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We measure the evolution of the correlation between black hole mass and host spheroid velocity dispersion (MBH-σ*) over the last 6 billion years, by studying three carefully selected samples of active galaxies at z = 0.57, z = 0.36 and z < 0.1. For all three samples, virial black hole masses are consistently estimated using the line dispersion of Hβ and the continuum luminosity at 5100 Å or Hα line luminosity, based on our cross calibration of the broad-line region size-luminosity relation. For the z = 0.57 sample, new stellar velocity dispersions are measured from high signal-to-noise ratio spectra obtained at the Keck Telescope, while for the two lower redshift samples they are compiled from previous works. Extending our previous result at z = 0.36, we find an offset from the local relation, suggesting that for fixed MBH, distant spheroids have on average smaller velocity dispersions than local ones. The measured offset at z = 0.57 is Δ log σ* = 0.12 ± 0.05 ± 0.06 (or Δ log MBH = 0.50 ± 0.22 ± 0.25), i.e., Δ log M BH = (3.1 ± 1.5) log (1 + z) + 0.05 ± 0.21. This is inconsistent with a tight and nonevolving universal M BH-σ* relation at the 95% CL. © 2008. The American Astronomical Society. All rights reserved.

We measure the evolution of the correlation between black hole mass and host spheroid velocity dispersion (MBH-σ*) over the last 6 billion years, by studying three carefully selected samples of active galaxies at z = 0.57, z = 0.36 and z < 0.1. For all three samples, virial black hole masses are consistently estimated using the line dispersion of Hβ and the continuum luminosity at 5100 Å or Hα line luminosity, based on our cross calibration of the broad-line region size-luminosity relation. For the z = 0.57 sample, new stellar velocity dispersions are measured from high signal-to-noise ratio spectra obtained at the Keck Telescope, while for the two lower redshift samples they are compiled from previous works. Extending our previous result at z = 0.36, we find an offset from the local relation, suggesting that for fixed MBH, distant spheroids have on average smaller velocity dispersions than local ones. The measured offset at z = 0.57 is Δ log σ* = 0.12 ± 0.05 ± 0.06 (or Δ log MBH = 0.50 ± 0.22 ± 0.25), i.e., Δ log M BH = (3.1 ± 1.5) log (1 + z) + 0.05 ± 0.21. This is inconsistent with a tight and nonevolving universal M BH-σ* relation at the 95% CL. © 2008. The American Astronomical Society. All rights reserved.

Black hole mass (MBH) is a fundamental property of active galactic nuclei (AGNs). In the distant universe, MBHis commonly estimated using the Mg II, Hβ, or Hα emission line widths and the optical/UV continuum or line luminosities as proxies for the characteristic velocity and size of the broad-line region. Although they all have a common calibration in the local universe, a number of different recipes are currently used in the literature. It is important to verify the relative accuracy and consistency of the recipes, as systematic changes could mimic evolutionary trends when comparing various samples. At z = 0.36, all three lines can be observed at optical wavelengths, providing a unique opportunity to compare different empirical recipes. We use spectra from the Keck Telescope and the Sloan Digital Sky Survey to compare MBHestimators for a sample of 19 AGNs at this redshift. We compare popular recipes available from the literature, finding that MBHestimates can differ up to 0.38 ± 0.05 dex in the mean (or 0.13 ± 0.05 dex, if the same virial coefficient is adopted). Finally, we provide a set of 30 internally self-consistent recipes for determining MBHfrom a variety of observables. The intrinsic scatter between cross-calibrated recipes is in the range 0.1-0.3 dex. This should be considered as a lower limit to the uncertainty of the MBHestimators. © 2008. The American Astronomical Society. All rights reserved.

We report the discovery of a z ∼ 9 Lyman break galaxy candidate, selected from the NICMOS Parallel Imaging Survey as a J-dropout with J 110 - H160 = 1.7. Spitzer/IRAC photometry reveals that the galaxy has a blue H160 - 3.6 μm color and a spectral break between 3.6 and 4.5 μm. We interpret this break as the Balmer break and derive a best-fit photometric redshift of z ∼ 9. We use Monte Carlo simulations to test the significance of this photometric redshift, and we show that there is a 96% probability of z ≥ 7. We estimate that the lower limit to the comoving number density of such galaxies at z ∼ 9 is ø > 3.8 × 10-6 Mpc-3. If the high redshift of this galaxy is confirmed, this will indicate that the luminous end of the rest-frame UV luminosity function has not evolved substantially from z ∼ 9 to z ∼ 3. Still, some small degeneracy remains between this z ∼ 9 model and models at z ∼ 2-3; deep optical imaging (reaching IAB ∼ 29) can rule out the lower z models. © 2008. The American Astronomical Society. All rights reserved.

