Showing papers by "Carol J. Lonsdale published in 2004"
DSM1, Imperial College London2, University of Bristol3, École Normale Supérieure4, European Southern Observatory5, University of Liège6, University of Birmingham7, University of Leicester8, University of Victoria9, United States Naval Research Laboratory10, California Institute of Technology11, University College Dublin12, Max Planck Society13
TL;DR: The XMM Large Scale Structure Survey with XMM (XMM-LSS) as discussed by the authors is a large-scale X-ray survey with the scope of extending the cosmological tests attempted using ROSAT cluster samples to two redshift bins between 0
Abstract: We have designed a medium deep large area X-ray survey with XMM - the XMM Large Scale Structure survey, XMM-LSS - with the scope of extending the cosmological tests attempted using ROSAT cluster samples to two redshift bins between 0
181 citations
California Institute of Technology1, University of California, San Diego2, Imperial College London3, University of Sussex4, National Radio Astronomy Observatory5, Jet Propulsion Laboratory6, University of Padua7, Spanish National Research Council8, University of Paris-Sud9, Cornell University10, University of Kent11, DSM12, Cardiff University13
TL;DR: In this paper, the authors characterize the Spitzer Wide-area Infrared Extragalactic Legacy Survey (SWIRE) galaxy populations in the SWIRE validation field within the Lockman Hole, based on the 3.6-24 μm Spitzer data and deep U, g', r', i' optical imaging within an area ~1/3 deg2 for ~16,000 Spitzer SWIRE sources.
Abstract: We characterize the Spitzer Wide-area Infrared Extragalactic Legacy Survey (SWIRE) galaxy populations in the SWIRE validation field within the Lockman Hole, based on the 3.6-24 μm Spitzer data and deep U, g', r', i' optical imaging within an area ~1/3 deg2 for ~16,000 Spitzer SWIRE sources. The entire SWIRE survey will discover over 2.3 million galaxies at 3.6 μm and almost 350,000 at 24 μm; ~70,000 of these will be five-band 3.6-24 μm detections. The colors cover a broad range, generally well represented by redshifted spectral energy distributions of known galaxy populations; however, significant samples of unusually blue objects in the [3.6]-[4.5] color are found, as well as many objects very red in the 3.6-24 μm mid-IR. Nine of these are investigated and are interpreted as star-forming systems, starbursts, and active galactic nuclei (AGNs) from z = 0.37 to 2.8, with luminosities from LIR = 1010.3 to 1013.7 L.
177 citations
TL;DR: In this article, the authors characterize the SWIRE galaxy populations in SWIRE validation field within the Lockman Hole, based on the 3.6-24$\mu$ Spitzer data and deep U,g',r',r' optical imaging within an area ~1/3 sq. deg for ~16,000 Spitzer-SWIRE sources.
Abstract: We characterize the SWIRE galaxy populations in the SWIRE validation field within the Lockman Hole, based on the 3.6-24$\mu$ Spitzer data and deep U,g',r',r' optical imaging within an area ~1/3 sq. deg for ~16,000 Spitzer-SWIRE sources. The entire SWIRE survey will discover over 2.3 million galaxies at 3.6$\mu$m and almost 350,000 at 24$\mu$m; ~70,000 of these will be 5-band 3.6-24$\mu$ detections. The colors cover a broad range, generally well represented by redshifted spectral energy distributions of known galaxy populations, however significant samples of unusually blue objects in the [3.6-4.5]$\mu$m color are found, as well as many objects very red in the 3.6-24$\mu$m mid-IR. Nine of these are investigated and are interpreted as star-forming systems, starbursts and AGN from z=0.37 to 2.8, with luminosities from L$_{IR}$=10$^{10.3}$ to 10$^{13.7}$ L$_{\odot}$
156 citations
TL;DR: In this paper, the authors present a new tool for the photometric estimate of stellar masses in distant galaxies, which combines sets of various simple stellar populations, with different normalizations and different amounts of dust extinction, for a given (Salpeter) IMF.
Abstract: We present a new tool for the photometric estimate of stellar masses in distant galaxies. The observed source spectral energy distributions are fitted by combining sets of various simple stellar populations, with different normalizations and different amounts of dust extinction, for a given (Salpeter) IMF. This treatment gives us the best flexibility and robustness when dealing with the widest variety of physical situation for the target galaxies, including inactive spheroidal and active starburst systems. We tested the code on three classes of sources: complete samples of dusty ISO-selected starbursts and of K-band selected ellipticals and S0s in the HDF South, and a representative sample of z ~ 2 to 3 Lyman-break galaxies in the HDF North. We pay particular attention in evaluating the uncertainties in the stellar mass estimate, due to degeneracies in the physical parameters, different star formation histories and different metallicities. Based on optical-NIR photometric data, the stellar masses are found to have overall uncertainties of a factor of ~2 for E/S0s, while for the starburst population these rise to factors 2-5 (even including ISO/15 µm photometric data), and up to ≥ 10 for Ly-break galaxies. Our analysis reveals in any case the latter to correspond to a galaxy population significantly less massive (M several 10^(10) M_⊙), possibly indicating substantial stellar build-up happening at z ~ 1 to 2 in the field galaxy population. Using simulated deep SIRTF/IRAC observations of starbursts and Lyman-break galaxies, we investigate how an extension of the wavelength dynamic range will decrease the uncertainties in the stellar mass estimate, and find that they will reduce for both classes to factors of 2-3, comparable to what found for E/S0s and good enough for statistically reliable determinations of the galaxy evolutionary mass functions.
