S. A. Stanford
A5015954432- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Calibration and Measurement Techniques
- CCD and CMOS Imaging Sensors
- Astro and Planetary Science
- Remote Sensing in Agriculture
- Solar and Space Plasma Dynamics
- Atomic and Molecular Physics
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Nuclear Physics and Applications
- GNSS positioning and interference
- Impact of Light on Environment and Health
University of California, Davis
2015-2024
Lawrence Livermore National Laboratory
2012-2023
University of California, Berkeley
1991-2011
University of California, Los Angeles
2011
Joint Institute for VLBI ERIC
2011
Planetary Science Institute
2003-2010
Czech Academy of Sciences, Institute of Geophysics
2001-2008
Association of Universities For Research In Astronomy
1998-2004
U.S. National Science Foundation
1998-2004
Kitt Peak National Observatory
1995-2004
The all sky surveys done by the Palomar Observatory Schmidt, European Southern and United Kingdom InfraRed Astronomical Satellite, Two Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts decades. Wide-field Infrared Explorer (WISE) is mapping whole following its launch on 2009 December 14. WISE began surveying 2010 January 14 completed first full coverage of July 17. survey will continue cover a second time until cryogen exhausted (anticipated...
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe were discovered over redshift interval 0.623 < z 1.415. Of these Ia, 14 pass our strict selection cuts are used in combination with world's sample to derive best current constraints on dark energy. new 10 beyond = 1, thereby nearly doubling statistical weight HST-discovered this redshift. Our...
The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 − W2 ⩾ 0.8 (i.e., [3.4]−[4.6] ⩾0.8, Vega), which identifies 61.9 ± 5.4 active galactic nucleus (AGN) candidates per deg2 to depth of ∼ 15.0. This implies much larger census luminous AGNs than found by typical wide-area surveys, attributable the fact that selection both unobscured (type 1) obscured 2) AGNs. Optical soft X-ray surveys...
We present new determinations of the cosmic expansion history from red-envelope galaxies. have obtained for this purpose high-quality spectra with Keck-LRIS spectrograph galaxies in 24 galaxy clusters redshift range 0.2 < z 1.0. complement these Keck high-quality, publicly available archival SPICES and VVDS surveys. improve over our previous measurements Simon et al. (2005) by providing two history: H(z) = 97 +- 62 km/sec/Mpc at 0.5 90 40 0.8. discuss uncertainty determination that arises...
We have carried out a survey of the north and south ecliptic poles, EP-N EP-S, respectively, with Spitzer Space Telescope Wide-field Infrared Survey Explorer (WISE). The primary objective was to cross-calibrate WISE Midcourse Experiment (MSX) photometric systems by developing set calibration stars that are common these infrared missions. poles were continuous viewing zones for due its polar-crossing orbit, making areas ideal both absolute internal calibrations. IRAC MIPS imaging covers...
We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg$^2$ South Pole Telescope (SPT) data. This work represents the complete sample detected at high significance in 2500-square-degree SPT-SZ survey, which was completed 2011. A total 677 (409) cluster candidates are identified above signal-to-noise threshold $\xi$ =4.5 (5.0). Ground- and space-based optical near-infrared (NIR) imaging confirms overdensities similarly colored galaxies...
We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z = 0.9. The sample is selected on the basis morphologies determined Hubble Space Telescope (HST) WFPC2 images and photometrically defined K band order minimize redshift-dependent selection biases. Using new ground-based photometry five optical infrared bands for each cluster, we examine evolution color-magnitude relation cluster galaxies, considering its slope, intercept,...
We present ground-based spectroscopic verification of 6 Y dwarfs (see also Cushing et al.), 89 T dwarfs, 8 L and 1 M dwarf identified by the Wide-field Infrared Survey Explorer (WISE). Eighty these are cold brown with spectral types ⩾T6, six which have been announced earlier Mainzer al. Burgasser color–color color–type diagrams showing locus M, L, T, in WISE color space. Near-infrared and, a few cases, optical spectra presented for discoveries. classifications as late early objects peculiar...
[Abridged] We present the results of a large program conducted with Very Large Telescope and Keck telescope to search for forming clusters galaxies near powerful radio at 2.0 < z 5.2. obtained narrow- broad-band images nine their surroundings. The imaging was used select candidate Lyman alpha emitting in ~3x3 Mpc^2 areas galaxies. A total 337 emitters were found rest-frame equivalent width EW_0 > 15 Sigma = EW_0/Delta 3. Follow-up spectroscopy confirmed 168 eight success rate our...
The Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at mid-infrared wavelengths 3.4, 4.6, 12 and 22 microns. mission was primarily designed to extract point sources, leaving resolved extended sources unexplored. We have begun a dedicated WISE Enhanced Resolution Galaxy Atlas (WERGA) project fully characterize large, nearby galaxies produce legacy image atlas source catalogue. Here we demonstrate first results of for sample 17 galaxies, chosen be large angular size, diverse...
Stern et al.(2012) presented a study of WISE selection AGN in the 2 deg^2 COSMOS field, finding that simple criterion W1-W2>=0.8 provides highly reliable and complete sample for W2<15.05, where W1 W2 passbands are centered at 3.4 4.6 microns, respectively. Here we extend this using larger 9 NOAO Deep Wide-Field Survey Bootes field which also has considerably deeper observations than find color-cut significantly loses reliability fainter fluxes. We define modified combining W1-W2 color...
