@article{17800, abstract = {Deep mid-infrared (MIR) observations could reveal a population of faint, high-redshift (z > 3), dusty starburst galaxies that are the progenitors of present-day spheroids or bulges and are beyond the reach of current instruments. We utilize a semianalytic galaxy formation scheme to find a range of models for the MIR galaxy counts, down to a flux level of a few nanojanskys. The models incorporate the formation of heavily dust-enshrouded stellar populations at high redshift and are consistent with existing observations, including faint counts at 1.6 μm in the NICMOS Hubble Deep Field, and the upper limit on the extragalactic MIR background from TeV gamma rays. Our models predict ~0.04-0.4 galaxies arcsec-2 at the threshold of 100 nJy at 6 μm, with a comparable or larger surface density at longer MIR wavelengths. We conclude that a significant new population of high-redshift galaxies could be detected by the James Webb Space Telescope. Such a population would constitute background noise for the Terrestrial Planet Finder (TPF) and could necessitate repeat observations: every TPF resolution element would have a chance of up to ~10% of being contaminated by a background galaxy.}, author = {Haiman, Zoltán and Spergel, David N. and Turner, Edwin L.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {630--637}, publisher = {American Astronomical Society}, title = {{Predictions for the counts of faint, high‐redshift galaxies in the mid‐infrared}}, doi = {10.1086/346201}, volume = {585}, year = {2003}, } @article{17723, abstract = {The recent discovery of bright quasars around redshift z=6 suggests that black holes (BHs) with masses in excess of 10^9 Msun have already assembled at a very early stage in the evolution of the universe. An alternative interpretation is that these quasars are powered by less massive BHs, but their fluxes are strongly magnified through gravitational lensing by intervening galaxies. Here we analyze the flux distribution of the Ly alpha emission of the quasar with the highest known redshift, SDSS 1030+0524, at z=6.28. We show that this object could not have been magnified by lensing by more than a factor of five. The constraint arises from the large observed size, 30 (comoving) Mpc, of the ionized region around this quasar, and relies crucially only on the assumption that the quasar is embedded in a largely neutral IGM. Based on the line/continuum ratio of SDSS 1030+0524, we argue further that this quasar also cannot be beamed by a significant factor. We conclude that the minimum mass for its resident BH is 4 x 10^8 Msun (for magnification by a factor of five); if the mass is this low, then the quasars had to switch on prior to redshift z=9. From the size of the ionized region, we are also able to place an absolute lower bound on the age of this quasar at t > 2 x 10^7 years.}, author = {Haiman, Zoltán and Cen, Renyue}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {702--707}, publisher = {American Astronomical Society}, title = {{A constraint on the gravitational lensing magnification and age of the redshift z = 6.28 Quasar SDSS 1030+0524}}, doi = {10.1086/342610}, volume = {578}, year = {2002}, } @article{17739, abstract = {An extensive sample of galaxy clusters will be available in the coming years, detected through their Sunyaev-Zeldovich effect (SZE). We use a semianalytic model to study the scientific yield of combining SZE data with X-ray and optical follow-up observations. If clusters at a given redshift z0 can be identified with virialized, spherical halos, they populate a well-defined "fundamental plane" (FP) in the parameter space of the three observables virial temperature (T), total Sunyaev-Zeldovich flux decrement (ΔSν), and angular size (θ). The location and orientation of the FP, as well as its redshift evolution, are sensitive to both the internal evolution of clusters and to the underlying cosmological parameters. We show that if clusters are not standard candles (e.g., because of feedback or energy injection), then this can be inferred from the FP. Likewise, we study the dependence of the FP on the cosmological parameters h, σ8, and Ω0, and quantify future constraints on these parameters. We also show that in the absence of any nongravitational effects, the scatter in the (ΔSν,T)-plane is significantly smaller than in either the (θ,T) or the (θ,ΔSν) planes. As a result, the ΔSν-T relation can be an exceptionally sensitive probe of both cluster physics and cosmological parameters. A comparison of the amount of scatter in these three scaling relations will test the origin (cosmological vs. stochastic) of the scatter.}, author = {Verde, Licia and Haiman, Zoltán and Spergel, David N.