We use high-resolution images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope to determine morphology, nuclear luminosity, and structural parameters of the spheroidal component for a sample of 20 Seyfert galaxies atz = 0.36. We combine these measurements with spectroscopic information from the Keck Telescope to determine the black hole mass-spheroid luminosity relation (MBH-LB), the fundamental plane (FP) of the host galaxies, and the black hole mass-spheroid velocity dispersion relation (MBH-σ). The FP is consistent with that of inactive spheroids at comparable redshifts. Assuming pure luminosity evolution, we find that the host spheroids had smaller luminosity and stellar velocity dispersion than today for a fixed MBH. The offsets correspond to Δ log LB,0 = 0.40 ± 0.11 ± 0.15 (Δlog MBH= 0.51 ± 0.14 ± 0.19) and Δloge σ = 0.13 ± 0.03 ± 0.05 (Δlog MBH = 0.54 ± 0.12 ± 0.21), respectively, for the MBH-L and M BH-σ relations (the double error bars indicate random and ystematic uncertainties, respectively). A detailed analysis of known systematic errors and selection effects shows that they cannot account for the observed offset. We conclude that the data are inconsistent with pure luminosity evolution and the existence of universal and tight scaling relations. In order to obey the three local scaling relations by z = 0, assuming no significant black hole growth, the distant spheroids have to grow their stellar mass by approximately 60% (Δ log Msph = 0.20 ± 0.14) in the next 4 billion years, while preserving their size and holding their stellar mass-to-light ratio approximately constant. The measured evolution can be expressed as MBH/Msph ∝ (1 + z) 1.5±1.0, consistent with black holes of a few × 10 8 M⊙ completing their growth before their host galaxies. Based on the disturbed morphologies of a fraction of the sample (6/20), we suggest collisional mergers with disk-dominated systems as the physical mechanism driving the evolution. © 2007. The American Astronomical Society. All rights reserved.

We report new follow-up spectroscopy of i′-dropout galaxies with an NB921-band depression found in the Subaru Deep Field. The NB921-depressed 1′-dropout selection method is expected to select galaxies with large equivalent-width Lyα emission over a wide redshift range, 6.0 ≲ z ≲ 6.5. Two of four observed targets show a strong emission line with a clear asymmetric profile, identified as Lyα emitters at z = 6.11 and 6.00. Their rest-frame equivalent widths are 153 Å and 114 Å, which are lower limits on the intrinsic equivalent widths. Through our spectroscopic observations (including previous ones) of NB921 -depressed i′-dropout galaxies, we identified 5 galaxies in total with a rest-frame equivalent width larger than 100 Å at 6.0 ≲ z ≲ 6.5 out of 8 photometric candidates, which suggests that the NB921 -depressed i′-dropout selection method is possibly an efficient way to search for Lyα emitters with a large Lyα equivalent width, in a wider redshift range than with usual narrow-band excess techniques. By combining these findings with our previous observational results, we infer that the fraction of broad-band selected galaxies having a rest-frame equivalent width larger than 100 Å is significantly higher at z ∼ 6 (the cosmic age of ∼1 Gyr) than that at z ∼ 3 (∼2 Gyr), being consistent with the idea that the typical stellar population of galaxies is significantly younger at z ∼ 6 than that at z ∼ 3. The NB921-depressed i′-dropout galaxies may be interesting candidates for hosts of massive, zero-metallicity Population III stars. © ESO 2007.

