Christopher N. A. Willmer
A5075259704- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- CCD and CMOS Imaging Sensors
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- Remote Sensing in Agriculture
- History and Developments in Astronomy
- Cosmology and Gravitation Theories
- Calibration and Measurement Techniques
- Computational Physics and Python Applications
- Pulsars and Gravitational Waves Research
- Advanced Optical Sensing Technologies
- Black Holes and Theoretical Physics
- Superconducting and THz Device Technology
University of Arizona
2016-2025
Valongo Observatory
1998-2007
National Observatory
1998-2007
University of California, Santa Cruz
1998-2006
National Council for Scientific and Technological Development
1998-2005
Laboratório Interinstitucional de e-Astronomia
1996-2002
Museu de Astronomia e Ciências Afins
1999
We analyze star formation (SF) as a function of stellar mass (M*) and redshift z in the All-Wavelength Extended Groth Strip International Survey. For 2905 field galaxies, complete to 1010(1010.8) M☉ at < 0.7(1), with Keck spectroscopic redshifts out = 1.1, we compile SF rates (SFRs) from emission lines, GALEX, Spitzer MIPS 24 μm photometry, optical-NIR M* measurements, HST morphologies. Galaxies reliable signs form distinct "main sequence" (MS), limited range SFRs given (1 σ ≲ ±0.3 dex),...
The DEEP2 and COMBO-17 surveys are used to study the evolution of luminosity function red blue galaxies $z \sim 1$. Schechter fits show that, since = 1$, $M^*_B$ dims by $\sim$ 1.3 mag per unit redshift for both color classes, $ϕ^*$ shows little change, while has formally nearly quadrupled. At face value, number density remained roughly constant $ z whereas that been rising. Luminosity densities support conclusions, but we note most red-galaxy occurs between our data local in highest bin,...
We describe the design and data sample from DEEP2 Galaxy Redshift Survey, densest largest precision-redshift survey of galaxies at z ~ 1 completed to date. The has conducted a comprehensive census massive galaxies, their properties, environments, large-scale structure down absolute magnitude M_B = -20 via ~90 nights observation on DEIMOS spectrograph Keck Observatory. covers an area 2.8 deg^2 divided into four separate fields, observed limiting apparent R_AB=24.1. Objects with < 0.7 are...
We characterize the mass-dependent evolution of more than 8000 galaxies using spectroscopic redshifts from DEEP2 Galaxy Redshift Survey in range 0.4 < z 1.4 and stellar masses calculated K-band photometry obtained at Palomar Observatory. This sample spans 1.5 deg2 four independent fields. Using rest-frame U - B color [O II] equivalent widths, we distinguish star-forming passive populations order to explore nature ``downsizing''—a pattern which sites active star formation shift high-mass...
In this the first of a series Letters, we present panchromatic data set in Extended Groth Strip region sky. Our survey, All-Wavelength International Survey (AEGIS), aims to study physical properties and evolutionary processes galaxies at z ~ 1. It includes following deep, wide-field imaging sets: Chandra/ACIS X-ray, GALEX ultraviolet, CFHT/MegaCam Legacy optical, CFHT/CFH12K Hubble Space Telescope/ACS optical NICMOS near-infrared, Palomar/WIRC Spitzer/IRAC mid-infrared, Spitzer/MIPS...
The quantitative morphological classification of distant galaxies is essential to the understanding evolution over history universe. This paper presents Hubble Space Telescope WFPC2 F606W and F814W photometric structural parameters for 7450 in "Groth Strip." These are based on a two-dimensional bulge + disk surface brightness model were obtained using an automated reduction analysis pipeline described detail here. A first set fits was performed separately each bandpass, second simultaneously...
The DEIMOS spectrograph has now been installed on the Keck-II telescope and commissioning is nearly complete. DEEP2 Redshift Survey, which will take approximately 120 nights at Keck Observatory over a three year period designed to utilize power of DEIMOS, began in summer 2002. multiplexing high efficiency enables us target 1000 faint galaxies per clear night. Our goal gather high-quality spectra \~60,000 with z>0.75 order study properties large scale clustering z ~ 1. survey be executed...
The evolution of the B-band galaxy luminosity function is measured using a sample more than 11,000 galaxies with spectroscopic redshifts from DEEP2 Redshift Survey. rest-frame M_B versus U-B color-magnitude diagram shows that bi-modality seen in locally still present at z > 1. Dividing trough this color bimodality into predominantly red and blue galaxies, we find each type evolves differently. Blue counts tend to shift brighter magnitudes constant number density, while remain largely...
<i>Aims. <i/>We use the deepest existing mid- and far-infrared observations (reaching ~3 mJy at 70 <i>μ<i/>m) obtained with <i>Spitzer<i/> in Great Observatories Origins Deep Survey (GOODS) Far Infrared Extragalactic Legacy survey (FIDEL) fields to derive evolution of rest-frame 15 <i>μ<i/>m, 35 total infrared luminosity functions galaxies spanning . We thereby quantify fractional contribution luminous comoving star formation rate density over this redshift range. In comparison previous...
We derive the evolution of infrared (IR) luminosity function (LF) over last 4/5ths cosmic time, using deep 24um and 70um imaging GOODS North South fields. use an extraction technique based on prior source positions at shorter wavelengths to build 24 catalogs. The majority (93%) sources have a spectroscopic (39%) or photometric redshift (54%) and, in our range interest (i.e., 1.3<z<2.3) ~20% redshifts. To extend study lower luminosities we perform stacking analysis characterize observed...
