A5082575274- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Advanced Vision and Imaging
- Experimental and Theoretical Physics Studies
- Relativity and Gravitational Theory
- Aquatic Invertebrate Ecology and Behavior
- CCD and CMOS Imaging Sensors
- Fish Ecology and Management Studies
- Remote Sensing in Agriculture
- Seismic Imaging and Inversion Techniques
- History and Developments in Astronomy
- Radio Astronomy Observations and Technology
- Calibration and Measurement Techniques
- Impact of Light on Environment and Health
Durham University
2013-2024
Durham Technical Community College
1999-2007
Dartmouth College
2006
Environmental Protection Agency
2006
Association of Universities For Research In Astronomy
2004
U.S. National Science Foundation
2004
Kitt Peak National Observatory
2004
Cerro Tololo Inter-American Observatory
2004
United Nations Industrial Development Organization
2003
Australian Astronomical Observatory
1984-1988
Pan-STARRS1 has carried out a set of distinct synoptic imaging sky surveys including the $3π$ Steradian Survey and Medium Deep in 5 bands ($grizy_{P1}$). The mean 5$σ$ point source limiting sensitivities stacked 3$π$ $grizy_{P1}$ are (23.3, 23.2, 23.1, 22.3, 21.4) respectively. upper bound on systematic uncertainty photometric calibration across is 7-12 millimag depending bandpass. astrometric using Gaia frame comes from comparison results with Gaia: standard deviation median residuals ($...
We report the final redshift release of 6dF Galaxy Survey, a combined and peculiar velocity survey over southern sky (|b|>10 deg). Its 136,304 spectra have yielded 110,256 new extragalactic redshifts catalogue 125,071 galaxies making near-complete samples with (K, H, J, r_F, b_J) <= (12.65, 12.95, 13.75, 15.60, 16.75). The median is 0.053. Survey data, including images, spectra, photometry redshifts, are available through an online database. describe changes to information in database since...
We have undertaken a detailed comparison of the colours early-type galaxies in Virgo and Coma clusters. In Paper I (this issue), we presented our system homogeneous U,V,J K photometric measurements for these galaxies. this paper, use data set to investigate universality colour–magnitude correlation. Our work reassesses anomaly noted by Aaronson, Persson & Frogel. Following authors, initially compare relative distances two clusters derived from L – σ U V correlations. However, contrast their...
The 6dF Galaxy Survey (6dFGS) aims to measure the redshifts of around 150,000 galaxies, and peculiar velocities a 15,000-member sub-sample, over almost entire southern sky. When complete, it will be largest redshift survey nearby universe, reaching out about z ~ 0.15, more than an order magnitude larger any velocity date. targets are all galaxies brighter K_tot = 12.75 in 2MASS Extended Source Catalog (XSC), supplemented by SuperCOSMOS that complete sample limits (H, J, r_F, b_J) (13.05,...
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. survey region is stripe 2.5° wide centered the celestial equator in Southern Galactic Cap that been imaged numerous times earlier years, enabling construction deep reference image discovery new objects. Supernova observations are being...
We present spectroscopic linestrength data for 4097 red-sequence galaxies in 93 low-redshift galaxy clusters, and use these to investigate variations average stellar populations as a function of mass. Our analysis includes an improved treatment nebular emission contamination, which affects ~10% the sample galaxies. Using population models D. Thomas collaborators, we simultaneously fit twelve observed linestrength-sigma relations terms common underlying trends age, [Z/H] (total metallicity)...
We have undertaken a comprehensive study of large sample early-type galaxies in the Virgo and Coma clusters.In first two papers, we present accurate UVJK photometry for total 94 elliptical SO galaxies.All U-and V-band measurements are based on CCD observations made with 2.5-m Isaac Newton Telescope.J-and K-band cluster were chopping photometer at United Kingdom Infrared Telescope (UKIRT ).Virgo land been taken from Persson, Frogel & Aaronson.The rms internal scatter these data respectively:...