SDF line-emitting galaxies in four narrowband filters at low and intermediate redshifts are presented. Broadband colors, follow-up optical spectroscopy, and multiple NB filters are used to distinguish Hα, [O II], and [O III] emitters at z = 0.07-1.47 to construct their LFs. These LFs are derived down to faint magnitudes, allowing for an accurate determination of the faint-end slope. With a large (N ∼ 200-900) sample for each redshift interval, a Schechter profile is fitted to each LF. Prior to dust extinction corrections, the [O III] and [O II] LFs agree reasonably well with those of Hippelein et al. The z = 0.08 Ha LF, which reaches 2 orders of magnitude fainter than Gallego et al., is steeper by 25%. This indicates that there are more low-luminosity star-forming galaxies for z < 0.1. The faint-end slope α and Φ*, show a strong redshift evolution, while L * shows little evolution. The evolution in α indicates that low-luminosity galaxies have a stronger evolution compared to brighter ones. Integrated SFR densities are derived via Hα, [O III], and [O III] for 0.07 < z < 1.47. A steep increase in the SFR density, as a function of redshift, is seen for 0.4 < z < 0.9. For z > 1, the SFR densities are similar. The latter is consistent with previous UVand [O II] measurements. Below z < 0.4, the SFR densities are consistent with several Ha, [O II], and UV measurements, but others are a factor of 2 higher. For example, the z = 0.066-0.092 LF agrees with Jones & Bland-Hawthorn, but at z = 0.24 and 0.40, their number densities are twice as high. This discrepancy can be explained by cosmic variance. © 2007. The American Astronomical Society. All rights reserved.

We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110 - H160 ≥ 2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 σ sensitivities of J 110 = 25.8 and H160 = 25.6 (AB). Distinguishing these candidates from dust-reddened star-forming galaxies at z ∼ 2-3 is difficult and will require longer wavelength observations. We consider the likelihood that any J-dropout LBGs exist in this survey and find that if L*z= 9.5 is significantly brighter than L*z=6 (a factor of 4), then a few J-dropout LBGs are likely. A similar increase in luminosity has been suggested by Eyles et al. and Yan et al., but the magnitude of this increase is uncertain. © 2007. The American Astronomical Society. All rights reserved.

We show that Type Ia supernovae (SNe Ia) are formed within both very young and old stellar populations, with observed rates that depend on the stellar mass and mean star formation rates (SFRs) of their host galaxies. Models in which the SN Ia rate depends solely on host galaxy stellar mass are ruled out with >99% confidence. Our analysis is based on 100 spectroscopically confirmed SNe Ia, plus 24 photometrically classified events, all from the Supernova Legacy Survey (SNLS) and distributed over 0.2 < z < 0.75. We estimate stellar masses and SFRs for the SN Ia host galaxies by fitting their broadband spectral energy distributions with the galaxy spectral synthesis code PÉGASE.2. We show that the SN Ia rate per unit mass is proportional to the specific SFR of the parent galaxies - more vigorously star-forming galaxies host more SNe Ia per unit stellar mass, broadly equivalent to the trend of increasing SN Ia rate in later type galaxies seen in the local universe. Following earlier suggestions for a simple "two-component" model approximating the SN Ia rate, we find bivariate linear dependencies of the SN Ia rate on both the stellar masses and the mean SFRs of the host systems. We find that the SN Ia rate can be well represented as the sum of 5.3 ± 1.1 × 10-14 SNe yr -1M⊙-1 and 3.9 ± 0.7 × 10-4 SNe yr-1 (M⊙ yr-1) -1 of star formation. We also demonstrate a dependence of distant SN Ia light-curve shapes on star formation in the host galaxy, similar to trends observed locally. Passive galaxies, with no star formation, preferentially host faster declining/dimmer SNe Ia, while brighter events are found in systems with ongoing star formation. © 2006. The American Astronomical Society. All rights reserved.

We present a measurement of the distant Type la supernova (SN Ia) rate derived from the first 2 yr of the Canada-France-Hawaii Telescope Supernova Legacy Survey. We observed four 1° × 1° fields with a typical temporal frequency of (Δt) ∼ 4 observer-frame days over time spans of 158-211 days per season for each field, with breaks during the full Moon. We used 8-10 m class telescopes for spectroscopic follow-up to confirm our candidates and determine their redshifts. Our starting sample consists of 73 spectroscopically verified SNe la in the redshift range 0.2 < z < 0.6. We derive a volumetric SN Ia rate of r V(〈z〉 = 0.47) = [0.42 0.090.13(syst.) ± 0.06(stat.)] × 10 -4 yr -1 Mpc 3, assuming h = 0.7, Ω m -0.3, and a flat cosmology. Using recently published galaxy luminosity functions derived in our redshift range, we derive a SN Ia rate per unit luminosity of r L(〈z〉 = 0.47) = 0.154 -0.0330.048(syst.) 0.0310.039(stat.) SN units. Using our rate alone, we place an upper limit on the component of SN la production that tracks the cosmic star formation history of 1 SN la per 10 3 M ⊙ of stars formed. Our rate and other rates from surveys using spectroscopic sample confirmation display only a modest evolution out to z = 0.55. © 2006. The American Astronomical Society. All rights reserved.