We present infrared observations of 66 starburst galaxies over a wide range oxygen abundances, to measure how metallicity affects their dust properties. The data include imaging and spectroscopy from the Spitzer Space Telescope, supplemented by groundbased near-infrared imaging. confirm strong correlation aromatic emission with metallicity, threshold at [12+log(O/H)]~8. large scatter in both radiation hardness dependence this behavior implies that it is not due single effect, but some...
We present the quantitative rest-frame B morphological evolution and galaxy merger fractions at 0.2 < z 1.2 as observed by All-wavelength Extended Groth Strip International Survey (AEGIS). use Gini coefficent M_20 to identify major mergers classify morphology for a volume-limited sample of 3009 galaxies brighter than 0.4 L_B^*, assuming pure luminosity 1.3 M_B per unit redshift. find that fraction remains roughly constant 10 +/- 2% 1.2. The E/S0/Sa increases from 21+/- 3% ~ 1.1 44 9% 0.3,...
This paper presents a table with estimates of the absolute magnitude Sun and conversions from $vegamag$ to AB ST systems for several wide-band filters used in ground space-based observatories. These use dustless spectral energy distribution (SED) Vega, calibrated absolutely using SED Sirius, set zero-points composite spectrum that coadds observations ultra-violet near infrared models Solar atmosphere. The uncertainty magnitudes is estimated comparing synthetic colors photometric measurements...
Abstract The Near Infrared Camera for the James Webb Space Telescope (JWST) is delivering imagery that astronomers have hoped ever since JWST was proposed back in 1990s. In Commissioning Period extended from right after launch to early 2022 July, NIRCam has been subjected a number of performance tests and operational checks. camera exceeding prelaunch expectations virtually all areas, with very few surprises discovered flight. also delivered needed by Wavefront Sensing Team use aligning...
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate z > 10 Lyman break galaxy in GOODS-North field with M UV = −21.5. derive a redshift 10.603 (lower than previous determinations) based on multiple emission lines our low and medium resolution spectra over 0.7 − 5.3 μm. significantly detect continuum measure blue rest-UV spectral slope β −2.4. Remarkably, we see spatially extended Lyman- α (despite highly neutral intergalactic expected at this early epoch),...
Abstract We present the data release and reduction process for Epoch 1 NIRCam observations Cosmic Evolution Early Release Science Survey (CEERS). These consist of imaging in six broadband filters (F115W, F150W, F200W, F277W, F356W F444W) one medium-band filter (F410M) over four pointings, obtained parallel with primary CEERS MIRI observations. reduced JWST Calibration Pipeline, custom modifications steps designed to address additional features challenges data. Here we provide a detailed...
Several theories have been proposed to describe the formation of black hole seeds in early Universe and explain emergence very massive holes observed first thousand million years after Big Bang
We give an overview and describe the rationale, methods, first results from NIRCam images of JWST "Prime Extragalactic Areas for Reionization Lensing Science" ("PEARLS") project. PEARLS uses up to eight filters survey several prime extragalactic areas: two fields at North Ecliptic Pole (NEP); seven gravitationally lensing clusters; high redshift proto-clusters; iconic backlit VV 191 galaxy system map its dust attenuation. also includes NIRISS spectra one NEP NIRSpec high-redshift quasars....
We present JWST NIRCam 9-band near-infrared imaging of the luminous $z=10.6$ galaxy GN-z11 from Advanced Deep Extragalactic Survey (JADES) GOODS-N field. find a spectral energy distribution (SED) entirely consistent with expected form high-redshift galaxy: clear blue continuum 1.5 to 4 microns complete dropout in F115W. The core is extremely compact imaging. analyze image two-component model, using point source and S\'{e}rsic profile that fits half-light radius 200 pc an index $n=0.9$....
Abstract JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view distant Universe. Adding to new legacy observations, we present first NIRCam imaging data release from Advanced Deep Extragalactic Survey (JADES), providing nine filters ∼25 arcmin 2 covering Hubble Ultra Field portions Great Observatories Origins South. Utilizing 87 on-sky dual-filter hours exposure time, these images reveal deepest ever near-infrared this iconic field....
ABSTRACT We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z &gt; 7 galaxies in the Early Release Observations JWST/NIRCam JWST/NIRSpec data SMACS J0723.3−7327 cluster. use Bayesian spectral energy distribution-fitting code prospector with a flexible star formation history (SFH), variable dust attenuation law, self-consistent model nebular emission (continuum lines). Importantly, we self-consistently fit both line fluxes from...
We present emission-line ratios from a sample of 27 Lyman-break galaxies z ∼ 5.5 − 9.5 with −17.0 < M 1500 −20.4, measured ultra-deep JWST/NIRSpec multi-object spectroscopy the JWST Advanced Deep Extragalactic Survey (JADES). used combination 28 h deep PRISM/CLEAR and 7 G 395 / F 290 LP observations to measure, or place strong constraints on, widely studied rest-frame optical emission lines including H α , β [O II ] λλ 3726, 3729, [Ne III λ 3869, 4959, 5007, I 6300, [N 6583, [S 6716, 6731...
Abstract We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ∼2 ∼4 μ m filters (NIRCam F182M, F210M, F430M, F460M, F480M; NIRISS F430M F480M in parallel) over 15.6 arcmin 2 Hubble Ultra Deep Field (UDF), thereby building on deepest multiwavelength data sets available anywhere sky. describe our science goals, design, NIRCam image reduction methods, release of science-ready mosaics, which...