}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {5--19}, publisher = {American Astronomical Society}, title = {{Are clusters standard candles? Galaxy cluster scaling relations with the Sunyaev‐Zeldovich effect}}, doi = {10.1086/344134}, volume = {581}, year = {2002}, } @article{17746, abstract = {For a source of Lyα radiation embedded in a neutral intergalactic medium (IGM) prior to the reionization epoch, the Lyα emission line is strongly suppressed by the intervening IGM. The damping wing of the so-called Gunn-Peterson trough can extend to the red side of the emission line and erase a significant fraction of the total line flux. However, the transmitted fraction increases with the size of the local cosmological H II region surrounding the source, and therefore with the ionizing luminosity and age of the source. Motivated by the recent discovery of a Lyα-emitting galaxy at a redshift z = 6.56 (Hu et al.), possibly prior to the reionization of the IGM, we revisit the effects of a neutral IGM on the Lyα emission line. We show that for faint sources with little or even no ionizing continuum, a sufficiently broad (Δv ≳ 300 km s^-1) emission line can still remain observable. In particular, the line detected by Hu et al. is consistent with a source embedded in a neutral IGM. We provide characterizations of the asymmetry and total transmitted flux of the Lyα line as functions of the ionizing emissivity of its source. We argue that a statistical sample of Lyα emitters extending beyond the reionization redshift can be a useful probe of reionization.}, author = {Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {L1--L4}, publisher = {American Astronomical Society}, title = {{The detectability of high-redshift Lyα emission lines prior to the reionization of the universe}}, doi = {10.1086/343101}, volume = {576}, year = {2002}, } @article{17779, abstract = {The first generation of stars is thought to have formed in low-mass halos with Tvir < 10^4 K where H2 cooling is paramount. However, the efficiency of H2 formation and cooling in these halos may have been severely limited by feedback processes. In this paper we investigate the radiative cooling and collapse of halos with virial temperatures Tvir > 10^4 K, i.e., those that can cool in the absence of H2 via neutral atomic lines. The evolution of these halos differs from their less massive counterparts. Efficient atomic line radiation allows rapid cooling to ~8000 K; subsequently the gas can contract nearly isothermally at this temperature. In the absence of H2 molecules, the gas would likely settle into a locally stable disk, and only disks with unusually low spin would be unstable. However, we find that the initial atomic line cooling leaves a large, out-of-equilibrium residual free electron fraction. This allows the molecular fraction to build up to a universal value of x ≈ 10^-3, almost independently of initial density and temperature. We show that this is a nonequilibrium freeze-out value that can be understood in terms of timescale arguments. Unlike in less massive halos, H2 formation and cooling is largely impervious to feedback from external UV fields, due to the high initial densities achieved by atomic cooling. The newly formed molecules cool the gas further to ~100 K and allow the gas to fragment on scales of a few times 100 M☉. We investigate the importance of various feedback effects such as H2 photodissociation from internal UV fields and radiation pressure due to Lyα photon trapping, which are likely to regulate the efficiency of star formation.}, author = {Oh, S. Peng and Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {558--572}, publisher = {American Astronomical Society}, title = {{Second‐generation objects in the universe: Radiative cooling and collapse of halos with virial temperatures above 10^4 K}}, doi = {10.1086/339393}, volume = {569}, year = {2002}, } @article{17798, abstract = {Recent discoveries by the Sloan Digital Sky Survey (SDSS) of four bright z ~ 6 quasars could constrain the mechanism by which the supermassive black holes powering these sources are assembled. Here we compute the probability that the fluxes of the quasars are strongly amplified by gravitational lensing and therefore the likelihood that the black hole masses are overestimated when they are inferred assuming Eddington luminosities. The poorly constrained shape of the intrinsic quasar luminosity function (LF) at redshift ~6 results in a large range of possible lensing probabilities. If the LF is either steep or extends to faint magnitudes, the probability for amplification by a factor μ ≳ 10 (and with only one image detectable by SDSS) can reach essentially 100%. We show that future observations, in particular, of either the current four quasars at the high angular resolution provided by the Hubble Space Telescope or an increased sample of ~20 z ~ 6 quasars at the current angular resolution, should either discover several gravitational lenses or else provide interesting new constraints on the shape of the z ~ 6 quasar LF.