We present a measurement of the distant Type la supernova (SN Ia) rate derived from the first 2 yr of the Canada-France-Hawaii Telescope Supernova Legacy Survey. We observed four 1° × 1° fields with a typical temporal frequency of (Δt) ∼ 4 observer-frame days over time spans of 158-211 days per season for each field, with breaks during the full Moon. We used 8-10 m class telescopes for spectroscopic follow-up to confirm our candidates and determine their redshifts. Our starting sample consists of 73 spectroscopically verified SNe la in the redshift range 0.2 < z < 0.6. We derive a volumetric SN Ia rate of r V(〈z〉 = 0.47) = [0.42 0.090.13(syst.) ± 0.06(stat.)] × 10 -4 yr -1 Mpc 3, assuming h = 0.7, Ω m -0.3, and a flat cosmology. Using recently published galaxy luminosity functions derived in our redshift range, we derive a SN Ia rate per unit luminosity of r L(〈z〉 = 0.47) = 0.154 -0.0330.048(syst.) 0.0310.039(stat.) SN units. Using our rate alone, we place an upper limit on the component of SN la production that tracks the cosmic star formation history of 1 SN la per 10 3 M ⊙ of stars formed. Our rate and other rates from surveys using spectroscopic sample confirmation display only a modest evolution out to z = 0.55. © 2006. The American Astronomical Society. All rights reserved.

We test the evolution of the correlation between black hole mass and bulge velocity dispersion (MBH-σ), using a carefully selected sample of 14 Seyfert 1 galaxies at z = 0.36±0.01. We measure velocity dispersion from stellar absorption lines around Mg b (5175 Å) and Fe (5270 Å) using high-S/N Keck spectra and estimate black hole mass from the Hβ line width and the optical luminosity at 5100 Å, based on the empirically calibrated photoionization method. We find a significant offset from the local relation, in the sense that velocity dispersions were smaller for given black hole masses at z = 0.36 than locally. We investigate various sources of systematic uncertainties and find that those cannot account for the observed offset. The measured offset is Δlog MBH = 0.62 ±0.10±0.25; i.e., Δlog σ = 0.15±0.03±0. 06, where the error bars include a random component and an upper limit to the systematics. At face value, this result implies a substantial growth of bulges in the last 4 Gyr, assuming that the local MBH-σ relation is the universal evolutionary endpoint. Along with two samples of active galaxies with consistently determined black hole mass and stellar velocity dispersion taken from the literature, we quantify the observed evolution with the best-fit linear relation: Δlog MBH = (1-66±0.43)z + (0.04±0.09) with respect to the local relationship of Tremaine and coworkers, and Δlog MBH = (1-55 ±0.46)z + (0.01 ±0.12) with respect to that of Ferrarese. This result is consistent with the growth of black holes predating the final growth of bulges at these mass scales (〈σ〉 = 170 km s-1). © 2006. The American Astronomical Society. All rights reserved.

We test the evolution of the correlation between black hole mass and bulge velocity dispersion (MBH-σ), using a carefully selected sample of 14 Seyfert 1 galaxies at z = 0.36±0.01. We measure velocity dispersion from stellar absorption lines around Mg b (5175 Å) and Fe (5270 Å) using high-S/N Keck spectra and estimate black hole mass from the Hβ line width and the optical luminosity at 5100 Å, based on the empirically calibrated photoionization method. We find a significant offset from the local relation, in the sense that velocity dispersions were smaller for given black hole masses at z = 0.36 than locally. We investigate various sources of systematic uncertainties and find that those cannot account for the observed offset. The measured offset is Δlog MBH = 0.62 ±0.10±0.25; i.e., Δlog σ = 0.15±0.03±0. 06, where the error bars include a random component and an upper limit to the systematics. At face value, this result implies a substantial growth of bulges in the last 4 Gyr, assuming that the local MBH-σ relation is the universal evolutionary endpoint. Along with two samples of active galaxies with consistently determined black hole mass and stellar velocity dispersion taken from the literature, we quantify the observed evolution with the best-fit linear relation: Δlog MBH = (1-66±0.43)z + (0.04±0.09) with respect to the local relationship of Tremaine and coworkers, and Δlog MBH = (1-55 ±0.46)z + (0.01 ±0.12) with respect to that of Ferrarese. This result is consistent with the growth of black holes predating the final growth of bulges at these mass scales (〈σ〉 = 170 km s-1). © 2006. The American Astronomical Society. All rights reserved.

