first metal-free stars (Pop III) for the cosmological reionization of HI and HeII. These stars have unusually hard spectra, with the integrated ionizing photon...
A FUSE Survey of Interstellar Molecular Hydrogen in Translucent Clouds (2002)
Rachford, Brian L., Snow, Theodore P., Tumlinson, Jason, Shull, J. Michael, Blair, William P., Ferlet, Roger, ...
We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J...
Ricotti, Massimo, Gnedin, Nickolay Y., Shull, J. Michael
In cold dark matter (CDM) cosmogonies, low-mass objects play an important role in the evolution of the universe. Not only are they the first luminous objects to shed light in a previously dark...
The Fate of the First Galaxies. II. Effects of Radiative Feedback (2001)
Ricotti, Massimo, Gnedin, Nickolay Y., Shull, J. Michael
[abridged]We use 3D cosmological simulations with radiative transfer to study the formation and evolution of the first galaxies in a LCDM cosmology. We find that the first luminous objects...
A FUSE Survey of Interstellar Molecular Hydrogen in the Small and Large Magellanic Clouds (2001)
Tumlinson, Jason, Shull, J. Michael, Rachford, Brian L., Browning, Matthew K., Snow, Theodore P., Fullerton, Alex W., ...
We describe a moderate-resolution FUSE survey of H2 along 70 sight lines to the Small and Large Magellanic Clouds, using hot stars as background sources. FUSE spectra of 67% of observed Magellanic...
Penton, Steven V., Stocke, John T., Shull, J. Michael
In this paper, we use large-angle, nearby galaxy redshift surveys to investigate the relationship between the 81 low-redshift Lya absorbers in our HST/GHRS survey and galaxies, superclusters, and...
High-Velocity Cloud Complex C: Galactic Fuel or galactic Waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven V., Stocke, John T., Shull, J. Michael, Tumlinson, Jason
We present HST GHRS and STIS observations of five QSOs that probe the prominent high-velocity cloud (HVC) Complex C, covering 10% of the northern sky. Based upon a single sightline measurement (Mrk...
Heating and Ionization of the Intergalactic Medium by an Early X-Ray Background (2001)
Venkatesan, Aparna, Giroux, Mark L., Shull, J. Michael
Observational studies indicate that the intergalactic medium (IGM) is highly ionized up to redshifts just over 6. A number of models have been developed to describe the process of reionization and...
Hubble and FUSE studies of Ly-alpha absorbers at low redshift (2001)
Ultraviolet spectrographs aboard the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have proved their value as sensitive probes of the low-density intergalactic...
Rachford, Brian L., Snow, Theodore P., Tumlinson, Jason, Shull, J. Michael, Roueff, E., Andre, M., ...
We report the second study from the FUSE survey of molecular hydrogen in translucent clouds, for the line of sight toward HD 110432. This star lies beyond the Coalsack dark nebula, and with E(B-V) =...
High-velocity cloud complex C: galactic fuel or galactic waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven P., Stocke, John T., Shull, J. Michael, Tumlinson, Jason, ...
Not available.
High-velocity cloud complex C: galactic fuel or galactic waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven P., Stocke, John T., Shull, J. Michael, Tumlinson, Jason
Not available.
High-velocity cloud complex C: galactic fuel or galactic waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven P., Stocke, John T., Shull, J. Michael, Tumlinson, Jason
Not available.
High-velocity cloud complex C: galactic fuel or galactic waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven P., Stocke, John T., Shull, J. Michael, Tumlinson, Jason
Not available.
High-velocity cloud complex C: galactic fuel or galactic waste? (2001)
Gibson, Brad K., Giroux, Mark L., Penton, Steven P., Stocke, John T., Shull, J. Michael, Tumlinson, Jason
Not available.
Ricotti, Massimo, Gnedin, Nickolay Y., Shull, J. Michael
We use one-dimensional radiative transfer simulations to study the evolution of H_2 gas-phase (H^- catalyzed) formation and photo-dissociation regions in the primordial universe. We find a new...