}, author = {Comerford, Julia M. and Haiman, Zoltán and Schaye, Joop}, issn = {1538-4357}, journal = {The Astrophysical Journal}, pages = {63--72}, publisher = {American Astronomical Society}, title = {{Constraining the Redshift z ~ 6 quasar luminosity function using gravitational lensing}}, doi = {10.1086/343116}, volume = {580}, year = {2002}, } @article{17803, abstract = {We reassess constraints on the cosmological baryon density from observations of the mean decrement and power spectrum of the Lyα forest, taking into account uncertainties in all free parameters in the simplest gravitational instability model. The uncertainty is dominated by that of the photoionizing background, but incomplete knowledge of the thermal state of the intergalactic medium also contributes significantly to the error budget. While current estimates of the baryon fraction from the forest do prefer values that are somewhat higher than the big bang nucleosynthesis value of Ωb h2 = 0.02 ± 0.001, the discrepancy is at most about 3 σ. For instance, assuming the highest estimate of the ionizing background, as indicated by recent measurements of a large escape fraction from Lyman break galaxies by Steidel, Pettini, & Adelberger, we find Ωbh2 = 0.045 ± 0.008. A recent measurement of the ionizing background from the proximity effect by Scott et al., on the other hand, implies Ωbh2 = 0.03 ± 0.01. We provide an expression from which future likelihoods for Ωb h2 can be derived as measurements of the ionizing background improve—consistency among constraints from the forest, nucleosynthesis, and the microwave background will provide a powerful test of the gravitational instability model for the forest and for large-scale structure in general. We also develop a formalism that treats lower bounds on the baryon density in a statistical manner, which is appropriate if only a lower bound on the ionizing background is known. Finally, we discuss the implications of the escape fraction measurement for the age, structure, and stellar content of Lyman break galaxies. We show that the observed hard spectrum from Lyman break galaxies requires a very young age (less than about 1 million years) and/or a top-heavy initial mass function. We also build a model in which an extended (non-disk-like) gas distribution allows a large escape fraction.}, author = {Hui, Lam and Haiman, Zoltán and Zaldarriaga, Matias and Alexander, Tal}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {525--533}, publisher = {American Astronomical Society}, title = {{Connections between the cosmic baryon fraction, the extragalactic ionizing background, and Lyman break galaxies}}, doi = {10.1086/324401}, volume = {564}, year = {2002}, } @article{17816, abstract = {The lifetime of the luminous phase of quasars is constrained by current observations to be 10^6 ≲ tQ ≲ 10^8 yr but is otherwise unknown. We model the quasar luminosity function in detail in the optical and X-ray bands using the Press-Schechter formalism and show that the expected clustering of quasars depends strongly on their assumed lifetime tQ. We quantify this dependence and find that existing measurements of the correlation length of quasars are consistent with the range 10^6 ≲ tQ ≲ 10^8 yr. We then show that future measurements of the power spectrum of quasars out to z ~ 3, from the Anglo-Australian Telescope Two-Degree Field or Sloan Digital Sky Survey, can significantly improve this constraint and in principle allow a precise determination of tQ. We estimate the systematic errors introduced by uncertainties in the modeling of the quasar-halo relationship, as well as by the possible existence of obscured quasars.}, author = {Haiman, Zoltán and Hui, Lam}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {27--38}, publisher = {American Astronomical Society}, title = {{Constraining the lifetime of quasars from their spatial clustering}}, doi = {10.1086/318330}, volume = {547}, year = {2001}, } @article{17824, abstract = {The ubiquity of supermassive black holes (SMBHs) at the centers of nearby luminous galaxies can arise from the multiple mergers experienced by dark matter halos in hierarchical structure formation models, even if only a small fraction of these galaxies harbor SMBHs at high redshifts. We illustrate this possibility using cosmological Monte Carlo simulations of the merger history of dark matter halos and their associated SMBHs. In our most extreme models, in order to populate nearly every bright galaxy with an SMBH at z = 0, only a few percent of the halos with virial