We present the properties of Ly Alpha emitters (LAEs) at z = 5.7 in theSubaru Deep Field. A photometric sample of 89 LAE candidates is constructedfrom narrow-band (NB816) data down to NB816 = 26.0 (AB) in a continuous 725arcmin^2 area. Spectra of 39 objects satisfying the photometric selectioncriteria for LAEs were obtained with Subaru and Keck II Telescopes, among which28 were confirmed LAEs, one was a nearby galaxy, and eight were unclassified.We also obtained spectra of another 24 NB816-excess objects in the field,identifying six additional LAEs. We find that the Ly Alpha luminosity functionderived from the photometric sample is reproduced well by a Schechter functionwith L* = (7.9+3.0-2.2) x 10^42 erg/s and phi* = (6.3+3.0-2.0) x 10^-4 Mpc^-3for alpha = -1.5 (fixed) over the whole luminosity range of L ~= 3x10^42 -3x10^43 erg/s. We then measure rest-frame Ly Alpha equivalent widths (EWs) forthe confirmed LAEs, to find that the median among the 28 objects satisfying thephotometric selection criteria is W_0^i = 233 A. We infer that 30% - 40% ofLAEs at z=5.7 exceed W_0^i = 240 A. These large-EW objects probably cannot beaccounted for by ordinary star-forming populations with a Salpeter IMF. We alsofind that LAEs with fainter far-UV luminosities have larger EWs. Finally, wederive the far-UV luminosity function of LAEs down to M_UV ~= -19.6 using thephotometric sample, and compare it with that of Lyman-break galaxies (LBGs). Wefind that as high as about 80% of LBGs at z ~ 6 have W_0^i >= 100 A, in sharpcontrast to lower-z counterparts.

We present the properties of Ly Alpha emitters (LAEs) at z = 5.7 in theSubaru Deep Field. A photometric sample of 89 LAE candidates is constructedfrom narrow-band (NB816) data down to NB816 = 26.0 (AB) in a continuous 725arcmin^2 area. Spectra of 39 objects satisfying the photometric selectioncriteria for LAEs were obtained with Subaru and Keck II Telescopes, among which28 were confirmed LAEs, one was a nearby galaxy, and eight were unclassified.We also obtained spectra of another 24 NB816-excess objects in the field,identifying six additional LAEs. We find that the Ly Alpha luminosity functionderived from the photometric sample is reproduced well by a Schechter functionwith L* = (7.9+3.0-2.2) x 10^42 erg/s and phi* = (6.3+3.0-2.0) x 10^-4 Mpc^-3for alpha = -1.5 (fixed) over the whole luminosity range of L ~= 3x10^42 -3x10^43 erg/s. We then measure rest-frame Ly Alpha equivalent widths (EWs) forthe confirmed LAEs, to find that the median among the 28 objects satisfying thephotometric selection criteria is W_0^i = 233 A. We infer that 30% - 40% ofLAEs at z=5.7 exceed W_0^i = 240 A. These large-EW objects probably cannot beaccounted for by ordinary star-forming populations with a Salpeter IMF. We alsofind that LAEs with fainter far-UV luminosities have larger EWs. Finally, wederive the far-UV luminosity function of LAEs down to M_UV ~= -19.6 using thephotometric sample, and compare it with that of Lyman-break galaxies (LBGs). Wefind that as high as about 80% of LBGs at z ~ 6 have W_0^i >= 100 A, in sharpcontrast to lower-z counterparts.

The search for the first illuminated astronomical sources in the universe is at the edge of the cosmic frontier. Promising techniques for discovering the first objects and their effects span the electromagnetic spectrum and include gravitational waves. We summarize a workshop on discovering and understanding these sources which was held in May 2005 through the Center for Cosmology at the University of California, Irvine. © 2005 Elsevier B.V. All rights reserved.