Probing the First Stars with Hydrogen and Helium Recombination Emission (2000)
Tumlinson, Jason, Giroux, Mark L., Shull, J. Michael
Unusual patterns of recombination emission from gas ionized by metal-free stars may distinguish early star-forming galaxies from their present-day counterparts. This pattern arises from the harder...
Sembach, Kenneth. R., Howk, J. Christopher, Savage, Blair. D., Shull, J. Michael
We present Far Ultraviolet Spectroscopic Explorer observations of the atomic and molecular absorption in high velocity cloud HVC 287.5+22.5+240, which lies in front of the ultraviolet-bright nucleus...
The Local Ly-alpha Forest: HI in Nearby Intergalactic Space (2000)
Stocke, John T., Shull, J. Michael, Penton, Steven V., Gibson, Brad K., Giroux, Mark L., McLin, Kevin M.
Detecting HI using redshifted Ly-alpha absorption lines is 1e6 times more sensitive than using the 21cm emission line. We review recent discoveries of HI Ly-alpha absorbers made with the Hubble Space...
Do High-Velocity Clouds Really Fuel Galactic Star Formation? (2000)
Gibson, Brad K., Giroux, Mark L., Stocke, John T., Shull, J. Michael
Tantalizing evidence has been presented supporting the suggestion that a large population of extragalactic gas clouds permeates the Local Group, a population which has been associated with the...
Metal Abundances in the Magellanic Stream (2000)
Gibson, Brad K., Giroux, Mark L., Penton, Steven V., Putman, Mary E., Stocke, John T., Shull, J. Michael
We report on the first metallicity determination for gas in the Magellanic Stream, using archival HST GHRS data for the background targets Fairall 9, III Zw 2, and NGC 7469. For Fairall 9, using two...
Intensive HST, RXTE and ASCA Monitoring of NGC 3516: Evidence Against Thermal Reprocessing (1999)
Edelson, Rick, Koratkar, Anuradha, Nandra, Kirpal, Goad, Michael, Peterson, Bradley M., Collier, Stefan, ...
During 1998 April 13-16, NGC 3516 was monitored almost continuously with HST for 10.3 hr in the UV and 2.8 d in the optical, and simultaneous RXTE and ASCA monitoring covered the same period. The...
Feedback from Galaxy Formation: Escaping Ionizing Radiation from Galaxies at High Redshift (1999)
Ricotti, Massimo, Shull, J. Michael
Several observational and theoretical arguments suggest that starburst galaxies may rival quasars as sources of metagalactic ionizing radiation at redshifts z > 3. Reionization of the intergalactic...
Zero-Metallicity Stars and the Effects of the First Stars on Reionization (1999)
Tumlinson, Jason, Shull, J. Michael
We present stellar structure and atmosphere models of metal-free stars and examine them from a cosmological point of view. Metal-free stars exhibit high effective temperatures and small sizes...
Penton, Steven V., Stocke, John T., Shull, J. Michael
We present the target selection, observations, and data reduction and analysis process for a program aimed at discovering numerous, weak (equivalent width < 100 mA) Lya absorption lines in the local...
Penton, Steven V., Shull, J. Michael, Stocke, John T.
In Paper I of this series (astro-ph/9911117) we described observations of 15 extragalactic targets taken with the Hubble Space Telescope GHRS/G160M grating for studies of the low-z Lya forest. We...
Tumlinson, Jason, Giroux, Mark L., Shull, J. Michael, Stocke, John T.
We present UV spectroscopy from HST/GHRS and reanalyze existing H_alpha images of the quasar/galaxy pair 3C 232/NGC 3067 and of the halo gas associated with NGC 3067. The spectra permit measurement...
The Evolution of the Effective Equation of State of the IGM (1999)
Ricotti, Massimo, Gnedin, Nickolay Y., Shull, J. Michael
We develop a method to extract the "effective equation of state" of the intergalactic medium from the doppler b parameter distribution of the low-density Lyman-alpha forest. We test the method on...
The Emergence of the modern universe: tracing the cosmic web (1999)
Shull, J. Michael, Savage, Blair, Morse, Jon, Neff, Susan, Clarke, John, Heckman, Tim, ...
