A5065532841- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Remote Sensing in Agriculture
- Impact of Light on Environment and Health
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Enzyme Structure and Function
- Calibration and Measurement Techniques
- Advanced Chemical Physics Studies
- Scientific Research and Discoveries
- Astronomical and nuclear sciences
- X-ray Diffraction in Crystallography
- Superconducting and THz Device Technology
- Optical Wireless Communication Technologies
- Particle Detector Development and Performance
- demographic modeling and climate adaptation
W.M. Keck Observatory
2018-2024
Gemini North Observatory
2006-2015
Gemini South Observatory
2004-2012
Carnegie Mellon University
2002-2005
NIU Observatory
2004
Rutgers, The State University of New Jersey
2000-2002
New Mexico State University
1997-2002
University of California, Berkeley
2002
Universidad de La Laguna
1984-1998
University of Birmingham
1991
We present in this paper a detailed analysis of the effect environment on star formation activity galaxies within Early Data Release (EDR) Sloan Digital Sky Survey (SDSS). have used Hα emission line to derive rate (SFR) for each galaxy volume-limited sample 8598 with 0.05 ≤ z 0.095 and M(r*) -20.45. find that SFR is strongly correlated local (projected) density, thus we here density-SFR relation analogous density-morphology relation. The density seen three ways. First, overall distribution...
We have studied the morphology–density relation and morphology–cluster-centric-radius using a volume-limited sample (0.05 < z 0.1, Mr* −20.5) of Sloan Digital Sky Survey (SDSS) data. Major improvements compared with previous work are: (i) automated galaxy morphology classification capable separating galaxies into four types; (ii) three-dimensional local density estimation; (iii) extension field region. found that in SDSS data for both our morphological classifiers, Cin Tauto, as fractions...
We analyse the observed correlation between galaxy environment and H-alpha emission line strength, using volume-limited samples group catalogues of 24968 galaxies drawn from 2dF Galaxy Redshift Survey (Mb<-19.5) Sloan Digital Sky (Mr<-20.6). characterise by 1) Sigma_5, surface number density determined projected distance to 5th nearest neighbour; 2) rho1.1 rho5.5, three-dimensional estimates obtained convolving distribution with Gaussian kernels dispersion 1.1 Mpc 5.5 Mpc, respectively. find...
The Sloan Digital Sky Survey (SDSS) first data release provides a database of 106000 unique galaxies in the main galaxy sample with measured spectra. A star-forming (SF) are identified from among 3079 these having 1.4 GHz luminosities FIRST, by using optical spectral diagnostics. Using as reference star formation rate (SFR) estimator insensitive to obscuration effects, SFRs derived SDSS Halpha, [OII] and u-band luminosities, well far-infrared IRAS, compared. It is established that...
We present the observed fraction of galaxies with an Active Galactic Nucleus (AGN) as a function environment in Early Data Release Sloan Digital Sky Survey (SDSS). Using 4921 between 0.05 <= z 0.095, and brighter than M_r* = -20.0 (or M* +1.45), we find at least ~ 20% these possess unambiguous detection AGN, but this could be high ~40% after model ambiguous emission line our sample. have studied environmental dependence using distance to 10^th nearest neighbor. As expected, observe that...
We present spectra of the most massive quiescent galaxy yet discovered at $z>3$, spectroscopically confirmed via detection Balmer absorption features in $H-$ and $K-$bands Keck/MOSFIRE. The confirm a with no significant ongoing star formation, consistent lack rest-frame UV flux overall photometric spectral energy distribution. With stellar mass $3.1^{+0.1}_{-0.2} \times 10^{11} ~\rm{M}_\odot$ $z = 3.493$, this is nearly three times more than highest redshift absorption-line identified known....
Abstract We present near-infrared spectroscopic confirmations of a sample 16 photometrically selected galaxies with stellar masses <?CDATA $\mathrm{log}({M}_{* }/{M}_{\odot })$?> >11 at redshift z > 3 from the XMM-VIDEO and COSMOS-UltraVISTA fields using Keck/MOSFIRE as part Massive Ancient Galaxies At NEar-infrared (MAGAZ3NE) survey. Eight ultramassive (UMGs) have specific star formation rates (sSFR) < 0.03 Gyr −1 , negligible emission lines. Another seven UMGs show lines...