This is the first paper in a series presenting and analyzing data for a k-selected sample of galaxies collected in order to identify and study galaxies at moderate to high redshift in rest-wavelength optical light. The sample contains 84 objects over six separate fields covering 75.6 arcmin2 down to K = 20-20.5. We combine the K band with UBVRIzJH multiband imaging, reaching depths of R ∼ 26. Two of the fields studied also have deep HST WFPC2 imaging, totaling more than 60 hr in the F300W, F450W, F606W, and F814W filters. Using artificial galaxy modeling and extraction, we measure 85% completeness limits down to K = 19.5-20,dependingonthefieldexamined. The derived K-band number counts are in good agreement with previous studies. We find a density for extremely red objects (EROs; R - K > 5) of 1.55 ±0.16 arcmin"2 for A; < 19.7, dominated by the 1714+5015 field (centered on 53w002), with an ERO number density more than 3 times that of the other sample fields. If we exclude the counts for 1714+5015, our density is 0.95 ± 0.14 arcmin"2. Both ERO densities are consistent with previous measurements due to the significant known cosmic variance of these red sources. Keck spectroscopic redshifts were obtained for 18 of the EROs, all but one of which are emission galaxies. None of the EROs in the 1714+5015 field for which we obtained spectroscopic redshifts are associated with the known z = 2.39 overdensity, although there are three different galaxy redshift pairs (z = 0.90,1.03, and 1.22). © 2006. The American Astronomical Society. All rights reserved.

We report new spectroscopy of two star-forming galaxies with strong Lyα emission at z = 6.03 and 6.04 in the Subaru Deep Field. These two objects are originally selected as i′-dropouts (i′ -z′ > 1.5) showing an interesting photometric property, the "NB921 depression." The NB921-band (centered at 9196 Å) magnitude is significantly depressed with respect to the z′-band magnitude. The optical spectra of these two objects exhibit asymmetric emission lines at λobs ∼ 8540 and ∼8560 Å, suggesting that these objects are Lyα emitters at z ∼ 6. The rest-frame equivalent widths of the Lyα emission of the two objects are 94 and 236 Å; the latter is the Lyα emitter with the largest Lyα equivalent width at z ≳ 6 ever spectroscopically confirmed. The spectroscopically measured Lyα fluxes of these two objects are consistent with the interpretation that the NB921 depression is caused by the contribution of the strong Lyα emission to the z′-band flux. Most of the NB921-depressed i′-dropout objects are thought to be strong Lyα emitters at 6.0 ≲ z ≲ 6.5; Galactic L and T dwarfs and NB921-dropout galaxies at z > 6.6 do not dominate the NB921-depressed i′-dropout sample. Thus, the NB921 -depression method is very useful for finding high-z Lyα emitters with a large Lyα equivalent width over a large redshift range, 6.0 ≲ z ≲ 6.5. Although the broadband-selected sample at z ∼ 3 contains only a small fraction of objects with a Lyα equivalent width larger than 100 Å, the i′-dropout sample of the Subaru Deep Field contains a much larger fraction of such strong Lyα emitters. This may imply a strong evolution of the Lyα equivalent width from z ≳ 6 to z ∼ 3. © 2005. The American Astronomical Society. All rights reserved.

The velocity dispersion of seven Seyfert 1 galaxies at z ∼ 0.37 is measured using high signal-to-noise ratio Keck spectra. Black hole (BH) mass estimates are obtained via an empirically calibrated photoionization method. We derive the BH mass velocity dispersion relationship at z ∼ 0.37. We find an offset with respect to the local relationship, in the sense of somewhat lower velocity dispersion at a fixed BH mass at z ∼ 0.37 than today, which is significant at the 97% level. The offset corresponds to Δ log σ = -0.16, with an rms scatter of 0.13 dex. If confirmed by larger samples and independent checks on systematic uncertainties and selection effects, this result would be consistent with spheroids evolving faster than BHs in the past 4 Gyr and inconsistent with pure luminosity evolution.

