L. Felipe Barrientos
A5053469648- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Distributed and Parallel Computing Systems
- Solar and Space Plasma Dynamics
- CCD and CMOS Imaging Sensors
- Astro and Planetary Science
- Advanced Optical Sensing Technologies
- Superconducting and THz Device Technology
- Medical Imaging Techniques and Applications
- Impact of Light on Environment and Health
- Particle Detector Development and Performance
- Atmospheric Ozone and Climate
- Remote Sensing in Agriculture
Pontificia Universidad Católica de Chile
2015-2024
University of Cambridge
2023
Millennium Institute of Astrophysics
2015-2018
U.S. National Science Foundation
2002-2007
Cerro Tololo Inter-American Observatory
2002-2007
University of Toronto
1996-2003
Association of Universities For Research In Astronomy
2002-2003
University of Chile
1993
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...
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of exciting science opportunities next decade. The Large Synoptic Survey Telescope (LSST) have an effective aperture 6.7 meters and imaging camera field view 9.6 deg^2, be devoted ten-year 20,000 deg^2 south +15 deg. Each pointing imaged 2000 times fifteen second exposures six broad from 0.35 1.1 microns, total point-source depth r~27.5. LSST Science Book describes basic...
We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz 218 made by the Atacama Cosmology Telescope (ACT) in three seasons of observations 2008 to 2010. A model primary secondary foreground is fit map power spectra lensing deflection spectrum, including contributions both thermal Sunyaev-Zeldovich (tSZ) effect kinematic (kSZ) effect, Poisson correlated anisotropy unresolved infrared sources, radio correlation between tSZ...
[Abridged] We present a catalog of 68 galaxy clusters, which 19 are new discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in Atacama Cosmology Telescope (ACT) survey 504 square degrees on celestial equator. A subsample 48 clusters within 270 degree region overlapping SDSS Stripe 82 is estimated to be 90% complete for M_500c > 4.5e14 Msun and 0.15 < z 0.8. While matched filters used detect sample studied further through "Profile Based Amplitude Analysis" using...
We present cosmological parameters derived from the angular power spectrum of cosmic microwave background (CMB) radiation observed at 148 GHz and 218 over 296 deg2 with Atacama Cosmology Telescope (ACT) during its 2008 season. ACT measures fluctuations scales 500 < ℓ 10, 000. fit a model for lensed CMB, Sunyaev–Zel'dovich (SZ), foreground contribution to spectra, including thermal kinetic SZ, Poisson radio infrared point sources, clustered sources. At = 3000, about half comes primary CMB...
We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample 162 Ly Alpha-Emitting (LAE) galaxies at z=3.1 discovered in deep narrow-band MUSYC imaging Extended Chandra Deep Field South. LAEs were selected to have observed frame equivalent widths >80A emission line fluxes >1.5E-17 erg/cm^2/s. Only 1% our LAE appears host AGN. The exhibit moderate spatial correlation length r_0=3.6+0.8-1.0 Mpc, corresponding bias factor b=1.7+0.3-0.4, which...
We report on 23 clusters detected blindly as Sunyaev–ZEL'DOVICH (SZ) decrements in a 148 GHz, 455 deg2 map of the southern sky made with data from Atacama Cosmology Telescope 2008 observing season. All SZ detections announced this work have confirmed optical counterparts. Ten are new discoveries. One newly discovered cluster, ACT-CL J0102−4915, redshift 0.75 (photometric), has an decrement comparable to most massive systems at lower redshifts. Simulations cluster recovery method reproduce...
The six-meter Atacama Cosmology Telescope (ACT) in Chile was built to measure the cosmic microwave background (CMB) at arcminute angular scales. We are building a new polarization sensitive receiver for ACT (ACTPol). ACTPol will characterize gravitational lensing of CMB and aims constrain sum neutrino masses with ~ 0.05 eV precision, running spectral index inflation-induced fluctuations, primordial helium abundance better than 1 %. Our observing fields overlap SDSS BOSS survey optical...
We present a detailed analysis from new multi-wavelength observations of the exceptional galaxy cluster ACT-CL J0102-4915 "El Gordo," likely most massive, hottest, X-ray luminous and brightest Sunyaev-Zeldovich (SZ) effect known at z>0.6. The Atacama Cosmology Telescope collaboration discovered El Gordo as significant SZ decrement in sky survey area 755 deg^2. Our VLT/FORS2 spectra 89 member galaxies yield redshift, z=0.870, velocity dispersion, s=1321+/-106 km/s. Chandra reveal hot system...
We present measurements of the cosmic microwave background (CMB) power spectrum made by Atacama Cosmology Telescope at 148 GHz and 218 GHz, as well cross-frequency between two channels. Our results clearly show second through seventh acoustic peaks in CMB spectrum. The these higher-order provide an additional test {\Lambda}CDM cosmological model. At l > 3000, we detect excess primary anisotropy CMB. lower multipoles 500 < find evidence for gravitational lensing 2.8{\sigma} level. also a low...
We present constraints on cosmological parameters based a sample of Sunyaev-Zel'dovich-selected galaxy clusters detected in millimeter-wave survey by the Atacama Cosmology Telescope. The cluster used this analysis consists 9 optically-confirmed high-mass comprising high-significance end total identified 455 square degrees sky surveyed during 2008 at 148 GHz. focus most massive systems to reduce degeneracy between unknown astrophysics and cosmology derived from SZ surveys. describe scaling...