We derive peculiar velocities for the 6dF Galaxy Survey (6dFGS) and describe velocity field of nearby (z < 0.055) Southern hemisphere. The survey comprises 8885 galaxies which we have previously reported Fundamental Plane data. obtain probability distributions redshift-space positions each these using a Bayesian approach. Accounting selection bias, find that logarithmic distance uncertainty is 0.11 dex, corresponding to 26 per cent in linear distance. use adaptive kernel smoothing map...
Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these is difficult, but important for understanding the assembly most massive galaxies. The Coma cluster one nearest truly clusters, and host to correspondingly large system globular clusters (GCs). We use imaging from HST/ACS Cluster Survey present first definitive detection population intracluster GCs (IGCs) that fills core not associated with individual GC surface density profile...
We present results from a blind survey to identify strong gravitational lenses among the population of low-redshift early-type galaxies. The SINFONI Nearby Elliptical Lens Locator Survey (SNELLS) uses integral-field infrared spectroscopy search for lensed emission line sources behind massive lens candidates at z < 0.055. From 27 galaxies observed, we have recovered one previously known (ESO 325−G004) = 0.034, and discovered two new systems, 0.031 0.052. All three high velocity dispersions (σ...
We present scaling relations between structural properties of nuclear star clusters and their host galaxies for a sample early-type dwarf observed as part the Hubble Space Telescope (HST) Advanced Camera Surveys (ACS) Coma Cluster Survey.We have analysed light profiles 200 in magnitude range 16.0 < m F814W 22.6 mag, corresponding to -19.0 M -12.4 mag.Nuclear are detected 80 per cent galaxies, thus doubling HST-observed with clusters.We confirm that cluster detection fraction decreases...
Measurement of peculiar velocities by combining redshifts and distance indicators is a powerful way to measure the growth rate cosmic structure test theories gravity at low redshift. Here we constrain comparing observed Fundamental Plane for 15894 galaxies from 6dF Galaxy Survey (6dFGS) Sloan Digital Sky (SDSS) with predicted densities 2M$++$ redshift survey. We velocity scale parameter $\beta \equiv {\Omega_m^\gamma}/b = 0.372^{+0.034}_{-0.050}$ $0.314^{+0.031}_{-0.047}$ 6dFGS SDSS...
We present scale-dependent measurements of the normalized growth rate structure fσ8(k, z = 0) using only peculiar motions galaxies. use data from 6-degree Field Galaxy Survey velocity sample together with a newly compiled low-redshift (z < 0.07) Type Ia supernovae. constrain in series Δk ∼ 0.03 h Mpc−1 bins to ∼35 per cent precision, including measurement on scales >300 h−1 Mpc, which represents one largest scale date. find no evidence for scale-dependence rate, or any statistically...
ABSTRACT We present a new catalogue of distances and peculiar velocities (PVs) 34 059 early-type galaxies derived from fundamental plane (FP) measurements using data the Sloan Digital Sky Survey (SDSS). This $7016\, \mathrm{deg}^{2}$ homogeneous sample comprises largest set PVs produced to date extends reach PV surveys up redshift limit z = 0.1. Our SDSS-based FP distance have mean uncertainty 23 per cent. Alongside data, we produce an ensemble 2048 mock galaxy catalogues that reproduce...
We present new spectroscopic data for 532 early-type galaxies, predominantly Abell cluster members with cz < 12 000 km s−1. tabulate 919 individual measurements, from six observing runs, recession velocity, cz, central velocity dispersion, σ, and magnesium line-strength indices, Mg2 Mgb. The median estimated error, per measurement, in σ is 5 cent. have errors of 0.009 mag. observed scatter between repeat measurements largely accounted by photon-counting errors. These will be employed...
We investigate the Mg-sigma and <Fe>-sigma relations in a sample of 72 early-type galaxies drawn mostly from cluster group environments using homogeneous data-set which is well-calibrated onto Lick/IDS system. The small intrinsic scatter Mg at given sigma gives upper limits on spread age metallicity 49% 32% respectively, if attributed to one quantity only variations are uncorrelated. age/metallicity distribution as inferred Hbeta vs <Fe> diagnostic diagram reinforces this conclusion, we find...