The velocity dispersion of seven Seyfert 1 galaxies at z ∼ 0.37 is measured using high signal-to-noise ratio Keck spectra. Black hole (BH) mass estimates are obtained via an empirically calibrated photoionization method. We derive the BH mass velocity dispersion relationship at z ∼ 0.37. We find an offset with respect to the local relationship, in the sense of somewhat lower velocity dispersion at a fixed BH mass at z ∼ 0.37 than today, which is significant at the 97% level. The offset corresponds to Δ log σ = -0.16, with an rms scatter of 0.13 dex. If confirmed by larger samples and independent checks on systematic uncertainties and selection effects, this result would be consistent with spheroids evolving faster than BHs in the past 4 Gyr and inconsistent with pure luminosity evolution.

We present near-infrared spectra of "A2," the primary counterarc to the gravitationally lensed galaxy MS 1512-cB58. The spectra show redshifted Hα, [N II], [O III], and Hβ at z = 2.729 ± 0.001. We observe the same Hα/[O III] ratio as cB58, which together with the redshift confirms that A2 is indeed another image of a single background galaxy. Published lensing reconstruction reports that A2 is a magnification of the entire source, while cB58 is an image of only a part. At marginal significance, A2 shows higher line-to-continuum ratios than cB58 (by a factor of ∼2), suggesting a nonuniform ratio of young to old stars across the galaxy. We observe a second emission-line source in the slit. This object, "W5," is predicted to be a lensed image of another galaxy at a redshift similar to cB58. W5 is blueshifted from cB58 by ∼400 km s-1 and has a significantly lower Hα/[0 III] ratio, confirming that it is an image of a different background galaxy in a group with cB58. The Hα emission line in W5 implies a star formation rate of 6 M⊙ yr-1 (H 0 = 70 km s-1 Mpc-1, ΩM = 0.3, ΩΛ = 0.7), after correcting for lensing magnification.

Averaged spectral energy distributions (SEDs) of active and starburst galaxies, from the 12 μm sample in the local universe, and QSOs, from an optically selected sample at a mean redshift (z) = 0.7, are built from optical, near-IR, and far-IR (FIR; IRAS and Infrared Space Observatory) photometric observations. These SEDs are then used to predict at various redshifts the number of Seyfert type 1 and type 2, starburst, and normal galaxies and QSOs that will be detected by future space missions dedicated to FIR and submillimeter astronomy, such as SIRTF and Herschel. These predictions are then compared with the expected capabilities and detection limits of future deep FIR surveys. Possible ways to identify active galactic nucleus candidates on FIR color-color plots for follow-up observations are then explored.

We present a measurement of the rate of distant Type la supernovae derived using four large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 deg2, 38 supernovae were detected at redshifts 0.25-0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type la supernova rate at a mean redshift z ≃ 0.55 of 1.53-0.25-0.31-0.28-0.32 × 10-4 h 3 Mpc-3 yr-1 or 0.58-0.09-0.09-0.10-0.10 h2 SNu (1 SNu = 1 supernova per century per 1010 LB⊙), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

We image 19 quasars with 22 damped Lyα systems (DLAs) using the F160W filter and the Near-Infrared Camera and Multi-Object Spectrograph on board the Hubble Space Telescope in both direct and coronagraphic modes. We reach 5 σ detection limits of ∼H = 22 in the majority of our images. We compare our observations to the observed Lyman break population of high-redshift galaxies as well as Bruzual & Charlot evolutionary models of present-day galaxies redshifted to the distances of the absorption systems. We predict H magnitudes for our DLAs, assuming that they are producing stars like an L* Lyman break galaxy (LBG) at their redshift. Comparing these predictions to our sensitivity, we find that we should be able to detect a galaxy around 0.5-1.0 L*(LBG) for most of our observations. We find only one new possible candidate, that near LBQS 0010-0012. This scarcity of candidates leads us to the conclusion that most damped Lyα systems are not drawn from a normal LBG luminosity function nor a local galaxy luminosity function placed at these high redshifts.

Measurements of [O III] emission in Lyman-break galaxies (LBGs) at z > 3 are presented. Four galaxies were observed with narrowband filters using the near-IR camera on the Keck I 10 m telescope. A fifth galaxy was observed spectroscopically during the commissioning of NIRSPEC, the new infrared spectrometer on Keck II. The emission-line spectrum is used to place limits on the metallicity. Comparing these new measurements with others available from the literature, we find that strong oxygen emission in LBGs may suggest subsolar metallicity for these objects. The [O III] λ5007 line is also used to estimate the star formation rate (SFR) of the LBGs. The inferred SFRs are higher than those estimated from the UV continuum, and may be evidence for dust extinction.