33 citations
TL;DR: In this paper, the angular correlation function of galaxies selected to have 3.6 μm fluxes brighter than 32 μJy in three fields totaling 2 deg2 in area is presented.
Abstract: We present the first analysis of large-scale clustering from the Spitzer Wide-area Infrared Extragalactic legacy survey (SWIRE). We compute the angular correlation function of galaxies selected to have 3.6 μm fluxes brighter than 32 μJy in three fields totaling 2 deg2 in area. In each field we detect clustering with a high level of significance. The amplitude and slope of the correlation function is consistent between the three fields and is modeled as w(θ) = Aθ1-γ with A = (0.6 ± 0.3) × 10-3,γ = 2.03 ± 0.10. With a fixed slope of γ = 1.8, we obtain an amplitude of A = (1.7 ± 0.1) × 10-3. Assuming an equivalent depth of K ≈ 18.7 mag we find that our errors are smaller but our results are consistent with existing clustering measurements in K-band surveys and with stable clustering models. We estimate our median redshift z 0.75, and this allows us to obtain an estimate of the three-dimensional correlation function ξ(r), for which we find r0 = 4.4 ± 0.1 h-1 Mpc.
28 citations
TL;DR: In this article, the authors present a new tool for the photometric estimate of stellar masses in distant galaxies, which is fitted by combining single stellar populations, with different SFRs and amounts of dust extinction.
Abstract: We present a new tool for the photometric estimate of stellar masses in distant galaxies. The observed SEDs are fitted by combining single stellar populations, with different SFRs and amounts of dust extinction. This approach gives us the best flexibility when dealing with the widest variety of physical situation for the target galaxies. In particular we tested the code on three classes of sources: dusty ISO-selected starbursts, K-band selected ellipticals/S0s and z=2-3 Lyman-break galaxies. We pay particular attention in evaluating the uncertainties in the stellar mass estimate, due to degeneracies in the physical parameters, different SFHs or metallicities. Based on optical-NIR photometric data, the stellar masses are found to have overall uncertainties of a factor of ~2 for E/S0s, ~2-5 for the starbursts population, and up to 10 for Ly-break galaxies. In any case the latter appear to correspond to a galaxy population significantly less massive than those observed at lower redshifts, possibly indicating substantial stellar build-up at z~1-2 in the field galaxy population. Using simulated deep SIRTF/IRAC observations of starbursts and Lyman-break galaxies, we investigate how an extension of the wavelength dynamic range will decrease the uncertainties in the stellar mass estimate, and find that they will reduce for both classes to factors of 2-3, good enough for statistically reliable determinations of the galaxy evolutionary mass functions.
TL;DR: The launch of SIRTF on August 25, 2003, opens an exciting new era for the infrared as discussed by the authors, which will measure the accumulation of stellar mass at high redshift, and the evolution of dusty systems (disks, starbursts & AGN) since z∼4, on size scales up to several hundred Mpc.
Abstract: The launch of SIRTF on August 25, 2003, opens an exciting new era for the infrared. Building on the legacy of IRAS, COBE & ISO, SIRTF will image the sky from 3.6–160μm in tiered surveys, from wide (∼80 sq. deg.) reaching z∼1 in depth for L FIR * galaxies, to small, deep, confusion-limited surveys. SIRTF will measure the accumulation of stellar mass at high redshift, and the evolution of dusty systems (disks, starbursts & AGN) since z∼4, on size scales up to several hundred Mpc. The next decade will also see two major all-sky IR surveys, ASTRO-F and WISE (Wide-field Infrared Survey Explorer), and the launch of Herschel and Planck.
Posted Content•
TL;DR: In this paper, the angular correlation function of galaxies selected to have 3.6 μm fluxes brighter than 32 μJy in three fields totaling two square degrees in area is computed.
Abstract: We present the first analysis of large-scale clustering from the Spitzer Widearea InfraRed Extragalactic legacy survey: SWIRE.We compute the angular correlation function of galaxies selected to have 3.6 μm fluxes brighter than 32 μJy in three fields totaling two square degrees in area. In each field we detect clustering with a high level of significance. The amplitude and slope of the correlation function is consistent between the three fields and is modeled as w(θ) = Aθ1−γ with A = (0.6 ± 0.3) × 10−3, γ = 2.03 ± 0.10. With a fixed slope of γ = 1.8, we obtain an amplitude of A = (1.7±0.1)×10−3. Assuming an equivalent depth of K ≈ 18.7 mag we find our errors are smaller but our results are consistent with existing clustering measurements in K-band surveys and with stable clustering models. We estimate our median redshift z ≃ 0.75 and this allows us to obtain an estimate of the three-dimensional correlation function ξ(r), for which we find r0 = 4.4 ± 0.1h−1 Mpc.