We present the XXL Survey, largest XMM programme totaling some 6.9 Ms to date and involving an international consortium of roughly 100 members. The Survey covers two extragalactic areas 25 deg2 each at a point-source sensitivity ~ 5E-15 erg/sec/cm2 in [0.5-2] keV band (completeness limit). survey's main goals are provide constraints on dark energy equation state from space-time distribution clusters galaxies serve as pathfinder for future, wide-area X-ray missions. review science objectives,...
(abridged) We present cosmological constraints obtained from galaxy clusters identified by their Sunyaev-Zel'dovich effect signature in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich survey. consider 377 cluster candidates at z>0.25 with a detection significance greater than five, corresponding to 95% purity threshold for compute on models using measured abundance as function of mass and redshift. include additional multi-wavelength observations, including Chandra X-ray data...
We explore the near-infrared (NIR) $K$-band properties of galaxies within 93 galaxy clusters and groups using data from 2MASS. use X-ray these to pinpoint cluster centers estimate masses. By stacking all systems, we study shape luminosity function distribution clusters. find that profile is well described by NFW with a concentration parameter c~3, no evidence for mass dependence concentration. Using this sample, whose masses span range $3\times10^{13}M_\odot$ $2\times10^{15}M_\odot$, confirm...
We explore the near-infrared properties of galaxies within 27 galaxy clusters using data from Two Micron All Sky Survey (2MASS). For a subsample 13 with available X-ray imaging data, we examine both and intracluster medium. show that K-band luminosity is correlated cluster mass, providing binding mass estimate accurate to 45%. The mass-to-light ratio in our ensemble increases by factor ~2 over range (1014-1015 M☉). total baryon fraction, showing it an increasing function mass. Using massive...
We analyze the ROSAT Deep Cluster Survey (RDCS) to derive cosmological constraints from evolution of cluster X-ray luminosity distribution. The sample contains 103 galaxy clusters out z ≃ 0.85 and flux limit Flim = 3 × 10-14 ergs s-1 cm-2 (RDCS-3) in [0.5-2.0] keV energy band, with a high-redshift extension containing four at 0.90 ≤ 1.26 brighter than 1 (RDCS-1). assume models be specified by matter density parameter Ωm, rms fluctuation amplitude 8 h-1 Mpc scale σ8, shape for cold dark...
We have identified 335 galaxy cluster and group candidates, 106 of which are at z > 1, using a 4.5 um selected sample objects from 7.25 deg^2 region in the Spitzer Infrared Array Camera (IRAC) Shallow Survey. Clusters were as 3-dimensional overdensities wavelet algorithm, based on photometric redshift probability distributions derived IRAC NOAO Deep Wide-Field Survey data. estimate only ~10% detections spurious. To date 12 1 candidates been confirmed spectroscopically, redshifts 1.06 to...
The South Pole Telescope (SPT) is currently surveying 2500 deg^2 of the southern sky to detect massive galaxy clusters out epoch their formation using Sunyaev-Zel'dovich (SZ) effect. This paper presents a catalog 26 most significant SZ cluster detections in full survey region. includes 14 which have been previously identified and 12 that are new discoveries. These were fields observed two differing noise depths: 1500 at final SPT depth 18 uK-arcmin 150 GHz, 1000 54 uK-arcmin. Clusters...
We report the first results from Clusters Around Radio-Loud AGN (CARLA) program, a Cycle 7 and 8 Spitzer Space Telescope snapshot program to investigate environments of large sample obscured unobscured luminous radio-loud at 1.2 < z 3.2. These data, obtained for 387 fields, reach 3.6 4.5 um depths [3.6] (AB) = 22.6 [4.5] 22.9 95% completeness level, which is two three times fainter than L* in this redshift range. By using color cut [3.6]-[4.5] > -0.1 (AB), efficiently selects high-redshift...
We analyze the star formation properties of 16 infrared-selected, spectroscopically confirmed galaxy clusters at $1 < z 1.5$ from Spitzer/IRAC Shallow Cluster Survey (ISCS). present new spectroscopic confirmation for six these high-redshift clusters, five which are $z>1.35$. Using infrared luminosities measured with deep Spitzer/MIPS observations 24 $\mu$m, along robust optical+IRAC photometric redshifts and SED-fitted stellar masses, we dust-obscured star-forming fractions, rates specific...
We present first results on the cooling properties derived from Chandra X-ray observations of 83 high-redshift (0.3 < z 1.2) massive galaxy clusters selected by their Sunyaev–Zel'dovich signature in South Pole Telescope data. measure each cluster's central time, entropy, and mass deposition rate, compare these to those for local cluster samples. find no significant evolution ∼ 0 1 distribution properties, suggesting that cores is stable over long periods time. also average cool core entropy...
We report the discovery by Wide-field Infrared Survey Explorer of z = 2.452 source WISE J181417.29+341224.9, first hyperluminous found in survey. 1814+3412 is also prototype for an all-sky sample ~1000 extremely luminous "W1W2-dropouts" (sources faint or undetected at 3.4 and 4.6 microns well detected 12 22 microns). The data a 350 micron detection give minimum bolometric luminosity 3.7 x 10^13 Lsun, with ~10^14 Lsun plausible. Followup images reveal four nearby sources: QSO two Lyman Break...