We report the discovery of MAGAZ3NE J095924+022537, a spectroscopically-confirmed protocluster at $z = 3.3665^{+0.0009}_{-0.0012}$ around $UVJ$-quiescent ultra-massive galaxy (UMG; $M_{\star}=2.34^{+0.23}_{-0.34}\times10^{11} {\rm M}_\odot$) in COSMOS UltraVISTA field. present total 38 members (14 spectroscopic and 24 photometric), including UMG. Notably, marked contrast to protoclusters previously reported this epoch which have been found contain predominantly star-forming members, we...
We present spectroscopic confirmation of an ultra-massive galaxy (UMG) with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>log</mml:mo><mml:mrow><mml:mo stretchy="true" form="prefix">(</mml:mo><mml:msub><mml:mi>M</mml:mi><mml:mo>⋆</mml:mo></mml:msub><mml:mi>/</mml:mi><mml:msub><mml:mi>M</mml:mi><mml:mo>⊙</mml:mo></mml:msub><mml:mo...
Aims.We present data from the CFHTLS Strong Lensing Legacy Survey (SL2S). Due to unsurpassed combined depth, area and image quality of Canada-France-Hawaii it is becoming possible uncover a large, statistically well-defined sample strong gravitational lenses which spans dark halo mass spectrum predicted by concordance model galaxy cluster haloes.
AIMS: We present data from the CFHTLS Strong Lensing Legacy Survey (SL2S). Due to unsurpassed combined depth, area and image quality of Canada-France-Hawaii it is becoming possible uncover a large, statistically well-defined sample strong gravitational lenses which spans dark halo mass spectrum predicted by concordance model galaxy cluster haloes. METHODS: describe development several automated procedures find various regimes in images. RESULTS: The preliminary about 40 lensing candidates...
We present the census of massive (log(M$_{*}$/M$_{\odot}$)$\geq 11$) galaxies at $3<z<6$ identified over COSMOS/UltraVISTA Ultra-Deep field stripes: consisting $\approx100$ and $\approx20$ high-confidence candidates $3<z<4$ $4<z<6$, respectively. The population is comprised post-starburst, UV star-forming dusty-star forming in roughly equal fractions, while UV-star-forming dominate $4<z<6$ . account for various sources biases SED modelling, finding that treatment emission line contamination...
In previous work on galaxy clusters, several authors reported a discovery of an unusual population galaxies, which have spiral morphologies, but do not show any star formation activity. These galaxies are called ``passive spirals'', and been interesting since it has difficult to understand the existence such galaxies. Using volume limited sample (0.05<z<0.1 Mr<-20.5; 25813 galaxies) Sloan Digital Sky Survey data, we found 73 (0.28$\pm$0.03%) passive studied their environments. It is that...
Abstract In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; <?CDATA $\mathrm{log}({M}_{* }/{M}_{\odot })$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mo>*</mml:mo> </mml:msub> stretchy="true">/</mml:mo> <mml:mo>⊙</mml:mo> stretchy="false">)</mml:mo> </mml:math> > 11), z ≳...
We present the first in-depth analysis of massive cluster AS1063. This is one hottest X-ray clusters discovered to date and undergoing a major merging event. The average temperature hot intracluster medium has been measured, using Chandra/ACIS-I, found be >11.5 keV. Optical spectroscopy, from GMOS-S, provided mean redshift 0.3461 large velocity dispersion 1840+230 − 150 km s−1. Both high suggest very (M200 > 2.5 × 1015 M☉) and/or merger system. model supported by small offset between galaxy...
ABSTRACT Motivated by spectroscopic confirmation of three overdense regions in the COSMOS field at z ∼ 3.35, we analyse uniquely deep multiwavelength photometry and extensive spectroscopy available to identify any further related structure. We construct a three-dimensional density map using Voronoi tesselation Monte Carlo method find additional significant overdensity. Here, present examine set six structures 3.20 &lt; 3.45 field, most well-characterized which, PCl J0959 + 0235, has 80...