temperatures above 104 K are required to harbor an SMBH at high redshift. This possibility must be included in studies of the luminosity function and the clustering properties of quasars. We predict the number of SMBH merger events that are detectable by the gravitational wave experiment Laser Interferometer Space Antenna (LISA), as a function of redshift, out to z = 5. Although the event rates can be significantly reduced in scenarios with rare SMBHs, a minimum of ~10 detectable merger events per year is predicted if SMBH binaries coalesce efficiently. The observed distribution of events with redshift could yield valuable information on the SMBH formation process. If SMBH binaries do not coalesce, we find that at least several SMBH slingshot ejections probably occurred from z = 5 to the present in each galaxy more massive than ~1011 M☉ at z = 0. Although our results are sensitive to the minimum cooling mass assumed for the formation of SMBHs, we expect the qualitative predictions of our models to be robust.}, author = {Menou, Kristen and Haiman, Zoltán and Narayanan, Vijay K.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {535--542}, publisher = {American Astronomical Society}, title = {{The merger history of supermassive black holes in galaxies}}, doi = {10.1086/322310}, volume = {558}, year = {2001}, } @article{17826, abstract = {The hardness of the ionizing continuum from the first sources of UV radiation plays a crucial role in the reionization of the intergalactic medium (IGM). While usual stellar populations have soft spectra, miniquasars or metal-free stars with high effective temperatures may emit hard photons, capable of doubly ionizing helium and increasing the IGM temperature. Absorption within the source and in the intervening IGM will render the ionizing continuum of high-redshift sources inaccessible to direct observation. Here we show that He recombination lines from the first luminous objects are potentially detectable by the Next Generation Space Telescope. Together with measurements of the Hα emission line, this detection can be used to infer the ratio of He II to H I ionizing photons, [mathematical formula]. A measurement of this ratio would shed light on the nature and emission mechanism of the first luminous sources, with important astrophysical consequences for the reheating and reionization of the IGM.}, author = {Oh, S. Peng and Haiman, Zoltán and Rees, Martin J.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {73--77}, publisher = {American Astronomical Society}, title = {{He II recombination lines from the first luminous objects}}, doi = {10.1086/320650}, volume = {553}, year = {2001}, } @article{17829, abstract = {The early stage in the formation of a galaxy inevitably involves a spatially extended distribution of infalling, cold gas. If a central luminous quasar turned on during this phase, it would result in significant extended Lyα emission, possibly accompanied by other lines. For halos condensing at redshifts 3 ≲ z ≲ 8 and having virial temperatures 2 × 105 K ≲ Tvir ≲ 2 × 106 K, this emission results in a "fuzz" of characteristic angular diameter of a few arcseconds and surface brightness ~10-18 to 10-16 ergs s-1 cm-2 arcsec-2. The fuzz around bright, high-redshift quasars could be detected in deep narrowband imaging with current telescopes, providing a direct constraint on galaxy formation models. The absence of detectable fuzz might suggest that most of the protogalaxy's gas settles to a self-gravitating disk before a quasar turns on. However, continued gas infall from large radii, or an on-going merger spreading cold gas over a large solid angle, during the luminous quasar phase could also result in extended Lyα emission, and can be constrained by deep narrowband imaging.}, author = {Haiman, Zoltán and Rees, Martin J.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {87--92}, publisher = {American Astronomical Society}, title = {{Extended Lyα emission around young quasars: A constraint on galaxy formation}}, doi = {10.1086/321567}, volume = {556}, year = {2001}, } @article{17831, abstract = {The recent discoveries of luminous quasars at high redshifts imply that black holes more massive than a few billion solar masses were already assembled when the universe was less than a billion years old. We show that the existence of these black holes is not surprising in popular hierarchical models of structure formation. For example, the black hole needed to power the quasar SDSS 1044-0125 at z = 5.8 could arise naturally from the growth of stellar-mass seeds forming at z > 10, when typical values are assumed for the radiative accretion efficiency (~0.1) and the bolometric accretion luminosity in Eddington units (~1). Nevertheless, SDSS 1044-0125 yields a nontrivial constraint on a combination of these parameters. Extrapolating our model to future surveys, we derive the highest plausible redshift for quasars that are not lensed or beamed, as a function of their apparent magnitude. We find that at a limiting magnitude of K ~ 20, quasar surveys can yield strong constraints on the growth of supermassive black holes out to z ~ 10.