Also archived in: arXiv: astro-ph/9907101 v1 7 Jul 1999
The emergence of the modern universe: tracing the cosmic web (1999)
Shull, J. Michael, Savage, Blair, Morse, Jon, Neff, Susan, Clarke, John, Heckman, Tim, ...
Also archived in: arXiv: astro-ph/9907101 v1 7 Jul 1999
Dove, James B., Shull, J. Michael, Ferrara, Andrea
By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying HI distribution, we estimate the fraction of ionizing photons...
The Low-Redshift Intergalactic Medium (1999)
Shull, J. Michael, Penton, Steven V., Stocke, John T.
The low-redshift Ly-alpha forest of absorption lines provides a probe of large-scale baryonic structures in the intergalactic medium, some of which may be remnants of physical conditions set up...
The Spectroscopic Detectability of Argon in the Lunar Atmosphere (1998)
Parker, Joel Wm., Stern, S. Alan, Gladstone, G. Randall, Shull, J. Michael
Direct measurements of the abundance of argon in the lunar atmosphere were made in 1973 by instruments placed on the Moon during the Apollo 17 mission, but the total daytime abundance is unknown due...
A Cluster of Low-Redshift Lyman-alpha Clouds toward PKS 2155-304. I. Limits on Metals and D/H (1998)
Shull, J. Michael, Penton, Steven V., Stocke, John T., Giroux, Mark L., Van Gorkom, J. H., Lee, Yong-Han, ...
We report observations from the Hubble Space Telescope (HST) and the VLA on the galactic environment, metallicity, and D/H in strong low-redshift Lya absorption systems toward the bright BL Lac...
The High-Redshift He II Gunn-Peterson Effect: Implications and Future Prospects (1998)
Fardal, Mark A., Giroux, Mark L., Shull, J. Michael
Absorption due to HeII Ly-alpha has been detected at low resolution in the spectra of four quasars between redshifts z = 2.74-3.29. We assess these observations, giving particular attention to the...
The Nature of the Low-redshift Ly-alpha Clouds (1997)
I discuss recent HST observations and interpretation of low-z Ly-alpha clouds toward nearby Seyferts and QSOs, including their frequency, space density, estimated mass, association with galaxies, and...
Structure and Evolution of The Intergalactic Medium: Conference Summary (1997)
Wasn't this a fun meeting? Yes, except for the rain. This summary highlights scientific themes of the 13th IAP conference: (1) The History of Baryons; (2) The History of Metals; (3) Reionization of...
Pian, Elena, Urry, C. Megan, Treves, Aldo, Maraschi, Laura, Penton, Steve, Shull, J. Michael, ...
PKS 2155-304, the brightest BL Lac object in the ultraviolet sky, was monitored with the IUE satellite at ~1 hour time-resolution for ten nearly uninterrupted days in May 1994. The campaign, which...
Giroux, Mark L., Shull, J. Michael
Recent measurements of Si IV/C IV ratios in the high-redshift Ly-alpha forest (Songaila & Cowie, AJ, 112, 335 [1996a]; Savaglio et al., A&A, in press [1997]) have opened a new window on chemical...
The HI Environment of Nearby Lyman-alpha Absorbers (1996)
Van Gorkom, J. H., Carilli, C. L., Stocke, John T., Perlman, Eric S., Shull, J. Michael
We present the results of a VLA and WSRT search for HI emission from the vicinity of seven nearby clouds, which were observed in Lya absorption with HST toward Mrk335, Mrk501 and PKS2155-304. We...
Intergalactic Hydrogen Clouds at Low-Redshift: Connections To Voids And Dwarf Galaxies (1995)
Shull, J. Michael, Stocke, John T., Penton, Steve
We provide new post-COSTAR data on one sightline (Mrk 421) and updated data from another (I Zw 1) from our Hubble Space Telescope (HST) survey of intergalactic Lyman-alpha clouds located along...
Madau, Piero, Shull, J. Michael
The recent discovery by Cowie \etal and Tytler \etal of metals in the \Lya clouds shows that the intergalactic medium (IGM) at high redshift is contaminated by the products of stars, and suggests...
Ultraviolet investigations of the intercloud medium and high velocity intersteller gas. (1976)
Thesis (Ph. D.)--Princeton.