We analyse in detail the peculiar velocity field traced by 56 clusters within 120 h−1 Mpc 'Streaming Motions of Abell Clusters' (SMAC) sample. The bulk flow SMAC sample is 687 ± 203 km s−1, toward l= 260°± 13°, b= 0°± 11°. discuss possible systematic errors and show that no effect larger than half random error. does not drop off significantly with depth, which suggests it generated structures on large scales. In particular, a Great Attractor as originally proposed Lynden-Bell et al. cannot...
We introduce the NOAO Fundamental Plane Survey (NFPS), a wide-field imaging/spectroscopic study of rich, low-redshift galaxy clusters. The survey targets X-ray–selected clusters at 0.010 < z 0.067, distributed over whole sky, with imaging and spectroscopic observations obtained for 93 This data set will be used in investigations properties cluster environment large-scale velocity fields through fundamental plane. In this paper, we present details sample construction strategies employed to...
We present optical and infrared observations of the unusual Type Ia supernova (SN) 2004eo. The light curves spectra closely resemble those prototypical SN 1992A, luminosity at maximum (M_B = -19.08) is close to average for a Ia. However, ejected 56Ni mass derived by modelling bolometric curve (about 0.45 solar masses) lies near lower limit distribution observed in normal SNe Accordingly, 2004eo shows relatively rapid post-maximum decline (Delta m_(B) 1.46), small expansion velocities ejecta,...
We have used new deep observations of the Coma cluster from Galaxy Evolution Explorer to visually identify 13 star-forming galaxies with asymmetric morphologies in ultraviolet (UV). Aided by wide-field optical broad-band and Hα imaging, we interpret features as being due star formation within gas stripped interaction environment. The selected objects display a range structures broad fan-shaped systems filaments knots (‘jellyfish’) narrower smoother tails extending up 100 kpc length. Some...
We present new VLT observations of the closest-known strong-lensing galaxy, sigma=330 km/s giant elliptical ESO325-G004. The low redshift lens (z_lens=0.035) results in arcs being formed at a small fraction effective radius, (R_Ein ~ R_Eff/4). At such radii, stars dominate lensing mass, so that provides direct probe stellar mass-to-light ratio, with only corrections needed for dark matter. galaxy lensed by ESO325-G004 was unknown until now, mass not securely determined. Using X-SHOOTER, we...
We present a catalogue of structural parameters for 8814 galaxies in the 25 fields HST/ACS Coma Treasury Survey. Parameters from S\'ersic fits to two-dimensional surface brightness distributions are given all our published photometric with mean effective brighter than 26.0 mag/sq. arcsec and 24.5 mag (equivalent absolute magnitude - 10.5), as by fits, F814W(AB). The sample comprises mixture members background objects; 424 have redshifts these 163 confirmed members. were carried out using...
We measure the bulk flow of local Universe using 6dF Galaxy Survey peculiar velocity sample (6dFGSv), largest and most homogeneous to date. 6dFGSv is a Fundamental Plane ∼104 velocities covering whole Southern hemisphere for galactic latitude |b| > 10°, out redshift z = 0.0537. apply 'minimum variance' weighting method, which allows us make robust measurement on scales 50 70 h−1 Mpc. investigate correct potential bias due lognormal uncertainties, verify our method by constructing Λ cold dark...
Abstract The Taipan galaxy survey (hereafter simply ‘Taipan’) is a multi-object spectroscopic starting in 2017 that will cover 2π steradians over the southern sky (δ ≲ 10°, | b ≳ 10°), and obtain optical spectra for about two million galaxies out to z < 0.4. use newly refurbished 1.2-m UK Schmidt Telescope at Siding Spring Observatory with new TAIPAN instrument, which includes an innovative ‘Starbugs’ positioning system capable of rapidly simultaneously deploying up 150 fibres (and 300...