}, author = {Haiman, Zoltán and Loeb, Abraham}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {459--463}, publisher = {American Astronomical Society}, title = {{What is the highest plausible redshift of luminous quasars?}}, doi = {10.1086/320586}, volume = {552}, year = {2001}, } @article{17832, abstract = {We study the constraints that high-redshift structure formation in the universe places on warm dark matter (WDM) dominated cosmological models. We modify the extended Press-Schechter formalism to derive the halo mass function in WDM models. We show that our predictions agree with recent numerical simulations at low redshift over the halo masses of interest. Applying our model to galaxy formation at high redshift, we find that the loss of power on small scales, together with the delayed collapse of low-mass objects, results in strong limits on the root-mean-square velocity dispersion vrms,0 of the WDM particles at redshift zero. For fermions decoupling while relativistic, these limits are equivalent to constraints on the mass mX of the particles. The presence of a ≈4 × 109 M☉ supermassive black hole at redshift 5.8, believed to power the quasar SDSS 1044-1215, implies mX ≳ 0.5 keV (or vrms,0 ≲ 0.10 km s-1), assuming that the quasar is unlensed and radiating at or below the Eddington limit. Reionization by redshift 5.8 also implies a limit on mX. If high-redshift galaxies produce ionizing photons with an efficiency similar to their redshift-three counterparts, we find mX ≳ 1.2 keV (or vrms,0 ≲ 0.03 s-1). However, given the uncertainties in current measurements from the proximity effect of the ionizing background at redshift three, values of mX as low as 0.75 keV (or vrms,0 = 0.06 s-1) are not ruled out. The limit weakens further to mX ≳ 0.4 keV (or vrms,0 ≲ 0.14 s-1), if, instead, the ionizing-photon production efficiency is 10 times greater at high redshift, but this limit will tighten considerably if reionization is shown in the future to have occurred at higher redshifts. WDM models with mX ≲ 1 keV (or vrms,0 ≳ 0.04 s-1) produce a low-luminosity cutoff in the high-redshift galaxy luminosity function that is directly detectable with the Next Generation Space Telescope, and which serves as a direct constraint on mX.}, author = {Barkana, Rennan and Haiman, Zoltán and Ostriker, Jeremiah P.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {482--496}, publisher = {American Astronomical Society}, title = {{Constraints on warm dark matter from cosmological reionization}}, doi = {10.1086/322393}, volume = {558}, year = {2001}, } @article{17840, abstract = {The large-scale structure of high-redshift galaxies produces correlated anisotropy in the far-infrared background (FIRB). In regions of the sky where the thermal emission from Galactic dust is well below average, these high-redshift correlations may be the most significant source of angular fluctuation power over a wide range of angular scales, from ~7' to ~3°, and frequencies, from ~400 to ~1000 GHz. The strength of this signal should allow detailed studies of the statistics of the FIRB fluctuations, including the shape of the angular power spectrum at a given frequency and the degree of coherence between FIRB maps at different frequencies. The FIRB correlations depend on and hence constrain the redshift-dependent spectral energy distributions, number counts, and clustering bias of the galaxies and active nuclei that contribute to the background. We quantify the accuracy to which Planck and a newly proposed balloon-borne mission, Explorer of Diffuse Galactic Emissions, could constrain models of the high-redshift universe through the measurement of FIRB fluctuations. We conclude that the average bias of high-redshift galaxies could be measured to an accuracy of ≲1% or, for example, separated into four redshift bins with ~10% accuracy.