We present a luminosity function for Hα emission from galaxies at redshifts between 0.7 and 1.9 based on slitless spectroscopy with the near-infrared camera and multiobject spectrometer on the Hubble Space Telescope. The luminosity function is well fit by a Schechter function over the range 6 × 1041 < L (Hα) < 2 × 1043 ergs s-1 with L* = 7 × 1042 ergs s-1 and φ* = 1.7 × 10-3 Mpc-3 for H0 = 50 km s-1 Mpc-1 and q0 = 0.5. We derive a volume-averaged star formation rate at z = 1.3 ± 0.5 of 0.13 M⊙ yr-1 Mpc-3 without correction for extinction. The star formation rate that we derive at ∼6500 Å is a factor of 3 higher than that deduced from 2800 Å continua. If this difference is caused entirely by reddening, the extinction correction at 2800 Å is quite significant. The precise magnitude of the total extinction correction at rest-frame UV wavelengths (e.g., 2800 and 1500 Å) is sensitive to the relative spatial distribution of the stars, gas, and dust, as well as to the extinction law. In the extreme case of a homogeneous foreground dust screen and a Milky Way or LMC extinction law, we derive a total extinction at 2800 Å of 2.1 mag, or a factor of 7 correction to the UV luminosity density. If we use the Calzetti reddening curve, which was derived for the model in which stars, gas, and dust are well mixed and nebular gas suffers more extinction than stars, our estimate of A2800 is increased by more than 1 mag.

We present the results of a narrowband survey of quasi-stellar-object (QSO) fields at redshifts that place the [O III] (5007 Å) emission line in the Δλ/λ ∼ 1% 2.16 μm filter. We have observed 3 arcmin 2 and detected one emission-line candidate object in the field around PC 1109 + 4642. We discuss the possibilities that this object is a star-forming galaxy at the QSO redshift, zem = 3.313, or a Seyfert galaxy. In the former case, we infer a star formation rate of 170 M⊙ yr-1 for this K′ = 21.3 object. The galaxy has a compact but resolved morphology, with an FWHM = 0″.6 or 4.2 kpc at z = 3.313 (H0 = 50 km s-1 Mpc-1 and q0 = 0.5). The comoving density of such objects in QSO environments appears to be 0.0033 Mpc-3, marginally lower (≤ 3 σ) than the density observed for Hoα-emitters in absorption-line fields at z ∼ 2.5 but similar to the density of Lyman-break galaxies at z ∼ 3. If, on the other hand, most of the line emission is [O III] from a Seyfert 2 nucleus at z = 3.31, then the high inferred volume density could imply a large evolution in the Seyfert 2 luminosity function from the current epoch. We find the field containing the object to also contain many faint extended objects in the K′ image but little significant excess over the expected number-magnitude relation. We discuss the implication of the emission line being a longer wavelength line at a lower redshift.

We study the feedback from an active galactic nucleus (AGN) on stellar formation within its host galaxy, mainly using one high-resolution numerical simulation of the jet propagation within the interstellar medium (ISM) of an early-type galaxy (ETG). In particular, we show that in a realistic simulation where the jet propagates into a two-phase ISM, star formation (SF) can initially be slightly enhanced and then, on time-scales of few million years, rapidly quenched, as a consequence both of the high temperatures attained and of the reduction of cloud mass (mainly due to Kelvin–Helmholtz instabilities). We then introduce a model of (prevalently) negative AGN feedback, where an exponentially declining star formation is quenched, on a very short time-scale, at a time tAGN, due to AGN feedback. Using the Bruzual and Charlot population synthesis model and our SF history, we predict galaxy colours from this model and match them to a sample of nearby ETGs showing signs of recent episodes of SF, see Kaviraj et al. We find that the quantity , where tgal is the galaxy age, is an excellent indicator of the presence of feedback processes, and peaks significantly around for our sample, consistent with feedback from recent energy injection by AGNs in relatively bright and massive nearby ETGs. Galaxies that have experienced this recent feedback show an enhancement of 3 mag in , with respect to the unperturbed, no-feedback evolution. Hence, they can be easily identified in large combined near UV-optical surveys. [ABSTRACT FROM AUTHOR]