We present a new, K-selected, optical-to-near infrared photometric catalog of the Extended Chandra Deep Field South (ECDFS), making it publicly available to astronomical community.22 The data set is founded on imaging, supplemented by original z'JK imaging collected as part MUltiwavelength Survey Yale–Chile (MUSYC). final consists photometry derived from UU38BVRIz'JK covering full ECDFS, plus H-band for approximately 80% field. 5σ flux limit point sources . This also nominal completeness and...
Abstract We present the first results from ongoing Lyman Alpha Galaxies in Epoch of Reionization (LAGER) project, which is largest narrowband survey for z ∼ 7 galaxies to date. Using a specially built filter NB964 superb large-area Dark Energy Camera (DECam) on NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr imaging data 3 deg 2 COSMOS field. have identified 23 Ly α Emitter candidates at = 6.9 central 2-deg region, where DECam and public multi-band images exist. The resulting...
Abstract We present a new measurement of the Ly α luminosity function (LF) at redshift z = 6.9, finding moderate evolution from 5.7 that is consistent with fully or largely ionized ∼ 7 intergalactic medium. Our result based on four fields LAGER (Lyman Alpha Galaxies in Epoch Reionization) project. survey volume 6.1 × 10 6 Mpc 3 double next largest survey. combine two (WIDE12 and GAMA15A) previously reported (COSMOS CDFS). In fields, we identify N 95 6.9 emitter (LAEs) candidates,...
We present weak gravitational lensing analysis of 22 high-redshift (z >~1) clusters based on Hubble Space Telescope images. Most in our sample provide significant signals and are well detected their reconstructed two-dimensional mass maps. Combining the current results previous weak-lensing studies five other high-z clusters, we compare masses these with observables. revisit question whether presence most massive is tension LambdaCDM structure formation paradigm. find that tightly correlated...
We present the first dynamical mass estimates and scaling relations for a sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The consists 16 massive clusters detected with Atacama Cosmology Telescope (ACT) over 455 sq. deg. area southern sky. Deep multi-object spectroscopic observations were taken to secure intermediate-resolution (R~700-800) spectra redshifts ~60 member galaxies on average per cluster. masses M_200c have been calculated using simulation-based between...
Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) increased their stellar mass by a factor of almost two between z~0.9 z~0.2. The further suggest more than half this is accreted through major mergers. Using sample 18 distant galaxy clusters with over 600 spectroscopically confirmed members them, we search for observational evidence mergers do play significant role. We find merger rate 0.38 +/- 0.14 per Gyr at z~1. While...
We present a measurement of the angular power spectrum cosmic microwave background (CMB) radiation observed at 148 GHz. The uses maps with 1.4' resolution made data from Atacama Cosmology Telescope (ACT). observations cover 228 square degrees southern sky, in 4.2-degree-wide strip centered on declination 53 South. CMB arcminute scales is particularly sensitive to Silk damping scale, Sunyaev-Zel'dovich (SZ) effect galaxy clusters, and emission by radio sources dusty galaxies. After masking...
(Abridged) We present a HST weak-lensing study of the merging galaxy cluster "El Gordo" (ACT-CL J0102-4915) at z=0.87 discovered by Atacama Cosmology Telescope collaboration as strongest SZ decrement in its ~1000 sq. deg survey. Our analysis confirms that ACT-CL J0102-4915 is indeed an extreme system consisting two massive (~10^15 Msun each) subclusters with projected separation ~0.7 Mpc. This binary mass structure revealed our lensing consistent distribution and dynamical carried out 89...
We present optical and X-ray properties for the first confirmed galaxy cluster sample selected by Sunyaev–Zel'dovich effect (SZE) from 148 GHz maps over 455 deg2 of sky made with Atacama Cosmology Telescope (ACT). These maps, coupled multi-band imaging on 4 m class telescopes, have yielded a 23 clusters redshifts between 0.118 1.066. Of these clusters, 10 are newly discovered. The selection this is approximately mass limited essentially independent redshift. provide positions, images,...
We present a description of the data reduction and mapmaking pipeline used for 2008 observing season Atacama Cosmology Telescope (ACT). The presented here at 148 GHz represent 12% 90 TB collected by ACT from 2007 to 2010. In we observed 136 days, producing total 1423 hours (11 band only), with daily average 10.5 observation. From these, 1085 were devoted 850 deg^2 stripe (11.2 9.1 deg) centered on declination -52.7 deg, while 175 280 (4.5 4.8 celestial equator. discuss sources statistical...
[abridged] The mass-size relation of early-type galaxies (ETGs) has been largely studied in the last years to probe mass assembly most massive objects Universe. In this paper, we focus on quiescent ETGs (Mstar/Msol > 3*10^10) living clusters (M200 ~ 10^14 Mstar) at 0.8< z <1.5, as compared those field same epoch. Our sample contains 400 and number field. Therefore, our is approximately an order magnitude larger than previous studies redshift range for galaxy clusters. We find that are...
The incidence of giant arcs due to strong-lensing clusters galaxies is known be discrepant with current theoretical expectations. This result derives from a comparison several cluster samples predictions in the framework currently favored $Λ$CDM cosmology, and one possible explanation for discrepancy that this cosmological model not correct. In paper we discuss Red-Sequence Cluster Survey (RCS), which again shows significant disagreement predictions. We briefly describe total eight strong...