}, author = {Knox, Lloyd and Cooray, Asantha and Eisenstein, Daniel and Haiman, Zoltán}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {7--20}, publisher = {American Astronomical Society}, title = {{Probing early structure formation with far‐infrared background correlations}}, doi = {10.1086/319732}, volume = {550}, year = {2001}, } @article{17846, abstract = {We show that the number and redshift distribution of galaxy clusters in future deep cluster surveys can place strong constraints on the matter density, Ωm, the vacuum energy density, ΩΛ, and the normalization of the matter power spectrum, σ8. Degeneracies between these parameters are different from those in studies of either high-redshift Type Ia supernovae or cosmic microwave background anisotropies. Using a mass threshold for cluster detection expected to be typical for upcoming Sunyaev-Zeldovich effect surveys, we find that constraints on Ωm and σ8 at the level of roughly 5% or better can be expected, assuming redshift information is known at least to z ~ 0.5 and in the absence of significant systematic errors. Without information past this redshift, ΩΛ is constrained to 25%. With complete redshift information, deep (Mlim ~ 1014 h-1 M☉), relatively small solid angle (~12 deg 2) surveys can further constrain ΩΛ to an accuracy of ~15%, while large solid angle surveys with ground-based, large-format bolometer arrays could measure ΩΛ to a precision of ~4% or better.}, author = {Holder, Gilbert and Haiman, Zoltán and Mohr, Joseph J.}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {L111--L114}, publisher = {American Astronomical Society}, title = {{Constraints on Ωm, ΩΛ, and σ8 from galaxy cluster redshift distributions}}, doi = {10.1086/324309}, volume = {560}, year = {2001}, } @article{17847, abstract = {At the earliest epochs of structure formation in cold dark matter (CDM) cosmologies, the smallest nonlinear objects are the numerous small halos that condense with virial temperatures below ~104 K. Such "minihalos" are not yet resolved in large-scale three-dimensional cosmological simulations. Here we employ a semianalytic method, combined with three-dimensional simulations of individual minihalos, to examine their importance during cosmological reionization. We show that, depending on when reionization takes place, they potentially play an important role as sinks of ionizing radiation. If reionization occurs at sufficiently high redshifts (zr ≳ 20), the intergalactic medium is heated to ~104 K and most minihalos never form. On the other hand, if zr ≲ 20, a significant fraction (≳10%) of all baryons have already collapsed into minihalos, and are subsequently removed from the halos by photoevaporation as the ionizing background flux builds up. We show that this process can require a significant budget of ionizing photons, exceeding the production by straightforward extrapolations back in time of known quasar and galaxy populations by a factor of up to ~10 and ~3, respectively.}, author = {Haiman, Zoltán and Abel, Tom and Madau, Piero}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {599--607}, publisher = {American Astronomical Society}, title = {{Photon consumption in minihalos during cosmological reionization}}, doi = {10.1086/320232}, volume = {551}, year = {2001}, } @article{17849, abstract = {We study the expected redshift evolution of galaxy cluster abundance between 0 ≲ z ≲ 3 in different cosmologies, including the effects of the cosmic equation of state parameter w ≡ p/ρ. Using the halo mass function obtained in recent large-scale numerical simulations, we model the expected cluster yields in a 12 deg2 Sunyaev-Zeldovich effect (SZE) survey and a deep 104 deg2 X-ray survey over a wide range of cosmological parameters. We quantify the statistical differences among cosmologies using both the total number and redshift distribution of clusters. Provided that the local cluster abundance is known to a few percent accuracy, we find only mild degeneracies between w and either Ωm or h. As a result, both surveys will provide improved constraints on Ωm and w. The Ωm-w degeneracy from both surveys is complementary to those found either in studies of cosmic microwave background (CMB) anisotropies or of high-redshift supernovae (SNe). As a result, combining these surveys together with either CMB or SNe studies can reduce the statistical uncertainty on both w and Ωm to levels below what could be obtained by combining only the latter two data sets. Our results indicate a formal statistical uncertainty of ≈3% (68% confidence) on both Ωm and w when the SZE survey is combined with either the CMB or SN data; the large number of clusters in the X-ray survey further suppresses the degeneracy between w and both Ωm and h. Systematics and internal evolution of cluster structure at the present pose uncertainties above these levels. We briefly discuss and quantify the relevant systematic errors. By focusing on clusters with measured temperatures in the X-ray survey, we reduce our sensitivity to systematics such as nonstandard evolution of internal cluster structure.}, author = {Haiman, Zoltán and Mohr, Joseph J. and Holder, Gilbert P.