We present here results on the composite luminosity functions of galaxies in clusters selected from SDSS Cut and Enhance cluster catalog (CE; Goto et al. 2001). construct function five bands, u,g,r,i z, using 204 CE ranging z=0.02 to z=0.25. use photometric redshifts functions. The robustness weighting scheme was tested Monte Carlo simulation. find slope LFs become flatter toward redder color band. Comparing with field (Blanton 2001), have brighter characteristic magnitude slopes g, r, i z...
Abstract We investigated the evolution of fractions late-type cluster galaxies as a function redshift using one largest, most uniform samples available. The sample consisted 514 clusters in range $0.02 \leq z\leq 0.3$ from Sloan Digital Sky Survey “Cut and Enhance” galaxy catalog. This catalog was created single automated cluster-finding algorithm applied to data telescope, with accurate CCD photometry, thus minimizing selection biases. used four independent methods analyze fraction....
We report the results of recent numerical simulations head-on merger a cooling flow cluster with an infalling subcluster galaxies. The objective these was to examine effects different types mergers (with 16 : 1 and 4 mass ratios) on evolution flows accretion rates 100 400 M☉ yr-1). two-dimensional were performed combined hydrodynamics/N-body code uniform grid resolution 20 kpc (~12 zones per core radius). In our simulations, disruption is indicated by dramatic increase (by factor 10-40) in...
To explore a greater realm of model phase space than has previously been mapped, we generate randomly chosen interior models for Uranus and Neptune. The are constrained by the observed mass, rotation rate, radius, gravitational moments two planets. New with composition gradient in outer third planetary radius found both Such gradients may play significant role controlling internal heat flow. In agreement previous models, find that pressure‐density relation central planets is consistent...
Abstract We present rest-frame optical spectroscopic observations of 24 Hot Dust-Obscured Galaxies (Hot DOGs) at redshifts 1.7–4.6 with KECK/NIRES. Our targets are selected, based on their extreme red colors, to be the highest-luminosity sources from WISE infrared survey. In 20 well-detected emission, we fit key [O iii ], H β , α [N ii and [S ] diagnostic lines constrain physical conditions. Of 17 a clear detection λ 5007 Å emission line, 15 display broad blueshifted asymmetric line...
We present new ROSAT PSPC X-ray pointed observations of nine Abell clusters that contain wide-angle tailed (WAT) radio galaxies. The sample WAT was selected from a VLA survey the catalog at 20 cm and All-Sky Survey (RASS). found up to eight (89%) show some evidence substructure. These also have clear isophotal twisting, ellipticity variation, isophote centroid variation as function distance central peak. Moreover, none these significant cluster-wide cooling flows in spite presence dominant...
We have discovered strong gravitational lensing features in the core of nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent feature is a highly-magnified, ring-shaped configuration four images around central cD galaxy. spectroscopic analysis puts this source at z~0.2. Located ~20" away from galaxy secondary tangential arc which has been identified as background with z~0.4. modeled potential core, taking into account mass cluster, BCG and other galaxies. derive...
We present multiwavelength observations of the Abell 1995 galaxy cluster. From an analysis X-ray spectroscopy and imaging data, we derive electron temperature, cluster core radius, central number density. Using optical 15 members, accurate redshift velocity dispersion. Finally, interferometric Sunyaev-Zeldovich effect toward at 28.5 GHz provides a measure integrated pressure through The are combined to determine angular diameter distance DA = 1294 Mpc (statistical followed by systematic...
Abstract We present rest-frame optical spectra from Keck/MOSFIRE and Keck/NIRES of 16 candidate ultramassive galaxies targeted as part the Massive Ancient Galaxies at z > 3 Near-Infrared Survey (MAGAZ3NE). These candidates were selected to have photometric redshifts ≲ phot <4, stellar masses <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">log</mml:mi> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub>...