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, pages = {545--561}, publisher = {American Astronomical Society}, title = {{Constraints on cosmological parameters from future galaxy cluster surveys}}, doi = {10.1086/320939}, volume = {553}, year = {2001}, } @article{17813, abstract = {Ionizing sources embedded in the neutral intergalactic medium (IGM) before cosmological reionization generate discrete H II regions. We show that a sufficiently bright quasar (for example, 1/10 as luminous as that recently discovered by Fan et al.) can ionize a large volume, allowing the transmission of a substantial fraction of the flux of its intrinsic Lyα emission line on both sides of the Lyα wavelength. The observed line profile is richly informative. We show that a sufficiently accurate, high spectral resolution (R ≈ 104) measurement of the line profile of a bright quasar is feasible using the Next Generation Space Telescope as well as large ground-based telescopes. Such a measurement has two potentially important applications. First, the red side of the Lyα emission line provides a way to measure the quasar lifetime. Second, the blue side provides a direct measure of the density fluctuations of the IGM at the quasar redshift. The estimate of the absorption of the red side is limited by the accuracy to which the intrinsic profile of the Lyα emission line is known. The blue side, however, does not sensitively depend on the intrinsic profile because the former is much narrower than the latter.}, author = {Cen, Renyue and Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {L75--L78}, publisher = {American Astronomical Society}, title = {{Quasar Strömgren spheres before cosmological reionization}}, doi = {10.1086/312937}, volume = {542}, year = {2000}, } @article{17814, abstract = {In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (Tvir ≲ 10^4 K) halos that collapse before reionization. The UVB at energies below 13.6 eV suppresses the formation of stars or black holes inside small halos by photodissociating their only cooling agent, molecular H2. We self-consistently compute the buildup of the early UVB in Press-Schechter models, coupled with H2 photodissociation both in the intergalactic medium (IGM) and inside virialized halos. We find that the intergalactic H2 has a negligible effect on the UVB, both because its initial optical depth is small (≲0.1) and because it is photodissociated at an early stage. If the UV sources in the first collapsed halos are stars, then their UV flux suppresses further star formation inside small halos. This results in a pause in the buildup of the UVB, and reionization is delayed until larger halos (Tvir ≳ 10^4 K) collapse. If the small halos host miniquasars with hard spectra extending to ~1 keV, then their X-rays balance the effects of the UVB, the negative feedback does not occur, and reionization could be caused by the small halos.}, author = {Haiman, Zoltán and Abel, Tom and Rees, Martin J.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {11--24}, publisher = {American Astronomical Society}, title = {{The radiative feedback of the first cosmological objects}}, doi = {10.1086/308723}, volume = {534}, year = {2000}, } @article{17817, abstract = {Recent observations of Type Ia supernovae (SNe) at redshifts 0 < z < 1 reveal a progressive dimming that has been interpreted as evidence for a cosmological constant of ΩΛ ~ 0.7. An alternative explanation of the SN results is an open universe with ΩΛ = 0 and the presence of ≳0.1 μm dust grains with a mass density of Ωdust ~ a few × 10-5 in the intergalactic (IG) medium. The same dust that dims the SNe absorbs the cosmic UV/optical background radiation around ~1 μm, and reemits it at far-infrared (FIR) wavelengths. Here we compare the FIR emission from IG dust with observations of the cosmic microwave (CMB) and cosmic far-infrared backgrounds (FIRB) by the DIRBE/FIRAS instruments. We find that the emission would not lead to measurable distortion of the CMB, but would represent a substantial fraction (≳75%) of the measured value of the FIRB in the 300-1000 μm range. This contribution would be marginally consistent with the present unresolved fraction of the observed FIRB in an open universe. However, we find that IG dust probably could not reconcile the standard Ω = 1 CDM model with the SN observations, even if the necessary quantity of dust existed. Future observations, capable of reliably resolving the FIRB to a flux limit of ~0.5 mJy, along with a more precise measure of the coarse-grained FIRB, will provide a definitive test of the IG dust hypothesis in all cosmologies.}, author = {Aguirre, Anthony and Haiman, Zoltán}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {28--36}, publisher = {American Astronomical Society}, title = {{Cosmological constant or intergalactic dust? Constraints from the cosmic far‐infrared background}}, doi = {10.1086/308557}, volume = {532}, year = {2000}, }